text: (function() {
    if (this.__polyfills_originalGlobals == null) {
      this.__polyfills_originalGlobals = {
        define: this.define,
        underscore: this._,
        less: this.less,
        eventemitter2: this.EventEmitter2,
        SelectorSet: this.SelectorSet
      };
    }
  
    this.define = void 0;
  
  }).call(this);
  
  //     Underscore.js 1.5.2
  //     http://underscorejs.org
  //     (c) 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
  //     Underscore may be freely distributed under the MIT license.
  
  (function() {
  
    // Baseline setup
    // --------------
  
    // Establish the root object, `window` in the browser, or `exports` on the server.
    var root = this;
  
    // Save the previous value of the `_` variable.
    var previousUnderscore = root._;
  
    // Establish the object that gets returned to break out of a loop iteration.
    var breaker = {};
  
    // Save bytes in the minified (but not gzipped) version:
    var ArrayProto = Array.prototype, ObjProto = Object.prototype, FuncProto = Function.prototype;
  
    // Create quick reference variables for speed access to core prototypes.
    var
      push             = ArrayProto.push,
      slice            = ArrayProto.slice,
      concat           = ArrayProto.concat,
      toString         = ObjProto.toString,
      hasOwnProperty   = ObjProto.hasOwnProperty;
  
    // All **ECMAScript 5** native function implementations that we hope to use
    // are declared here.
    var
      nativeForEach      = ArrayProto.forEach,
      nativeMap          = ArrayProto.map,
      nativeReduce       = ArrayProto.reduce,
      nativeReduceRight  = ArrayProto.reduceRight,
      nativeFilter       = ArrayProto.filter,
      nativeEvery        = ArrayProto.every,
      nativeSome         = ArrayProto.some,
      nativeIndexOf      = ArrayProto.indexOf,
      nativeLastIndexOf  = ArrayProto.lastIndexOf,
      nativeIsArray      = Array.isArray,
      nativeKeys         = Object.keys,
      nativeBind         = FuncProto.bind;
  
    // Create a safe reference to the Underscore object for use below.
    var _ = function(obj) {
      if (obj instanceof _) return obj;
      if (!(this instanceof _)) return new _(obj);
      this._wrapped = obj;
    };
  
    // Export the Underscore object for **Node.js**, with
    // backwards-compatibility for the old `require()` API. If we're in
    // the browser, add `_` as a global object via a string identifier,
    // for Closure Compiler "advanced" mode.
    if (typeof exports !== 'undefined') {
      if (typeof module !== 'undefined' && module.exports) {
        exports = module.exports = _;
      }
      exports._ = _;
    } else {
      root._ = _;
    }
  
    // Current version.
    _.VERSION = '1.5.2';
  
    // Collection Functions
    // --------------------
  
    // The cornerstone, an `each` implementation, aka `forEach`.
    // Handles objects with the built-in `forEach`, arrays, and raw objects.
    // Delegates to **ECMAScript 5**'s native `forEach` if available.
    var each = _.each = _.forEach = function(obj, iterator, context) {
      if (obj == null) return;
      if (nativeForEach && obj.forEach === nativeForEach) {
        obj.forEach(iterator, context);
      } else if (obj.length === +obj.length) {
        for (var i = 0, length = obj.length; i < length; i++) {
          if (iterator.call(context, obj[i], i, obj) === breaker) return;
        }
      } else {
        var keys = _.keys(obj);
        for (var i = 0, length = keys.length; i < length; i++) {
          if (iterator.call(context, obj[keys[i]], keys[i], obj) === breaker) return;
        }
      }
    };
  
    // Return the results of applying the iterator to each element.
    // Delegates to **ECMAScript 5**'s native `map` if available.
    _.map = _.collect = function(obj, iterator, context) {
      var results = [];
      if (obj == null) return results;
      if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context);
      each(obj, function(value, index, list) {
        results.push(iterator.call(context, value, index, list));
      });
      return results;
    };
  
    var reduceError = 'Reduce of empty array with no initial value';
  
    // **Reduce** builds up a single result from a list of values, aka `inject`,
    // or `foldl`. Delegates to **ECMAScript 5**'s native `reduce` if available.
    _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) {
      var initial = arguments.length > 2;
      if (obj == null) obj = [];
      if (nativeReduce && obj.reduce === nativeReduce) {
        if (context) iterator = _.bind(iterator, context);
        return initial ? obj.reduce(iterator, memo) : obj.reduce(iterator);
      }
      each(obj, function(value, index, list) {
        if (!initial) {
          memo = value;
          initial = true;
        } else {
          memo = iterator.call(context, memo, value, index, list);
        }
      });
      if (!initial) throw new TypeError(reduceError);
      return memo;
    };
  
    // The right-associative version of reduce, also known as `foldr`.
    // Delegates to **ECMAScript 5**'s native `reduceRight` if available.
    _.reduceRight = _.foldr = function(obj, iterator, memo, context) {
      var initial = arguments.length > 2;
      if (obj == null) obj = [];
      if (nativeReduceRight && obj.reduceRight === nativeReduceRight) {
        if (context) iterator = _.bind(iterator, context);
        return initial ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
      }
      var length = obj.length;
      if (length !== +length) {
        var keys = _.keys(obj);
        length = keys.length;
      }
      each(obj, function(value, index, list) {
        index = keys ? keys[--length] : --length;
        if (!initial) {
          memo = obj[index];
          initial = true;
        } else {
          memo = iterator.call(context, memo, obj[index], index, list);
        }
      });
      if (!initial) throw new TypeError(reduceError);
      return memo;
    };
  
    // Return the first value which passes a truth test. Aliased as `detect`.
    _.find = _.detect = function(obj, iterator, context) {
      var result;
      any(obj, function(value, index, list) {
        if (iterator.call(context, value, index, list)) {
          result = value;
          return true;
        }
      });
      return result;
    };
  
    // Return all the elements that pass a truth test.
    // Delegates to **ECMAScript 5**'s native `filter` if available.
    // Aliased as `select`.
    _.filter = _.select = function(obj, iterator, context) {
      var results = [];
      if (obj == null) return results;
      if (nativeFilter && obj.filter === nativeFilter) return obj.filter(iterator, context);
      each(obj, function(value, index, list) {
        if (iterator.call(context, value, index, list)) results.push(value);
      });
      return results;
    };
  
    // Return all the elements for which a truth test fails.
    _.reject = function(obj, iterator, context) {
      return _.filter(obj, function(value, index, list) {
        return !iterator.call(context, value, index, list);
      }, context);
    };
  
    // Determine whether all of the elements match a truth test.
    // Delegates to **ECMAScript 5**'s native `every` if available.
    // Aliased as `all`.
    _.every = _.all = function(obj, iterator, context) {
      iterator || (iterator = _.identity);
      var result = true;
      if (obj == null) return result;
      if (nativeEvery && obj.every === nativeEvery) return obj.every(iterator, context);
      each(obj, function(value, index, list) {
        if (!(result = result && iterator.call(context, value, index, list))) return breaker;
      });
      return !!result;
    };
  
    // Determine if at least one element in the object matches a truth test.
    // Delegates to **ECMAScript 5**'s native `some` if available.
    // Aliased as `any`.
    var any = _.some = _.any = function(obj, iterator, context) {
      iterator || (iterator = _.identity);
      var result = false;
      if (obj == null) return result;
      if (nativeSome && obj.some === nativeSome) return obj.some(iterator, context);
      each(obj, function(value, index, list) {
        if (result || (result = iterator.call(context, value, index, list))) return breaker;
      });
      return !!result;
    };
  
    // Determine if the array or object contains a given value (using `===`).
    // Aliased as `include`.
    _.contains = _.include = function(obj, target) {
      if (obj == null) return false;
      if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
      return any(obj, function(value) {
        return value === target;
      });
    };
  
    // Invoke a method (with arguments) on every item in a collection.
    _.invoke = function(obj, method) {
      var args = slice.call(arguments, 2);
      var isFunc = _.isFunction(method);
      return _.map(obj, function(value) {
        return (isFunc ? method : value[method]).apply(value, args);
      });
    };
  
    // Convenience version of a common use case of `map`: fetching a property.
    _.pluck = function(obj, key) {
      return _.map(obj, function(value){ return value[key]; });
    };
  
    // Convenience version of a common use case of `filter`: selecting only objects
    // containing specific `key:value` pairs.
    _.where = function(obj, attrs, first) {
      if (_.isEmpty(attrs)) return first ? void 0 : [];
      return _[first ? 'find' : 'filter'](obj, function(value) {
        for (var key in attrs) {
          if (attrs[key] !== value[key]) return false;
        }
        return true;
      });
    };
  
    // Convenience version of a common use case of `find`: getting the first object
    // containing specific `key:value` pairs.
    _.findWhere = function(obj, attrs) {
      return _.where(obj, attrs, true);
    };
  
    // Return the maximum element or (element-based computation).
    // Can't optimize arrays of integers longer than 65,535 elements.
    // See [WebKit Bug 80797](https://bugs.webkit.org/show_bug.cgi?id=80797)
    _.max = function(obj, iterator, context) {
      if (!iterator && _.isArray(obj) && obj[0] === +obj[0] && obj.length < 65535) {
        return Math.max.apply(Math, obj);
      }
      if (!iterator && _.isEmpty(obj)) return -Infinity;
      var result = {computed : -Infinity, value: -Infinity};
      each(obj, function(value, index, list) {
        var computed = iterator ? iterator.call(context, value, index, list) : value;
        computed > result.computed && (result = {value : value, computed : computed});
      });
      return result.value;
    };
  
    // Return the minimum element (or element-based computation).
    _.min = function(obj, iterator, context) {
      if (!iterator && _.isArray(obj) && obj[0] === +obj[0] && obj.length < 65535) {
        return Math.min.apply(Math, obj);
      }
      if (!iterator && _.isEmpty(obj)) return Infinity;
      var result = {computed : Infinity, value: Infinity};
      each(obj, function(value, index, list) {
        var computed = iterator ? iterator.call(context, value, index, list) : value;
        computed < result.computed && (result = {value : value, computed : computed});
      });
      return result.value;
    };
  
    // Shuffle an array, using the modern version of the 
    // [Fisher-Yates shuffle](http://en.wikipedia.org/wiki/Fisher–Yates_shuffle).
    _.shuffle = function(obj) {
      var rand;
      var index = 0;
      var shuffled = [];
      each(obj, function(value) {
        rand = _.random(index++);
        shuffled[index - 1] = shuffled[rand];
        shuffled[rand] = value;
      });
      return shuffled;
    };
  
    // Sample **n** random values from an array.
    // If **n** is not specified, returns a single random element from the array.
    // The internal `guard` argument allows it to work with `map`.
    _.sample = function(obj, n, guard) {
      if (arguments.length < 2 || guard) {
        return obj[_.random(obj.length - 1)];
      }
      return _.shuffle(obj).slice(0, Math.max(0, n));
    };
  
    // An internal function to generate lookup iterators.
    var lookupIterator = function(value) {
      return _.isFunction(value) ? value : function(obj){ return obj[value]; };
    };
  
    // Sort the object's values by a criterion produced by an iterator.
    _.sortBy = function(obj, value, context) {
      var iterator = lookupIterator(value);
      return _.pluck(_.map(obj, function(value, index, list) {
        return {
          value: value,
          index: index,
          criteria: iterator.call(context, value, index, list)
        };
      }).sort(function(left, right) {
        var a = left.criteria;
        var b = right.criteria;
        if (a !== b) {
          if (a > b || a === void 0) return 1;
          if (a < b || b === void 0) return -1;
        }
        return left.index - right.index;
      }), 'value');
    };
  
    // An internal function used for aggregate "group by" operations.
    var group = function(behavior) {
      return function(obj, value, context) {
        var result = {};
        var iterator = value == null ? _.identity : lookupIterator(value);
        each(obj, function(value, index) {
          var key = iterator.call(context, value, index, obj);
          behavior(result, key, value);
        });
        return result;
      };
    };
  
    // Groups the object's values by a criterion. Pass either a string attribute
    // to group by, or a function that returns the criterion.
    _.groupBy = group(function(result, key, value) {
      (_.has(result, key) ? result[key] : (result[key] = [])).push(value);
    });
  
    // Indexes the object's values by a criterion, similar to `groupBy`, but for
    // when you know that your index values will be unique.
    _.indexBy = group(function(result, key, value) {
      result[key] = value;
    });
  
    // Counts instances of an object that group by a certain criterion. Pass
    // either a string attribute to count by, or a function that returns the
    // criterion.
    _.countBy = group(function(result, key) {
      _.has(result, key) ? result[key]++ : result[key] = 1;
    });
  
    // Use a comparator function to figure out the smallest index at which
    // an object should be inserted so as to maintain order. Uses binary search.
    _.sortedIndex = function(array, obj, iterator, context) {
      iterator = iterator == null ? _.identity : lookupIterator(iterator);
      var value = iterator.call(context, obj);
      var low = 0, high = array.length;
      while (low < high) {
        var mid = (low + high) >>> 1;
        iterator.call(context, array[mid]) < value ? low = mid + 1 : high = mid;
      }
      return low;
    };
  
    // Safely create a real, live array from anything iterable.
    _.toArray = function(obj) {
      if (!obj) return [];
      if (_.isArray(obj)) return slice.call(obj);
      if (obj.length === +obj.length) return _.map(obj, _.identity);
      return _.values(obj);
    };
  
    // Return the number of elements in an object.
    _.size = function(obj) {
      if (obj == null) return 0;
      return (obj.length === +obj.length) ? obj.length : _.keys(obj).length;
    };
  
    // Array Functions
    // ---------------
  
    // Get the first element of an array. Passing **n** will return the first N
    // values in the array. Aliased as `head` and `take`. The **guard** check
    // allows it to work with `_.map`.
    _.first = _.head = _.take = function(array, n, guard) {
      if (array == null) return void 0;
      return (n == null) || guard ? array[0] : slice.call(array, 0, n);
    };
  
    // Returns everything but the last entry of the array. Especially useful on
    // the arguments object. Passing **n** will return all the values in
    // the array, excluding the last N. The **guard** check allows it to work with
    // `_.map`.
    _.initial = function(array, n, guard) {
      return slice.call(array, 0, array.length - ((n == null) || guard ? 1 : n));
    };
  
    // Get the last element of an array. Passing **n** will return the last N
    // values in the array. The **guard** check allows it to work with `_.map`.
    _.last = function(array, n, guard) {
      if (array == null) return void 0;
      if ((n == null) || guard) {
        return array[array.length - 1];
      } else {
        return slice.call(array, Math.max(array.length - n, 0));
      }
    };
  
    // Returns everything but the first entry of the array. Aliased as `tail` and `drop`.
    // Especially useful on the arguments object. Passing an **n** will return
    // the rest N values in the array. The **guard**
    // check allows it to work with `_.map`.
    _.rest = _.tail = _.drop = function(array, n, guard) {
      return slice.call(array, (n == null) || guard ? 1 : n);
    };
  
    // Trim out all falsy values from an array.
    _.compact = function(array) {
      return _.filter(array, _.identity);
    };
  
    // Internal implementation of a recursive `flatten` function.
    var flatten = function(input, shallow, output) {
      if (shallow && _.every(input, _.isArray)) {
        return concat.apply(output, input);
      }
      each(input, function(value) {
        if (_.isArray(value) || _.isArguments(value)) {
          shallow ? push.apply(output, value) : flatten(value, shallow, output);
        } else {
          output.push(value);
        }
      });
      return output;
    };
  
    // Flatten out an array, either recursively (by default), or just one level.
    _.flatten = function(array, shallow) {
      return flatten(array, shallow, []);
    };
  
    // Return a version of the array that does not contain the specified value(s).
    _.without = function(array) {
      return _.difference(array, slice.call(arguments, 1));
    };
  
    // Produce a duplicate-free version of the array. If the array has already
    // been sorted, you have the option of using a faster algorithm.
    // Aliased as `unique`.
    _.uniq = _.unique = function(array, isSorted, iterator, context) {
      if (_.isFunction(isSorted)) {
        context = iterator;
        iterator = isSorted;
        isSorted = false;
      }
      var initial = iterator ? _.map(array, iterator, context) : array;
      var results = [];
      var seen = [];
      each(initial, function(value, index) {
        if (isSorted ? (!index || seen[seen.length - 1] !== value) : !_.contains(seen, value)) {
          seen.push(value);
          results.push(array[index]);
        }
      });
      return results;
    };
  
    // Produce an array that contains the union: each distinct element from all of
    // the passed-in arrays.
    _.union = function() {
      return _.uniq(_.flatten(arguments, true));
    };
  
    // Produce an array that contains every item shared between all the
    // passed-in arrays.
    _.intersection = function(array) {
      var rest = slice.call(arguments, 1);
      return _.filter(_.uniq(array), function(item) {
        return _.every(rest, function(other) {
          return _.indexOf(other, item) >= 0;
        });
      });
    };
  
    // Take the difference between one array and a number of other arrays.
    // Only the elements present in just the first array will remain.
    _.difference = function(array) {
      var rest = concat.apply(ArrayProto, slice.call(arguments, 1));
      return _.filter(array, function(value){ return !_.contains(rest, value); });
    };
  
    // Zip together multiple lists into a single array -- elements that share
    // an index go together.
    _.zip = function() {
      var length = _.max(_.pluck(arguments, "length").concat(0));
      var results = new Array(length);
      for (var i = 0; i < length; i++) {
        results[i] = _.pluck(arguments, '' + i);
      }
      return results;
    };
  
    // Converts lists into objects. Pass either a single array of `[key, value]`
    // pairs, or two parallel arrays of the same length -- one of keys, and one of
    // the corresponding values.
    _.object = function(list, values) {
      if (list == null) return {};
      var result = {};
      for (var i = 0, length = list.length; i < length; i++) {
        if (values) {
          result[list[i]] = values[i];
        } else {
          result[list[i][0]] = list[i][1];
        }
      }
      return result;
    };
  
    // If the browser doesn't supply us with indexOf (I'm looking at you, **MSIE**),
    // we need this function. Return the position of the first occurrence of an
    // item in an array, or -1 if the item is not included in the array.
    // Delegates to **ECMAScript 5**'s native `indexOf` if available.
    // If the array is large and already in sort order, pass `true`
    // for **isSorted** to use binary search.
    _.indexOf = function(array, item, isSorted) {
      if (array == null) return -1;
      var i = 0, length = array.length;
      if (isSorted) {
        if (typeof isSorted == 'number') {
          i = (isSorted < 0 ? Math.max(0, length + isSorted) : isSorted);
        } else {
          i = _.sortedIndex(array, item);
          return array[i] === item ? i : -1;
        }
      }
      if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item, isSorted);
      for (; i < length; i++) if (array[i] === item) return i;
      return -1;
    };
  
    // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available.
    _.lastIndexOf = function(array, item, from) {
      if (array == null) return -1;
      var hasIndex = from != null;
      if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) {
        return hasIndex ? array.lastIndexOf(item, from) : array.lastIndexOf(item);
      }
      var i = (hasIndex ? from : array.length);
      while (i--) if (array[i] === item) return i;
      return -1;
    };
  
    // Generate an integer Array containing an arithmetic progression. A port of
    // the native Python `range()` function. See
    // [the Python documentation](http://docs.python.org/library/functions.html#range).
    _.range = function(start, stop, step) {
      if (arguments.length <= 1) {
        stop = start || 0;
        start = 0;
      }
      step = arguments[2] || 1;
  
      var length = Math.max(Math.ceil((stop - start) / step), 0);
      var idx = 0;
      var range = new Array(length);
  
      while(idx < length) {
        range[idx++] = start;
        start += step;
      }
  
      return range;
    };
  
    // Function (ahem) Functions
    // ------------------
  
    // Reusable constructor function for prototype setting.
    var ctor = function(){};
  
    // Create a function bound to a given object (assigning `this`, and arguments,
    // optionally). Delegates to **ECMAScript 5**'s native `Function.bind` if
    // available.
    _.bind = function(func, context) {
      var args, bound;
      if (nativeBind && func.bind === nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
      if (!_.isFunction(func)) throw new TypeError;
      args = slice.call(arguments, 2);
      return bound = function() {
        if (!(this instanceof bound)) return func.apply(context, args.concat(slice.call(arguments)));
        ctor.prototype = func.prototype;
        var self = new ctor;
        ctor.prototype = null;
        var result = func.apply(self, args.concat(slice.call(arguments)));
        if (Object(result) === result) return result;
        return self;
      };
    };
  
    // Partially apply a function by creating a version that has had some of its
    // arguments pre-filled, without changing its dynamic `this` context.
    _.partial = function(func) {
      var args = slice.call(arguments, 1);
      return function() {
        return func.apply(this, args.concat(slice.call(arguments)));
      };
    };
  
    // Bind all of an object's methods to that object. Useful for ensuring that
    // all callbacks defined on an object belong to it.
    _.bindAll = function(obj) {
      var funcs = slice.call(arguments, 1);
      if (funcs.length === 0) throw new Error("bindAll must be passed function names");
      each(funcs, function(f) { obj[f] = _.bind(obj[f], obj); });
      return obj;
    };
  
    // Memoize an expensive function by storing its results.
    _.memoize = function(func, hasher) {
      var memo = {};
      hasher || (hasher = _.identity);
      return function() {
        var key = hasher.apply(this, arguments);
        return _.has(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
      };
    };
  
    // Delays a function for the given number of milliseconds, and then calls
    // it with the arguments supplied.
    _.delay = function(func, wait) {
      var args = slice.call(arguments, 2);
      return setTimeout(function(){ return func.apply(null, args); }, wait);
    };
  
    // Defers a function, scheduling it to run after the current call stack has
    // cleared.
    _.defer = function(func) {
      return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
    };
  
    // Returns a function, that, when invoked, will only be triggered at most once
    // during a given window of time. Normally, the throttled function will run
    // as much as it can, without ever going more than once per `wait` duration;
    // but if you'd like to disable the execution on the leading edge, pass
    // `{leading: false}`. To disable execution on the trailing edge, ditto.
    _.throttle = function(func, wait, options) {
      var context, args, result;
      var timeout = null;
      var previous = 0;
      options || (options = {});
      var later = function() {
        previous = options.leading === false ? 0 : new Date;
        timeout = null;
        result = func.apply(context, args);
      };
      return function() {
        var now = new Date;
        if (!previous && options.leading === false) previous = now;
        var remaining = wait - (now - previous);
        context = this;
        args = arguments;
        if (remaining <= 0) {
          clearTimeout(timeout);
          timeout = null;
          previous = now;
          result = func.apply(context, args);
        } else if (!timeout && options.trailing !== false) {
          timeout = setTimeout(later, remaining);
        }
        return result;
      };
    };
  
    // Returns a function, that, as long as it continues to be invoked, will not
    // be triggered. The function will be called after it stops being called for
    // N milliseconds. If `immediate` is passed, trigger the function on the
    // leading edge, instead of the trailing.
    _.debounce = function(func, wait, immediate) {
      var timeout, args, context, timestamp, result;
      return function() {
        context = this;
        args = arguments;
        timestamp = new Date();
        var later = function() {
          var last = (new Date()) - timestamp;
          if (last < wait) {
            timeout = setTimeout(later, wait - last);
          } else {
            timeout = null;
            if (!immediate) result = func.apply(context, args);
          }
        };
        var callNow = immediate && !timeout;
        if (!timeout) {
          timeout = setTimeout(later, wait);
        }
        if (callNow) result = func.apply(context, args);
        return result;
      };
    };
  
    // Returns a function that will be executed at most one time, no matter how
    // often you call it. Useful for lazy initialization.
    _.once = function(func) {
      var ran = false, memo;
      return function() {
        if (ran) return memo;
        ran = true;
        memo = func.apply(this, arguments);
        func = null;
        return memo;
      };
    };
  
    // Returns the first function passed as an argument to the second,
    // allowing you to adjust arguments, run code before and after, and
    // conditionally execute the original function.
    _.wrap = function(func, wrapper) {
      return function() {
        var args = [func];
        push.apply(args, arguments);
        return wrapper.apply(this, args);
      };
    };
  
    // Returns a function that is the composition of a list of functions, each
    // consuming the return value of the function that follows.
    _.compose = function() {
      var funcs = arguments;
      return function() {
        var args = arguments;
        for (var i = funcs.length - 1; i >= 0; i--) {
          args = [funcs[i].apply(this, args)];
        }
        return args[0];
      };
    };
  
    // Returns a function that will only be executed after being called N times.
    _.after = function(times, func) {
      return function() {
        if (--times < 1) {
          return func.apply(this, arguments);
        }
      };
    };
  
    // Object Functions
    // ----------------
  
    // Retrieve the names of an object's properties.
    // Delegates to **ECMAScript 5**'s native `Object.keys`
    _.keys = nativeKeys || function(obj) {
      if (obj !== Object(obj)) throw new TypeError('Invalid object');
      var keys = [];
      for (var key in obj) if (_.has(obj, key)) keys.push(key);
      return keys;
    };
  
    // Retrieve the values of an object's properties.
    _.values = function(obj) {
      var keys = _.keys(obj);
      var length = keys.length;
      var values = new Array(length);
      for (var i = 0; i < length; i++) {
        values[i] = obj[keys[i]];
      }
      return values;
    };
  
    // Convert an object into a list of `[key, value]` pairs.
    _.pairs = function(obj) {
      var keys = _.keys(obj);
      var length = keys.length;
      var pairs = new Array(length);
      for (var i = 0; i < length; i++) {
        pairs[i] = [keys[i], obj[keys[i]]];
      }
      return pairs;
    };
  
    // Invert the keys and values of an object. The values must be serializable.
    _.invert = function(obj) {
      var result = {};
      var keys = _.keys(obj);
      for (var i = 0, length = keys.length; i < length; i++) {
        result[obj[keys[i]]] = keys[i];
      }
      return result;
    };
  
    // Return a sorted list of the function names available on the object.
    // Aliased as `methods`
    _.functions = _.methods = function(obj) {
      var names = [];
      for (var key in obj) {
        if (_.isFunction(obj[key])) names.push(key);
      }
      return names.sort();
    };
  
    // Extend a given object with all the properties in passed-in object(s).
    _.extend = function(obj) {
      each(slice.call(arguments, 1), function(source) {
        if (source) {
          for (var prop in source) {
            obj[prop] = source[prop];
          }
        }
      });
      return obj;
    };
  
    // Return a copy of the object only containing the whitelisted properties.
    _.pick = function(obj) {
      var copy = {};
      var keys = concat.apply(ArrayProto, slice.call(arguments, 1));
      each(keys, function(key) {
        if (key in obj) copy[key] = obj[key];
      });
      return copy;
    };
  
     // Return a copy of the object without the blacklisted properties.
    _.omit = function(obj) {
      var copy = {};
      var keys = concat.apply(ArrayProto, slice.call(arguments, 1));
      for (var key in obj) {
        if (!_.contains(keys, key)) copy[key] = obj[key];
      }
      return copy;
    };
  
    // Fill in a given object with default properties.
    _.defaults = function(obj) {
      each(slice.call(arguments, 1), function(source) {
        if (source) {
          for (var prop in source) {
            if (obj[prop] === void 0) obj[prop] = source[prop];
          }
        }
      });
      return obj;
    };
  
    // Create a (shallow-cloned) duplicate of an object.
    _.clone = function(obj) {
      if (!_.isObject(obj)) return obj;
      return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
    };
  
    // Invokes interceptor with the obj, and then returns obj.
    // The primary purpose of this method is to "tap into" a method chain, in
    // order to perform operations on intermediate results within the chain.
    _.tap = function(obj, interceptor) {
      interceptor(obj);
      return obj;
    };
  
    // Internal recursive comparison function for `isEqual`.
    var eq = function(a, b, aStack, bStack) {
      // Identical objects are equal. `0 === -0`, but they aren't identical.
      // See the [Harmony `egal` proposal](http://wiki.ecmascript.org/doku.php?id=harmony:egal).
      if (a === b) return a !== 0 || 1 / a == 1 / b;
      // A strict comparison is necessary because `null == undefined`.
      if (a == null || b == null) return a === b;
      // Unwrap any wrapped objects.
      if (a instanceof _) a = a._wrapped;
      if (b instanceof _) b = b._wrapped;
      // Compare `[[Class]]` names.
      var className = toString.call(a);
      if (className != toString.call(b)) return false;
      switch (className) {
        // Strings, numbers, dates, and booleans are compared by value.
        case '[object String]':
          // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is
          // equivalent to `new String("5")`.
          return a == String(b);
        case '[object Number]':
          // `NaN`s are equivalent, but non-reflexive. An `egal` comparison is performed for
          // other numeric values.
          return a != +a ? b != +b : (a == 0 ? 1 / a == 1 / b : a == +b);
        case '[object Date]':
        case '[object Boolean]':
          // Coerce dates and booleans to numeric primitive values. Dates are compared by their
          // millisecond representations. Note that invalid dates with millisecond representations
          // of `NaN` are not equivalent.
          return +a == +b;
        // RegExps are compared by their source patterns and flags.
        case '[object RegExp]':
          return a.source == b.source &&
                 a.global == b.global &&
                 a.multiline == b.multiline &&
                 a.ignoreCase == b.ignoreCase;
      }
      if (typeof a != 'object' || typeof b != 'object') return false;
      // Assume equality for cyclic structures. The algorithm for detecting cyclic
      // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
      var length = aStack.length;
      while (length--) {
        // Linear search. Performance is inversely proportional to the number of
        // unique nested structures.
        if (aStack[length] == a) return bStack[length] == b;
      }
      // Objects with different constructors are not equivalent, but `Object`s
      // from different frames are.
      var aCtor = a.constructor, bCtor = b.constructor;
      if (aCtor !== bCtor && !(_.isFunction(aCtor) && (aCtor instanceof aCtor) &&
                               _.isFunction(bCtor) && (bCtor instanceof bCtor))) {
        return false;
      }
      // Add the first object to the stack of traversed objects.
      aStack.push(a);
      bStack.push(b);
      var size = 0, result = true;
      // Recursively compare objects and arrays.
      if (className == '[object Array]') {
        // Compare array lengths to determine if a deep comparison is necessary.
        size = a.length;
        result = size == b.length;
        if (result) {
          // Deep compare the contents, ignoring non-numeric properties.
          while (size--) {
            if (!(result = eq(a[size], b[size], aStack, bStack))) break;
          }
        }
      } else {
        // Deep compare objects.
        for (var key in a) {
          if (_.has(a, key)) {
            // Count the expected number of properties.
            size++;
            // Deep compare each member.
            if (!(result = _.has(b, key) && eq(a[key], b[key], aStack, bStack))) break;
          }
        }
        // Ensure that both objects contain the same number of properties.
        if (result) {
          for (key in b) {
            if (_.has(b, key) && !(size--)) break;
          }
          result = !size;
        }
      }
      // Remove the first object from the stack of traversed objects.
      aStack.pop();
      bStack.pop();
      return result;
    };
  
    // Perform a deep comparison to check if two objects are equal.
    _.isEqual = function(a, b) {
      return eq(a, b, [], []);
    };
  
    // Is a given array, string, or object empty?
    // An "empty" object has no enumerable own-properties.
    _.isEmpty = function(obj) {
      if (obj == null) return true;
      if (_.isArray(obj) || _.isString(obj)) return obj.length === 0;
      for (var key in obj) if (_.has(obj, key)) return false;
      return true;
    };
  
    // Is a given value a DOM element?
    _.isElement = function(obj) {
      return !!(obj && obj.nodeType === 1);
    };
  
    // Is a given value an array?
    // Delegates to ECMA5's native Array.isArray
    _.isArray = nativeIsArray || function(obj) {
      return toString.call(obj) == '[object Array]';
    };
  
    // Is a given variable an object?
    _.isObject = function(obj) {
      return obj === Object(obj);
    };
  
    // Add some isType methods: isArguments, isFunction, isString, isNumber, isDate, isRegExp.
    each(['Arguments', 'Function', 'String', 'Number', 'Date', 'RegExp'], function(name) {
      _['is' + name] = function(obj) {
        return toString.call(obj) == '[object ' + name + ']';
      };
    });
  
    // Define a fallback version of the method in browsers (ahem, IE), where
    // there isn't any inspectable "Arguments" type.
    if (!_.isArguments(arguments)) {
      _.isArguments = function(obj) {
        return !!(obj && _.has(obj, 'callee'));
      };
    }
  
    // Optimize `isFunction` if appropriate.
    if (typeof (/./) !== 'function') {
      _.isFunction = function(obj) {
        return typeof obj === 'function';
      };
    }
  
    // Is a given object a finite number?
    _.isFinite = function(obj) {
      return isFinite(obj) && !isNaN(parseFloat(obj));
    };
  
    // Is the given value `NaN`? (NaN is the only number which does not equal itself).
    _.isNaN = function(obj) {
      return _.isNumber(obj) && obj != +obj;
    };
  
    // Is a given value a boolean?
    _.isBoolean = function(obj) {
      return obj === true || obj === false || toString.call(obj) == '[object Boolean]';
    };
  
    // Is a given value equal to null?
    _.isNull = function(obj) {
      return obj === null;
    };
  
    // Is a given variable undefined?
    _.isUndefined = function(obj) {
      return obj === void 0;
    };
  
    // Shortcut function for checking if an object has a given property directly
    // on itself (in other words, not on a prototype).
    _.has = function(obj, key) {
      return hasOwnProperty.call(obj, key);
    };
  
    // Utility Functions
    // -----------------
  
    // Run Underscore.js in *noConflict* mode, returning the `_` variable to its
    // previous owner. Returns a reference to the Underscore object.
    _.noConflict = function() {
      root._ = previousUnderscore;
      return this;
    };
  
    // Keep the identity function around for default iterators.
    _.identity = function(value) {
      return value;
    };
  
    // Run a function **n** times.
    _.times = function(n, iterator, context) {
      var accum = Array(Math.max(0, n));
      for (var i = 0; i < n; i++) accum[i] = iterator.call(context, i);
      return accum;
    };
  
    // Return a random integer between min and max (inclusive).
    _.random = function(min, max) {
      if (max == null) {
        max = min;
        min = 0;
      }
      return min + Math.floor(Math.random() * (max - min + 1));
    };
  
    // List of HTML entities for escaping.
    var entityMap = {
      escape: {
        '&': '&amp;',
        '<': '&lt;',
        '>': '&gt;',
        '"': '&quot;',
        "'": '&#x27;'
      }
    };
    entityMap.unescape = _.invert(entityMap.escape);
  
    // Regexes containing the keys and values listed immediately above.
    var entityRegexes = {
      escape:   new RegExp('[' + _.keys(entityMap.escape).join('') + ']', 'g'),
      unescape: new RegExp('(' + _.keys(entityMap.unescape).join('|') + ')', 'g')
    };
  
    // Functions for escaping and unescaping strings to/from HTML interpolation.
    _.each(['escape', 'unescape'], function(method) {
      _[method] = function(string) {
        if (string == null) return '';
        return ('' + string).replace(entityRegexes[method], function(match) {
          return entityMap[method][match];
        });
      };
    });
  
    // If the value of the named `property` is a function then invoke it with the
    // `object` as context; otherwise, return it.
    _.result = function(object, property) {
      if (object == null) return void 0;
      var value = object[property];
      return _.isFunction(value) ? value.call(object) : value;
    };
  
    // Add your own custom functions to the Underscore object.
    _.mixin = function(obj) {
      each(_.functions(obj), function(name) {
        var func = _[name] = obj[name];
        _.prototype[name] = function() {
          var args = [this._wrapped];
          push.apply(args, arguments);
          return result.call(this, func.apply(_, args));
        };
      });
    };
  
    // Generate a unique integer id (unique within the entire client session).
    // Useful for temporary DOM ids.
    var idCounter = 0;
    _.uniqueId = function(prefix) {
      var id = ++idCounter + '';
      return prefix ? prefix + id : id;
    };
  
    // By default, Underscore uses ERB-style template delimiters, change the
    // following template settings to use alternative delimiters.
    _.templateSettings = {
      evaluate    : /<%([\s\S]+?)%>/g,
      interpolate : /<%=([\s\S]+?)%>/g,
      escape      : /<%-([\s\S]+?)%>/g
    };
  
    // When customizing `templateSettings`, if you don't want to define an
    // interpolation, evaluation or escaping regex, we need one that is
    // guaranteed not to match.
    var noMatch = /(.)^/;
  
    // Certain characters need to be escaped so that they can be put into a
    // string literal.
    var escapes = {
      "'":      "'",
      '\\':     '\\',
      '\r':     'r',
      '\n':     'n',
      '\t':     't',
      '\u2028': 'u2028',
      '\u2029': 'u2029'
    };
  
    var escaper = /\\|'|\r|\n|\t|\u2028|\u2029/g;
  
    // JavaScript micro-templating, similar to John Resig's implementation.
    // Underscore templating handles arbitrary delimiters, preserves whitespace,
    // and correctly escapes quotes within interpolated code.
    _.template = function(text, data, settings) {
      var render;
      settings = _.defaults({}, settings, _.templateSettings);
  
      // Combine delimiters into one regular expression via alternation.
      var matcher = new RegExp([
        (settings.escape || noMatch).source,
        (settings.interpolate || noMatch).source,
        (settings.evaluate || noMatch).source
      ].join('|') + '|$', 'g');
  
      // Compile the template source, escaping string literals appropriately.
      var index = 0;
      var source = "__p+='";
      text.replace(matcher, function(match, escape, interpolate, evaluate, offset) {
        source += text.slice(index, offset)
          .replace(escaper, function(match) { return '\\' + escapes[match]; });
  
        if (escape) {
          source += "'+\n((__t=(" + escape + "))==null?'':_.escape(__t))+\n'";
        }
        if (interpolate) {
          source += "'+\n((__t=(" + interpolate + "))==null?'':__t)+\n'";
        }
        if (evaluate) {
          source += "';\n" + evaluate + "\n__p+='";
        }
        index = offset + match.length;
        return match;
      });
      source += "';\n";
  
      // If a variable is not specified, place data values in local scope.
      if (!settings.variable) source = 'with(obj||{}){\n' + source + '}\n';
  
      source = "var __t,__p='',__j=Array.prototype.join," +
        "print=function(){__p+=__j.call(arguments,'');};\n" +
        source + "return __p;\n";
  
      try {
        render = new Function(settings.variable || 'obj', '_', source);
      } catch (e) {
        e.source = source;
        throw e;
      }
  
      if (data) return render(data, _);
      var template = function(data) {
        return render.call(this, data, _);
      };
  
      // Provide the compiled function source as a convenience for precompilation.
      template.source = 'function(' + (settings.variable || 'obj') + '){\n' + source + '}';
  
      return template;
    };
  
    // Add a "chain" function, which will delegate to the wrapper.
    _.chain = function(obj) {
      return _(obj).chain();
    };
  
    // OOP
    // ---------------
    // If Underscore is called as a function, it returns a wrapped object that
    // can be used OO-style. This wrapper holds altered versions of all the
    // underscore functions. Wrapped objects may be chained.
  
    // Helper function to continue chaining intermediate results.
    var result = function(obj) {
      return this._chain ? _(obj).chain() : obj;
    };
  
    // Add all of the Underscore functions to the wrapper object.
    _.mixin(_);
  
    // Add all mutator Array functions to the wrapper.
    each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
      var method = ArrayProto[name];
      _.prototype[name] = function() {
        var obj = this._wrapped;
        method.apply(obj, arguments);
        if ((name == 'shift' || name == 'splice') && obj.length === 0) delete obj[0];
        return result.call(this, obj);
      };
    });
  
    // Add all accessor Array functions to the wrapper.
    each(['concat', 'join', 'slice'], function(name) {
      var method = ArrayProto[name];
      _.prototype[name] = function() {
        return result.call(this, method.apply(this._wrapped, arguments));
      };
    });
  
    _.extend(_.prototype, {
  
      // Start chaining a wrapped Underscore object.
      chain: function() {
        this._chain = true;
        return this;
      },
  
      // Extracts the result from a wrapped and chained object.
      value: function() {
        return this._wrapped;
      }
  
    });
  
  }).call(this);
  
  /*!
   * Sizzle CSS Selector Engine v1.10.19
   * http://sizzlejs.com/
   *
   * Copyright 2013 jQuery Foundation, Inc. and other contributors
   * Released under the MIT license
   * http://jquery.org/license
   *
   * Date: 2014-04-18
   */
  (function( window ) {
  
  var i,
  	support,
  	Expr,
  	getText,
  	isXML,
  	tokenize,
  	compile,
  	select,
  	outermostContext,
  	sortInput,
  	hasDuplicate,
  
  	// Local document vars
  	setDocument,
  	document,
  	docElem,
  	documentIsHTML,
  	rbuggyQSA,
  	rbuggyMatches,
  	matches,
  	contains,
  
  	// Instance-specific data
  	expando = "sizzle" + -(new Date()),
  	preferredDoc = window.document,
  	dirruns = 0,
  	done = 0,
  	classCache = createCache(),
  	tokenCache = createCache(),
  	compilerCache = createCache(),
  	sortOrder = function( a, b ) {
  		if ( a === b ) {
  			hasDuplicate = true;
  		}
  		return 0;
  	},
  
  	// General-purpose constants
  	strundefined = typeof undefined,
  	MAX_NEGATIVE = 1 << 31,
  
  	// Instance methods
  	hasOwn = ({}).hasOwnProperty,
  	arr = [],
  	pop = arr.pop,
  	push_native = arr.push,
  	push = arr.push,
  	slice = arr.slice,
  	// Use a stripped-down indexOf if we can't use a native one
  	indexOf = arr.indexOf || function( elem ) {
  		var i = 0,
  			len = this.length;
  		for ( ; i < len; i++ ) {
  			if ( this[i] === elem ) {
  				return i;
  			}
  		}
  		return -1;
  	},
  
  	booleans = "checked|selected|async|autofocus|autoplay|controls|defer|disabled|hidden|ismap|loop|multiple|open|readonly|required|scoped",
  
  	// Regular expressions
  
  	// Whitespace characters http://www.w3.org/TR/css3-selectors/#whitespace
  	whitespace = "[\\x20\\t\\r\\n\\f]",
  	// http://www.w3.org/TR/css3-syntax/#characters
  	characterEncoding = "(?:\\\\.|[\\w-]|[^\\x00-\\xa0])+",
  
  	// Loosely modeled on CSS identifier characters
  	// An unquoted value should be a CSS identifier http://www.w3.org/TR/css3-selectors/#attribute-selectors
  	// Proper syntax: http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier
  	identifier = characterEncoding.replace( "w", "w#" ),
  
  	// Attribute selectors: http://www.w3.org/TR/selectors/#attribute-selectors
  	attributes = "\\[" + whitespace + "*(" + characterEncoding + ")(?:" + whitespace +
  		// Operator (capture 2)
  		"*([*^$|!~]?=)" + whitespace +
  		// "Attribute values must be CSS identifiers [capture 5] or strings [capture 3 or capture 4]"
  		"*(?:'((?:\\\\.|[^\\\\'])*)'|\"((?:\\\\.|[^\\\\\"])*)\"|(" + identifier + "))|)" + whitespace +
  		"*\\]",
  
  	pseudos = ":(" + characterEncoding + ")(?:\\((" +
  		// To reduce the number of selectors needing tokenize in the preFilter, prefer arguments:
  		// 1. quoted (capture 3; capture 4 or capture 5)
  		"('((?:\\\\.|[^\\\\'])*)'|\"((?:\\\\.|[^\\\\\"])*)\")|" +
  		// 2. simple (capture 6)
  		"((?:\\\\.|[^\\\\()[\\]]|" + attributes + ")*)|" +
  		// 3. anything else (capture 2)
  		".*" +
  		")\\)|)",
  
  	// Leading and non-escaped trailing whitespace, capturing some non-whitespace characters preceding the latter
  	rtrim = new RegExp( "^" + whitespace + "+|((?:^|[^\\\\])(?:\\\\.)*)" + whitespace + "+$", "g" ),
  
  	rcomma = new RegExp( "^" + whitespace + "*," + whitespace + "*" ),
  	rcombinators = new RegExp( "^" + whitespace + "*([>+~]|" + whitespace + ")" + whitespace + "*" ),
  
  	rattributeQuotes = new RegExp( "=" + whitespace + "*([^\\]'\"]*?)" + whitespace + "*\\]", "g" ),
  
  	rpseudo = new RegExp( pseudos ),
  	ridentifier = new RegExp( "^" + identifier + "$" ),
  
  	matchExpr = {
  		"ID": new RegExp( "^#(" + characterEncoding + ")" ),
  		"CLASS": new RegExp( "^\\.(" + characterEncoding + ")" ),
  		"TAG": new RegExp( "^(" + characterEncoding.replace( "w", "w*" ) + ")" ),
  		"ATTR": new RegExp( "^" + attributes ),
  		"PSEUDO": new RegExp( "^" + pseudos ),
  		"CHILD": new RegExp( "^:(only|first|last|nth|nth-last)-(child|of-type)(?:\\(" + whitespace +
  			"*(even|odd|(([+-]|)(\\d*)n|)" + whitespace + "*(?:([+-]|)" + whitespace +
  			"*(\\d+)|))" + whitespace + "*\\)|)", "i" ),
  		"bool": new RegExp( "^(?:" + booleans + ")$", "i" ),
  		// For use in libraries implementing .is()
  		// We use this for POS matching in `select`
  		"needsContext": new RegExp( "^" + whitespace + "*[>+~]|:(even|odd|eq|gt|lt|nth|first|last)(?:\\(" +
  			whitespace + "*((?:-\\d)?\\d*)" + whitespace + "*\\)|)(?=[^-]|$)", "i" )
  	},
  
  	rinputs = /^(?:input|select|textarea|button)$/i,
  	rheader = /^h\d$/i,
  
  	rnative = /^[^{]+\{\s*\[native \w/,
  
  	// Easily-parseable/retrievable ID or TAG or CLASS selectors
  	rquickExpr = /^(?:#([\w-]+)|(\w+)|\.([\w-]+))$/,
  
  	rsibling = /[+~]/,
  	rescape = /'|\\/g,
  
  	// CSS escapes http://www.w3.org/TR/CSS21/syndata.html#escaped-characters
  	runescape = new RegExp( "\\\\([\\da-f]{1,6}" + whitespace + "?|(" + whitespace + ")|.)", "ig" ),
  	funescape = function( _, escaped, escapedWhitespace ) {
  		var high = "0x" + escaped - 0x10000;
  		// NaN means non-codepoint
  		// Support: Firefox<24
  		// Workaround erroneous numeric interpretation of +"0x"
  		return high !== high || escapedWhitespace ?
  			escaped :
  			high < 0 ?
  				// BMP codepoint
  				String.fromCharCode( high + 0x10000 ) :
  				// Supplemental Plane codepoint (surrogate pair)
  				String.fromCharCode( high >> 10 | 0xD800, high & 0x3FF | 0xDC00 );
  	};
  
  // Optimize for push.apply( _, NodeList )
  try {
  	push.apply(
  		(arr = slice.call( preferredDoc.childNodes )),
  		preferredDoc.childNodes
  	);
  	// Support: Android<4.0
  	// Detect silently failing push.apply
  	arr[ preferredDoc.childNodes.length ].nodeType;
  } catch ( e ) {
  	push = { apply: arr.length ?
  
  		// Leverage slice if possible
  		function( target, els ) {
  			push_native.apply( target, slice.call(els) );
  		} :
  
  		// Support: IE<9
  		// Otherwise append directly
  		function( target, els ) {
  			var j = target.length,
  				i = 0;
  			// Can't trust NodeList.length
  			while ( (target[j++] = els[i++]) ) {}
  			target.length = j - 1;
  		}
  	};
  }
  
  function Sizzle( selector, context, results, seed ) {
  	var match, elem, m, nodeType,
  		// QSA vars
  		i, groups, old, nid, newContext, newSelector;
  
  	if ( ( context ? context.ownerDocument || context : preferredDoc ) !== document ) {
  		setDocument( context );
  	}
  
  	context = context || document;
  	results = results || [];
  
  	if ( !selector || typeof selector !== "string" ) {
  		return results;
  	}
  
  	if ( (nodeType = context.nodeType) !== 1 && nodeType !== 9 ) {
  		return [];
  	}
  
  	if ( documentIsHTML && !seed ) {
  
  		// Shortcuts
  		if ( (match = rquickExpr.exec( selector )) ) {
  			// Speed-up: Sizzle("#ID")
  			if ( (m = match[1]) ) {
  				if ( nodeType === 9 ) {
  					elem = context.getElementById( m );
  					// Check parentNode to catch when Blackberry 4.6 returns
  					// nodes that are no longer in the document (jQuery #6963)
  					if ( elem && elem.parentNode ) {
  						// Handle the case where IE, Opera, and Webkit return items
  						// by name instead of ID
  						if ( elem.id === m ) {
  							results.push( elem );
  							return results;
  						}
  					} else {
  						return results;
  					}
  				} else {
  					// Context is not a document
  					if ( context.ownerDocument && (elem = context.ownerDocument.getElementById( m )) &&
  						contains( context, elem ) && elem.id === m ) {
  						results.push( elem );
  						return results;
  					}
  				}
  
  			// Speed-up: Sizzle("TAG")
  			} else if ( match[2] ) {
  				push.apply( results, context.getElementsByTagName( selector ) );
  				return results;
  
  			// Speed-up: Sizzle(".CLASS")
  			} else if ( (m = match[3]) && support.getElementsByClassName && context.getElementsByClassName ) {
  				push.apply( results, context.getElementsByClassName( m ) );
  				return results;
  			}
  		}
  
  		// QSA path
  		if ( support.qsa && (!rbuggyQSA || !rbuggyQSA.test( selector )) ) {
  			nid = old = expando;
  			newContext = context;
  			newSelector = nodeType === 9 && selector;
  
  			// qSA works strangely on Element-rooted queries
  			// We can work around this by specifying an extra ID on the root
  			// and working up from there (Thanks to Andrew Dupont for the technique)
  			// IE 8 doesn't work on object elements
  			if ( nodeType === 1 && context.nodeName.toLowerCase() !== "object" ) {
  				groups = tokenize( selector );
  
  				if ( (old = context.getAttribute("id")) ) {
  					nid = old.replace( rescape, "\\$&" );
  				} else {
  					context.setAttribute( "id", nid );
  				}
  				nid = "[id='" + nid + "'] ";
  
  				i = groups.length;
  				while ( i-- ) {
  					groups[i] = nid + toSelector( groups[i] );
  				}
  				newContext = rsibling.test( selector ) && testContext( context.parentNode ) || context;
  				newSelector = groups.join(",");
  			}
  
  			if ( newSelector ) {
  				try {
  					push.apply( results,
  						newContext.querySelectorAll( newSelector )
  					);
  					return results;
  				} catch(qsaError) {
  				} finally {
  					if ( !old ) {
  						context.removeAttribute("id");
  					}
  				}
  			}
  		}
  	}
  
  	// All others
  	return select( selector.replace( rtrim, "$1" ), context, results, seed );
  }
  
  /**
   * Create key-value caches of limited size
   * @returns {Function(string, Object)} Returns the Object data after storing it on itself with
   *	property name the (space-suffixed) string and (if the cache is larger than Expr.cacheLength)
   *	deleting the oldest entry
   */
  function createCache() {
  	var keys = [];
  
  	function cache( key, value ) {
  		// Use (key + " ") to avoid collision with native prototype properties (see Issue #157)
  		if ( keys.push( key + " " ) > Expr.cacheLength ) {
  			// Only keep the most recent entries
  			delete cache[ keys.shift() ];
  		}
  		return (cache[ key + " " ] = value);
  	}
  	return cache;
  }
  
  /**
   * Mark a function for special use by Sizzle
   * @param {Function} fn The function to mark
   */
  function markFunction( fn ) {
  	fn[ expando ] = true;
  	return fn;
  }
  
  /**
   * Support testing using an element
   * @param {Function} fn Passed the created div and expects a boolean result
   */
  function assert( fn ) {
  	var div = document.createElement("div");
  
  	try {
  		return !!fn( div );
  	} catch (e) {
  		return false;
  	} finally {
  		// Remove from its parent by default
  		if ( div.parentNode ) {
  			div.parentNode.removeChild( div );
  		}
  		// release memory in IE
  		div = null;
  	}
  }
  
  /**
   * Adds the same handler for all of the specified attrs
   * @param {String} attrs Pipe-separated list of attributes
   * @param {Function} handler The method that will be applied
   */
  function addHandle( attrs, handler ) {
  	var arr = attrs.split("|"),
  		i = attrs.length;
  
  	while ( i-- ) {
  		Expr.attrHandle[ arr[i] ] = handler;
  	}
  }
  
  /**
   * Checks document order of two siblings
   * @param {Element} a
   * @param {Element} b
   * @returns {Number} Returns less than 0 if a precedes b, greater than 0 if a follows b
   */
  function siblingCheck( a, b ) {
  	var cur = b && a,
  		diff = cur && a.nodeType === 1 && b.nodeType === 1 &&
  			( ~b.sourceIndex || MAX_NEGATIVE ) -
  			( ~a.sourceIndex || MAX_NEGATIVE );
  
  	// Use IE sourceIndex if available on both nodes
  	if ( diff ) {
  		return diff;
  	}
  
  	// Check if b follows a
  	if ( cur ) {
  		while ( (cur = cur.nextSibling) ) {
  			if ( cur === b ) {
  				return -1;
  			}
  		}
  	}
  
  	return a ? 1 : -1;
  }
  
  /**
   * Returns a function to use in pseudos for input types
   * @param {String} type
   */
  function createInputPseudo( type ) {
  	return function( elem ) {
  		var name = elem.nodeName.toLowerCase();
  		return name === "input" && elem.type === type;
  	};
  }
  
  /**
   * Returns a function to use in pseudos for buttons
   * @param {String} type
   */
  function createButtonPseudo( type ) {
  	return function( elem ) {
  		var name = elem.nodeName.toLowerCase();
  		return (name === "input" || name === "button") && elem.type === type;
  	};
  }
  
  /**
   * Returns a function to use in pseudos for positionals
   * @param {Function} fn
   */
  function createPositionalPseudo( fn ) {
  	return markFunction(function( argument ) {
  		argument = +argument;
  		return markFunction(function( seed, matches ) {
  			var j,
  				matchIndexes = fn( [], seed.length, argument ),
  				i = matchIndexes.length;
  
  			// Match elements found at the specified indexes
  			while ( i-- ) {
  				if ( seed[ (j = matchIndexes[i]) ] ) {
  					seed[j] = !(matches[j] = seed[j]);
  				}
  			}
  		});
  	});
  }
  
  /**
   * Checks a node for validity as a Sizzle context
   * @param {Element|Object=} context
   * @returns {Element|Object|Boolean} The input node if acceptable, otherwise a falsy value
   */
  function testContext( context ) {
  	return context && typeof context.getElementsByTagName !== strundefined && context;
  }
  
  // Expose support vars for convenience
  support = Sizzle.support = {};
  
  /**
   * Detects XML nodes
   * @param {Element|Object} elem An element or a document
   * @returns {Boolean} True iff elem is a non-HTML XML node
   */
  isXML = Sizzle.isXML = function( elem ) {
  	// documentElement is verified for cases where it doesn't yet exist
  	// (such as loading iframes in IE - #4833)
  	var documentElement = elem && (elem.ownerDocument || elem).documentElement;
  	return documentElement ? documentElement.nodeName !== "HTML" : false;
  };
  
  /**
   * Sets document-related variables once based on the current document
   * @param {Element|Object} [doc] An element or document object to use to set the document
   * @returns {Object} Returns the current document
   */
  setDocument = Sizzle.setDocument = function( node ) {
  	var hasCompare,
  		doc = node ? node.ownerDocument || node : preferredDoc,
  		parent = doc.defaultView;
  
  	// If no document and documentElement is available, return
  	if ( doc === document || doc.nodeType !== 9 || !doc.documentElement ) {
  		return document;
  	}
  
  	// Set our document
  	document = doc;
  	docElem = doc.documentElement;
  
  	// Support tests
  	documentIsHTML = !isXML( doc );
  
  	// Support: IE>8
  	// If iframe document is assigned to "document" variable and if iframe has been reloaded,
  	// IE will throw "permission denied" error when accessing "document" variable, see jQuery #13936
  	// IE6-8 do not support the defaultView property so parent will be undefined
  	if ( parent && parent !== parent.top ) {
  		// IE11 does not have attachEvent, so all must suffer
  		if ( parent.addEventListener ) {
  			parent.addEventListener( "unload", function() {
  				setDocument();
  			}, false );
  		} else if ( parent.attachEvent ) {
  			parent.attachEvent( "onunload", function() {
  				setDocument();
  			});
  		}
  	}
  
  	/* Attributes
  	---------------------------------------------------------------------- */
  
  	// Support: IE<8
  	// Verify that getAttribute really returns attributes and not properties (excepting IE8 booleans)
  	support.attributes = assert(function( div ) {
  		div.className = "i";
  		return !div.getAttribute("className");
  	});
  
  	/* getElement(s)By*
  	---------------------------------------------------------------------- */
  
  	// Check if getElementsByTagName("*") returns only elements
  	support.getElementsByTagName = assert(function( div ) {
  		div.appendChild( doc.createComment("") );
  		return !div.getElementsByTagName("*").length;
  	});
  
  	// Check if getElementsByClassName can be trusted
  	support.getElementsByClassName = rnative.test( doc.getElementsByClassName ) && assert(function( div ) {
  		div.innerHTML = "<div class='a'></div><div class='a i'></div>";
  
  		// Support: Safari<4
  		// Catch class over-caching
  		div.firstChild.className = "i";
  		// Support: Opera<10
  		// Catch gEBCN failure to find non-leading classes
  		return div.getElementsByClassName("i").length === 2;
  	});
  
  	// Support: IE<10
  	// Check if getElementById returns elements by name
  	// The broken getElementById methods don't pick up programatically-set names,
  	// so use a roundabout getElementsByName test
  	support.getById = assert(function( div ) {
  		docElem.appendChild( div ).id = expando;
  		return !doc.getElementsByName || !doc.getElementsByName( expando ).length;
  	});
  
  	// ID find and filter
  	if ( support.getById ) {
  		Expr.find["ID"] = function( id, context ) {
  			if ( typeof context.getElementById !== strundefined && documentIsHTML ) {
  				var m = context.getElementById( id );
  				// Check parentNode to catch when Blackberry 4.6 returns
  				// nodes that are no longer in the document #6963
  				return m && m.parentNode ? [ m ] : [];
  			}
  		};
  		Expr.filter["ID"] = function( id ) {
  			var attrId = id.replace( runescape, funescape );
  			return function( elem ) {
  				return elem.getAttribute("id") === attrId;
  			};
  		};
  	} else {
  		// Support: IE6/7
  		// getElementById is not reliable as a find shortcut
  		delete Expr.find["ID"];
  
  		Expr.filter["ID"] =  function( id ) {
  			var attrId = id.replace( runescape, funescape );
  			return function( elem ) {
  				var node = typeof elem.getAttributeNode !== strundefined && elem.getAttributeNode("id");
  				return node && node.value === attrId;
  			};
  		};
  	}
  
  	// Tag
  	Expr.find["TAG"] = support.getElementsByTagName ?
  		function( tag, context ) {
  			if ( typeof context.getElementsByTagName !== strundefined ) {
  				return context.getElementsByTagName( tag );
  			}
  		} :
  		function( tag, context ) {
  			var elem,
  				tmp = [],
  				i = 0,
  				results = context.getElementsByTagName( tag );
  
  			// Filter out possible comments
  			if ( tag === "*" ) {
  				while ( (elem = results[i++]) ) {
  					if ( elem.nodeType === 1 ) {
  						tmp.push( elem );
  					}
  				}
  
  				return tmp;
  			}
  			return results;
  		};
  
  	// Class
  	Expr.find["CLASS"] = support.getElementsByClassName && function( className, context ) {
  		if ( typeof context.getElementsByClassName !== strundefined && documentIsHTML ) {
  			return context.getElementsByClassName( className );
  		}
  	};
  
  	/* QSA/matchesSelector
  	---------------------------------------------------------------------- */
  
  	// QSA and matchesSelector support
  
  	// matchesSelector(:active) reports false when true (IE9/Opera 11.5)
  	rbuggyMatches = [];
  
  	// qSa(:focus) reports false when true (Chrome 21)
  	// We allow this because of a bug in IE8/9 that throws an error
  	// whenever `document.activeElement` is accessed on an iframe
  	// So, we allow :focus to pass through QSA all the time to avoid the IE error
  	// See http://bugs.jquery.com/ticket/13378
  	rbuggyQSA = [];
  
  	if ( (support.qsa = rnative.test( doc.querySelectorAll )) ) {
  		// Build QSA regex
  		// Regex strategy adopted from Diego Perini
  		assert(function( div ) {
  			// Select is set to empty string on purpose
  			// This is to test IE's treatment of not explicitly
  			// setting a boolean content attribute,
  			// since its presence should be enough
  			// http://bugs.jquery.com/ticket/12359
  			div.innerHTML = "<select msallowclip=''><option selected=''></option></select>";
  
  			// Support: IE8, Opera 11-12.16
  			// Nothing should be selected when empty strings follow ^= or $= or *=
  			// The test attribute must be unknown in Opera but "safe" for WinRT
  			// http://msdn.microsoft.com/en-us/library/ie/hh465388.aspx#attribute_section
  			if ( div.querySelectorAll("[msallowclip^='']").length ) {
  				rbuggyQSA.push( "[*^$]=" + whitespace + "*(?:''|\"\")" );
  			}
  
  			// Support: IE8
  			// Boolean attributes and "value" are not treated correctly
  			if ( !div.querySelectorAll("[selected]").length ) {
  				rbuggyQSA.push( "\\[" + whitespace + "*(?:value|" + booleans + ")" );
  			}
  
  			// Webkit/Opera - :checked should return selected option elements
  			// http://www.w3.org/TR/2011/REC-css3-selectors-20110929/#checked
  			// IE8 throws error here and will not see later tests
  			if ( !div.querySelectorAll(":checked").length ) {
  				rbuggyQSA.push(":checked");
  			}
  		});
  
  		assert(function( div ) {
  			// Support: Windows 8 Native Apps
  			// The type and name attributes are restricted during .innerHTML assignment
  			var input = doc.createElement("input");
  			input.setAttribute( "type", "hidden" );
  			div.appendChild( input ).setAttribute( "name", "D" );
  
  			// Support: IE8
  			// Enforce case-sensitivity of name attribute
  			if ( div.querySelectorAll("[name=d]").length ) {
  				rbuggyQSA.push( "name" + whitespace + "*[*^$|!~]?=" );
  			}
  
  			// FF 3.5 - :enabled/:disabled and hidden elements (hidden elements are still enabled)
  			// IE8 throws error here and will not see later tests
  			if ( !div.querySelectorAll(":enabled").length ) {
  				rbuggyQSA.push( ":enabled", ":disabled" );
  			}
  
  			// Opera 10-11 does not throw on post-comma invalid pseudos
  			div.querySelectorAll("*,:x");
  			rbuggyQSA.push(",.*:");
  		});
  	}
  
  	if ( (support.matchesSelector = rnative.test( (matches = docElem.matches ||
  		docElem.webkitMatchesSelector ||
  		docElem.mozMatchesSelector ||
  		docElem.oMatchesSelector ||
  		docElem.msMatchesSelector) )) ) {
  
  		assert(function( div ) {
  			// Check to see if it's possible to do matchesSelector
  			// on a disconnected node (IE 9)
  			support.disconnectedMatch = matches.call( div, "div" );
  
  			// This should fail with an exception
  			// Gecko does not error, returns false instead
  			matches.call( div, "[s!='']:x" );
  			rbuggyMatches.push( "!=", pseudos );
  		});
  	}
  
  	rbuggyQSA = rbuggyQSA.length && new RegExp( rbuggyQSA.join("|") );
  	rbuggyMatches = rbuggyMatches.length && new RegExp( rbuggyMatches.join("|") );
  
  	/* Contains
  	---------------------------------------------------------------------- */
  	hasCompare = rnative.test( docElem.compareDocumentPosition );
  
  	// Element contains another
  	// Purposefully does not implement inclusive descendent
  	// As in, an element does not contain itself
  	contains = hasCompare || rnative.test( docElem.contains ) ?
  		function( a, b ) {
  			var adown = a.nodeType === 9 ? a.documentElement : a,
  				bup = b && b.parentNode;
  			return a === bup || !!( bup && bup.nodeType === 1 && (
  				adown.contains ?
  					adown.contains( bup ) :
  					a.compareDocumentPosition && a.compareDocumentPosition( bup ) & 16
  			));
  		} :
  		function( a, b ) {
  			if ( b ) {
  				while ( (b = b.parentNode) ) {
  					if ( b === a ) {
  						return true;
  					}
  				}
  			}
  			return false;
  		};
  
  	/* Sorting
  	---------------------------------------------------------------------- */
  
  	// Document order sorting
  	sortOrder = hasCompare ?
  	function( a, b ) {
  
  		// Flag for duplicate removal
  		if ( a === b ) {
  			hasDuplicate = true;
  			return 0;
  		}
  
  		// Sort on method existence if only one input has compareDocumentPosition
  		var compare = !a.compareDocumentPosition - !b.compareDocumentPosition;
  		if ( compare ) {
  			return compare;
  		}
  
  		// Calculate position if both inputs belong to the same document
  		compare = ( a.ownerDocument || a ) === ( b.ownerDocument || b ) ?
  			a.compareDocumentPosition( b ) :
  
  			// Otherwise we know they are disconnected
  			1;
  
  		// Disconnected nodes
  		if ( compare & 1 ||
  			(!support.sortDetached && b.compareDocumentPosition( a ) === compare) ) {
  
  			// Choose the first element that is related to our preferred document
  			if ( a === doc || a.ownerDocument === preferredDoc && contains(preferredDoc, a) ) {
  				return -1;
  			}
  			if ( b === doc || b.ownerDocument === preferredDoc && contains(preferredDoc, b) ) {
  				return 1;
  			}
  
  			// Maintain original order
  			return sortInput ?
  				( indexOf.call( sortInput, a ) - indexOf.call( sortInput, b ) ) :
  				0;
  		}
  
  		return compare & 4 ? -1 : 1;
  	} :
  	function( a, b ) {
  		// Exit early if the nodes are identical
  		if ( a === b ) {
  			hasDuplicate = true;
  			return 0;
  		}
  
  		var cur,
  			i = 0,
  			aup = a.parentNode,
  			bup = b.parentNode,
  			ap = [ a ],
  			bp = [ b ];
  
  		// Parentless nodes are either documents or disconnected
  		if ( !aup || !bup ) {
  			return a === doc ? -1 :
  				b === doc ? 1 :
  				aup ? -1 :
  				bup ? 1 :
  				sortInput ?
  				( indexOf.call( sortInput, a ) - indexOf.call( sortInput, b ) ) :
  				0;
  
  		// If the nodes are siblings, we can do a quick check
  		} else if ( aup === bup ) {
  			return siblingCheck( a, b );
  		}
  
  		// Otherwise we need full lists of their ancestors for comparison
  		cur = a;
  		while ( (cur = cur.parentNode) ) {
  			ap.unshift( cur );
  		}
  		cur = b;
  		while ( (cur = cur.parentNode) ) {
  			bp.unshift( cur );
  		}
  
  		// Walk down the tree looking for a discrepancy
  		while ( ap[i] === bp[i] ) {
  			i++;
  		}
  
  		return i ?
  			// Do a sibling check if the nodes have a common ancestor
  			siblingCheck( ap[i], bp[i] ) :
  
  			// Otherwise nodes in our document sort first
  			ap[i] === preferredDoc ? -1 :
  			bp[i] === preferredDoc ? 1 :
  			0;
  	};
  
  	return doc;
  };
  
  Sizzle.matches = function( expr, elements ) {
  	return Sizzle( expr, null, null, elements );
  };
  
  Sizzle.matchesSelector = function( elem, expr ) {
  	// Set document vars if needed
  	if ( ( elem.ownerDocument || elem ) !== document ) {
  		setDocument( elem );
  	}
  
  	// Make sure that attribute selectors are quoted
  	expr = expr.replace( rattributeQuotes, "='$1']" );
  
  	if ( support.matchesSelector && documentIsHTML &&
  		( !rbuggyMatches || !rbuggyMatches.test( expr ) ) &&
  		( !rbuggyQSA     || !rbuggyQSA.test( expr ) ) ) {
  
  		try {
  			var ret = matches.call( elem, expr );
  
  			// IE 9's matchesSelector returns false on disconnected nodes
  			if ( ret || support.disconnectedMatch ||
  					// As well, disconnected nodes are said to be in a document
  					// fragment in IE 9
  					elem.document && elem.document.nodeType !== 11 ) {
  				return ret;
  			}
  		} catch(e) {}
  	}
  
  	return Sizzle( expr, document, null, [ elem ] ).length > 0;
  };
  
  Sizzle.contains = function( context, elem ) {
  	// Set document vars if needed
  	if ( ( context.ownerDocument || context ) !== document ) {
  		setDocument( context );
  	}
  	return contains( context, elem );
  };
  
  Sizzle.attr = function( elem, name ) {
  	// Set document vars if needed
  	if ( ( elem.ownerDocument || elem ) !== document ) {
  		setDocument( elem );
  	}
  
  	var fn = Expr.attrHandle[ name.toLowerCase() ],
  		// Don't get fooled by Object.prototype properties (jQuery #13807)
  		val = fn && hasOwn.call( Expr.attrHandle, name.toLowerCase() ) ?
  			fn( elem, name, !documentIsHTML ) :
  			undefined;
  
  	return val !== undefined ?
  		val :
  		support.attributes || !documentIsHTML ?
  			elem.getAttribute( name ) :
  			(val = elem.getAttributeNode(name)) && val.specified ?
  				val.value :
  				null;
  };
  
  Sizzle.error = function( msg ) {
  	throw new Error( "Syntax error, unrecognized expression: " + msg );
  };
  
  /**
   * Document sorting and removing duplicates
   * @param {ArrayLike} results
   */
  Sizzle.uniqueSort = function( results ) {
  	var elem,
  		duplicates = [],
  		j = 0,
  		i = 0;
  
  	// Unless we *know* we can detect duplicates, assume their presence
  	hasDuplicate = !support.detectDuplicates;
  	sortInput = !support.sortStable && results.slice( 0 );
  	results.sort( sortOrder );
  
  	if ( hasDuplicate ) {
  		while ( (elem = results[i++]) ) {
  			if ( elem === results[ i ] ) {
  				j = duplicates.push( i );
  			}
  		}
  		while ( j-- ) {
  			results.splice( duplicates[ j ], 1 );
  		}
  	}
  
  	// Clear input after sorting to release objects
  	// See https://github.com/jquery/sizzle/pull/225
  	sortInput = null;
  
  	return results;
  };
  
  /**
   * Utility function for retrieving the text value of an array of DOM nodes
   * @param {Array|Element} elem
   */
  getText = Sizzle.getText = function( elem ) {
  	var node,
  		ret = "",
  		i = 0,
  		nodeType = elem.nodeType;
  
  	if ( !nodeType ) {
  		// If no nodeType, this is expected to be an array
  		while ( (node = elem[i++]) ) {
  			// Do not traverse comment nodes
  			ret += getText( node );
  		}
  	} else if ( nodeType === 1 || nodeType === 9 || nodeType === 11 ) {
  		// Use textContent for elements
  		// innerText usage removed for consistency of new lines (jQuery #11153)
  		if ( typeof elem.textContent === "string" ) {
  			return elem.textContent;
  		} else {
  			// Traverse its children
  			for ( elem = elem.firstChild; elem; elem = elem.nextSibling ) {
  				ret += getText( elem );
  			}
  		}
  	} else if ( nodeType === 3 || nodeType === 4 ) {
  		return elem.nodeValue;
  	}
  	// Do not include comment or processing instruction nodes
  
  	return ret;
  };
  
  Expr = Sizzle.selectors = {
  
  	// Can be adjusted by the user
  	cacheLength: 50,
  
  	createPseudo: markFunction,
  
  	match: matchExpr,
  
  	attrHandle: {},
  
  	find: {},
  
  	relative: {
  		">": { dir: "parentNode", first: true },
  		" ": { dir: "parentNode" },
  		"+": { dir: "previousSibling", first: true },
  		"~": { dir: "previousSibling" }
  	},
  
  	preFilter: {
  		"ATTR": function( match ) {
  			match[1] = match[1].replace( runescape, funescape );
  
  			// Move the given value to match[3] whether quoted or unquoted
  			match[3] = ( match[3] || match[4] || match[5] || "" ).replace( runescape, funescape );
  
  			if ( match[2] === "~=" ) {
  				match[3] = " " + match[3] + " ";
  			}
  
  			return match.slice( 0, 4 );
  		},
  
  		"CHILD": function( match ) {
  			/* matches from matchExpr["CHILD"]
  				1 type (only|nth|...)
  				2 what (child|of-type)
  				3 argument (even|odd|\d*|\d*n([+-]\d+)?|...)
  				4 xn-component of xn+y argument ([+-]?\d*n|)
  				5 sign of xn-component
  				6 x of xn-component
  				7 sign of y-component
  				8 y of y-component
  			*/
  			match[1] = match[1].toLowerCase();
  
  			if ( match[1].slice( 0, 3 ) === "nth" ) {
  				// nth-* requires argument
  				if ( !match[3] ) {
  					Sizzle.error( match[0] );
  				}
  
  				// numeric x and y parameters for Expr.filter.CHILD
  				// remember that false/true cast respectively to 0/1
  				match[4] = +( match[4] ? match[5] + (match[6] || 1) : 2 * ( match[3] === "even" || match[3] === "odd" ) );
  				match[5] = +( ( match[7] + match[8] ) || match[3] === "odd" );
  
  			// other types prohibit arguments
  			} else if ( match[3] ) {
  				Sizzle.error( match[0] );
  			}
  
  			return match;
  		},
  
  		"PSEUDO": function( match ) {
  			var excess,
  				unquoted = !match[6] && match[2];
  
  			if ( matchExpr["CHILD"].test( match[0] ) ) {
  				return null;
  			}
  
  			// Accept quoted arguments as-is
  			if ( match[3] ) {
  				match[2] = match[4] || match[5] || "";
  
  			// Strip excess characters from unquoted arguments
  			} else if ( unquoted && rpseudo.test( unquoted ) &&
  				// Get excess from tokenize (recursively)
  				(excess = tokenize( unquoted, true )) &&
  				// advance to the next closing parenthesis
  				(excess = unquoted.indexOf( ")", unquoted.length - excess ) - unquoted.length) ) {
  
  				// excess is a negative index
  				match[0] = match[0].slice( 0, excess );
  				match[2] = unquoted.slice( 0, excess );
  			}
  
  			// Return only captures needed by the pseudo filter method (type and argument)
  			return match.slice( 0, 3 );
  		}
  	},
  
  	filter: {
  
  		"TAG": function( nodeNameSelector ) {
  			var nodeName = nodeNameSelector.replace( runescape, funescape ).toLowerCase();
  			return nodeNameSelector === "*" ?
  				function() { return true; } :
  				function( elem ) {
  					return elem.nodeName && elem.nodeName.toLowerCase() === nodeName;
  				};
  		},
  
  		"CLASS": function( className ) {
  			var pattern = classCache[ className + " " ];
  
  			return pattern ||
  				(pattern = new RegExp( "(^|" + whitespace + ")" + className + "(" + whitespace + "|$)" )) &&
  				classCache( className, function( elem ) {
  					return pattern.test( typeof elem.className === "string" && elem.className || typeof elem.getAttribute !== strundefined && elem.getAttribute("class") || "" );
  				});
  		},
  
  		"ATTR": function( name, operator, check ) {
  			return function( elem ) {
  				var result = Sizzle.attr( elem, name );
  
  				if ( result == null ) {
  					return operator === "!=";
  				}
  				if ( !operator ) {
  					return true;
  				}
  
  				result += "";
  
  				return operator === "=" ? result === check :
  					operator === "!=" ? result !== check :
  					operator === "^=" ? check && result.indexOf( check ) === 0 :
  					operator === "*=" ? check && result.indexOf( check ) > -1 :
  					operator === "$=" ? check && result.slice( -check.length ) === check :
  					operator === "~=" ? ( " " + result + " " ).indexOf( check ) > -1 :
  					operator === "|=" ? result === check || result.slice( 0, check.length + 1 ) === check + "-" :
  					false;
  			};
  		},
  
  		"CHILD": function( type, what, argument, first, last ) {
  			var simple = type.slice( 0, 3 ) !== "nth",
  				forward = type.slice( -4 ) !== "last",
  				ofType = what === "of-type";
  
  			return first === 1 && last === 0 ?
  
  				// Shortcut for :nth-*(n)
  				function( elem ) {
  					return !!elem.parentNode;
  				} :
  
  				function( elem, context, xml ) {
  					var cache, outerCache, node, diff, nodeIndex, start,
  						dir = simple !== forward ? "nextSibling" : "previousSibling",
  						parent = elem.parentNode,
  						name = ofType && elem.nodeName.toLowerCase(),
  						useCache = !xml && !ofType;
  
  					if ( parent ) {
  
  						// :(first|last|only)-(child|of-type)
  						if ( simple ) {
  							while ( dir ) {
  								node = elem;
  								while ( (node = node[ dir ]) ) {
  									if ( ofType ? node.nodeName.toLowerCase() === name : node.nodeType === 1 ) {
  										return false;
  									}
  								}
  								// Reverse direction for :only-* (if we haven't yet done so)
  								start = dir = type === "only" && !start && "nextSibling";
  							}
  							return true;
  						}
  
  						start = [ forward ? parent.firstChild : parent.lastChild ];
  
  						// non-xml :nth-child(...) stores cache data on `parent`
  						if ( forward && useCache ) {
  							// Seek `elem` from a previously-cached index
  							outerCache = parent[ expando ] || (parent[ expando ] = {});
  							cache = outerCache[ type ] || [];
  							nodeIndex = cache[0] === dirruns && cache[1];
  							diff = cache[0] === dirruns && cache[2];
  							node = nodeIndex && parent.childNodes[ nodeIndex ];
  
  							while ( (node = ++nodeIndex && node && node[ dir ] ||
  
  								// Fallback to seeking `elem` from the start
  								(diff = nodeIndex = 0) || start.pop()) ) {
  
  								// When found, cache indexes on `parent` and break
  								if ( node.nodeType === 1 && ++diff && node === elem ) {
  									outerCache[ type ] = [ dirruns, nodeIndex, diff ];
  									break;
  								}
  							}
  
  						// Use previously-cached element index if available
  						} else if ( useCache && (cache = (elem[ expando ] || (elem[ expando ] = {}))[ type ]) && cache[0] === dirruns ) {
  							diff = cache[1];
  
  						// xml :nth-child(...) or :nth-last-child(...) or :nth(-last)?-of-type(...)
  						} else {
  							// Use the same loop as above to seek `elem` from the start
  							while ( (node = ++nodeIndex && node && node[ dir ] ||
  								(diff = nodeIndex = 0) || start.pop()) ) {
  
  								if ( ( ofType ? node.nodeName.toLowerCase() === name : node.nodeType === 1 ) && ++diff ) {
  									// Cache the index of each encountered element
  									if ( useCache ) {
  										(node[ expando ] || (node[ expando ] = {}))[ type ] = [ dirruns, diff ];
  									}
  
  									if ( node === elem ) {
  										break;
  									}
  								}
  							}
  						}
  
  						// Incorporate the offset, then check against cycle size
  						diff -= last;
  						return diff === first || ( diff % first === 0 && diff / first >= 0 );
  					}
  				};
  		},
  
  		"PSEUDO": function( pseudo, argument ) {
  			// pseudo-class names are case-insensitive
  			// http://www.w3.org/TR/selectors/#pseudo-classes
  			// Prioritize by case sensitivity in case custom pseudos are added with uppercase letters
  			// Remember that setFilters inherits from pseudos
  			var args,
  				fn = Expr.pseudos[ pseudo ] || Expr.setFilters[ pseudo.toLowerCase() ] ||
  					Sizzle.error( "unsupported pseudo: " + pseudo );
  
  			// The user may use createPseudo to indicate that
  			// arguments are needed to create the filter function
  			// just as Sizzle does
  			if ( fn[ expando ] ) {
  				return fn( argument );
  			}
  
  			// But maintain support for old signatures
  			if ( fn.length > 1 ) {
  				args = [ pseudo, pseudo, "", argument ];
  				return Expr.setFilters.hasOwnProperty( pseudo.toLowerCase() ) ?
  					markFunction(function( seed, matches ) {
  						var idx,
  							matched = fn( seed, argument ),
  							i = matched.length;
  						while ( i-- ) {
  							idx = indexOf.call( seed, matched[i] );
  							seed[ idx ] = !( matches[ idx ] = matched[i] );
  						}
  					}) :
  					function( elem ) {
  						return fn( elem, 0, args );
  					};
  			}
  
  			return fn;
  		}
  	},
  
  	pseudos: {
  		// Potentially complex pseudos
  		"not": markFunction(function( selector ) {
  			// Trim the selector passed to compile
  			// to avoid treating leading and trailing
  			// spaces as combinators
  			var input = [],
  				results = [],
  				matcher = compile( selector.replace( rtrim, "$1" ) );
  
  			return matcher[ expando ] ?
  				markFunction(function( seed, matches, context, xml ) {
  					var elem,
  						unmatched = matcher( seed, null, xml, [] ),
  						i = seed.length;
  
  					// Match elements unmatched by `matcher`
  					while ( i-- ) {
  						if ( (elem = unmatched[i]) ) {
  							seed[i] = !(matches[i] = elem);
  						}
  					}
  				}) :
  				function( elem, context, xml ) {
  					input[0] = elem;
  					matcher( input, null, xml, results );
  					return !results.pop();
  				};
  		}),
  
  		"has": markFunction(function( selector ) {
  			return function( elem ) {
  				return Sizzle( selector, elem ).length > 0;
  			};
  		}),
  
  		"contains": markFunction(function( text ) {
  			return function( elem ) {
  				return ( elem.textContent || elem.innerText || getText( elem ) ).indexOf( text ) > -1;
  			};
  		}),
  
  		// "Whether an element is represented by a :lang() selector
  		// is based solely on the element's language value
  		// being equal to the identifier C,
  		// or beginning with the identifier C immediately followed by "-".
  		// The matching of C against the element's language value is performed case-insensitively.
  		// The identifier C does not have to be a valid language name."
  		// http://www.w3.org/TR/selectors/#lang-pseudo
  		"lang": markFunction( function( lang ) {
  			// lang value must be a valid identifier
  			if ( !ridentifier.test(lang || "") ) {
  				Sizzle.error( "unsupported lang: " + lang );
  			}
  			lang = lang.replace( runescape, funescape ).toLowerCase();
  			return function( elem ) {
  				var elemLang;
  				do {
  					if ( (elemLang = documentIsHTML ?
  						elem.lang :
  						elem.getAttribute("xml:lang") || elem.getAttribute("lang")) ) {
  
  						elemLang = elemLang.toLowerCase();
  						return elemLang === lang || elemLang.indexOf( lang + "-" ) === 0;
  					}
  				} while ( (elem = elem.parentNode) && elem.nodeType === 1 );
  				return false;
  			};
  		}),
  
  		// Miscellaneous
  		"target": function( elem ) {
  			var hash = window.location && window.location.hash;
  			return hash && hash.slice( 1 ) === elem.id;
  		},
  
  		"root": function( elem ) {
  			return elem === docElem;
  		},
  
  		"focus": function( elem ) {
  			return elem === document.activeElement && (!document.hasFocus || document.hasFocus()) && !!(elem.type || elem.href || ~elem.tabIndex);
  		},
  
  		// Boolean properties
  		"enabled": function( elem ) {
  			return elem.disabled === false;
  		},
  
  		"disabled": function( elem ) {
  			return elem.disabled === true;
  		},
  
  		"checked": function( elem ) {
  			// In CSS3, :checked should return both checked and selected elements
  			// http://www.w3.org/TR/2011/REC-css3-selectors-20110929/#checked
  			var nodeName = elem.nodeName.toLowerCase();
  			return (nodeName === "input" && !!elem.checked) || (nodeName === "option" && !!elem.selected);
  		},
  
  		"selected": function( elem ) {
  			// Accessing this property makes selected-by-default
  			// options in Safari work properly
  			if ( elem.parentNode ) {
  				elem.parentNode.selectedIndex;
  			}
  
  			return elem.selected === true;
  		},
  
  		// Contents
  		"empty": function( elem ) {
  			// http://www.w3.org/TR/selectors/#empty-pseudo
  			// :empty is negated by element (1) or content nodes (text: 3; cdata: 4; entity ref: 5),
  			//   but not by others (comment: 8; processing instruction: 7; etc.)
  			// nodeType < 6 works because attributes (2) do not appear as children
  			for ( elem = elem.firstChild; elem; elem = elem.nextSibling ) {
  				if ( elem.nodeType < 6 ) {
  					return false;
  				}
  			}
  			return true;
  		},
  
  		"parent": function( elem ) {
  			return !Expr.pseudos["empty"]( elem );
  		},
  
  		// Element/input types
  		"header": function( elem ) {
  			return rheader.test( elem.nodeName );
  		},
  
  		"input": function( elem ) {
  			return rinputs.test( elem.nodeName );
  		},
  
  		"button": function( elem ) {
  			var name = elem.nodeName.toLowerCase();
  			return name === "input" && elem.type === "button" || name === "button";
  		},
  
  		"text": function( elem ) {
  			var attr;
  			return elem.nodeName.toLowerCase() === "input" &&
  				elem.type === "text" &&
  
  				// Support: IE<8
  				// New HTML5 attribute values (e.g., "search") appear with elem.type === "text"
  				( (attr = elem.getAttribute("type")) == null || attr.toLowerCase() === "text" );
  		},
  
  		// Position-in-collection
  		"first": createPositionalPseudo(function() {
  			return [ 0 ];
  		}),
  
  		"last": createPositionalPseudo(function( matchIndexes, length ) {
  			return [ length - 1 ];
  		}),
  
  		"eq": createPositionalPseudo(function( matchIndexes, length, argument ) {
  			return [ argument < 0 ? argument + length : argument ];
  		}),
  
  		"even": createPositionalPseudo(function( matchIndexes, length ) {
  			var i = 0;
  			for ( ; i < length; i += 2 ) {
  				matchIndexes.push( i );
  			}
  			return matchIndexes;
  		}),
  
  		"odd": createPositionalPseudo(function( matchIndexes, length ) {
  			var i = 1;
  			for ( ; i < length; i += 2 ) {
  				matchIndexes.push( i );
  			}
  			return matchIndexes;
  		}),
  
  		"lt": createPositionalPseudo(function( matchIndexes, length, argument ) {
  			var i = argument < 0 ? argument + length : argument;
  			for ( ; --i >= 0; ) {
  				matchIndexes.push( i );
  			}
  			return matchIndexes;
  		}),
  
  		"gt": createPositionalPseudo(function( matchIndexes, length, argument ) {
  			var i = argument < 0 ? argument + length : argument;
  			for ( ; ++i < length; ) {
  				matchIndexes.push( i );
  			}
  			return matchIndexes;
  		})
  	}
  };
  
  Expr.pseudos["nth"] = Expr.pseudos["eq"];
  
  // Add button/input type pseudos
  for ( i in { radio: true, checkbox: true, file: true, password: true, image: true } ) {
  	Expr.pseudos[ i ] = createInputPseudo( i );
  }
  for ( i in { submit: true, reset: true } ) {
  	Expr.pseudos[ i ] = createButtonPseudo( i );
  }
  
  // Easy API for creating new setFilters
  function setFilters() {}
  setFilters.prototype = Expr.filters = Expr.pseudos;
  Expr.setFilters = new setFilters();
  
  tokenize = Sizzle.tokenize = function( selector, parseOnly ) {
  	var matched, match, tokens, type,
  		soFar, groups, preFilters,
  		cached = tokenCache[ selector + " " ];
  
  	if ( cached ) {
  		return parseOnly ? 0 : cached.slice( 0 );
  	}
  
  	soFar = selector;
  	groups = [];
  	preFilters = Expr.preFilter;
  
  	while ( soFar ) {
  
  		// Comma and first run
  		if ( !matched || (match = rcomma.exec( soFar )) ) {
  			if ( match ) {
  				// Don't consume trailing commas as valid
  				soFar = soFar.slice( match[0].length ) || soFar;
  			}
  			groups.push( (tokens = []) );
  		}
  
  		matched = false;
  
  		// Combinators
  		if ( (match = rcombinators.exec( soFar )) ) {
  			matched = match.shift();
  			tokens.push({
  				value: matched,
  				// Cast descendant combinators to space
  				type: match[0].replace( rtrim, " " )
  			});
  			soFar = soFar.slice( matched.length );
  		}
  
  		// Filters
  		for ( type in Expr.filter ) {
  			if ( (match = matchExpr[ type ].exec( soFar )) && (!preFilters[ type ] ||
  				(match = preFilters[ type ]( match ))) ) {
  				matched = match.shift();
  				tokens.push({
  					value: matched,
  					type: type,
  					matches: match
  				});
  				soFar = soFar.slice( matched.length );
  			}
  		}
  
  		if ( !matched ) {
  			break;
  		}
  	}
  
  	// Return the length of the invalid excess
  	// if we're just parsing
  	// Otherwise, throw an error or return tokens
  	return parseOnly ?
  		soFar.length :
  		soFar ?
  			Sizzle.error( selector ) :
  			// Cache the tokens
  			tokenCache( selector, groups ).slice( 0 );
  };
  
  function toSelector( tokens ) {
  	var i = 0,
  		len = tokens.length,
  		selector = "";
  	for ( ; i < len; i++ ) {
  		selector += tokens[i].value;
  	}
  	return selector;
  }
  
  function addCombinator( matcher, combinator, base ) {
  	var dir = combinator.dir,
  		checkNonElements = base && dir === "parentNode",
  		doneName = done++;
  
  	return combinator.first ?
  		// Check against closest ancestor/preceding element
  		function( elem, context, xml ) {
  			while ( (elem = elem[ dir ]) ) {
  				if ( elem.nodeType === 1 || checkNonElements ) {
  					return matcher( elem, context, xml );
  				}
  			}
  		} :
  
  		// Check against all ancestor/preceding elements
  		function( elem, context, xml ) {
  			var oldCache, outerCache,
  				newCache = [ dirruns, doneName ];
  
  			// We can't set arbitrary data on XML nodes, so they don't benefit from dir caching
  			if ( xml ) {
  				while ( (elem = elem[ dir ]) ) {
  					if ( elem.nodeType === 1 || checkNonElements ) {
  						if ( matcher( elem, context, xml ) ) {
  							return true;
  						}
  					}
  				}
  			} else {
  				while ( (elem = elem[ dir ]) ) {
  					if ( elem.nodeType === 1 || checkNonElements ) {
  						outerCache = elem[ expando ] || (elem[ expando ] = {});
  						if ( (oldCache = outerCache[ dir ]) &&
  							oldCache[ 0 ] === dirruns && oldCache[ 1 ] === doneName ) {
  
  							// Assign to newCache so results back-propagate to previous elements
  							return (newCache[ 2 ] = oldCache[ 2 ]);
  						} else {
  							// Reuse newcache so results back-propagate to previous elements
  							outerCache[ dir ] = newCache;
  
  							// A match means we're done; a fail means we have to keep checking
  							if ( (newCache[ 2 ] = matcher( elem, context, xml )) ) {
  								return true;
  							}
  						}
  					}
  				}
  			}
  		};
  }
  
  function elementMatcher( matchers ) {
  	return matchers.length > 1 ?
  		function( elem, context, xml ) {
  			var i = matchers.length;
  			while ( i-- ) {
  				if ( !matchers[i]( elem, context, xml ) ) {
  					return false;
  				}
  			}
  			return true;
  		} :
  		matchers[0];
  }
  
  function multipleContexts( selector, contexts, results ) {
  	var i = 0,
  		len = contexts.length;
  	for ( ; i < len; i++ ) {
  		Sizzle( selector, contexts[i], results );
  	}
  	return results;
  }
  
  function condense( unmatched, map, filter, context, xml ) {
  	var elem,
  		newUnmatched = [],
  		i = 0,
  		len = unmatched.length,
  		mapped = map != null;
  
  	for ( ; i < len; i++ ) {
  		if ( (elem = unmatched[i]) ) {
  			if ( !filter || filter( elem, context, xml ) ) {
  				newUnmatched.push( elem );
  				if ( mapped ) {
  					map.push( i );
  				}
  			}
  		}
  	}
  
  	return newUnmatched;
  }
  
  function setMatcher( preFilter, selector, matcher, postFilter, postFinder, postSelector ) {
  	if ( postFilter && !postFilter[ expando ] ) {
  		postFilter = setMatcher( postFilter );
  	}
  	if ( postFinder && !postFinder[ expando ] ) {
  		postFinder = setMatcher( postFinder, postSelector );
  	}
  	return markFunction(function( seed, results, context, xml ) {
  		var temp, i, elem,
  			preMap = [],
  			postMap = [],
  			preexisting = results.length,
  
  			// Get initial elements from seed or context
  			elems = seed || multipleContexts( selector || "*", context.nodeType ? [ context ] : context, [] ),
  
  			// Prefilter to get matcher input, preserving a map for seed-results synchronization
  			matcherIn = preFilter && ( seed || !selector ) ?
  				condense( elems, preMap, preFilter, context, xml ) :
  				elems,
  
  			matcherOut = matcher ?
  				// If we have a postFinder, or filtered seed, or non-seed postFilter or preexisting results,
  				postFinder || ( seed ? preFilter : preexisting || postFilter ) ?
  
  					// ...intermediate processing is necessary
  					[] :
  
  					// ...otherwise use results directly
  					results :
  				matcherIn;
  
  		// Find primary matches
  		if ( matcher ) {
  			matcher( matcherIn, matcherOut, context, xml );
  		}
  
  		// Apply postFilter
  		if ( postFilter ) {
  			temp = condense( matcherOut, postMap );
  			postFilter( temp, [], context, xml );
  
  			// Un-match failing elements by moving them back to matcherIn
  			i = temp.length;
  			while ( i-- ) {
  				if ( (elem = temp[i]) ) {
  					matcherOut[ postMap[i] ] = !(matcherIn[ postMap[i] ] = elem);
  				}
  			}
  		}
  
  		if ( seed ) {
  			if ( postFinder || preFilter ) {
  				if ( postFinder ) {
  					// Get the final matcherOut by condensing this intermediate into postFinder contexts
  					temp = [];
  					i = matcherOut.length;
  					while ( i-- ) {
  						if ( (elem = matcherOut[i]) ) {
  							// Restore matcherIn since elem is not yet a final match
  							temp.push( (matcherIn[i] = elem) );
  						}
  					}
  					postFinder( null, (matcherOut = []), temp, xml );
  				}
  
  				// Move matched elements from seed to results to keep them synchronized
  				i = matcherOut.length;
  				while ( i-- ) {
  					if ( (elem = matcherOut[i]) &&
  						(temp = postFinder ? indexOf.call( seed, elem ) : preMap[i]) > -1 ) {
  
  						seed[temp] = !(results[temp] = elem);
  					}
  				}
  			}
  
  		// Add elements to results, through postFinder if defined
  		} else {
  			matcherOut = condense(
  				matcherOut === results ?
  					matcherOut.splice( preexisting, matcherOut.length ) :
  					matcherOut
  			);
  			if ( postFinder ) {
  				postFinder( null, results, matcherOut, xml );
  			} else {
  				push.apply( results, matcherOut );
  			}
  		}
  	});
  }
  
  function matcherFromTokens( tokens ) {
  	var checkContext, matcher, j,
  		len = tokens.length,
  		leadingRelative = Expr.relative[ tokens[0].type ],
  		implicitRelative = leadingRelative || Expr.relative[" "],
  		i = leadingRelative ? 1 : 0,
  
  		// The foundational matcher ensures that elements are reachable from top-level context(s)
  		matchContext = addCombinator( function( elem ) {
  			return elem === checkContext;
  		}, implicitRelative, true ),
  		matchAnyContext = addCombinator( function( elem ) {
  			return indexOf.call( checkContext, elem ) > -1;
  		}, implicitRelative, true ),
  		matchers = [ function( elem, context, xml ) {
  			return ( !leadingRelative && ( xml || context !== outermostContext ) ) || (
  				(checkContext = context).nodeType ?
  					matchContext( elem, context, xml ) :
  					matchAnyContext( elem, context, xml ) );
  		} ];
  
  	for ( ; i < len; i++ ) {
  		if ( (matcher = Expr.relative[ tokens[i].type ]) ) {
  			matchers = [ addCombinator(elementMatcher( matchers ), matcher) ];
  		} else {
  			matcher = Expr.filter[ tokens[i].type ].apply( null, tokens[i].matches );
  
  			// Return special upon seeing a positional matcher
  			if ( matcher[ expando ] ) {
  				// Find the next relative operator (if any) for proper handling
  				j = ++i;
  				for ( ; j < len; j++ ) {
  					if ( Expr.relative[ tokens[j].type ] ) {
  						break;
  					}
  				}
  				return setMatcher(
  					i > 1 && elementMatcher( matchers ),
  					i > 1 && toSelector(
  						// If the preceding token was a descendant combinator, insert an implicit any-element `*`
  						tokens.slice( 0, i - 1 ).concat({ value: tokens[ i - 2 ].type === " " ? "*" : "" })
  					).replace( rtrim, "$1" ),
  					matcher,
  					i < j && matcherFromTokens( tokens.slice( i, j ) ),
  					j < len && matcherFromTokens( (tokens = tokens.slice( j )) ),
  					j < len && toSelector( tokens )
  				);
  			}
  			matchers.push( matcher );
  		}
  	}
  
  	return elementMatcher( matchers );
  }
  
  function matcherFromGroupMatchers( elementMatchers, setMatchers ) {
  	var bySet = setMatchers.length > 0,
  		byElement = elementMatchers.length > 0,
  		superMatcher = function( seed, context, xml, results, outermost ) {
  			var elem, j, matcher,
  				matchedCount = 0,
  				i = "0",
  				unmatched = seed && [],
  				setMatched = [],
  				contextBackup = outermostContext,
  				// We must always have either seed elements or outermost context
  				elems = seed || byElement && Expr.find["TAG"]( "*", outermost ),
  				// Use integer dirruns iff this is the outermost matcher
  				dirrunsUnique = (dirruns += contextBackup == null ? 1 : Math.random() || 0.1),
  				len = elems.length;
  
  			if ( outermost ) {
  				outermostContext = context !== document && context;
  			}
  
  			// Add elements passing elementMatchers directly to results
  			// Keep `i` a string if there are no elements so `matchedCount` will be "00" below
  			// Support: IE<9, Safari
  			// Tolerate NodeList properties (IE: "length"; Safari: <number>) matching elements by id
  			for ( ; i !== len && (elem = elems[i]) != null; i++ ) {
  				if ( byElement && elem ) {
  					j = 0;
  					while ( (matcher = elementMatchers[j++]) ) {
  						if ( matcher( elem, context, xml ) ) {
  							results.push( elem );
  							break;
  						}
  					}
  					if ( outermost ) {
  						dirruns = dirrunsUnique;
  					}
  				}
  
  				// Track unmatched elements for set filters
  				if ( bySet ) {
  					// They will have gone through all possible matchers
  					if ( (elem = !matcher && elem) ) {
  						matchedCount--;
  					}
  
  					// Lengthen the array for every element, matched or not
  					if ( seed ) {
  						unmatched.push( elem );
  					}
  				}
  			}
  
  			// Apply set filters to unmatched elements
  			matchedCount += i;
  			if ( bySet && i !== matchedCount ) {
  				j = 0;
  				while ( (matcher = setMatchers[j++]) ) {
  					matcher( unmatched, setMatched, context, xml );
  				}
  
  				if ( seed ) {
  					// Reintegrate element matches to eliminate the need for sorting
  					if ( matchedCount > 0 ) {
  						while ( i-- ) {
  							if ( !(unmatched[i] || setMatched[i]) ) {
  								setMatched[i] = pop.call( results );
  							}
  						}
  					}
  
  					// Discard index placeholder values to get only actual matches
  					setMatched = condense( setMatched );
  				}
  
  				// Add matches to results
  				push.apply( results, setMatched );
  
  				// Seedless set matches succeeding multiple successful matchers stipulate sorting
  				if ( outermost && !seed && setMatched.length > 0 &&
  					( matchedCount + setMatchers.length ) > 1 ) {
  
  					Sizzle.uniqueSort( results );
  				}
  			}
  
  			// Override manipulation of globals by nested matchers
  			if ( outermost ) {
  				dirruns = dirrunsUnique;
  				outermostContext = contextBackup;
  			}
  
  			return unmatched;
  		};
  
  	return bySet ?
  		markFunction( superMatcher ) :
  		superMatcher;
  }
  
  compile = Sizzle.compile = function( selector, match /* Internal Use Only */ ) {
  	var i,
  		setMatchers = [],
  		elementMatchers = [],
  		cached = compilerCache[ selector + " " ];
  
  	if ( !cached ) {
  		// Generate a function of recursive functions that can be used to check each element
  		if ( !match ) {
  			match = tokenize( selector );
  		}
  		i = match.length;
  		while ( i-- ) {
  			cached = matcherFromTokens( match[i] );
  			if ( cached[ expando ] ) {
  				setMatchers.push( cached );
  			} else {
  				elementMatchers.push( cached );
  			}
  		}
  
  		// Cache the compiled function
  		cached = compilerCache( selector, matcherFromGroupMatchers( elementMatchers, setMatchers ) );
  
  		// Save selector and tokenization
  		cached.selector = selector;
  	}
  	return cached;
  };
  
  /**
   * A low-level selection function that works with Sizzle's compiled
   *  selector functions
   * @param {String|Function} selector A selector or a pre-compiled
   *  selector function built with Sizzle.compile
   * @param {Element} context
   * @param {Array} [results]
   * @param {Array} [seed] A set of elements to match against
   */
  select = Sizzle.select = function( selector, context, results, seed ) {
  	var i, tokens, token, type, find,
  		compiled = typeof selector === "function" && selector,
  		match = !seed && tokenize( (selector = compiled.selector || selector) );
  
  	results = results || [];
  
  	// Try to minimize operations if there is no seed and only one group
  	if ( match.length === 1 ) {
  
  		// Take a shortcut and set the context if the root selector is an ID
  		tokens = match[0] = match[0].slice( 0 );
  		if ( tokens.length > 2 && (token = tokens[0]).type === "ID" &&
  				support.getById && context.nodeType === 9 && documentIsHTML &&
  				Expr.relative[ tokens[1].type ] ) {
  
  			context = ( Expr.find["ID"]( token.matches[0].replace(runescape, funescape), context ) || [] )[0];
  			if ( !context ) {
  				return results;
  
  			// Precompiled matchers will still verify ancestry, so step up a level
  			} else if ( compiled ) {
  				context = context.parentNode;
  			}
  
  			selector = selector.slice( tokens.shift().value.length );
  		}
  
  		// Fetch a seed set for right-to-left matching
  		i = matchExpr["needsContext"].test( selector ) ? 0 : tokens.length;
  		while ( i-- ) {
  			token = tokens[i];
  
  			// Abort if we hit a combinator
  			if ( Expr.relative[ (type = token.type) ] ) {
  				break;
  			}
  			if ( (find = Expr.find[ type ]) ) {
  				// Search, expanding context for leading sibling combinators
  				if ( (seed = find(
  					token.matches[0].replace( runescape, funescape ),
  					rsibling.test( tokens[0].type ) && testContext( context.parentNode ) || context
  				)) ) {
  
  					// If seed is empty or no tokens remain, we can return early
  					tokens.splice( i, 1 );
  					selector = seed.length && toSelector( tokens );
  					if ( !selector ) {
  						push.apply( results, seed );
  						return results;
  					}
  
  					break;
  				}
  			}
  		}
  	}
  
  	// Compile and execute a filtering function if one is not provided
  	// Provide `match` to avoid retokenization if we modified the selector above
  	( compiled || compile( selector, match ) )(
  		seed,
  		context,
  		!documentIsHTML,
  		results,
  		rsibling.test( selector ) && testContext( context.parentNode ) || context
  	);
  	return results;
  };
  
  // One-time assignments
  
  // Sort stability
  support.sortStable = expando.split("").sort( sortOrder ).join("") === expando;
  
  // Support: Chrome<14
  // Always assume duplicates if they aren't passed to the comparison function
  support.detectDuplicates = !!hasDuplicate;
  
  // Initialize against the default document
  setDocument();
  
  // Support: Webkit<537.32 - Safari 6.0.3/Chrome 25 (fixed in Chrome 27)
  // Detached nodes confoundingly follow *each other*
  support.sortDetached = assert(function( div1 ) {
  	// Should return 1, but returns 4 (following)
  	return div1.compareDocumentPosition( document.createElement("div") ) & 1;
  });
  
  // Support: IE<8
  // Prevent attribute/property "interpolation"
  // http://msdn.microsoft.com/en-us/library/ms536429%28VS.85%29.aspx
  if ( !assert(function( div ) {
  	div.innerHTML = "<a href='#'></a>";
  	return div.firstChild.getAttribute("href") === "#" ;
  }) ) {
  	addHandle( "type|href|height|width", function( elem, name, isXML ) {
  		if ( !isXML ) {
  			return elem.getAttribute( name, name.toLowerCase() === "type" ? 1 : 2 );
  		}
  	});
  }
  
  // Support: IE<9
  // Use defaultValue in place of getAttribute("value")
  if ( !support.attributes || !assert(function( div ) {
  	div.innerHTML = "<input/>";
  	div.firstChild.setAttribute( "value", "" );
  	return div.firstChild.getAttribute( "value" ) === "";
  }) ) {
  	addHandle( "value", function( elem, name, isXML ) {
  		if ( !isXML && elem.nodeName.toLowerCase() === "input" ) {
  			return elem.defaultValue;
  		}
  	});
  }
  
  // Support: IE<9
  // Use getAttributeNode to fetch booleans when getAttribute lies
  if ( !assert(function( div ) {
  	return div.getAttribute("disabled") == null;
  }) ) {
  	addHandle( booleans, function( elem, name, isXML ) {
  		var val;
  		if ( !isXML ) {
  			return elem[ name ] === true ? name.toLowerCase() :
  					(val = elem.getAttributeNode( name )) && val.specified ?
  					val.value :
  				null;
  		}
  	});
  }
  
  // EXPOSE
  if ( typeof define === "function" && define.amd ) {
  	define(function() { return Sizzle; });
  // Sizzle requires that there be a global window in Common-JS like environments
  } else if ( typeof module !== "undefined" && module.exports ) {
  	module.exports = Sizzle;
  } else {
  	window.Sizzle = Sizzle;
  }
  // EXPOSE
  
  })( window );
  
  /*! 
   * LESS - Leaner CSS v1.6.0 
   * http://lesscss.org 
   * 
   * Copyright (c) 2009-2014, Alexis Sellier <self@cloudhead.net> 
   * Licensed under the Apache v2 License. 
   * 
   */ 
  
   /** * @license Apache v2
   */ 
  
  
  
  (function (window, undefined) {//
  // Stub out `require` in the browser
  //
  function require(arg) {
      return window.less[arg.split('/')[1]];
  };
  
  
  if (typeof(window.less) === 'undefined' || typeof(window.less.nodeType) !== 'undefined') { window.less = {}; }
  less = window.less;
  tree = window.less.tree = {};
  less.mode = 'browser';
  
  var less, tree;
  
  // Node.js does not have a header file added which defines less
  if (less === undefined) {
      less = exports;
      tree = require('./tree');
      less.mode = 'node';
  }
  //
  // less.js - parser
  //
  //    A relatively straight-forward predictive parser.
  //    There is no tokenization/lexing stage, the input is parsed
  //    in one sweep.
  //
  //    To make the parser fast enough to run in the browser, several
  //    optimization had to be made:
  //
  //    - Matching and slicing on a huge input is often cause of slowdowns.
  //      The solution is to chunkify the input into smaller strings.
  //      The chunks are stored in the `chunks` var,
  //      `j` holds the current chunk index, and `currentPos` holds
  //      the index of the current chunk in relation to `input`.
  //      This gives us an almost 4x speed-up.
  //
  //    - In many cases, we don't need to match individual tokens;
  //      for example, if a value doesn't hold any variables, operations
  //      or dynamic references, the parser can effectively 'skip' it,
  //      treating it as a literal.
  //      An example would be '1px solid #000' - which evaluates to itself,
  //      we don't need to know what the individual components are.
  //      The drawback, of course is that you don't get the benefits of
  //      syntax-checking on the CSS. This gives us a 50% speed-up in the parser,
  //      and a smaller speed-up in the code-gen.
  //
  //
  //    Token matching is done with the `$` function, which either takes
  //    a terminal string or regexp, or a non-terminal function to call.
  //    It also takes care of moving all the indices forwards.
  //
  //
  less.Parser = function Parser(env) {
      var input,       // LeSS input string
          i,           // current index in `input`
          j,           // current chunk
          temp,        // temporarily holds a chunk's state, for backtracking
          memo,        // temporarily holds `i`, when backtracking
          furthest,    // furthest index the parser has gone to
          chunks,      // chunkified input
          current,     // current chunk
          currentPos,  // index of current chunk, in `input`
          parser,
          parsers,
          rootFilename = env && env.filename;
  
      // Top parser on an import tree must be sure there is one "env"
      // which will then be passed around by reference.
      if (!(env instanceof tree.parseEnv)) {
          env = new tree.parseEnv(env);
      }
  
      var imports = this.imports = {
          paths: env.paths || [],  // Search paths, when importing
          queue: [],               // Files which haven't been imported yet
          files: env.files,        // Holds the imported parse trees
          contents: env.contents,  // Holds the imported file contents
          contentsIgnoredChars: env.contentsIgnoredChars, // lines inserted, not in the original less
          mime:  env.mime,         // MIME type of .less files
          error: null,             // Error in parsing/evaluating an import
          push: function (path, currentFileInfo, importOptions, callback) {
              var parserImports = this;
              this.queue.push(path);
  
              var fileParsedFunc = function (e, root, fullPath) {
                  parserImports.queue.splice(parserImports.queue.indexOf(path), 1); // Remove the path from the queue
  
                  var importedPreviously = fullPath in parserImports.files || fullPath === rootFilename;
  
                  parserImports.files[fullPath] = root;                        // Store the root
  
                  if (e && !parserImports.error) { parserImports.error = e; }
  
                  callback(e, root, importedPreviously, fullPath);
              };
  
              if (less.Parser.importer) {
                  less.Parser.importer(path, currentFileInfo, fileParsedFunc, env);
              } else {
                  less.Parser.fileLoader(path, currentFileInfo, function(e, contents, fullPath, newFileInfo) {
                      if (e) {fileParsedFunc(e); return;}
  
                      var newEnv = new tree.parseEnv(env);
  
                      newEnv.currentFileInfo = newFileInfo;
                      newEnv.processImports = false;
                      newEnv.contents[fullPath] = contents;
  
                      if (currentFileInfo.reference || importOptions.reference) {
                          newFileInfo.reference = true;
                      }
  
                      if (importOptions.inline) {
                          fileParsedFunc(null, contents, fullPath);
                      } else {
                          new(less.Parser)(newEnv).parse(contents, function (e, root) {
                              fileParsedFunc(e, root, fullPath);
                          });
                      }
                  }, env);
              }
          }
      };
  
      function save()    { temp = current; memo = currentPos = i; }
      function restore() { current = temp; currentPos = i = memo; }
  
      function sync() {
          if (i > currentPos) {
              current = current.slice(i - currentPos);
              currentPos = i;
          }
      }
      function isWhitespace(str, pos) {
          var code = str.charCodeAt(pos | 0);
          return (code <= 32) && (code === 32 || code === 10 || code === 9);
      }
      //
      // Parse from a token, regexp or string, and move forward if match
      //
      function $(tok) {
          var tokType = typeof tok,
              match, length;
  
          // Either match a single character in the input,
          // or match a regexp in the current chunk (`current`).
          //
          if (tokType === "string") {
              if (input.charAt(i) !== tok) {
                  return null;
              }
              skipWhitespace(1);
              return tok;
          }
  
          // regexp
          sync ();
          if (! (match = tok.exec(current))) {
              return null;
          }
  
          length = match[0].length;
  
          // The match is confirmed, add the match length to `i`,
          // and consume any extra white-space characters (' ' || '\n')
          // which come after that. The reason for this is that LeSS's
          // grammar is mostly white-space insensitive.
          //
          skipWhitespace(length);
  
          if(typeof(match) === 'string') {
              return match;
          } else {
              return match.length === 1 ? match[0] : match;
          }
      }
  
      // Specialization of $(tok)
      function $re(tok) {
          if (i > currentPos) {
              current = current.slice(i - currentPos);
              currentPos = i;
          }
          var m = tok.exec(current);
          if (!m) {
              return null;
          }
  
          skipWhitespace(m[0].length);
          if(typeof m === "string") {
              return m;
          }
  
          return m.length === 1 ? m[0] : m;
      }
  
      var _$re = $re;
  
      // Specialization of $(tok)
      function $char(tok) {
          if (input.charAt(i) !== tok) {
              return null;
          }
          skipWhitespace(1);
          return tok;
      }
  
      function skipWhitespace(length) {
          var oldi = i, oldj = j,
              curr = i - currentPos,
              endIndex = i + current.length - curr,
              mem = (i += length),
              inp = input,
              c;
  
          for (; i < endIndex; i++) {
              c = inp.charCodeAt(i);
              if (c > 32) {
                  break;
              }
  
              if ((c !== 32) && (c !== 10) && (c !== 9) && (c !== 13)) {
                  break;
              }
           }
  
          current = current.slice(length + i - mem + curr);
          currentPos = i;
  
          if (!current.length && (j < chunks.length - 1)) {
              current = chunks[++j];
          }
  
          return oldi !== i || oldj !== j;
      }
  
      function expect(arg, msg) {
          var result = (typeof arg === "function") ? arg.call(parsers) : $(arg);
          if (result) {
              return result;
          }
          error(msg || (typeof(arg) === 'string' ? "expected '" + arg + "' got '" + input.charAt(i) + "'"
                                                 : "unexpected token"));
      }
  
      // Specialization of expect()
      function expectChar(arg, msg) {
          if (input.charAt(i) === arg) {
              skipWhitespace(1);
              return arg;
          }
          error(msg || "expected '" + arg + "' got '" + input.charAt(i) + "'");
      }
  
      function error(msg, type) {
          var e = new Error(msg);
          e.index = i;
          e.type = type || 'Syntax';
          throw e;
      }
  
      // Same as $(), but don't change the state of the parser,
      // just return the match.
      function peek(tok) {
          if (typeof(tok) === 'string') {
              return input.charAt(i) === tok;
          } else {
              return tok.test(current);
          }
      }
  
      // Specialization of peek()
      function peekChar(tok) {
          return input.charAt(i) === tok;
      }
  
  
      function getInput(e, env) {
          if (e.filename && env.currentFileInfo.filename && (e.filename !== env.currentFileInfo.filename)) {
              return parser.imports.contents[e.filename];
          } else {
              return input;
          }
      }
  
      function getLocation(index, inputStream) {
          var n = index + 1,
              line = null,
              column = -1;
  
          while (--n >= 0 && inputStream.charAt(n) !== '\n') {
              column++;
          }
  
          if (typeof index === 'number') {
              line = (inputStream.slice(0, index).match(/\n/g) || "").length;
          }
  
          return {
              line: line,
              column: column
          };
      }
  
      function getDebugInfo(index, inputStream, env) {
          var filename = env.currentFileInfo.filename;
          if(less.mode !== 'browser' && less.mode !== 'rhino') {
              filename = require('path').resolve(filename);
          }
  
          return {
              lineNumber: getLocation(index, inputStream).line + 1,
              fileName: filename
          };
      }
  
      function LessError(e, env) {
          var input = getInput(e, env),
              loc = getLocation(e.index, input),
              line = loc.line,
              col  = loc.column,
              callLine = e.call && getLocation(e.call, input).line,
              lines = input.split('\n');
  
          this.type = e.type || 'Syntax';
          this.message = e.message;
          this.filename = e.filename || env.currentFileInfo.filename;
          this.index = e.index;
          this.line = typeof(line) === 'number' ? line + 1 : null;
          this.callLine = callLine + 1;
          this.callExtract = lines[callLine];
          this.stack = e.stack;
          this.column = col;
          this.extract = [
              lines[line - 1],
              lines[line],
              lines[line + 1]
          ];
      }
  
      LessError.prototype = new Error();
      LessError.prototype.constructor = LessError;
  
      this.env = env = env || {};
  
      // The optimization level dictates the thoroughness of the parser,
      // the lower the number, the less nodes it will create in the tree.
      // This could matter for debugging, or if you want to access
      // the individual nodes in the tree.
      this.optimization = ('optimization' in this.env) ? this.env.optimization : 1;
  
      //
      // The Parser
      //
      parser = {
  
          imports: imports,
          //
          // Parse an input string into an abstract syntax tree,
          // @param str A string containing 'less' markup
          // @param callback call `callback` when done.
          // @param [additionalData] An optional map which can contains vars - a map (key, value) of variables to apply
          //
          parse: function (str, callback, additionalData) {
              var root, line, lines, error = null, globalVars, modifyVars, preText = "";
  
              i = j = currentPos = furthest = 0;
  
              globalVars = (additionalData && additionalData.globalVars) ? less.Parser.serializeVars(additionalData.globalVars) + '\n' : '';
              modifyVars = (additionalData && additionalData.modifyVars) ? '\n' + less.Parser.serializeVars(additionalData.modifyVars) : '';
  
              if (globalVars || (additionalData && additionalData.banner)) {
                  preText = ((additionalData && additionalData.banner) ? additionalData.banner : "") + globalVars;
                  parser.imports.contentsIgnoredChars[env.currentFileInfo.filename] = preText.length;
              }
  
              str = str.replace(/\r\n/g, '\n');
              // Remove potential UTF Byte Order Mark
              input = str = preText + str.replace(/^\uFEFF/, '') + modifyVars;
              parser.imports.contents[env.currentFileInfo.filename] = str;
  
              // Split the input into chunks.
              chunks = (function (input) {
                  var len = input.length, level = 0, parenLevel = 0,
                      lastOpening, lastClosing, lastMultiComment, lastMultiCommentEndBrace,
                      chunks = [], emitFrom = 0,
                      parserCurrentIndex, currentChunkStartIndex, cc, cc2, matched;
  
                  function fail(msg, index) {
                      error = new(LessError)({
                          index: index || parserCurrentIndex,
                          type: 'Parse',
                          message: msg,
                          filename: env.currentFileInfo.filename
                      }, env);
                  }
  
                  function emitChunk(force) {
                      var len = parserCurrentIndex - emitFrom;
                      if (((len < 512) && !force) || !len) {
                          return;
                      }
                      chunks.push(input.slice(emitFrom, parserCurrentIndex + 1));
                      emitFrom = parserCurrentIndex + 1;
                  }
  
                  for (parserCurrentIndex = 0; parserCurrentIndex < len; parserCurrentIndex++) {
                      cc = input.charCodeAt(parserCurrentIndex);
                      if (((cc >= 97) && (cc <= 122)) || (cc < 34)) {
                          // a-z or whitespace
                          continue;
                      }
  
                      switch (cc) {
                          case 40:                        // (
                              parenLevel++; continue;
                          case 41:                        // )
                              parenLevel--; continue;
                          case 59:                        // ;
                              if (!parenLevel) { emitChunk(); }
                              continue;
                          case 123:                       // {
                              level++; lastOpening = parserCurrentIndex; continue;
                          case 125:                       // }
                              level--; lastClosing = parserCurrentIndex;
                              if (!level) { emitChunk(); }
                              continue;
                          case 92:                        // \
                              if (parserCurrentIndex < len - 1) { parserCurrentIndex++; continue; }
                              return fail("unescaped `\\`");
                          case 34:
                          case 39:
                          case 96:                        // ", ' and `
                              matched = 0;
                              currentChunkStartIndex = parserCurrentIndex;
                              for (parserCurrentIndex = parserCurrentIndex + 1; parserCurrentIndex < len; parserCurrentIndex++) {
                                  cc2 = input.charCodeAt(parserCurrentIndex);
                                  if (cc2 > 96) { continue; }
                                  if (cc2 == cc) { matched = 1; break; }
                                  if (cc2 == 92) {        // \
                                      if (parserCurrentIndex == len - 1) {
                                          return fail("unescaped `\\`");
                                      }
                                      parserCurrentIndex++;
                                  }
                              }
                              if (matched) { continue; }
                              return fail("unmatched `" + String.fromCharCode(cc) + "`", currentChunkStartIndex);
                          case 47:                        // /, check for comment
                              if (parenLevel || (parserCurrentIndex == len - 1)) { continue; }
                              cc2 = input.charCodeAt(parserCurrentIndex + 1);
                              if (cc2 == 47) {
                                  // //, find lnfeed
                                  for (parserCurrentIndex = parserCurrentIndex + 2; parserCurrentIndex < len; parserCurrentIndex++) {
                                      cc2 = input.charCodeAt(parserCurrentIndex);
                                      if ((cc2 <= 13) && ((cc2 == 10) || (cc2 == 13))) { break; }
                                  }
                              } else if (cc2 == 42) {
                                  // /*, find */
                                  lastMultiComment = currentChunkStartIndex = parserCurrentIndex;
                                  for (parserCurrentIndex = parserCurrentIndex + 2; parserCurrentIndex < len - 1; parserCurrentIndex++) {
                                      cc2 = input.charCodeAt(parserCurrentIndex);
                                      if (cc2 == 125) { lastMultiCommentEndBrace = parserCurrentIndex; }
                                      if (cc2 != 42) { continue; }
                                      if (input.charCodeAt(parserCurrentIndex + 1) == 47) { break; }
                                  }
                                  if (parserCurrentIndex == len - 1) {
                                      return fail("missing closing `*/`", currentChunkStartIndex);
                                  }
                              }
                              continue;
                          case 42:                       // *, check for unmatched */
                              if ((parserCurrentIndex < len - 1) && (input.charCodeAt(parserCurrentIndex + 1) == 47)) {
                                  return fail("unmatched `/*`");
                              }
                              continue;
                      }
                  }
  
                  if (level !== 0) {
                      if (level > 0) {
                          if ((lastMultiComment > lastOpening) && (lastMultiCommentEndBrace > lastMultiComment)) {
                              return fail("missing closing `}` or `*/`", lastOpening);
                          } else {
                              return fail("missing closing `}`", lastOpening);
                          }
                      }
                      return fail("missing opening `{`", lastClosing);
                  } else if (parenLevel !== 0) {
                      return fail((parenLevel > 0) ? "missing closing `)`" : "missing opening `(`");
                  }
  
                  emitChunk(true);
                  return chunks;
              })(str);
  
              if (error) {
                  return callback(new(LessError)(error, env));
              }
  
              current = chunks[0];
  
              // Start with the primary rule.
              // The whole syntax tree is held under a Ruleset node,
              // with the `root` property set to true, so no `{}` are
              // output. The callback is called when the input is parsed.
              try {
                  root = new(tree.Ruleset)(null, this.parsers.primary());
                  root.root = true;
                  root.firstRoot = true;
              } catch (e) {
                  return callback(new(LessError)(e, env));
              }
  
              root.toCSS = (function (evaluate) {
                  return function (options, variables) {
                      options = options || {};
                      var evaldRoot,
                          css,
                          evalEnv = new tree.evalEnv(options);
                          
                      //
                      // Allows setting variables with a hash, so:
                      //
                      //   `{ color: new(tree.Color)('#f01') }` will become:
                      //
                      //   new(tree.Rule)('@color',
                      //     new(tree.Value)([
                      //       new(tree.Expression)([
                      //         new(tree.Color)('#f01')
                      //       ])
                      //     ])
                      //   )
                      //
                      if (typeof(variables) === 'object' && !Array.isArray(variables)) {
                          variables = Object.keys(variables).map(function (k) {
                              var value = variables[k];
  
                              if (! (value instanceof tree.Value)) {
                                  if (! (value instanceof tree.Expression)) {
                                      value = new(tree.Expression)([value]);
                                  }
                                  value = new(tree.Value)([value]);
                              }
                              return new(tree.Rule)('@' + k, value, false, null, 0);
                          });
                          evalEnv.frames = [new(tree.Ruleset)(null, variables)];
                      }
  
                      try {
                          var preEvalVisitors = [],
                              visitors = [
                                  new(tree.joinSelectorVisitor)(),
                                  new(tree.processExtendsVisitor)(),
                                  new(tree.toCSSVisitor)({compress: Boolean(options.compress)})
                              ], i, root = this;
  
                          if (options.plugins) {
                              for(i =0; i < options.plugins.length; i++) {
                                  if (options.plugins[i].isPreEvalVisitor) {
                                      preEvalVisitors.push(options.plugins[i]);
                                  } else {
                                      if (options.plugins[i].isPreVisitor) {
                                          visitors.splice(0, 0, options.plugins[i]);
                                      } else {
                                          visitors.push(options.plugins[i]);
                                      }
                                  }
                              }
                          }
  
                          for(i = 0; i < preEvalVisitors.length; i++) {
                              preEvalVisitors[i].run(root);
                          }
  
                          evaldRoot = evaluate.call(root, evalEnv);
  
                          for(i = 0; i < visitors.length; i++) {
                              visitors[i].run(evaldRoot);
                          }
  
                          if (options.sourceMap) {
                              evaldRoot = new tree.sourceMapOutput(
                                  {
                                      contentsIgnoredCharsMap: parser.imports.contentsIgnoredChars,
                                      writeSourceMap: options.writeSourceMap,
                                      rootNode: evaldRoot,
                                      contentsMap: parser.imports.contents,
                                      sourceMapFilename: options.sourceMapFilename,
                                      sourceMapURL: options.sourceMapURL,
                                      outputFilename: options.sourceMapOutputFilename,
                                      sourceMapBasepath: options.sourceMapBasepath,
                                      sourceMapRootpath: options.sourceMapRootpath,
                                      outputSourceFiles: options.outputSourceFiles,
                                      sourceMapGenerator: options.sourceMapGenerator
                                  });
                          }
  
                          css = evaldRoot.toCSS({
                                  compress: Boolean(options.compress),
                                  dumpLineNumbers: env.dumpLineNumbers,
                                  strictUnits: Boolean(options.strictUnits)});
                      } catch (e) {
                          throw new(LessError)(e, env);
                      }
  
                      if (options.cleancss && less.mode === 'node') {
                          var CleanCSS = require('clean-css'),
                              cleancssOptions = options.cleancssOptions || {};
  
                          if (cleancssOptions.keepSpecialComments === undefined) {
                              cleancssOptions.keepSpecialComments = "*";
                          }
                          cleancssOptions.processImport = false;
                          cleancssOptions.noRebase = true;
                          if (cleancssOptions.noAdvanced === undefined) {
                              cleancssOptions.noAdvanced = true;
                          }
  
                          return new CleanCSS(cleancssOptions).minify(css);
                      } else if (options.compress) {
                          return css.replace(/(^(\s)+)|((\s)+$)/g, "");
                      } else {
                          return css;
                      }
                  };
              })(root.eval);
  
              // If `i` is smaller than the `input.length - 1`,
              // it means the parser wasn't able to parse the whole
              // string, so we've got a parsing error.
              //
              // We try to extract a \n delimited string,
              // showing the line where the parse error occured.
              // We split it up into two parts (the part which parsed,
              // and the part which didn't), so we can color them differently.
              if (i < input.length - 1) {
                  i = furthest;
                  var loc = getLocation(i, input);
                  lines = input.split('\n');
                  line = loc.line + 1;
  
                  error = {
                      type: "Parse",
                      message: "Unrecognised input",
                      index: i,
                      filename: env.currentFileInfo.filename,
                      line: line,
                      column: loc.column,
                      extract: [
                          lines[line - 2],
                          lines[line - 1],
                          lines[line]
                      ]
                  };
              }
  
              var finish = function (e) {
                  e = error || e || parser.imports.error;
  
                  if (e) {
                      if (!(e instanceof LessError)) {
                          e = new(LessError)(e, env);
                      }
  
                      return callback(e);
                  }
                  else {
                      return callback(null, root);
                  }
              };
  
              if (env.processImports !== false) {
                  new tree.importVisitor(this.imports, finish)
                      .run(root);
              } else {
                  return finish();
              }
          },
  
          //
          // Here in, the parsing rules/functions
          //
          // The basic structure of the syntax tree generated is as follows:
          //
          //   Ruleset ->  Rule -> Value -> Expression -> Entity
          //
          // Here's some LESS code:
          //
          //    .class {
          //      color: #fff;
          //      border: 1px solid #000;
          //      width: @w + 4px;
          //      > .child {...}
          //    }
          //
          // And here's what the parse tree might look like:
          //
          //     Ruleset (Selector '.class', [
          //         Rule ("color",  Value ([Expression [Color #fff]]))
          //         Rule ("border", Value ([Expression [Dimension 1px][Keyword "solid"][Color #000]]))
          //         Rule ("width",  Value ([Expression [Operation "+" [Variable "@w"][Dimension 4px]]]))
          //         Ruleset (Selector [Element '>', '.child'], [...])
          //     ])
          //
          //  In general, most rules will try to parse a token with the `$()` function, and if the return
          //  value is truly, will return a new node, of the relevant type. Sometimes, we need to check
          //  first, before parsing, that's when we use `peek()`.
          //
          parsers: parsers = {
              //
              // The `primary` rule is the *entry* and *exit* point of the parser.
              // The rules here can appear at any level of the parse tree.
              //
              // The recursive nature of the grammar is an interplay between the `block`
              // rule, which represents `{ ... }`, the `ruleset` rule, and this `primary` rule,
              // as represented by this simplified grammar:
              //
              //     primary  →  (ruleset | rule)+
              //     ruleset  →  selector+ block
              //     block    →  '{' primary '}'
              //
              // Only at one point is the primary rule not called from the
              // block rule: at the root level.
              //
              primary: function () {
                  var mixin = this.mixin, $re = _$re, root = [], node;
  
                  while (true)
                  {
                      node = this.extendRule() || mixin.definition() || this.rule() || this.ruleset() ||
                          mixin.call() || this.comment() || this.directive();
                      if (node) {
                          root.push(node);
                      } else {
                          if (!($re(/^[\s\n]+/) || $re(/^;+/))) {
                              break;
                          }
                      }
                  }
  
                  return root;
              },
  
              // We create a Comment node for CSS comments `/* */`,
              // but keep the LeSS comments `//` silent, by just skipping
              // over them.
              comment: function () {
                  var comment;
  
                  if (input.charAt(i) !== '/') { return; }
  
                  if (input.charAt(i + 1) === '/') {
                      return new(tree.Comment)($re(/^\/\/.*/), true, i, env.currentFileInfo);
                  }
                  comment = $re(/^\/\*(?:[^*]|\*+[^\/*])*\*+\/\n?/);
                  if (comment) {
                      return new(tree.Comment)(comment, false, i, env.currentFileInfo);
                  }
              },
  
              comments: function () {
                  var comment, comments = [];
  
                  while(true) {
                      comment = this.comment();
                      if (!comment) {
                          break;
                      }
                      comments.push(comment);
                  }
  
                  return comments;
              },
  
              //
              // Entities are tokens which can be found inside an Expression
              //
              entities: {
                  //
                  // A string, which supports escaping " and '
                  //
                  //     "milky way" 'he\'s the one!'
                  //
                  quoted: function () {
                      var str, j = i, e, index = i;
  
                      if (input.charAt(j) === '~') { j++; e = true; } // Escaped strings
                      if (input.charAt(j) !== '"' && input.charAt(j) !== "'") { return; }
  
                      if (e) { $char('~'); }
  
                      str = $re(/^"((?:[^"\\\r\n]|\\.)*)"|'((?:[^'\\\r\n]|\\.)*)'/);
                      if (str) {
                          return new(tree.Quoted)(str[0], str[1] || str[2], e, index, env.currentFileInfo);
                      }
                  },
  
                  //
                  // A catch-all word, such as:
                  //
                  //     black border-collapse
                  //
                  keyword: function () {
                      var k;
  
                      k = $re(/^[_A-Za-z-][_A-Za-z0-9-]*/);
                      if (k) {
                          var color = tree.Color.fromKeyword(k);
                          if (color) {
                              return color;
                          }
                          return new(tree.Keyword)(k);
                      }
                  },
  
                  //
                  // A function call
                  //
                  //     rgb(255, 0, 255)
                  //
                  // We also try to catch IE's `alpha()`, but let the `alpha` parser
                  // deal with the details.
                  //
                  // The arguments are parsed with the `entities.arguments` parser.
                  //
                  call: function () {
                      var name, nameLC, args, alpha_ret, index = i;
  
                      name = /^([\w-]+|%|progid:[\w\.]+)\(/.exec(current);
                      if (!name) { return; }
  
                      name = name[1];
                      nameLC = name.toLowerCase();
                      if (nameLC === 'url') {
                          return null;
                      }
  
                      i += name.length;
  
                      if (nameLC === 'alpha') {
                          alpha_ret = parsers.alpha();
                          if(typeof alpha_ret !== 'undefined') {
                              return alpha_ret;
                          }
                      }
  
                      $char('('); // Parse the '(' and consume whitespace.
  
                      args = this.arguments();
  
                      if (! $char(')')) {
                          return;
                      }
  
                      if (name) { return new(tree.Call)(name, args, index, env.currentFileInfo); }
                  },
                  arguments: function () {
                      var args = [], arg;
  
                      while (true) {
                          arg = this.assignment() || parsers.expression();
                          if (!arg) {
                              break;
                          }
                          args.push(arg);
                          if (! $char(',')) {
                              break;
                          }
                      }
                      return args;
                  },
                  literal: function () {
                      return this.dimension() ||
                             this.color() ||
                             this.quoted() ||
                             this.unicodeDescriptor();
                  },
  
                  // Assignments are argument entities for calls.
                  // They are present in ie filter properties as shown below.
                  //
                  //     filter: progid:DXImageTransform.Microsoft.Alpha( *opacity=50* )
                  //
  
                  assignment: function () {
                      var key, value;
                      key = $re(/^\w+(?=\s?=)/i);
                      if (!key) {
                          return;
                      }
                      if (!$char('=')) {
                          return;
                      }
                      value = parsers.entity();
                      if (value) {
                          return new(tree.Assignment)(key, value);
                      }
                  },
  
                  //
                  // Parse url() tokens
                  //
                  // We use a specific rule for urls, because they don't really behave like
                  // standard function calls. The difference is that the argument doesn't have
                  // to be enclosed within a string, so it can't be parsed as an Expression.
                  //
                  url: function () {
                      var value;
  
                      if (input.charAt(i) !== 'u' || !$re(/^url\(/)) {
                          return;
                      }
  
                      value = this.quoted() || this.variable() ||
                              $re(/^(?:(?:\\[\(\)'"])|[^\(\)'"])+/) || "";
  
                      expectChar(')');
  
                      return new(tree.URL)((value.value != null || value instanceof tree.Variable)
                                          ? value : new(tree.Anonymous)(value), env.currentFileInfo);
                  },
  
                  //
                  // A Variable entity, such as `@fink`, in
                  //
                  //     width: @fink + 2px
                  //
                  // We use a different parser for variable definitions,
                  // see `parsers.variable`.
                  //
                  variable: function () {
                      var name, index = i;
  
                      if (input.charAt(i) === '@' && (name = $re(/^@@?[\w-]+/))) {
                          return new(tree.Variable)(name, index, env.currentFileInfo);
                      }
                  },
  
                  // A variable entity useing the protective {} e.g. @{var}
                  variableCurly: function () {
                      var curly, index = i;
  
                      if (input.charAt(i) === '@' && (curly = $re(/^@\{([\w-]+)\}/))) {
                          return new(tree.Variable)("@" + curly[1], index, env.currentFileInfo);
                      }
                  },
  
                  //
                  // A Hexadecimal color
                  //
                  //     #4F3C2F
                  //
                  // `rgb` and `hsl` colors are parsed through the `entities.call` parser.
                  //
                  color: function () {
                      var rgb;
  
                      if (input.charAt(i) === '#' && (rgb = $re(/^#([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})/))) {
                          return new(tree.Color)(rgb[1]);
                      }
                  },
  
                  //
                  // A Dimension, that is, a number and a unit
                  //
                  //     0.5em 95%
                  //
                  dimension: function () {
                      var value, c = input.charCodeAt(i);
                      //Is the first char of the dimension 0-9, '.', '+' or '-'
                      if ((c > 57 || c < 43) || c === 47 || c == 44) {
                          return;
                      }
  
                      value = $re(/^([+-]?\d*\.?\d+)(%|[a-z]+)?/);
                      if (value) {
                          return new(tree.Dimension)(value[1], value[2]);
                      }
                  },
  
                  //
                  // A unicode descriptor, as is used in unicode-range
                  //
                  // U+0??  or U+00A1-00A9
                  //
                  unicodeDescriptor: function () {
                      var ud;
  
                      ud = $re(/^U\+[0-9a-fA-F?]+(\-[0-9a-fA-F?]+)?/);
                      if (ud) {
                          return new(tree.UnicodeDescriptor)(ud[0]);
                      }
                  },
  
                  //
                  // JavaScript code to be evaluated
                  //
                  //     `window.location.href`
                  //
                  javascript: function () {
                      var str, j = i, e;
  
                      if (input.charAt(j) === '~') { j++; e = true; } // Escaped strings
                      if (input.charAt(j) !== '`') { return; }
                      if (env.javascriptEnabled !== undefined && !env.javascriptEnabled) {
                          error("You are using JavaScript, which has been disabled.");
                      }
  
                      if (e) { $char('~'); }
  
                      str = $re(/^`([^`]*)`/);
                      if (str) {
                          return new(tree.JavaScript)(str[1], i, e);
                      }
                  }
              },
  
              //
              // The variable part of a variable definition. Used in the `rule` parser
              //
              //     @fink:
              //
              variable: function () {
                  var name;
  
                  if (input.charAt(i) === '@' && (name = $re(/^(@[\w-]+)\s*:/))) { return name[1]; }
              },
  
              //
              // extend syntax - used to extend selectors
              //
              extend: function(isRule) {
                  var elements, e, index = i, option, extendList, extend;
  
                  if (!(isRule ? $re(/^&:extend\(/) : $re(/^:extend\(/))) { return; }
  
                  do {
                      option = null;
                      elements = null;
                      while (! (option = $re(/^(all)(?=\s*(\)|,))/))) {
                          e = this.element();
                          if (!e) { break; }
                          if (elements) { elements.push(e); } else { elements = [ e ]; }
                      }
  
                      option = option && option[1];
  
                      extend = new(tree.Extend)(new(tree.Selector)(elements), option, index);
                      if (extendList) { extendList.push(extend); } else { extendList = [ extend ]; }
  
                  } while($char(","));
                  
                  expect(/^\)/);
  
                  if (isRule) {
                      expect(/^;/);
                  }
  
                  return extendList;
              },
  
              //
              // extendRule - used in a rule to extend all the parent selectors
              //
              extendRule: function() {
                  return this.extend(true);
              },
              
              //
              // Mixins
              //
              mixin: {
                  //
                  // A Mixin call, with an optional argument list
                  //
                  //     #mixins > .square(#fff);
                  //     .rounded(4px, black);
                  //     .button;
                  //
                  // The `while` loop is there because mixins can be
                  // namespaced, but we only support the child and descendant
                  // selector for now.
                  //
                  call: function () {
                      var s = input.charAt(i), important = false, index = i,
                          elements, elem, e, c, args;
  
                      if (s !== '.' && s !== '#') { return; }
  
                      save(); // stop us absorbing part of an invalid selector
  
                      while (true) {
                          e = $re(/^[#.](?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+/);
                          if (!e) {
                              break;
                          }
                          elem = new(tree.Element)(c, e, i, env.currentFileInfo);
                          if (elements) { elements.push(elem); } else { elements = [ elem ]; }
                          c = $char('>');
                      }
                      if ($char('(')) {
                          args = this.args(true).args;
                          expectChar(')');
                      }
  
                      if (parsers.important()) {
                          important = true;
                      }
  
                      if (elements && ($char(';') || peekChar('}'))) {
                          return new(tree.mixin.Call)(elements, args, index, env.currentFileInfo, important);
                      }
  
                      restore();
                  },
                  args: function (isCall) {
                      var parsers = parser.parsers, entities = parsers.entities,
                          returner = { args:null, variadic: false },
                          expressions = [], argsSemiColon = [], argsComma = [],
                          isSemiColonSeperated, expressionContainsNamed, name, nameLoop, value, arg;
  
                      while (true) {
                          if (isCall) {
                              arg = parsers.expression();
                          } else {
                              parsers.comments();
                              if (input.charAt(i) === '.' && $re(/^\.{3}/)) {
                                  returner.variadic = true;
                                  if ($char(";") && !isSemiColonSeperated) {
                                      isSemiColonSeperated = true;
                                  }
                                  (isSemiColonSeperated ? argsSemiColon : argsComma)
                                      .push({ variadic: true });
                                  break;
                              }
                              arg = entities.variable() || entities.literal() || entities.keyword();
                          }
  
                          if (!arg) {
                              break;
                          }
  
                          nameLoop = null;
                          if (arg.throwAwayComments) {
                              arg.throwAwayComments();
                          }
                          value = arg;
                          var val = null;
  
                          if (isCall) {
                              // Variable
                              if (arg.value.length == 1) {
                                  val = arg.value[0];
                              }
                          } else {
                              val = arg;
                          }
  
                          if (val && val instanceof tree.Variable) {
                              if ($char(':')) {
                                  if (expressions.length > 0) {
                                      if (isSemiColonSeperated) {
                                          error("Cannot mix ; and , as delimiter types");
                                      }
                                      expressionContainsNamed = true;
                                  }
                                  value = expect(parsers.expression);
                                  nameLoop = (name = val.name);
                              } else if (!isCall && $re(/^\.{3}/)) {
                                  returner.variadic = true;
                                  if ($char(";") && !isSemiColonSeperated) {
                                      isSemiColonSeperated = true;
                                  }
                                  (isSemiColonSeperated ? argsSemiColon : argsComma)
                                      .push({ name: arg.name, variadic: true });
                                  break;
                              } else if (!isCall) {
                                  name = nameLoop = val.name;
                                  value = null;
                              }
                          }
  
                          if (value) {
                              expressions.push(value);
                          }
  
                          argsComma.push({ name:nameLoop, value:value });
  
                          if ($char(',')) {
                              continue;
                          }
  
                          if ($char(';') || isSemiColonSeperated) {
  
                              if (expressionContainsNamed) {
                                  error("Cannot mix ; and , as delimiter types");
                              }
  
                              isSemiColonSeperated = true;
  
                              if (expressions.length > 1) {
                                  value = new(tree.Value)(expressions);
                              }
                              argsSemiColon.push({ name:name, value:value });
  
                              name = null;
                              expressions = [];
                              expressionContainsNamed = false;
                          }
                      }
  
                      returner.args = isSemiColonSeperated ? argsSemiColon : argsComma;
                      return returner;
                  },
                  //
                  // A Mixin definition, with a list of parameters
                  //
                  //     .rounded (@radius: 2px, @color) {
                  //        ...
                  //     }
                  //
                  // Until we have a finer grained state-machine, we have to
                  // do a look-ahead, to make sure we don't have a mixin call.
                  // See the `rule` function for more information.
                  //
                  // We start by matching `.rounded (`, and then proceed on to
                  // the argument list, which has optional default values.
                  // We store the parameters in `params`, with a `value` key,
                  // if there is a value, such as in the case of `@radius`.
                  //
                  // Once we've got our params list, and a closing `)`, we parse
                  // the `{...}` block.
                  //
                  definition: function () {
                      var name, params = [], match, ruleset, cond, variadic = false;
                      if ((input.charAt(i) !== '.' && input.charAt(i) !== '#') ||
                          peek(/^[^{]*\}/)) {
                          return;
                      }
  
                      save();
  
                      match = $re(/^([#.](?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+)\s*\(/);
                      if (match) {
                          name = match[1];
  
                          var argInfo = this.args(false);
                          params = argInfo.args;
                          variadic = argInfo.variadic;
  
                          // .mixincall("@{a}");
                          // looks a bit like a mixin definition.. so we have to be nice and restore
                          if (!$char(')')) {
                              furthest = i;
                              restore();
                          }
                          
                          parsers.comments();
  
                          if ($re(/^when/)) { // Guard
                              cond = expect(parsers.conditions, 'expected condition');
                          }
  
                          ruleset = parsers.block();
  
                          if (ruleset) {
                              return new(tree.mixin.Definition)(name, params, ruleset, cond, variadic);
                          } else {
                              restore();
                          }
                      }
                  }
              },
  
              //
              // Entities are the smallest recognized token,
              // and can be found inside a rule's value.
              //
              entity: function () {
                  var entities = this.entities;
  
                  return entities.literal() || entities.variable() || entities.url() ||
                         entities.call()    || entities.keyword()  || entities.javascript() ||
                         this.comment();
              },
  
              //
              // A Rule terminator. Note that we use `peek()` to check for '}',
              // because the `block` rule will be expecting it, but we still need to make sure
              // it's there, if ';' was ommitted.
              //
              end: function () {
                  return $char(';') || peekChar('}');
              },
  
              //
              // IE's alpha function
              //
              //     alpha(opacity=88)
              //
              alpha: function () {
                  var value;
  
                  if (! $re(/^\(opacity=/i)) { return; }
                  value = $re(/^\d+/) || this.entities.variable();
                  if (value) {
                      expectChar(')');
                      return new(tree.Alpha)(value);
                  }
              },
  
              //
              // A Selector Element
              //
              //     div
              //     + h1
              //     #socks
              //     input[type="text"]
              //
              // Elements are the building blocks for Selectors,
              // they are made out of a `Combinator` (see combinator rule),
              // and an element name, such as a tag a class, or `*`.
              //
              element: function () {
                  var e, c, v;
  
                  c = this.combinator();
  
                  e = $re(/^(?:\d+\.\d+|\d+)%/) || $re(/^(?:[.#]?|:*)(?:[\w-]|[^\x00-\x9f]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+/) ||
                      $char('*') || $char('&') || this.attribute() || $re(/^\([^()@]+\)/) || $re(/^[\.#](?=@)/) ||
                      this.entities.variableCurly();
  
                  if (! e) {
                      if ($char('(')) {
                          if ((v = this.selector()) && $char(')')) {
                              e = new(tree.Paren)(v);
                          }
                      }
                  }
  
                  if (e) { return new(tree.Element)(c, e, i, env.currentFileInfo); }
              },
  
              //
              // Combinators combine elements together, in a Selector.
              //
              // Because our parser isn't white-space sensitive, special care
              // has to be taken, when parsing the descendant combinator, ` `,
              // as it's an empty space. We have to check the previous character
              // in the input, to see if it's a ` ` character. More info on how
              // we deal with this in *combinator.js*.
              //
              combinator: function () {
                  var c = input.charAt(i);
  
                  if (c === '>' || c === '+' || c === '~' || c === '|') {
                      i++;
                      while (isWhitespace(input, i)) { i++; }
                      return new(tree.Combinator)(c);
                  } else if (isWhitespace(input, i - 1)) {
                      return new(tree.Combinator)(" ");
                  } else {
                      return new(tree.Combinator)(null);
                  }
              },
              //
              // A CSS selector (see selector below)
              // with less extensions e.g. the ability to extend and guard
              //
              lessSelector: function () {
                  return this.selector(true);
              },
              //
              // A CSS Selector
              //
              //     .class > div + h1
              //     li a:hover
              //
              // Selectors are made out of one or more Elements, see above.
              //
              selector: function (isLess) {
                  var $re = _$re, elements, extendList, c, e, extend, when, condition;
  
                  while ((isLess && (extend = this.extend())) || (isLess && (when = $re(/^when/))) || (e = this.element())) {
                      if (when) {
                          condition = expect(this.conditions, 'expected condition');
                      } else if (condition) {
                          error("CSS guard can only be used at the end of selector");
                      } else if (extend) {
                          if (extendList) { extendList.push(extend); } else { extendList = [ extend ]; }
                      } else {
                          if (extendList) { error("Extend can only be used at the end of selector"); }
                          c = input.charAt(i);
                          if (elements) { elements.push(e); } else { elements = [ e ]; }
                          e = null;
                      }
                      if (c === '{' || c === '}' || c === ';' || c === ',' || c === ')') {
                          break;
                      }
                  }
  
                  if (elements) { return new(tree.Selector)(elements, extendList, condition, i, env.currentFileInfo); }
                  if (extendList) { error("Extend must be used to extend a selector, it cannot be used on its own"); }
              },
              attribute: function () {
                  if (! $char('[')) { return; }
  
                  var entities = this.entities,
                      key, val, op;
  
                  if (!(key = entities.variableCurly())) {
                      key = expect(/^(?:[_A-Za-z0-9-\*]*\|)?(?:[_A-Za-z0-9-]|\\.)+/);
                  }
  
                  op = $re(/^[|~*$^]?=/);
                  if (op) {
                      val = entities.quoted() || $re(/^[0-9]+%/) || $re(/^[\w-]+/) || entities.variableCurly();
                  }
  
                  expectChar(']');
  
                  return new(tree.Attribute)(key, op, val);
              },
  
              //
              // The `block` rule is used by `ruleset` and `mixin.definition`.
              // It's a wrapper around the `primary` rule, with added `{}`.
              //
              block: function () {
                  var content;
                  if ($char('{') && (content = this.primary()) && $char('}')) {
                      return content;
                  }
              },
  
              //
              // div, .class, body > p {...}
              //
              ruleset: function () {
                  var selectors, s, rules, debugInfo;
                  
                  save();
  
                  if (env.dumpLineNumbers) {
                      debugInfo = getDebugInfo(i, input, env);
                  }
  
                  while (true) {
                      s = this.lessSelector();
                      if (!s) {
                          break;
                      }
                      if (selectors) { selectors.push(s); } else { selectors = [ s ]; }
                      this.comments();
                      if (! $char(',')) { break; }
                      if (s.condition) {
                          error("Guards are only currently allowed on a single selector.");
                      }
                      this.comments();
                  }
  
                  if (selectors && (rules = this.block())) {
                      var ruleset = new(tree.Ruleset)(selectors, rules, env.strictImports);
                      if (env.dumpLineNumbers) {
                          ruleset.debugInfo = debugInfo;
                      }
                      return ruleset;
                  } else {
                      // Backtrack
                      furthest = i;
                      restore();
                  }
              },
              rule: function (tryAnonymous) {
                  var name, value, c = input.charAt(i), important, merge = false;
                  save();
  
                  if (c === '.' || c === '#' || c === '&') { return; }
  
                  name = this.variable() || this.ruleProperty();
                  if (name) {
                      // prefer to try to parse first if its a variable or we are compressing
                      // but always fallback on the other one
                      value = !tryAnonymous && (env.compress || (name.charAt && (name.charAt(0) === '@'))) ?
                          (this.value() || this.anonymousValue()) :
                          (this.anonymousValue() || this.value());
  
                      important = this.important();
                      
                      // a name returned by this.ruleProperty() is always an array of the form:
                      // ["", "string-1", ..., "string-n", ""] or ["", "string-1", ..., "string-n", "+"]
                      merge = name.pop && (name.pop() === "+");
  
                      if (value && this.end()) {
                          return new (tree.Rule)(name, value, important, merge, memo, env.currentFileInfo);
                      } else {
                          furthest = i;
                          restore();
                          if (value && !tryAnonymous) {
                              return this.rule(true);
                          }
                      }
                  }
              },
              anonymousValue: function () {
                  var match;
                  match = /^([^@+\/'"*`(;{}-]*);/.exec(current);
                  if (match) {
                      i += match[0].length - 1;
                      return new(tree.Anonymous)(match[1]);
                  }
              },
  
              //
              // An @import directive
              //
              //     @import "lib";
              //
              // Depending on our environemnt, importing is done differently:
              // In the browser, it's an XHR request, in Node, it would be a
              // file-system operation. The function used for importing is
              // stored in `import`, which we pass to the Import constructor.
              //
              "import": function () {
                  var path, features, index = i;
  
                  save();
  
                  var dir = $re(/^@import?\s+/);
  
                  var options = (dir ? this.importOptions() : null) || {};
  
                  if (dir && (path = this.entities.quoted() || this.entities.url())) {
                      features = this.mediaFeatures();
                      if ($char(';')) {
                          features = features && new(tree.Value)(features);
                          return new(tree.Import)(path, features, options, index, env.currentFileInfo);
                      }
                  }
  
                  restore();
              },
  
              importOptions: function() {
                  var o, options = {}, optionName, value;
  
                  // list of options, surrounded by parens
                  if (! $char('(')) { return null; }
                  do {
                      o = this.importOption();
                      if (o) {
                          optionName = o;
                          value = true;
                          switch(optionName) {
                              case "css":
                                  optionName = "less";
                                  value = false;
                              break;
                              case "once":
                                  optionName = "multiple";
                                  value = false;
                              break;
                          }
                          options[optionName] = value;
                          if (! $char(',')) { break; }
                      }
                  } while (o);
                  expectChar(')');
                  return options;
              },
  
              importOption: function() {
                  var opt = $re(/^(less|css|multiple|once|inline|reference)/);
                  if (opt) {
                      return opt[1];
                  }
              },
  
              mediaFeature: function () {
                  var entities = this.entities, nodes = [], e, p;
                  do {
                      e = entities.keyword() || entities.variable();
                      if (e) {
                          nodes.push(e);
                      } else if ($char('(')) {
                          p = this.property();
                          e = this.value();
                          if ($char(')')) {
                              if (p && e) {
                                  nodes.push(new(tree.Paren)(new(tree.Rule)(p, e, null, null, i, env.currentFileInfo, true)));
                              } else if (e) {
                                  nodes.push(new(tree.Paren)(e));
                              } else {
                                  return null;
                              }
                          } else { return null; }
                      }
                  } while (e);
  
                  if (nodes.length > 0) {
                      return new(tree.Expression)(nodes);
                  }
              },
  
              mediaFeatures: function () {
                  var entities = this.entities, features = [], e;
                  do {
                      e = this.mediaFeature();
                      if (e) {
                          features.push(e);
                          if (! $char(',')) { break; }
                      } else {
                          e = entities.variable();
                          if (e) {
                              features.push(e);
                              if (! $char(',')) { break; }
                          }
                      }
                  } while (e);
  
                  return features.length > 0 ? features : null;
              },
  
              media: function () {
                  var features, rules, media, debugInfo;
  
                  if (env.dumpLineNumbers) {
                      debugInfo = getDebugInfo(i, input, env);
                  }
  
                  if ($re(/^@media/)) {
                      features = this.mediaFeatures();
  
                      rules = this.block();
                      if (rules) {
                          media = new(tree.Media)(rules, features, i, env.currentFileInfo);
                          if (env.dumpLineNumbers) {
                              media.debugInfo = debugInfo;
                          }
                          return media;
                      }
                  }
              },
  
              //
              // A CSS Directive
              //
              //     @charset "utf-8";
              //
              directive: function () {
                  var name, value, rules, nonVendorSpecificName,
                      hasBlock, hasIdentifier, hasExpression, identifier;
  
                  if (input.charAt(i) !== '@') { return; }
  
                  value = this['import']() || this.media();
                  if (value) {
                      return value;
                  }
  
                  save();
  
                  name = $re(/^@[a-z-]+/);
                  
                  if (!name) { return; }
  
                  nonVendorSpecificName = name;
                  if (name.charAt(1) == '-' && name.indexOf('-', 2) > 0) {
                      nonVendorSpecificName = "@" + name.slice(name.indexOf('-', 2) + 1);
                  }
  
                  switch(nonVendorSpecificName) {
                      case "@font-face":
                          hasBlock = true;
                          break;
                      case "@viewport":
                      case "@top-left":
                      case "@top-left-corner":
                      case "@top-center":
                      case "@top-right":
                      case "@top-right-corner":
                      case "@bottom-left":
                      case "@bottom-left-corner":
                      case "@bottom-center":
                      case "@bottom-right":
                      case "@bottom-right-corner":
                      case "@left-top":
                      case "@left-middle":
                      case "@left-bottom":
                      case "@right-top":
                      case "@right-middle":
                      case "@right-bottom":
                          hasBlock = true;
                          break;
                      case "@host":
                      case "@page":
                      case "@document":
                      case "@supports":
                      case "@keyframes":
                          hasBlock = true;
                          hasIdentifier = true;
                          break;
                      case "@namespace":
                          hasExpression = true;
                          break;
                  }
  
                  if (hasIdentifier) {
                      identifier = ($re(/^[^{]+/) || '').trim();
                      if (identifier) {
                          name += " " + identifier;
                      }
                  }
  
                  if (hasBlock) {
                      rules = this.block();
                      if (rules) {
                          return new(tree.Directive)(name, rules, i, env.currentFileInfo);
                      }
                  } else {
                      value = hasExpression ? this.expression() : this.entity();
                      if (value && $char(';')) {
                          var directive = new(tree.Directive)(name, value, i, env.currentFileInfo);
                          if (env.dumpLineNumbers) {
                              directive.debugInfo = getDebugInfo(i, input, env);
                          }
                          return directive;
                      }
                  }
  
                  restore();
              },
  
              //
              // A Value is a comma-delimited list of Expressions
              //
              //     font-family: Baskerville, Georgia, serif;
              //
              // In a Rule, a Value represents everything after the `:`,
              // and before the `;`.
              //
              value: function () {
                  var e, expressions = [];
  
                  do {
                      e = this.expression();
                      if (e) {
                          expressions.push(e);
                          if (! $char(',')) { break; }
                      }
                  } while(e);
  
                  if (expressions.length > 0) {
                      return new(tree.Value)(expressions);
                  }
              },
              important: function () {
                  if (input.charAt(i) === '!') {
                      return $re(/^! *important/);
                  }
              },
              sub: function () {
                  var a, e;
  
                  if ($char('(')) {
                      a = this.addition();
                      if (a) {
                          e = new(tree.Expression)([a]);
                          expectChar(')');
                          e.parens = true;
                          return e;
                      }
                  }
              },
              multiplication: function () {
                  var m, a, op, operation, isSpaced;
                  m = this.operand();
                  if (m) {
                      isSpaced = isWhitespace(input, i - 1);
                      while (true) {
                          if (peek(/^\/[*\/]/)) {
                              break;
                          }
                          op = $char('/') || $char('*');
  
                          if (!op) { break; }
  
                          a = this.operand();
  
                          if (!a) { break; }
  
                          m.parensInOp = true;
                          a.parensInOp = true;
                          operation = new(tree.Operation)(op, [operation || m, a], isSpaced);
                          isSpaced = isWhitespace(input, i - 1);
                      }
                      return operation || m;
                  }
              },
              addition: function () {
                  var m, a, op, operation, isSpaced;
                  m = this.multiplication();
                  if (m) {
                      isSpaced = isWhitespace(input, i - 1);
                      while (true) {
                          op = $re(/^[-+]\s+/) || (!isSpaced && ($char('+') || $char('-')));
                          if (!op) {
                              break;
                          }
                          a = this.multiplication();
                          if (!a) {
                              break;
                          }
                          
                          m.parensInOp = true;
                          a.parensInOp = true;
                          operation = new(tree.Operation)(op, [operation || m, a], isSpaced);
                          isSpaced = isWhitespace(input, i - 1);
                      }
                      return operation || m;
                  }
              },
              conditions: function () {
                  var a, b, index = i, condition;
  
                  a = this.condition();
                  if (a) {
                      while (true) {
                          if (!peek(/^,\s*(not\s*)?\(/) || !$char(',')) {
                              break;
                          }
                          b = this.condition();
                          if (!b) {
                              break;
                          }
                          condition = new(tree.Condition)('or', condition || a, b, index);
                      }
                      return condition || a;
                  }
              },
              condition: function () {
                  var entities = this.entities, index = i, negate = false,
                      a, b, c, op;
  
                  if ($re(/^not/)) { negate = true; }
                  expectChar('(');
                  a = this.addition() || entities.keyword() || entities.quoted();
                  if (a) {
                      op = $re(/^(?:>=|<=|=<|[<=>])/);
                      if (op) {
                          b = this.addition() || entities.keyword() || entities.quoted();
                          if (b) {
                              c = new(tree.Condition)(op, a, b, index, negate);
                          } else {
                              error('expected expression');
                          }
                      } else {
                          c = new(tree.Condition)('=', a, new(tree.Keyword)('true'), index, negate);
                      }
                      expectChar(')');
                      return $re(/^and/) ? new(tree.Condition)('and', c, this.condition()) : c;
                  }
              },
  
              //
              // An operand is anything that can be part of an operation,
              // such as a Color, or a Variable
              //
              operand: function () {
                  var entities = this.entities,
                      p = input.charAt(i + 1), negate;
  
                  if (input.charAt(i) === '-' && (p === '@' || p === '(')) { negate = $char('-'); }
                  var o = this.sub() || entities.dimension() ||
                          entities.color() || entities.variable() ||
                          entities.call();
  
                  if (negate) {
                      o.parensInOp = true;
                      o = new(tree.Negative)(o);
                  }
  
                  return o;
              },
  
              //
              // Expressions either represent mathematical operations,
              // or white-space delimited Entities.
              //
              //     1px solid black
              //     @var * 2
              //
              expression: function () {
                  var entities = [], e, delim;
  
                  do {
                      e = this.addition() || this.entity();
                      if (e) {
                          entities.push(e);
                          // operations do not allow keyword "/" dimension (e.g. small/20px) so we support that here
                          if (!peek(/^\/[\/*]/)) {
                              delim = $char('/');
                              if (delim) {
                                  entities.push(new(tree.Anonymous)(delim));
                              }
                          }
                      }
                  } while (e);
                  if (entities.length > 0) {
                      return new(tree.Expression)(entities);
                  }
              },
              property: function () {
                  var name = $re(/^(\*?-?[_a-zA-Z0-9-]+)\s*:/);
                  if (name) {
                      return name[1];
                  }
              },
              ruleProperty: function () {
                  var c = current, name = [], index = [], length = 0;
                  
                  function match(re) {
                      var a = re.exec(c);
                      if (a) {
                          index.push(i + length);
                          length += a[0].length;
                          c = c.slice(a[1].length);
                          return name.push(a[1]);
                      }
                  }
  
                  match(/^(\*?)/);
                  while (match(/^((?:[\w-]+)|(?:@\{[\w-]+\}))/)); // !
                  if ((name.length > 1) && match(/^\s*(\+?)\s*:/)) {
                      // at last, we have the complete match now. move forward, 
                      // convert @{var}s to tree.Variable(s) and return:
                      skipWhitespace(length);
                      for (var k in name) {
                          if (name[k].charAt(0) === '@') {
                              name[k] = new tree.Variable('@' + name[k].slice(2, -1), 
                                  index[k], env.currentFileInfo);
                          }
                      }
                      return name;
                  }
              }
          }
      };
      return parser;
  };
  less.Parser.serializeVars = function(vars) {
      var s = '';
  
      for (var name in vars) {
          if (Object.hasOwnProperty.call(vars, name)) {
              var value = vars[name];
              s += ((name[0] === '@') ? '' : '@') + name +': '+ value +
                      ((('' + value).slice(-1) === ';') ? '' : ';');
          }
      }
  
      return s;
  };
  (function (tree) {
  
  tree.functions = {
      rgb: function (r, g, b) {
          return this.rgba(r, g, b, 1.0);
      },
      rgba: function (r, g, b, a) {
          var rgb = [r, g, b].map(function (c) { return scaled(c, 255); });
          a = number(a);
          return new(tree.Color)(rgb, a);
      },
      hsl: function (h, s, l) {
          return this.hsla(h, s, l, 1.0);
      },
      hsla: function (h, s, l, a) {
          function hue(h) {
              h = h < 0 ? h + 1 : (h > 1 ? h - 1 : h);
              if      (h * 6 < 1) { return m1 + (m2 - m1) * h * 6; }
              else if (h * 2 < 1) { return m2; }
              else if (h * 3 < 2) { return m1 + (m2 - m1) * (2/3 - h) * 6; }
              else                { return m1; }
          }
  
          h = (number(h) % 360) / 360;
          s = clamp(number(s)); l = clamp(number(l)); a = clamp(number(a));
  
          var m2 = l <= 0.5 ? l * (s + 1) : l + s - l * s;
          var m1 = l * 2 - m2;
  
          return this.rgba(hue(h + 1/3) * 255,
                           hue(h)       * 255,
                           hue(h - 1/3) * 255,
                           a);
      },
  
      hsv: function(h, s, v) {
          return this.hsva(h, s, v, 1.0);
      },
  
      hsva: function(h, s, v, a) {
          h = ((number(h) % 360) / 360) * 360;
          s = number(s); v = number(v); a = number(a);
  
          var i, f;
          i = Math.floor((h / 60) % 6);
          f = (h / 60) - i;
  
          var vs = [v,
                    v * (1 - s),
                    v * (1 - f * s),
                    v * (1 - (1 - f) * s)];
          var perm = [[0, 3, 1],
                      [2, 0, 1],
                      [1, 0, 3],
                      [1, 2, 0],
                      [3, 1, 0],
                      [0, 1, 2]];
  
          return this.rgba(vs[perm[i][0]] * 255,
                           vs[perm[i][1]] * 255,
                           vs[perm[i][2]] * 255,
                           a);
      },
  
      hue: function (color) {
          return new(tree.Dimension)(Math.round(color.toHSL().h));
      },
      saturation: function (color) {
          return new(tree.Dimension)(Math.round(color.toHSL().s * 100), '%');
      },
      lightness: function (color) {
          return new(tree.Dimension)(Math.round(color.toHSL().l * 100), '%');
      },
      hsvhue: function(color) {
          return new(tree.Dimension)(Math.round(color.toHSV().h));
      },
      hsvsaturation: function (color) {
          return new(tree.Dimension)(Math.round(color.toHSV().s * 100), '%');
      },
      hsvvalue: function (color) {
          return new(tree.Dimension)(Math.round(color.toHSV().v * 100), '%');
      },
      red: function (color) {
          return new(tree.Dimension)(color.rgb[0]);
      },
      green: function (color) {
          return new(tree.Dimension)(color.rgb[1]);
      },
      blue: function (color) {
          return new(tree.Dimension)(color.rgb[2]);
      },
      alpha: function (color) {
          return new(tree.Dimension)(color.toHSL().a);
      },
      luma: function (color) {
          return new(tree.Dimension)(Math.round(color.luma() * color.alpha * 100), '%');
      },
      saturate: function (color, amount) {
          // filter: saturate(3.2);
          // should be kept as is, so check for color
          if (!color.rgb) {
              return null;
          }
          var hsl = color.toHSL();
  
          hsl.s += amount.value / 100;
          hsl.s = clamp(hsl.s);
          return hsla(hsl);
      },
      desaturate: function (color, amount) {
          var hsl = color.toHSL();
  
          hsl.s -= amount.value / 100;
          hsl.s = clamp(hsl.s);
          return hsla(hsl);
      },
      lighten: function (color, amount) {
          var hsl = color.toHSL();
  
          hsl.l += amount.value / 100;
          hsl.l = clamp(hsl.l);
          return hsla(hsl);
      },
      darken: function (color, amount) {
          var hsl = color.toHSL();
  
          hsl.l -= amount.value / 100;
          hsl.l = clamp(hsl.l);
          return hsla(hsl);
      },
      fadein: function (color, amount) {
          var hsl = color.toHSL();
  
          hsl.a += amount.value / 100;
          hsl.a = clamp(hsl.a);
          return hsla(hsl);
      },
      fadeout: function (color, amount) {
          var hsl = color.toHSL();
  
          hsl.a -= amount.value / 100;
          hsl.a = clamp(hsl.a);
          return hsla(hsl);
      },
      fade: function (color, amount) {
          var hsl = color.toHSL();
  
          hsl.a = amount.value / 100;
          hsl.a = clamp(hsl.a);
          return hsla(hsl);
      },
      spin: function (color, amount) {
          var hsl = color.toHSL();
          var hue = (hsl.h + amount.value) % 360;
  
          hsl.h = hue < 0 ? 360 + hue : hue;
  
          return hsla(hsl);
      },
      //
      // Copyright (c) 2006-2009 Hampton Catlin, Nathan Weizenbaum, and Chris Eppstein
      // http://sass-lang.com
      //
      mix: function (color1, color2, weight) {
          if (!weight) {
              weight = new(tree.Dimension)(50);
          }
          var p = weight.value / 100.0;
          var w = p * 2 - 1;
          var a = color1.toHSL().a - color2.toHSL().a;
  
          var w1 = (((w * a == -1) ? w : (w + a) / (1 + w * a)) + 1) / 2.0;
          var w2 = 1 - w1;
  
          var rgb = [color1.rgb[0] * w1 + color2.rgb[0] * w2,
                     color1.rgb[1] * w1 + color2.rgb[1] * w2,
                     color1.rgb[2] * w1 + color2.rgb[2] * w2];
  
          var alpha = color1.alpha * p + color2.alpha * (1 - p);
  
          return new(tree.Color)(rgb, alpha);
      },
      greyscale: function (color) {
          return this.desaturate(color, new(tree.Dimension)(100));
      },
      contrast: function (color, dark, light, threshold) {
          // filter: contrast(3.2);
          // should be kept as is, so check for color
          if (!color.rgb) {
              return null;
          }
          if (typeof light === 'undefined') {
              light = this.rgba(255, 255, 255, 1.0);
          }
          if (typeof dark === 'undefined') {
              dark = this.rgba(0, 0, 0, 1.0);
          }
          //Figure out which is actually light and dark!
          if (dark.luma() > light.luma()) {
              var t = light;
              light = dark;
              dark = t;
          }
          if (typeof threshold === 'undefined') {
              threshold = 0.43;
          } else {
              threshold = number(threshold);
          }
          if (color.luma() < threshold) {
              return light;
          } else {
              return dark;
          }
      },
      e: function (str) {
          return new(tree.Anonymous)(str instanceof tree.JavaScript ? str.evaluated : str);
      },
      escape: function (str) {
          return new(tree.Anonymous)(encodeURI(str.value).replace(/=/g, "%3D").replace(/:/g, "%3A").replace(/#/g, "%23").replace(/;/g, "%3B").replace(/\(/g, "%28").replace(/\)/g, "%29"));
      },
      '%': function (quoted /* arg, arg, ...*/) {
          var args = Array.prototype.slice.call(arguments, 1),
              str = quoted.value;
  
          for (var i = 0; i < args.length; i++) {
              /*jshint loopfunc:true */
              str = str.replace(/%[sda]/i, function(token) {
                  var value = token.match(/s/i) ? args[i].value : args[i].toCSS();
                  return token.match(/[A-Z]$/) ? encodeURIComponent(value) : value;
              });
          }
          str = str.replace(/%%/g, '%');
          return new(tree.Quoted)('"' + str + '"', str);
      },
      unit: function (val, unit) {
          if(!(val instanceof tree.Dimension)) {
              throw { type: "Argument", message: "the first argument to unit must be a number" + (val instanceof tree.Operation ? ". Have you forgotten parenthesis?" : "") };
          }
          return new(tree.Dimension)(val.value, unit ? unit.toCSS() : "");
      },
      convert: function (val, unit) {
          return val.convertTo(unit.value);
      },
      round: function (n, f) {
          var fraction = typeof(f) === "undefined" ? 0 : f.value;
          return _math(function(num) { return num.toFixed(fraction); }, null, n);
      },
      pi: function () {
          return new(tree.Dimension)(Math.PI);
      },
      mod: function(a, b) {
          return new(tree.Dimension)(a.value % b.value, a.unit);
      },
      pow: function(x, y) {
          if (typeof x === "number" && typeof y === "number") {
              x = new(tree.Dimension)(x);
              y = new(tree.Dimension)(y);
          } else if (!(x instanceof tree.Dimension) || !(y instanceof tree.Dimension)) {
              throw { type: "Argument", message: "arguments must be numbers" };
          }
  
          return new(tree.Dimension)(Math.pow(x.value, y.value), x.unit);
      },
      _minmax: function (isMin, args) {
          args = Array.prototype.slice.call(args);
          switch(args.length) {
          case 0: throw { type: "Argument", message: "one or more arguments required" };
          case 1: return args[0];
          }
          var i, j, current, currentUnified, referenceUnified, unit,
              order  = [], // elems only contains original argument values.
              values = {}; // key is the unit.toString() for unified tree.Dimension values,
                           // value is the index into the order array.
          for (i = 0; i < args.length; i++) {
              current = args[i];
              if (!(current instanceof tree.Dimension)) {
                  order.push(current);
                  continue;
              }
              currentUnified = current.unify();
              unit = currentUnified.unit.toString();
              j = values[unit];
              if (j === undefined) {
                  values[unit] = order.length;
                  order.push(current);
                  continue;
              }
              referenceUnified = order[j].unify();
              if ( isMin && currentUnified.value < referenceUnified.value ||
                  !isMin && currentUnified.value > referenceUnified.value) {
                  order[j] = current;
              }
          }
          if (order.length == 1) {
              return order[0];
          }
          args = order.map(function (a) { return a.toCSS(this.env); })
                      .join(this.env.compress ? "," : ", ");
          return new(tree.Anonymous)((isMin ? "min" : "max") + "(" + args + ")");
      },
      min: function () {
          return this._minmax(true, arguments);
      },
      max: function () {
          return this._minmax(false, arguments);
      },
      argb: function (color) {
          return new(tree.Anonymous)(color.toARGB());
      },
      percentage: function (n) {
          return new(tree.Dimension)(n.value * 100, '%');
      },
      color: function (n) {
          if (n instanceof tree.Quoted) {
              var colorCandidate = n.value,
                  returnColor;
              returnColor = tree.Color.fromKeyword(colorCandidate);
              if (returnColor) {
                  return returnColor;
              }
              if (/^#([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})/.test(colorCandidate)) {
                  return new(tree.Color)(colorCandidate.slice(1));
              }
              throw { type: "Argument", message: "argument must be a color keyword or 3/6 digit hex e.g. #FFF" };
          } else {
              throw { type: "Argument", message: "argument must be a string" };
          }
      },
      iscolor: function (n) {
          return this._isa(n, tree.Color);
      },
      isnumber: function (n) {
          return this._isa(n, tree.Dimension);
      },
      isstring: function (n) {
          return this._isa(n, tree.Quoted);
      },
      iskeyword: function (n) {
          return this._isa(n, tree.Keyword);
      },
      isurl: function (n) {
          return this._isa(n, tree.URL);
      },
      ispixel: function (n) {
          return this.isunit(n, 'px');
      },
      ispercentage: function (n) {
          return this.isunit(n, '%');
      },
      isem: function (n) {
          return this.isunit(n, 'em');
      },
      isunit: function (n, unit) {
          return (n instanceof tree.Dimension) && n.unit.is(unit.value || unit) ? tree.True : tree.False;
      },
      _isa: function (n, Type) {
          return (n instanceof Type) ? tree.True : tree.False;
      },
      tint: function(color, amount) {
          return this.mix(this.rgb(255,255,255), color, amount);
      },
      shade: function(color, amount) {
          return this.mix(this.rgb(0, 0, 0), color, amount);
      },   
      extract: function(values, index) {
          index = index.value - 1; // (1-based index)       
          // handle non-array values as an array of length 1
          // return 'undefined' if index is invalid
          return Array.isArray(values.value) 
              ? values.value[index] : Array(values)[index];
      },
      length: function(values) {
          var n = Array.isArray(values.value) ? values.value.length : 1;
          return new tree.Dimension(n);
      },
  
      "data-uri": function(mimetypeNode, filePathNode) {
  
          if (typeof window !== 'undefined') {
              return new tree.URL(filePathNode || mimetypeNode, this.currentFileInfo).eval(this.env);
          }
  
          var mimetype = mimetypeNode.value;
          var filePath = (filePathNode && filePathNode.value);
  
          var fs = require("fs"),
              path = require("path"),
              useBase64 = false;
  
          if (arguments.length < 2) {
              filePath = mimetype;
          }
  
          if (this.env.isPathRelative(filePath)) {
              if (this.currentFileInfo.relativeUrls) {
                  filePath = path.join(this.currentFileInfo.currentDirectory, filePath);
              } else {
                  filePath = path.join(this.currentFileInfo.entryPath, filePath);
              }
          }
  
          // detect the mimetype if not given
          if (arguments.length < 2) {
              var mime;
              try {
                  mime = require('mime');
              } catch (ex) {
                  mime = tree._mime;
              }
  
              mimetype = mime.lookup(filePath);
  
              // use base 64 unless it's an ASCII or UTF-8 format
              var charset = mime.charsets.lookup(mimetype);
              useBase64 = ['US-ASCII', 'UTF-8'].indexOf(charset) < 0;
              if (useBase64) { mimetype += ';base64'; }
          }
          else {
              useBase64 = /;base64$/.test(mimetype);
          }
  
          var buf = fs.readFileSync(filePath);
  
          // IE8 cannot handle a data-uri larger than 32KB. If this is exceeded
          // and the --ieCompat flag is enabled, return a normal url() instead.
          var DATA_URI_MAX_KB = 32,
              fileSizeInKB = parseInt((buf.length / 1024), 10);
          if (fileSizeInKB >= DATA_URI_MAX_KB) {
  
              if (this.env.ieCompat !== false) {
                  if (!this.env.silent) {
                      console.warn("Skipped data-uri embedding of %s because its size (%dKB) exceeds IE8-safe %dKB!", filePath, fileSizeInKB, DATA_URI_MAX_KB);
                  }
  
                  return new tree.URL(filePathNode || mimetypeNode, this.currentFileInfo).eval(this.env);
              }
          }
  
          buf = useBase64 ? buf.toString('base64')
                          : encodeURIComponent(buf);
  
          var uri = "'data:" + mimetype + ',' + buf + "'";
          return new(tree.URL)(new(tree.Anonymous)(uri));
      },
  
      "svg-gradient": function(direction) {
  
          function throwArgumentDescriptor() {
              throw { type: "Argument", message: "svg-gradient expects direction, start_color [start_position], [color position,]..., end_color [end_position]" };
          }
  
          if (arguments.length < 3) {
              throwArgumentDescriptor();
          }
          var stops = Array.prototype.slice.call(arguments, 1),
              gradientDirectionSvg,
              gradientType = "linear",
              rectangleDimension = 'x="0" y="0" width="1" height="1"',
              useBase64 = true,
              renderEnv = {compress: false},
              returner,
              directionValue = direction.toCSS(renderEnv),
              i, color, position, positionValue, alpha;
  
          switch (directionValue) {
              case "to bottom":
                  gradientDirectionSvg = 'x1="0%" y1="0%" x2="0%" y2="100%"';
                  break;
              case "to right":
                  gradientDirectionSvg = 'x1="0%" y1="0%" x2="100%" y2="0%"';
                  break;
              case "to bottom right":
                  gradientDirectionSvg = 'x1="0%" y1="0%" x2="100%" y2="100%"';
                  break;
              case "to top right":
                  gradientDirectionSvg = 'x1="0%" y1="100%" x2="100%" y2="0%"';
                  break;
              case "ellipse":
              case "ellipse at center":
                  gradientType = "radial";
                  gradientDirectionSvg = 'cx="50%" cy="50%" r="75%"';
                  rectangleDimension = 'x="-50" y="-50" width="101" height="101"';
                  break;
              default:
                  throw { type: "Argument", message: "svg-gradient direction must be 'to bottom', 'to right', 'to bottom right', 'to top right' or 'ellipse at center'" };
          }
          returner = '<?xml version="1.0" ?>' +
              '<svg xmlns="http://www.w3.org/2000/svg" version="1.1" width="100%" height="100%" viewBox="0 0 1 1" preserveAspectRatio="none">' +
              '<' + gradientType + 'Gradient id="gradient" gradientUnits="userSpaceOnUse" ' + gradientDirectionSvg + '>';
  
          for (i = 0; i < stops.length; i+= 1) {
              if (stops[i].value) {
                  color = stops[i].value[0];
                  position = stops[i].value[1];
              } else {
                  color = stops[i];
                  position = undefined;
              }
  
              if (!(color instanceof tree.Color) || (!((i === 0 || i+1 === stops.length) && position === undefined) && !(position instanceof tree.Dimension))) {
                  throwArgumentDescriptor();
              }
              positionValue = position ? position.toCSS(renderEnv) : i === 0 ? "0%" : "100%";
              alpha = color.alpha;
              returner += '<stop offset="' + positionValue + '" stop-color="' + color.toRGB() + '"' + (alpha < 1 ? ' stop-opacity="' + alpha + '"' : '') + '/>';
          }
          returner += '</' + gradientType + 'Gradient>' +
                      '<rect ' + rectangleDimension + ' fill="url(#gradient)" /></svg>';
  
          if (useBase64) {
              // only works in node, needs interface to what is supported in environment
              try {
                  returner = new Buffer(returner).toString('base64');
              } catch(e) {
                  useBase64 = false;
              }
          }
  
          returner = "'data:image/svg+xml" + (useBase64 ? ";base64" : "") + "," + returner + "'";
          return new(tree.URL)(new(tree.Anonymous)(returner));
      }
  };
  
  // these static methods are used as a fallback when the optional 'mime' dependency is missing
  tree._mime = {
      // this map is intentionally incomplete
      // if you want more, install 'mime' dep
      _types: {
          '.htm' : 'text/html',
          '.html': 'text/html',
          '.gif' : 'image/gif',
          '.jpg' : 'image/jpeg',
          '.jpeg': 'image/jpeg',
          '.png' : 'image/png'
      },
      lookup: function (filepath) {
          var ext = require('path').extname(filepath),
              type = tree._mime._types[ext];
          if (type === undefined) {
              throw new Error('Optional dependency "mime" is required for ' + ext);
          }
          return type;
      },
      charsets: {
          lookup: function (type) {
              // assumes all text types are UTF-8
              return type && (/^text\//).test(type) ? 'UTF-8' : '';
          }
      }
  };
  
  // Math
  
  var mathFunctions = {
   // name,  unit
      ceil:  null, 
      floor: null, 
      sqrt:  null, 
      abs:   null,
      tan:   "", 
      sin:   "", 
      cos:   "",
      atan:  "rad", 
      asin:  "rad", 
      acos:  "rad"
  };
  
  function _math(fn, unit, n) {
      if (!(n instanceof tree.Dimension)) {
          throw { type: "Argument", message: "argument must be a number" };
      }
      if (unit == null) {
          unit = n.unit;
      } else {
          n = n.unify();
      }
      return new(tree.Dimension)(fn(parseFloat(n.value)), unit);
  }
  
  // ~ End of Math
  
  // Color Blending
  // ref: http://www.w3.org/TR/compositing-1
  
  function colorBlend(mode, color1, color2) {
      var ab = color1.alpha, cb, // backdrop
          as = color2.alpha, cs, // source
          ar, cr, r = [];        // result
          
      ar = as + ab * (1 - as);
      for (var i = 0; i < 3; i++) {
          cb = color1.rgb[i] / 255;
          cs = color2.rgb[i] / 255;
          cr = mode(cb, cs);
          if (ar) {
              cr = (as * cs + ab * (cb 
                  - as * (cb + cs - cr))) / ar;
          }
          r[i] = cr * 255;
      }
      
      return new(tree.Color)(r, ar);
  }
  
  var colorBlendMode = {
      multiply: function(cb, cs) {
          return cb * cs;
      },
      screen: function(cb, cs) {
          return cb + cs - cb * cs;
      },   
      overlay: function(cb, cs) {
          cb *= 2;
          return (cb <= 1)
              ? colorBlendMode.multiply(cb, cs)
              : colorBlendMode.screen(cb - 1, cs);
      },
      softlight: function(cb, cs) {
          var d = 1, e = cb;
          if (cs > 0.5) {
              e = 1;
              d = (cb > 0.25) ? Math.sqrt(cb)
                  : ((16 * cb - 12) * cb + 4) * cb;
          }            
          return cb - (1 - 2 * cs) * e * (d - cb);
      },
      hardlight: function(cb, cs) {
          return colorBlendMode.overlay(cs, cb);
      },
      difference: function(cb, cs) {
          return Math.abs(cb - cs);
      },
      exclusion: function(cb, cs) {
          return cb + cs - 2 * cb * cs;
      },
  
      // non-w3c functions:
      average: function(cb, cs) {
          return (cb + cs) / 2;
      },
      negation: function(cb, cs) {
          return 1 - Math.abs(cb + cs - 1);
      }
  };
  
  // ~ End of Color Blending
  
  tree.defaultFunc = {
      eval: function () {
          var v = this.value_, e = this.error_;
          if (e) {
              throw e;
          }
          if (v != null) {
              return v ? tree.True : tree.False;
          }
      },
      value: function (v) {
          this.value_ = v;
      },
      error: function (e) {
          this.error_ = e;
      },
      reset: function () {
          this.value_ = this.error_ = null;
      }
  };
  
  function initFunctions() {
      var f, tf = tree.functions;
      
      // math
      for (f in mathFunctions) {
          tf[f] = _math.bind(null, Math[f], mathFunctions[f]);
      }
      
      // color blending
      for (f in colorBlendMode) {
          tf[f] = colorBlend.bind(null, colorBlendMode[f]);
      }
      
      // default
      f = tree.defaultFunc;
      tf.default = f.eval.bind(f);
      
  } initFunctions();
  
  function hsla(color) {
      return tree.functions.hsla(color.h, color.s, color.l, color.a);
  }
  
  function scaled(n, size) {
      if (n instanceof tree.Dimension && n.unit.is('%')) {
          return parseFloat(n.value * size / 100);
      } else {
          return number(n);
      }
  }
  
  function number(n) {
      if (n instanceof tree.Dimension) {
          return parseFloat(n.unit.is('%') ? n.value / 100 : n.value);
      } else if (typeof(n) === 'number') {
          return n;
      } else {
          throw {
              error: "RuntimeError",
              message: "color functions take numbers as parameters"
          };
      }
  }
  
  function clamp(val) {
      return Math.min(1, Math.max(0, val));
  }
  
  tree.functionCall = function(env, currentFileInfo) {
      this.env = env;
      this.currentFileInfo = currentFileInfo;
  };
  
  tree.functionCall.prototype = tree.functions;
  
  })(require('./tree'));
  
  (function (tree) {
      tree.colors = {
          'aliceblue':'#f0f8ff',
          'antiquewhite':'#faebd7',
          'aqua':'#00ffff',
          'aquamarine':'#7fffd4',
          'azure':'#f0ffff',
          'beige':'#f5f5dc',
          'bisque':'#ffe4c4',
          'black':'#000000',
          'blanchedalmond':'#ffebcd',
          'blue':'#0000ff',
          'blueviolet':'#8a2be2',
          'brown':'#a52a2a',
          'burlywood':'#deb887',
          'cadetblue':'#5f9ea0',
          'chartreuse':'#7fff00',
          'chocolate':'#d2691e',
          'coral':'#ff7f50',
          'cornflowerblue':'#6495ed',
          'cornsilk':'#fff8dc',
          'crimson':'#dc143c',
          'cyan':'#00ffff',
          'darkblue':'#00008b',
          'darkcyan':'#008b8b',
          'darkgoldenrod':'#b8860b',
          'darkgray':'#a9a9a9',
          'darkgrey':'#a9a9a9',
          'darkgreen':'#006400',
          'darkkhaki':'#bdb76b',
          'darkmagenta':'#8b008b',
          'darkolivegreen':'#556b2f',
          'darkorange':'#ff8c00',
          'darkorchid':'#9932cc',
          'darkred':'#8b0000',
          'darksalmon':'#e9967a',
          'darkseagreen':'#8fbc8f',
          'darkslateblue':'#483d8b',
          'darkslategray':'#2f4f4f',
          'darkslategrey':'#2f4f4f',
          'darkturquoise':'#00ced1',
          'darkviolet':'#9400d3',
          'deeppink':'#ff1493',
          'deepskyblue':'#00bfff',
          'dimgray':'#696969',
          'dimgrey':'#696969',
          'dodgerblue':'#1e90ff',
          'firebrick':'#b22222',
          'floralwhite':'#fffaf0',
          'forestgreen':'#228b22',
          'fuchsia':'#ff00ff',
          'gainsboro':'#dcdcdc',
          'ghostwhite':'#f8f8ff',
          'gold':'#ffd700',
          'goldenrod':'#daa520',
          'gray':'#808080',
          'grey':'#808080',
          'green':'#008000',
          'greenyellow':'#adff2f',
          'honeydew':'#f0fff0',
          'hotpink':'#ff69b4',
          'indianred':'#cd5c5c',
          'indigo':'#4b0082',
          'ivory':'#fffff0',
          'khaki':'#f0e68c',
          'lavender':'#e6e6fa',
          'lavenderblush':'#fff0f5',
          'lawngreen':'#7cfc00',
          'lemonchiffon':'#fffacd',
          'lightblue':'#add8e6',
          'lightcoral':'#f08080',
          'lightcyan':'#e0ffff',
          'lightgoldenrodyellow':'#fafad2',
          'lightgray':'#d3d3d3',
          'lightgrey':'#d3d3d3',
          'lightgreen':'#90ee90',
          'lightpink':'#ffb6c1',
          'lightsalmon':'#ffa07a',
          'lightseagreen':'#20b2aa',
          'lightskyblue':'#87cefa',
          'lightslategray':'#778899',
          'lightslategrey':'#778899',
          'lightsteelblue':'#b0c4de',
          'lightyellow':'#ffffe0',
          'lime':'#00ff00',
          'limegreen':'#32cd32',
          'linen':'#faf0e6',
          'magenta':'#ff00ff',
          'maroon':'#800000',
          'mediumaquamarine':'#66cdaa',
          'mediumblue':'#0000cd',
          'mediumorchid':'#ba55d3',
          'mediumpurple':'#9370d8',
          'mediumseagreen':'#3cb371',
          'mediumslateblue':'#7b68ee',
          'mediumspringgreen':'#00fa9a',
          'mediumturquoise':'#48d1cc',
          'mediumvioletred':'#c71585',
          'midnightblue':'#191970',
          'mintcream':'#f5fffa',
          'mistyrose':'#ffe4e1',
          'moccasin':'#ffe4b5',
          'navajowhite':'#ffdead',
          'navy':'#000080',
          'oldlace':'#fdf5e6',
          'olive':'#808000',
          'olivedrab':'#6b8e23',
          'orange':'#ffa500',
          'orangered':'#ff4500',
          'orchid':'#da70d6',
          'palegoldenrod':'#eee8aa',
          'palegreen':'#98fb98',
          'paleturquoise':'#afeeee',
          'palevioletred':'#d87093',
          'papayawhip':'#ffefd5',
          'peachpuff':'#ffdab9',
          'peru':'#cd853f',
          'pink':'#ffc0cb',
          'plum':'#dda0dd',
          'powderblue':'#b0e0e6',
          'purple':'#800080',
          'red':'#ff0000',
          'rosybrown':'#bc8f8f',
          'royalblue':'#4169e1',
          'saddlebrown':'#8b4513',
          'salmon':'#fa8072',
          'sandybrown':'#f4a460',
          'seagreen':'#2e8b57',
          'seashell':'#fff5ee',
          'sienna':'#a0522d',
          'silver':'#c0c0c0',
          'skyblue':'#87ceeb',
          'slateblue':'#6a5acd',
          'slategray':'#708090',
          'slategrey':'#708090',
          'snow':'#fffafa',
          'springgreen':'#00ff7f',
          'steelblue':'#4682b4',
          'tan':'#d2b48c',
          'teal':'#008080',
          'thistle':'#d8bfd8',
          'tomato':'#ff6347',
          'turquoise':'#40e0d0',
          'violet':'#ee82ee',
          'wheat':'#f5deb3',
          'white':'#ffffff',
          'whitesmoke':'#f5f5f5',
          'yellow':'#ffff00',
          'yellowgreen':'#9acd32'
      };
  })(require('./tree'));
  
  (function (tree) {
  
  tree.debugInfo = function(env, ctx, lineSeperator) {
      var result="";
      if (env.dumpLineNumbers && !env.compress) {
          switch(env.dumpLineNumbers) {
              case 'comments':
                  result = tree.debugInfo.asComment(ctx);
                  break;
              case 'mediaquery':
                  result = tree.debugInfo.asMediaQuery(ctx);
                  break;
              case 'all':
                  result = tree.debugInfo.asComment(ctx) + (lineSeperator || "") + tree.debugInfo.asMediaQuery(ctx);
                  break;
          }
      }
      return result;
  };
  
  tree.debugInfo.asComment = function(ctx) {
      return '/* line ' + ctx.debugInfo.lineNumber + ', ' + ctx.debugInfo.fileName + ' */\n';
  };
  
  tree.debugInfo.asMediaQuery = function(ctx) {
      return '@media -sass-debug-info{filename{font-family:' +
          ('file://' + ctx.debugInfo.fileName).replace(/([.:/\\])/g, function (a) {
              if (a == '\\') {
                  a = '\/';
              }
              return '\\' + a;
          }) +
          '}line{font-family:\\00003' + ctx.debugInfo.lineNumber + '}}\n';
  };
  
  tree.find = function (obj, fun) {
      for (var i = 0, r; i < obj.length; i++) {
          r = fun.call(obj, obj[i]);
          if (r) { return r; }
      }
      return null;
  };
  
  tree.jsify = function (obj) {
      if (Array.isArray(obj.value) && (obj.value.length > 1)) {
          return '[' + obj.value.map(function (v) { return v.toCSS(false); }).join(', ') + ']';
      } else {
          return obj.toCSS(false);
      }
  };
  
  tree.toCSS = function (env) {
      var strs = [];
      this.genCSS(env, {
          add: function(chunk, fileInfo, index) {
              strs.push(chunk);
          },
          isEmpty: function () {
              return strs.length === 0;
          }
      });
      return strs.join('');
  };
  
  tree.outputRuleset = function (env, output, rules) {
      var ruleCnt = rules.length, i;
      env.tabLevel = (env.tabLevel | 0) + 1;
  
      // Compressed
      if (env.compress) {
          output.add('{');
          for (i = 0; i < ruleCnt; i++) {
              rules[i].genCSS(env, output);
          }
          output.add('}');
          env.tabLevel--;
          return;
      }
  
      // Non-compressed
      var tabSetStr = '\n' + Array(env.tabLevel).join("  "), tabRuleStr = tabSetStr + "  ";
      if (!ruleCnt) {
          output.add(" {" + tabSetStr + '}');
      } else {
          output.add(" {" + tabRuleStr);
          rules[0].genCSS(env, output);
          for (i = 1; i < ruleCnt; i++) {
              output.add(tabRuleStr);
              rules[i].genCSS(env, output);
          }
          output.add(tabSetStr + '}');
      }
  
      env.tabLevel--;
  };
  
  })(require('./tree'));
  
  (function (tree) {
  
  tree.Alpha = function (val) {
      this.value = val;
  };
  tree.Alpha.prototype = {
      type: "Alpha",
      accept: function (visitor) {
          this.value = visitor.visit(this.value);
      },
      eval: function (env) {
          if (this.value.eval) { return new tree.Alpha(this.value.eval(env)); }
          return this;
      },
      genCSS: function (env, output) {
          output.add("alpha(opacity=");
  
          if (this.value.genCSS) {
              this.value.genCSS(env, output);
          } else {
              output.add(this.value);
          }
  
          output.add(")");
      },
      toCSS: tree.toCSS
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Anonymous = function (string, index, currentFileInfo, mapLines) {
      this.value = string.value || string;
      this.index = index;
      this.mapLines = mapLines;
      this.currentFileInfo = currentFileInfo;
  };
  tree.Anonymous.prototype = {
      type: "Anonymous",
      eval: function () { 
          return new tree.Anonymous(this.value, this.index, this.currentFileInfo, this.mapLines);
      },
      compare: function (x) {
          if (!x.toCSS) {
              return -1;
          }
          
          var left = this.toCSS(),
              right = x.toCSS();
          
          if (left === right) {
              return 0;
          }
          
          return left < right ? -1 : 1;
      },
      genCSS: function (env, output) {
          output.add(this.value, this.currentFileInfo, this.index, this.mapLines);
      },
      toCSS: tree.toCSS
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Assignment = function (key, val) {
      this.key = key;
      this.value = val;
  };
  tree.Assignment.prototype = {
      type: "Assignment",
      accept: function (visitor) {
          this.value = visitor.visit(this.value);
      },
      eval: function (env) {
          if (this.value.eval) {
              return new(tree.Assignment)(this.key, this.value.eval(env));
          }
          return this;
      },
      genCSS: function (env, output) {
          output.add(this.key + '=');
          if (this.value.genCSS) {
              this.value.genCSS(env, output);
          } else {
              output.add(this.value);
          }
      },
      toCSS: tree.toCSS
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  //
  // A function call node.
  //
  tree.Call = function (name, args, index, currentFileInfo) {
      this.name = name;
      this.args = args;
      this.index = index;
      this.currentFileInfo = currentFileInfo;
  };
  tree.Call.prototype = {
      type: "Call",
      accept: function (visitor) {
          if (this.args) {
              this.args = visitor.visitArray(this.args);
          }
      },
      //
      // When evaluating a function call,
      // we either find the function in `tree.functions` [1],
      // in which case we call it, passing the  evaluated arguments,
      // if this returns null or we cannot find the function, we 
      // simply print it out as it appeared originally [2].
      //
      // The *functions.js* file contains the built-in functions.
      //
      // The reason why we evaluate the arguments, is in the case where
      // we try to pass a variable to a function, like: `saturate(@color)`.
      // The function should receive the value, not the variable.
      //
      eval: function (env) {
          var args = this.args.map(function (a) { return a.eval(env); }),
              nameLC = this.name.toLowerCase(),
              result, func;
  
          if (nameLC in tree.functions) { // 1.
              try {
                  func = new tree.functionCall(env, this.currentFileInfo);
                  result = func[nameLC].apply(func, args);
                  if (result != null) {
                      return result;
                  }
              } catch (e) {
                  throw { type: e.type || "Runtime",
                          message: "error evaluating function `" + this.name + "`" +
                                   (e.message ? ': ' + e.message : ''),
                          index: this.index, filename: this.currentFileInfo.filename };
              }
          }
  
          return new tree.Call(this.name, args, this.index, this.currentFileInfo);
      },
  
      genCSS: function (env, output) {
          output.add(this.name + "(", this.currentFileInfo, this.index);
  
          for(var i = 0; i < this.args.length; i++) {
              this.args[i].genCSS(env, output);
              if (i + 1 < this.args.length) {
                  output.add(", ");
              }
          }
  
          output.add(")");
      },
  
      toCSS: tree.toCSS
  };
  
  })(require('../tree'));
  
  (function (tree) {
  //
  // RGB Colors - #ff0014, #eee
  //
  tree.Color = function (rgb, a) {
      //
      // The end goal here, is to parse the arguments
      // into an integer triplet, such as `128, 255, 0`
      //
      // This facilitates operations and conversions.
      //
      if (Array.isArray(rgb)) {
          this.rgb = rgb;
      } else if (rgb.length == 6) {
          this.rgb = rgb.match(/.{2}/g).map(function (c) {
              return parseInt(c, 16);
          });
      } else {
          this.rgb = rgb.split('').map(function (c) {
              return parseInt(c + c, 16);
          });
      }
      this.alpha = typeof(a) === 'number' ? a : 1;
  };
  
  var transparentKeyword = "transparent";
  
  tree.Color.prototype = {
      type: "Color",
      eval: function () { return this; },
      luma: function () { return (0.2126 * this.rgb[0] / 255) + (0.7152 * this.rgb[1] / 255) + (0.0722 * this.rgb[2] / 255); },
  
      genCSS: function (env, output) {
          output.add(this.toCSS(env));
      },
      toCSS: function (env, doNotCompress) {
          var compress = env && env.compress && !doNotCompress;
  
          // If we have some transparency, the only way to represent it
          // is via `rgba`. Otherwise, we use the hex representation,
          // which has better compatibility with older browsers.
          // Values are capped between `0` and `255`, rounded and zero-padded.
          if (this.alpha < 1) {
              if (this.alpha === 0 && this.isTransparentKeyword) {
                  return transparentKeyword;
              }
              return "rgba(" + this.rgb.map(function (c) {
                  return clamp(Math.round(c), 255);
              }).concat(clamp(this.alpha, 1))
                  .join(',' + (compress ? '' : ' ')) + ")";
          } else {
              var color = this.toRGB();
  
              if (compress) {
                  var splitcolor = color.split('');
  
                  // Convert color to short format
                  if (splitcolor[1] === splitcolor[2] && splitcolor[3] === splitcolor[4] && splitcolor[5] === splitcolor[6]) {
                      color = '#' + splitcolor[1] + splitcolor[3] + splitcolor[5];
                  }
              }
  
              return color;
          }
      },
  
      //
      // Operations have to be done per-channel, if not,
      // channels will spill onto each other. Once we have
      // our result, in the form of an integer triplet,
      // we create a new Color node to hold the result.
      //
      operate: function (env, op, other) {
          var rgb = [];
          var alpha = this.alpha * (1 - other.alpha) + other.alpha;
          for (var c = 0; c < 3; c++) {
              rgb[c] = tree.operate(env, op, this.rgb[c], other.rgb[c]);
          }
          return new(tree.Color)(rgb, alpha);
      },
  
      toRGB: function () {
          return toHex(this.rgb);
      },
  
      toHSL: function () {
          var r = this.rgb[0] / 255,
              g = this.rgb[1] / 255,
              b = this.rgb[2] / 255,
              a = this.alpha;
  
          var max = Math.max(r, g, b), min = Math.min(r, g, b);
          var h, s, l = (max + min) / 2, d = max - min;
  
          if (max === min) {
              h = s = 0;
          } else {
              s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
  
              switch (max) {
                  case r: h = (g - b) / d + (g < b ? 6 : 0); break;
                  case g: h = (b - r) / d + 2;               break;
                  case b: h = (r - g) / d + 4;               break;
              }
              h /= 6;
          }
          return { h: h * 360, s: s, l: l, a: a };
      },
      //Adapted from http://mjijackson.com/2008/02/rgb-to-hsl-and-rgb-to-hsv-color-model-conversion-algorithms-in-javascript
      toHSV: function () {
          var r = this.rgb[0] / 255,
              g = this.rgb[1] / 255,
              b = this.rgb[2] / 255,
              a = this.alpha;
  
          var max = Math.max(r, g, b), min = Math.min(r, g, b);
          var h, s, v = max;
  
          var d = max - min;
          if (max === 0) {
              s = 0;
          } else {
              s = d / max;
          }
  
          if (max === min) {
              h = 0;
          } else {
              switch(max){
                  case r: h = (g - b) / d + (g < b ? 6 : 0); break;
                  case g: h = (b - r) / d + 2; break;
                  case b: h = (r - g) / d + 4; break;
              }
              h /= 6;
          }
          return { h: h * 360, s: s, v: v, a: a };
      },
      toARGB: function () {
          return toHex([this.alpha * 255].concat(this.rgb));
      },
      compare: function (x) {
          if (!x.rgb) {
              return -1;
          }
          
          return (x.rgb[0] === this.rgb[0] &&
              x.rgb[1] === this.rgb[1] &&
              x.rgb[2] === this.rgb[2] &&
              x.alpha === this.alpha) ? 0 : -1;
      }
  };
  
  tree.Color.fromKeyword = function(keyword) {
      if (tree.colors.hasOwnProperty(keyword)) {
          // detect named color
          return new(tree.Color)(tree.colors[keyword].slice(1));
      }
      if (keyword === transparentKeyword) {
          var transparent = new(tree.Color)([0, 0, 0], 0);
          transparent.isTransparentKeyword = true;
          return transparent;
      }
  };
  
  function toHex(v) {
      return '#' + v.map(function (c) {
          c = clamp(Math.round(c), 255);
          return (c < 16 ? '0' : '') + c.toString(16);
      }).join('');
  }
  
  function clamp(v, max) {
      return Math.min(Math.max(v, 0), max); 
  }
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Comment = function (value, silent, index, currentFileInfo) {
      this.value = value;
      this.silent = !!silent;
      this.currentFileInfo = currentFileInfo;
  };
  tree.Comment.prototype = {
      type: "Comment",
      genCSS: function (env, output) {
          if (this.debugInfo) {
              output.add(tree.debugInfo(env, this), this.currentFileInfo, this.index);
          }
          output.add(this.value.trim()); //TODO shouldn't need to trim, we shouldn't grab the \n
      },
      toCSS: tree.toCSS,
      isSilent: function(env) {
          var isReference = (this.currentFileInfo && this.currentFileInfo.reference && !this.isReferenced),
              isCompressed = env.compress && !this.value.match(/^\/\*!/);
          return this.silent || isReference || isCompressed;
      },
      eval: function () { return this; },
      markReferenced: function () {
          this.isReferenced = true;
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Condition = function (op, l, r, i, negate) {
      this.op = op.trim();
      this.lvalue = l;
      this.rvalue = r;
      this.index = i;
      this.negate = negate;
  };
  tree.Condition.prototype = {
      type: "Condition",
      accept: function (visitor) {
          this.lvalue = visitor.visit(this.lvalue);
          this.rvalue = visitor.visit(this.rvalue);
      },
      eval: function (env) {
          var a = this.lvalue.eval(env),
              b = this.rvalue.eval(env);
  
          var i = this.index, result;
  
          result = (function (op) {
              switch (op) {
                  case 'and':
                      return a && b;
                  case 'or':
                      return a || b;
                  default:
                      if (a.compare) {
                          result = a.compare(b);
                      } else if (b.compare) {
                          result = b.compare(a);
                      } else {
                          throw { type: "Type",
                                  message: "Unable to perform comparison",
                                  index: i };
                      }
                      switch (result) {
                          case -1: return op === '<' || op === '=<' || op === '<=';
                          case  0: return op === '=' || op === '>=' || op === '=<' || op === '<=';
                          case  1: return op === '>' || op === '>=';
                      }
              }
          })(this.op);
          return this.negate ? !result : result;
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  //
  // A number with a unit
  //
  tree.Dimension = function (value, unit) {
      this.value = parseFloat(value);
      this.unit = (unit && unit instanceof tree.Unit) ? unit :
        new(tree.Unit)(unit ? [unit] : undefined);
  };
  
  tree.Dimension.prototype = {
      type: "Dimension",
      accept: function (visitor) {
          this.unit = visitor.visit(this.unit);
      },
      eval: function (env) {
          return this;
      },
      toColor: function () {
          return new(tree.Color)([this.value, this.value, this.value]);
      },
      genCSS: function (env, output) {
          if ((env && env.strictUnits) && !this.unit.isSingular()) {
              throw new Error("Multiple units in dimension. Correct the units or use the unit function. Bad unit: "+this.unit.toString());
          }
  
          var value = this.value,
              strValue = String(value);
  
          if (value !== 0 && value < 0.000001 && value > -0.000001) {
              // would be output 1e-6 etc.
              strValue = value.toFixed(20).replace(/0+$/, "");
          }
  
          if (env && env.compress) {
              // Zero values doesn't need a unit
              if (value === 0 && this.unit.isLength()) {
                  output.add(strValue);
                  return;
              }
  
              // Float values doesn't need a leading zero
              if (value > 0 && value < 1) {
                  strValue = (strValue).substr(1);
              }
          }
  
          output.add(strValue);
          this.unit.genCSS(env, output);
      },
      toCSS: tree.toCSS,
  
      // In an operation between two Dimensions,
      // we default to the first Dimension's unit,
      // so `1px + 2` will yield `3px`.
      operate: function (env, op, other) {
          /*jshint noempty:false */
          var value = tree.operate(env, op, this.value, other.value),
              unit = this.unit.clone();
  
          if (op === '+' || op === '-') {
              if (unit.numerator.length === 0 && unit.denominator.length === 0) {
                  unit.numerator = other.unit.numerator.slice(0);
                  unit.denominator = other.unit.denominator.slice(0);
              } else if (other.unit.numerator.length === 0 && unit.denominator.length === 0) {
                  // do nothing
              } else {
                  other = other.convertTo(this.unit.usedUnits());
  
                  if(env.strictUnits && other.unit.toString() !== unit.toString()) {
                    throw new Error("Incompatible units. Change the units or use the unit function. Bad units: '" + unit.toString() +
                      "' and '" + other.unit.toString() + "'.");
                  }
  
                  value = tree.operate(env, op, this.value, other.value);
              }
          } else if (op === '*') {
              unit.numerator = unit.numerator.concat(other.unit.numerator).sort();
              unit.denominator = unit.denominator.concat(other.unit.denominator).sort();
              unit.cancel();
          } else if (op === '/') {
              unit.numerator = unit.numerator.concat(other.unit.denominator).sort();
              unit.denominator = unit.denominator.concat(other.unit.numerator).sort();
              unit.cancel();
          }
          return new(tree.Dimension)(value, unit);
      },
  
      compare: function (other) {
          if (other instanceof tree.Dimension) {
              var a = this.unify(), b = other.unify(),
                  aValue = a.value, bValue = b.value;
  
              if (bValue > aValue) {
                  return -1;
              } else if (bValue < aValue) {
                  return 1;
              } else {
                  if (!b.unit.isEmpty() && a.unit.compare(b.unit) !== 0) {
                      return -1;
                  }
                  return 0;
              }
          } else {
              return -1;
          }
      },
  
      unify: function () {
          return this.convertTo({ length: 'm', duration: 's', angle: 'rad' });
      },
  
      convertTo: function (conversions) {
          var value = this.value, unit = this.unit.clone(),
              i, groupName, group, targetUnit, derivedConversions = {}, applyUnit;
  
          if (typeof conversions === 'string') {
              for(i in tree.UnitConversions) {
                  if (tree.UnitConversions[i].hasOwnProperty(conversions)) {
                      derivedConversions = {};
                      derivedConversions[i] = conversions;
                  }
              }
              conversions = derivedConversions;
          }
          applyUnit = function (atomicUnit, denominator) {
            /*jshint loopfunc:true */
              if (group.hasOwnProperty(atomicUnit)) {
                  if (denominator) {
                      value = value / (group[atomicUnit] / group[targetUnit]);
                  } else {
                      value = value * (group[atomicUnit] / group[targetUnit]);
                  }
  
                  return targetUnit;
              }
  
              return atomicUnit;
          };
  
          for (groupName in conversions) {
              if (conversions.hasOwnProperty(groupName)) {
                  targetUnit = conversions[groupName];
                  group = tree.UnitConversions[groupName];
  
                  unit.map(applyUnit);
              }
          }
  
          unit.cancel();
  
          return new(tree.Dimension)(value, unit);
      }
  };
  
  // http://www.w3.org/TR/css3-values/#absolute-lengths
  tree.UnitConversions = {
      length: {
           'm': 1,
          'cm': 0.01,
          'mm': 0.001,
          'in': 0.0254,
          'pt': 0.0254 / 72,
          'pc': 0.0254 / 72 * 12
      },
      duration: {
          's': 1,
          'ms': 0.001
      },
      angle: {
          'rad': 1/(2*Math.PI),
          'deg': 1/360,
          'grad': 1/400,
          'turn': 1
      }
  };
  
  tree.Unit = function (numerator, denominator, backupUnit) {
      this.numerator = numerator ? numerator.slice(0).sort() : [];
      this.denominator = denominator ? denominator.slice(0).sort() : [];
      this.backupUnit = backupUnit;
  };
  
  tree.Unit.prototype = {
      type: "Unit",
      clone: function () {
          return new tree.Unit(this.numerator.slice(0), this.denominator.slice(0), this.backupUnit);
      },
      genCSS: function (env, output) {
          if (this.numerator.length >= 1) {
              output.add(this.numerator[0]);
          } else
          if (this.denominator.length >= 1) {
              output.add(this.denominator[0]);
          } else
          if ((!env || !env.strictUnits) && this.backupUnit) {
              output.add(this.backupUnit);
          }
      },
      toCSS: tree.toCSS,
  
      toString: function () {
        var i, returnStr = this.numerator.join("*");
        for (i = 0; i < this.denominator.length; i++) {
            returnStr += "/" + this.denominator[i];
        }
        return returnStr;
      },
  
      compare: function (other) {
          return this.is(other.toString()) ? 0 : -1;
      },
  
      is: function (unitString) {
          return this.toString() === unitString;
      },
  
      isLength: function () {
          return Boolean(this.toCSS().match(/px|em|%|in|cm|mm|pc|pt|ex/));
      },
  
      isEmpty: function () {
          return this.numerator.length === 0 && this.denominator.length === 0;
      },
  
      isSingular: function() {
          return this.numerator.length <= 1 && this.denominator.length === 0;
      },
  
      map: function(callback) {
          var i;
  
          for (i = 0; i < this.numerator.length; i++) {
              this.numerator[i] = callback(this.numerator[i], false);
          }
  
          for (i = 0; i < this.denominator.length; i++) {
              this.denominator[i] = callback(this.denominator[i], true);
          }
      },
  
      usedUnits: function() {
          var group, result = {}, mapUnit;
  
          mapUnit = function (atomicUnit) {
          /*jshint loopfunc:true */
              if (group.hasOwnProperty(atomicUnit) && !result[groupName]) {
                  result[groupName] = atomicUnit;
              }
  
              return atomicUnit;
          };
  
          for (var groupName in tree.UnitConversions) {
              if (tree.UnitConversions.hasOwnProperty(groupName)) {
                  group = tree.UnitConversions[groupName];
  
                  this.map(mapUnit);
              }
          }
  
          return result;
      },
  
      cancel: function () {
          var counter = {}, atomicUnit, i, backup;
  
          for (i = 0; i < this.numerator.length; i++) {
              atomicUnit = this.numerator[i];
              if (!backup) {
                  backup = atomicUnit;
              }
              counter[atomicUnit] = (counter[atomicUnit] || 0) + 1;
          }
  
          for (i = 0; i < this.denominator.length; i++) {
              atomicUnit = this.denominator[i];
              if (!backup) {
                  backup = atomicUnit;
              }
              counter[atomicUnit] = (counter[atomicUnit] || 0) - 1;
          }
  
          this.numerator = [];
          this.denominator = [];
  
          for (atomicUnit in counter) {
              if (counter.hasOwnProperty(atomicUnit)) {
                  var count = counter[atomicUnit];
  
                  if (count > 0) {
                      for (i = 0; i < count; i++) {
                          this.numerator.push(atomicUnit);
                      }
                  } else if (count < 0) {
                      for (i = 0; i < -count; i++) {
                          this.denominator.push(atomicUnit);
                      }
                  }
              }
          }
  
          if (this.numerator.length === 0 && this.denominator.length === 0 && backup) {
              this.backupUnit = backup;
          }
  
          this.numerator.sort();
          this.denominator.sort();
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Directive = function (name, value, index, currentFileInfo) {
      this.name = name;
  
      if (Array.isArray(value)) {
          this.rules = [new(tree.Ruleset)(null, value)];
          this.rules[0].allowImports = true;
      } else {
          this.value = value;
      }
      this.currentFileInfo = currentFileInfo;
  
  };
  tree.Directive.prototype = {
      type: "Directive",
      accept: function (visitor) {
          if (this.rules) {
              this.rules = visitor.visitArray(this.rules);
          }
          if (this.value) {
              this.value = visitor.visit(this.value);
          }
      },
      genCSS: function (env, output) {
          output.add(this.name, this.currentFileInfo, this.index);
          if (this.rules) {
              tree.outputRuleset(env, output, this.rules);
          } else {
              output.add(' ');
              this.value.genCSS(env, output);
              output.add(';');
          }
      },
      toCSS: tree.toCSS,
      eval: function (env) {
          var evaldDirective = this;
          if (this.rules) {
              env.frames.unshift(this);
              evaldDirective = new(tree.Directive)(this.name, null, this.index, this.currentFileInfo);
              evaldDirective.rules = [this.rules[0].eval(env)];
              evaldDirective.rules[0].root = true;
              env.frames.shift();
          }
          return evaldDirective;
      },
      variable: function (name) { return tree.Ruleset.prototype.variable.call(this.rules[0], name); },
      find: function () { return tree.Ruleset.prototype.find.apply(this.rules[0], arguments); },
      rulesets: function () { return tree.Ruleset.prototype.rulesets.apply(this.rules[0]); },
      markReferenced: function () {
          var i, rules;
          this.isReferenced = true;
          if (this.rules) {
              rules = this.rules[0].rules;
              for (i = 0; i < rules.length; i++) {
                  if (rules[i].markReferenced) {
                      rules[i].markReferenced();
                  }
              }
          }
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Element = function (combinator, value, index, currentFileInfo) {
      this.combinator = combinator instanceof tree.Combinator ?
                        combinator : new(tree.Combinator)(combinator);
  
      if (typeof(value) === 'string') {
          this.value = value.trim();
      } else if (value) {
          this.value = value;
      } else {
          this.value = "";
      }
      this.index = index;
      this.currentFileInfo = currentFileInfo;
  };
  tree.Element.prototype = {
      type: "Element",
      accept: function (visitor) {
          var value = this.value;
          this.combinator = visitor.visit(this.combinator);
          if (typeof value === "object") {
              this.value = visitor.visit(value);
          }
      },
      eval: function (env) {
          return new(tree.Element)(this.combinator,
                                   this.value.eval ? this.value.eval(env) : this.value,
                                   this.index,
                                   this.currentFileInfo);
      },
      genCSS: function (env, output) {
          output.add(this.toCSS(env), this.currentFileInfo, this.index);
      },
      toCSS: function (env) {
          var value = (this.value.toCSS ? this.value.toCSS(env) : this.value);
          if (value === '' && this.combinator.value.charAt(0) === '&') {
              return '';
          } else {
              return this.combinator.toCSS(env || {}) + value;
          }
      }
  };
  
  tree.Attribute = function (key, op, value) {
      this.key = key;
      this.op = op;
      this.value = value;
  };
  tree.Attribute.prototype = {
      type: "Attribute",
      eval: function (env) {
          return new(tree.Attribute)(this.key.eval ? this.key.eval(env) : this.key,
              this.op, (this.value && this.value.eval) ? this.value.eval(env) : this.value);
      },
      genCSS: function (env, output) {
          output.add(this.toCSS(env));
      },
      toCSS: function (env) {
          var value = this.key.toCSS ? this.key.toCSS(env) : this.key;
  
          if (this.op) {
              value += this.op;
              value += (this.value.toCSS ? this.value.toCSS(env) : this.value);
          }
  
          return '[' + value + ']';
      }
  };
  
  tree.Combinator = function (value) {
      if (value === ' ') {
          this.value = ' ';
      } else {
          this.value = value ? value.trim() : "";
      }
  };
  tree.Combinator.prototype = {
      type: "Combinator",
      _outputMap: {
          ''  : '',
          ' ' : ' ',
          ':' : ' :',
          '+' : ' + ',
          '~' : ' ~ ',
          '>' : ' > ',
          '|' : '|'
      },
      _outputMapCompressed: {
          ''  : '',
          ' ' : ' ',
          ':' : ' :',
          '+' : '+',
          '~' : '~',
          '>' : '>',
          '|' : '|'
      },
      genCSS: function (env, output) {
          output.add((env.compress ? this._outputMapCompressed : this._outputMap)[this.value]);
      },
      toCSS: tree.toCSS
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Expression = function (value) { this.value = value; };
  tree.Expression.prototype = {
      type: "Expression",
      accept: function (visitor) {
          if (this.value) {
              this.value = visitor.visitArray(this.value);
          }
      },
      eval: function (env) {
          var returnValue,
              inParenthesis = this.parens && !this.parensInOp,
              doubleParen = false;
          if (inParenthesis) {
              env.inParenthesis();
          }
          if (this.value.length > 1) {
              returnValue = new(tree.Expression)(this.value.map(function (e) {
                  return e.eval(env);
              }));
          } else if (this.value.length === 1) {
              if (this.value[0].parens && !this.value[0].parensInOp) {
                  doubleParen = true;
              }
              returnValue = this.value[0].eval(env);
          } else {
              returnValue = this;
          }
          if (inParenthesis) {
              env.outOfParenthesis();
          }
          if (this.parens && this.parensInOp && !(env.isMathOn()) && !doubleParen) {
              returnValue = new(tree.Paren)(returnValue);
          }
          return returnValue;
      },
      genCSS: function (env, output) {
          for(var i = 0; i < this.value.length; i++) {
              this.value[i].genCSS(env, output);
              if (i + 1 < this.value.length) {
                  output.add(" ");
              }
          }
      },
      toCSS: tree.toCSS,
      throwAwayComments: function () {
          this.value = this.value.filter(function(v) {
              return !(v instanceof tree.Comment);
          });
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Extend = function Extend(selector, option, index) {
      this.selector = selector;
      this.option = option;
      this.index = index;
      this.object_id = tree.Extend.next_id++;
      this.parent_ids = [this.object_id];
  
      switch(option) {
          case "all":
              this.allowBefore = true;
              this.allowAfter = true;
          break;
          default:
              this.allowBefore = false;
              this.allowAfter = false;
          break;
      }
  };
  tree.Extend.next_id = 0;
  
  tree.Extend.prototype = {
      type: "Extend",
      accept: function (visitor) {
          this.selector = visitor.visit(this.selector);
      },
      eval: function (env) {
          return new(tree.Extend)(this.selector.eval(env), this.option, this.index);
      },
      clone: function (env) {
          return new(tree.Extend)(this.selector, this.option, this.index);
      },
      findSelfSelectors: function (selectors) {
          var selfElements = [],
              i,
              selectorElements;
  
          for(i = 0; i < selectors.length; i++) {
              selectorElements = selectors[i].elements;
              // duplicate the logic in genCSS function inside the selector node.
              // future TODO - move both logics into the selector joiner visitor
              if (i > 0 && selectorElements.length && selectorElements[0].combinator.value === "") {
                  selectorElements[0].combinator.value = ' ';
              }
              selfElements = selfElements.concat(selectors[i].elements);
          }
  
          this.selfSelectors = [{ elements: selfElements }];
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  //
  // CSS @import node
  //
  // The general strategy here is that we don't want to wait
  // for the parsing to be completed, before we start importing
  // the file. That's because in the context of a browser,
  // most of the time will be spent waiting for the server to respond.
  //
  // On creation, we push the import path to our import queue, though
  // `import,push`, we also pass it a callback, which it'll call once
  // the file has been fetched, and parsed.
  //
  tree.Import = function (path, features, options, index, currentFileInfo) {
      this.options = options;
      this.index = index;
      this.path = path;
      this.features = features;
      this.currentFileInfo = currentFileInfo;
  
      if (this.options.less !== undefined || this.options.inline) {
          this.css = !this.options.less || this.options.inline;
      } else {
          var pathValue = this.getPath();
          if (pathValue && /css([\?;].*)?$/.test(pathValue)) {
              this.css = true;
          }
      }
  };
  
  //
  // The actual import node doesn't return anything, when converted to CSS.
  // The reason is that it's used at the evaluation stage, so that the rules
  // it imports can be treated like any other rules.
  //
  // In `eval`, we make sure all Import nodes get evaluated, recursively, so
  // we end up with a flat structure, which can easily be imported in the parent
  // ruleset.
  //
  tree.Import.prototype = {
      type: "Import",
      accept: function (visitor) {
          if (this.features) {
              this.features = visitor.visit(this.features);
          }
          this.path = visitor.visit(this.path);
          if (!this.options.inline && this.root) {
              this.root = visitor.visit(this.root);
          }
      },
      genCSS: function (env, output) {
          if (this.css) {
              output.add("@import ", this.currentFileInfo, this.index);
              this.path.genCSS(env, output);
              if (this.features) {
                  output.add(" ");
                  this.features.genCSS(env, output);
              }
              output.add(';');
          }
      },
      toCSS: tree.toCSS,
      getPath: function () {
          if (this.path instanceof tree.Quoted) {
              var path = this.path.value;
              return (this.css !== undefined || /(\.[a-z]*$)|([\?;].*)$/.test(path)) ? path : path + '.less';
          } else if (this.path instanceof tree.URL) {
              return this.path.value.value;
          }
          return null;
      },
      evalForImport: function (env) {
          return new(tree.Import)(this.path.eval(env), this.features, this.options, this.index, this.currentFileInfo);
      },
      evalPath: function (env) {
          var path = this.path.eval(env);
          var rootpath = this.currentFileInfo && this.currentFileInfo.rootpath;
  
          if (!(path instanceof tree.URL)) {
              if (rootpath) {
                  var pathValue = path.value;
                  // Add the base path if the import is relative
                  if (pathValue && env.isPathRelative(pathValue)) {
                      path.value = rootpath + pathValue;
                  }
              }
              path.value = env.normalizePath(path.value);
          }
  
          return path;
      },
      eval: function (env) {
          var ruleset, features = this.features && this.features.eval(env);
  
          if (this.skip) { return []; }
  
          if (this.options.inline) {
              //todo needs to reference css file not import
              var contents = new(tree.Anonymous)(this.root, 0, {filename: this.importedFilename}, true);
              return this.features ? new(tree.Media)([contents], this.features.value) : [contents];
          } else if (this.css) {
              var newImport = new(tree.Import)(this.evalPath(env), features, this.options, this.index);
              if (!newImport.css && this.error) {
                  throw this.error;
              }
              return newImport;
          } else {
              ruleset = new(tree.Ruleset)(null, this.root.rules.slice(0));
  
              ruleset.evalImports(env);
  
              return this.features ? new(tree.Media)(ruleset.rules, this.features.value) : ruleset.rules;
          }
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.JavaScript = function (string, index, escaped) {
      this.escaped = escaped;
      this.expression = string;
      this.index = index;
  };
  tree.JavaScript.prototype = {
      type: "JavaScript",
      eval: function (env) {
          var result,
              that = this,
              context = {};
  
          var expression = this.expression.replace(/@\{([\w-]+)\}/g, function (_, name) {
              return tree.jsify(new(tree.Variable)('@' + name, that.index).eval(env));
          });
  
          try {
              expression = new(Function)('return (' + expression + ')');
          } catch (e) {
              throw { message: "JavaScript evaluation error: " + e.message + " from `" + expression + "`" ,
                      index: this.index };
          }
  
          for (var k in env.frames[0].variables()) {
              /*jshint loopfunc:true */
              context[k.slice(1)] = {
                  value: env.frames[0].variables()[k].value,
                  toJS: function () {
                      return this.value.eval(env).toCSS();
                  }
              };
          }
  
          try {
              result = expression.call(context);
          } catch (e) {
              throw { message: "JavaScript evaluation error: '" + e.name + ': ' + e.message + "'" ,
                      index: this.index };
          }
          if (typeof(result) === 'number') {
              return new(tree.Dimension)(result);
          } else if (typeof(result) === 'string') {
              return new(tree.Quoted)('"' + result + '"', result, this.escaped, this.index);
          } else if (Array.isArray(result)) {
              return new(tree.Anonymous)(result.join(', '));
          } else {
              return new(tree.Anonymous)(result);
          }
      }
  };
  
  })(require('../tree'));
  
  
  (function (tree) {
  
  tree.Keyword = function (value) { this.value = value; };
  tree.Keyword.prototype = {
      type: "Keyword",
      eval: function () { return this; },
      genCSS: function (env, output) {
          output.add(this.value);
      },
      toCSS: tree.toCSS,
      compare: function (other) {
          if (other instanceof tree.Keyword) {
              return other.value === this.value ? 0 : 1;
          } else {
              return -1;
          }
      }
  };
  
  tree.True = new(tree.Keyword)('true');
  tree.False = new(tree.Keyword)('false');
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Media = function (value, features, index, currentFileInfo) {
      this.index = index;
      this.currentFileInfo = currentFileInfo;
  
      var selectors = this.emptySelectors();
  
      this.features = new(tree.Value)(features);
      this.rules = [new(tree.Ruleset)(selectors, value)];
      this.rules[0].allowImports = true;
  };
  tree.Media.prototype = {
      type: "Media",
      accept: function (visitor) {
          if (this.features) {
              this.features = visitor.visit(this.features);
          }
          if (this.rules) {
              this.rules = visitor.visitArray(this.rules);
          }
      },
      genCSS: function (env, output) {
          output.add('@media ', this.currentFileInfo, this.index);
          this.features.genCSS(env, output);
          tree.outputRuleset(env, output, this.rules);
      },
      toCSS: tree.toCSS,
      eval: function (env) {
          if (!env.mediaBlocks) {
              env.mediaBlocks = [];
              env.mediaPath = [];
          }
          
          var media = new(tree.Media)(null, [], this.index, this.currentFileInfo);
          if(this.debugInfo) {
              this.rules[0].debugInfo = this.debugInfo;
              media.debugInfo = this.debugInfo;
          }
          var strictMathBypass = false;
          if (!env.strictMath) {
              strictMathBypass = true;
              env.strictMath = true;
          }
          try {
              media.features = this.features.eval(env);
          }
          finally {
              if (strictMathBypass) {
                  env.strictMath = false;
              }
          }
          
          env.mediaPath.push(media);
          env.mediaBlocks.push(media);
          
          env.frames.unshift(this.rules[0]);
          media.rules = [this.rules[0].eval(env)];
          env.frames.shift();
          
          env.mediaPath.pop();
  
          return env.mediaPath.length === 0 ? media.evalTop(env) :
                      media.evalNested(env);
      },
      variable: function (name) { return tree.Ruleset.prototype.variable.call(this.rules[0], name); },
      find: function () { return tree.Ruleset.prototype.find.apply(this.rules[0], arguments); },
      rulesets: function () { return tree.Ruleset.prototype.rulesets.apply(this.rules[0]); },
      emptySelectors: function() { 
          var el = new(tree.Element)('', '&', this.index, this.currentFileInfo);
          return [new(tree.Selector)([el], null, null, this.index, this.currentFileInfo)];
      },
      markReferenced: function () {
          var i, rules = this.rules[0].rules;
          this.isReferenced = true;
          for (i = 0; i < rules.length; i++) {
              if (rules[i].markReferenced) {
                  rules[i].markReferenced();
              }
          }
      },
  
      evalTop: function (env) {
          var result = this;
  
          // Render all dependent Media blocks.
          if (env.mediaBlocks.length > 1) {
              var selectors = this.emptySelectors();
              result = new(tree.Ruleset)(selectors, env.mediaBlocks);
              result.multiMedia = true;
          }
  
          delete env.mediaBlocks;
          delete env.mediaPath;
  
          return result;
      },
      evalNested: function (env) {
          var i, value,
              path = env.mediaPath.concat([this]);
  
          // Extract the media-query conditions separated with `,` (OR).
          for (i = 0; i < path.length; i++) {
              value = path[i].features instanceof tree.Value ?
                          path[i].features.value : path[i].features;
              path[i] = Array.isArray(value) ? value : [value];
          }
  
          // Trace all permutations to generate the resulting media-query.
          //
          // (a, b and c) with nested (d, e) ->
          //    a and d
          //    a and e
          //    b and c and d
          //    b and c and e
          this.features = new(tree.Value)(this.permute(path).map(function (path) {
              path = path.map(function (fragment) {
                  return fragment.toCSS ? fragment : new(tree.Anonymous)(fragment);
              });
  
              for(i = path.length - 1; i > 0; i--) {
                  path.splice(i, 0, new(tree.Anonymous)("and"));
              }
  
              return new(tree.Expression)(path);
          }));
  
          // Fake a tree-node that doesn't output anything.
          return new(tree.Ruleset)([], []);
      },
      permute: function (arr) {
        if (arr.length === 0) {
            return [];
        } else if (arr.length === 1) {
            return arr[0];
        } else {
            var result = [];
            var rest = this.permute(arr.slice(1));
            for (var i = 0; i < rest.length; i++) {
                for (var j = 0; j < arr[0].length; j++) {
                    result.push([arr[0][j]].concat(rest[i]));
                }
            }
            return result;
        }
      },
      bubbleSelectors: function (selectors) {
        this.rules = [new(tree.Ruleset)(selectors.slice(0), [this.rules[0]])];
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.mixin = {};
  tree.mixin.Call = function (elements, args, index, currentFileInfo, important) {
      this.selector = new(tree.Selector)(elements);
      this.arguments = (args && args.length) ? args : null;
      this.index = index;
      this.currentFileInfo = currentFileInfo;
      this.important = important;
  };
  tree.mixin.Call.prototype = {
      type: "MixinCall",
      accept: function (visitor) {
          if (this.selector) {
              this.selector = visitor.visit(this.selector);
          }
          if (this.arguments) {
              this.arguments = visitor.visitArray(this.arguments);
          }
      },
      eval: function (env) {
          var mixins, mixin, args, rules = [], match = false, i, m, f, isRecursive, isOneFound, rule;
          var candidates = [], candidate, conditionResult = [], defaultFunc = tree.defaultFunc, defaultUsed = false; 
  
          args = this.arguments && this.arguments.map(function (a) {
              return { name: a.name, value: a.value.eval(env) };
          });
  
          for (i = 0; i < env.frames.length; i++) {
              if ((mixins = env.frames[i].find(this.selector)).length > 0) {
                  isOneFound = true;
                  
                  // To make `default()` function independent of definition order we have two "subpasses" here.
                  // At first we evaluate each guard *twice* (with `default() == true` and `default() == false`),
                  // and build candidate list with corresponding flags. Then, when we know all possible matches,
                  // we make a final decision.
                  
                  for (m = 0; m < mixins.length; m++) {
                      mixin = mixins[m];
                      isRecursive = false;
                      for(f = 0; f < env.frames.length; f++) {
                          if ((!(mixin instanceof tree.mixin.Definition)) && mixin === (env.frames[f].originalRuleset || env.frames[f])) {
                              isRecursive = true;
                              break;
                          }
                      }
                      if (isRecursive) {
                          continue;
                      }
                      
                      if (mixin.matchArgs(args, env)) {  
                          candidate = {mixin: mixin};
                          
                          if (mixin.matchCondition) { 
                              for (f = 0; f < 2; f++) {
                                  defaultFunc.value(f);
                                  conditionResult[f] = mixin.matchCondition(args, env);
                              }
                              if (conditionResult[0] || conditionResult[1]) {
                                  if (conditionResult[0] != conditionResult[1]) {
                                      if (defaultUsed) {
                                          // todo: ideally, it would make sense to also print the candidate 
                                          // mixin definitions that cause the conflict (current one and the
                                          // mixin that set defaultUsed flag). But is there any easy method 
                                          // to get their filename/line/index info here?
                                          throw { type: 'Runtime',
                                              message: 'Ambiguous use of `default()` found when matching for `'
                                                  + this.format(args) + '`',
                                              index: this.index, filename: this.currentFileInfo.filename };
                                      }
                                      
                                      defaultUsed                   = true;
                                      candidate.matchIfDefault      = true;
                                      candidate.matchIfDefaultValue = conditionResult[1];
                                  }
  
                                  candidates.push(candidate);
                              }   
                          }
                          else {
                              candidates.push(candidate);
                          }
                          
                          match = true;
                      }
                  }
                  
                  defaultFunc.reset();
                  
                  for (m in candidates) {
                      candidate = candidates[m];
                      if (!candidate.matchIfDefault || (candidate.matchIfDefaultValue == (candidates.length == 1))) {
                          try {
                              mixin = candidate.mixin;
                              if (!(mixin instanceof tree.mixin.Definition)) {
                                  mixin = new tree.mixin.Definition("", [], mixin.rules, null, false);
                                  mixin.originalRuleset = mixins[m].originalRuleset || mixins[m];
                              }
                              //if (this.important) {
                              //    isImportant = env.isImportant;
                              //    env.isImportant = true;
                              //}
                              Array.prototype.push.apply(
                                    rules, mixin.eval(env, args, this.important).rules);
                              //if (this.important) {
                              //    env.isImportant = isImportant;
                              //}
                          } catch (e) {
                              throw { message: e.message, index: this.index, filename: this.currentFileInfo.filename, stack: e.stack };
                          }
                      }
                  }
                  
                  if (match) {
                      if (!this.currentFileInfo || !this.currentFileInfo.reference) {
                          for (i = 0; i < rules.length; i++) {
                              rule = rules[i];
                              if (rule.markReferenced) {
                                  rule.markReferenced();
                              }
                          }
                      }
                      return rules;
                  }
              }
          }
          if (isOneFound) {
              throw { type:    'Runtime',
                      message: 'No matching definition was found for `' + this.format(args) + '`',
                      index:   this.index, filename: this.currentFileInfo.filename };
          } else {
              throw { type:    'Name',
                      message: this.selector.toCSS().trim() + " is undefined",
                      index:   this.index, filename: this.currentFileInfo.filename };
          }
      },
      format: function (args) {
          return this.selector.toCSS().trim() + '(' +
              (args ? args.map(function (a) {
                  var argValue = "";
                  if (a.name) {
                      argValue += a.name + ":";
                  }
                  if (a.value.toCSS) {
                      argValue += a.value.toCSS();
                  } else {
                      argValue += "???";
                  }
                  return argValue;
              }).join(', ') : "") + ")";
      }
  };
  
  tree.mixin.Definition = function (name, params, rules, condition, variadic) {
      this.name = name;
      this.selectors = [new(tree.Selector)([new(tree.Element)(null, name, this.index, this.currentFileInfo)])];
      this.params = params;
      this.condition = condition;
      this.variadic = variadic;
      this.arity = params.length;
      this.rules = rules;
      this._lookups = {};
      this.required = params.reduce(function (count, p) {
          if (!p.name || (p.name && !p.value)) { return count + 1; }
          else                                 { return count; }
      }, 0);
      this.parent = tree.Ruleset.prototype;
      this.frames = [];
  };
  tree.mixin.Definition.prototype = {
      type: "MixinDefinition",
      accept: function (visitor) {
          if (this.params && this.params.length) {
              this.params = visitor.visitArray(this.params);
          }
          this.rules = visitor.visitArray(this.rules);
          if (this.condition) {
              this.condition = visitor.visit(this.condition);
          }
      },
      variable:  function (name) { return this.parent.variable.call(this, name); },
      variables: function ()     { return this.parent.variables.call(this); },
      find:      function ()     { return this.parent.find.apply(this, arguments); },
      rulesets:  function ()     { return this.parent.rulesets.apply(this); },
  
      evalParams: function (env, mixinEnv, args, evaldArguments) {
          /*jshint boss:true */
          var frame = new(tree.Ruleset)(null, null),
              varargs, arg,
              params = this.params.slice(0),
              i, j, val, name, isNamedFound, argIndex;
  
          mixinEnv = new tree.evalEnv(mixinEnv, [frame].concat(mixinEnv.frames));
  
          if (args) {
              args = args.slice(0);
  
              for(i = 0; i < args.length; i++) {
                  arg = args[i];
                  if (name = (arg && arg.name)) {
                      isNamedFound = false;
                      for(j = 0; j < params.length; j++) {
                          if (!evaldArguments[j] && name === params[j].name) {
                              evaldArguments[j] = arg.value.eval(env);
                              frame.prependRule(new(tree.Rule)(name, arg.value.eval(env)));
                              isNamedFound = true;
                              break;
                          }
                      }
                      if (isNamedFound) {
                          args.splice(i, 1);
                          i--;
                          continue;
                      } else {
                          throw { type: 'Runtime', message: "Named argument for " + this.name +
                              ' ' + args[i].name + ' not found' };
                      }
                  }
              }
          }
          argIndex = 0;
          for (i = 0; i < params.length; i++) {
              if (evaldArguments[i]) { continue; }
  
              arg = args && args[argIndex];
  
              if (name = params[i].name) {
                  if (params[i].variadic && args) {
                      varargs = [];
                      for (j = argIndex; j < args.length; j++) {
                          varargs.push(args[j].value.eval(env));
                      }
                      frame.prependRule(new(tree.Rule)(name, new(tree.Expression)(varargs).eval(env)));
                  } else {
                      val = arg && arg.value;
                      if (val) {
                          val = val.eval(env);
                      } else if (params[i].value) {
                          val = params[i].value.eval(mixinEnv);
                          frame.resetCache();
                      } else {
                          throw { type: 'Runtime', message: "wrong number of arguments for " + this.name +
                              ' (' + args.length + ' for ' + this.arity + ')' };
                      }
                      
                      frame.prependRule(new(tree.Rule)(name, val));
                      evaldArguments[i] = val;
                  }
              }
  
              if (params[i].variadic && args) {
                  for (j = argIndex; j < args.length; j++) {
                      evaldArguments[j] = args[j].value.eval(env);
                  }
              }
              argIndex++;
          }
  
          return frame;
      },
      eval: function (env, args, important) {
          var _arguments = [],
              mixinFrames = this.frames.concat(env.frames),
              frame = this.evalParams(env, new(tree.evalEnv)(env, mixinFrames), args, _arguments),
              rules, ruleset;
  
          frame.prependRule(new(tree.Rule)('@arguments', new(tree.Expression)(_arguments).eval(env)));
  
          rules = this.rules.slice(0);
  
          ruleset = new(tree.Ruleset)(null, rules);
          ruleset.originalRuleset = this;
          ruleset = ruleset.eval(new(tree.evalEnv)(env, [this, frame].concat(mixinFrames)));
          if (important) {
              ruleset = this.parent.makeImportant.apply(ruleset);
          }
          return ruleset;
      },
      matchCondition: function (args, env) {
          if (this.condition && !this.condition.eval(
              new(tree.evalEnv)(env,
                  [this.evalParams(env, new(tree.evalEnv)(env, this.frames.concat(env.frames)), args, [])] // the parameter variables
                      .concat(this.frames) // the parent namespace/mixin frames
                      .concat(env.frames)))) { // the current environment frames
              return false;
          }
          return true;
      },
      matchArgs: function (args, env) {
          var argsLength = (args && args.length) || 0, len;
  
          if (! this.variadic) {
              if (argsLength < this.required)                               { return false; }
              if (argsLength > this.params.length)                          { return false; }
          } else {
              if (argsLength < (this.required - 1))                         { return false; }
          }
  
          len = Math.min(argsLength, this.arity);
  
          for (var i = 0; i < len; i++) {
              if (!this.params[i].name && !this.params[i].variadic) {
                  if (args[i].value.eval(env).toCSS() != this.params[i].value.eval(env).toCSS()) {
                      return false;
                  }
              }
          }
          return true;
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Negative = function (node) {
      this.value = node;
  };
  tree.Negative.prototype = {
      type: "Negative",
      accept: function (visitor) {
          this.value = visitor.visit(this.value);
      },
      genCSS: function (env, output) {
          output.add('-');
          this.value.genCSS(env, output);
      },
      toCSS: tree.toCSS,
      eval: function (env) {
          if (env.isMathOn()) {
              return (new(tree.Operation)('*', [new(tree.Dimension)(-1), this.value])).eval(env);
          }
          return new(tree.Negative)(this.value.eval(env));
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Operation = function (op, operands, isSpaced) {
      this.op = op.trim();
      this.operands = operands;
      this.isSpaced = isSpaced;
  };
  tree.Operation.prototype = {
      type: "Operation",
      accept: function (visitor) {
          this.operands = visitor.visit(this.operands);
      },
      eval: function (env) {
          var a = this.operands[0].eval(env),
              b = this.operands[1].eval(env);
  
          if (env.isMathOn()) {
              if (a instanceof tree.Dimension && b instanceof tree.Color) {
                  a = a.toColor();
              }
              if (b instanceof tree.Dimension && a instanceof tree.Color) {
                  b = b.toColor();
              }
              if (!a.operate) {
                  throw { type: "Operation",
                          message: "Operation on an invalid type" };
              }
  
              return a.operate(env, this.op, b);
          } else {
              return new(tree.Operation)(this.op, [a, b], this.isSpaced);
          }
      },
      genCSS: function (env, output) {
          this.operands[0].genCSS(env, output);
          if (this.isSpaced) {
              output.add(" ");
          }
          output.add(this.op);
          if (this.isSpaced) {
              output.add(" ");
          }
          this.operands[1].genCSS(env, output);
      },
      toCSS: tree.toCSS
  };
  
  tree.operate = function (env, op, a, b) {
      switch (op) {
          case '+': return a + b;
          case '-': return a - b;
          case '*': return a * b;
          case '/': return a / b;
      }
  };
  
  })(require('../tree'));
  
  
  (function (tree) {
  
  tree.Paren = function (node) {
      this.value = node;
  };
  tree.Paren.prototype = {
      type: "Paren",
      accept: function (visitor) {
          this.value = visitor.visit(this.value);
      },
      genCSS: function (env, output) {
          output.add('(');
          this.value.genCSS(env, output);
          output.add(')');
      },
      toCSS: tree.toCSS,
      eval: function (env) {
          return new(tree.Paren)(this.value.eval(env));
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Quoted = function (str, content, escaped, index, currentFileInfo) {
      this.escaped = escaped;
      this.value = content || '';
      this.quote = str.charAt(0);
      this.index = index;
      this.currentFileInfo = currentFileInfo;
  };
  tree.Quoted.prototype = {
      type: "Quoted",
      genCSS: function (env, output) {
          if (!this.escaped) {
              output.add(this.quote, this.currentFileInfo, this.index);
          }
          output.add(this.value);
          if (!this.escaped) {
              output.add(this.quote);
          }
      },
      toCSS: tree.toCSS,
      eval: function (env) {
          var that = this;
          var value = this.value.replace(/`([^`]+)`/g, function (_, exp) {
              return new(tree.JavaScript)(exp, that.index, true).eval(env).value;
          }).replace(/@\{([\w-]+)\}/g, function (_, name) {
              var v = new(tree.Variable)('@' + name, that.index, that.currentFileInfo).eval(env, true);
              return (v instanceof tree.Quoted) ? v.value : v.toCSS();
          });
          return new(tree.Quoted)(this.quote + value + this.quote, value, this.escaped, this.index, this.currentFileInfo);
      },
      compare: function (x) {
          if (!x.toCSS) {
              return -1;
          }
          
          var left = this.toCSS(),
              right = x.toCSS();
          
          if (left === right) {
              return 0;
          }
          
          return left < right ? -1 : 1;
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Rule = function (name, value, important, merge, index, currentFileInfo, inline) {
      this.name = name;
      this.value = (value instanceof tree.Value) ? value : new(tree.Value)([value]);
      this.important = important ? ' ' + important.trim() : '';
      this.merge = merge;
      this.index = index;
      this.currentFileInfo = currentFileInfo;
      this.inline = inline || false;
      this.variable = name.charAt && (name.charAt(0) === '@');
  };
  
  tree.Rule.prototype = {
      type: "Rule",
      accept: function (visitor) {
          this.value = visitor.visit(this.value);
      },
      genCSS: function (env, output) {
          output.add(this.name + (env.compress ? ':' : ': '), this.currentFileInfo, this.index);
          try {
              this.value.genCSS(env, output);
          }
          catch(e) {
              e.index = this.index;
              e.filename = this.currentFileInfo.filename;
              throw e;
          }
          output.add(this.important + ((this.inline || (env.lastRule && env.compress)) ? "" : ";"), this.currentFileInfo, this.index);
      },
      toCSS: tree.toCSS,
      eval: function (env) {
          var strictMathBypass = false;
          var name = this.name.map ? 
              this.name.map( function(v) {
                  return v.eval ? v.eval(env).value : v;
              }).join('') : this.name;
          if (name === "font" && !env.strictMath) {
              strictMathBypass = true;
              env.strictMath = true;
          }
          try {
              return new(tree.Rule)(name,
                                this.value.eval(env),
                                this.important,
                                this.merge,
                                this.index, this.currentFileInfo, this.inline);
          }
          catch(e) {
              if (e.index === undefined) {
                  e.index = this.index;
              }
              throw e;
          }
          finally {
              if (strictMathBypass) {
                  env.strictMath = false;
              }
          }
      },
      makeImportant: function () {
          return new(tree.Rule)(this.name,
                                this.value,
                                "!important",
                                this.merge,
                                this.index, this.currentFileInfo, this.inline);
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Ruleset = function (selectors, rules, strictImports) {
      this.selectors = selectors;
      this.rules = rules;
      this._lookups = {};
      this.strictImports = strictImports;
  };
  tree.Ruleset.prototype = {
      type: "Ruleset",
      accept: function (visitor) {
          if (this.paths) {
              visitor.visitArray(this.paths, true);
          } else if (this.selectors) {
              this.selectors = visitor.visitArray(this.selectors);
          }
          if (this.rules && this.rules.length) {
              this.rules = visitor.visitArray(this.rules);
          }
      },
      eval: function (env) {
          var thisSelectors = this.selectors, selectors, 
              selCnt, i, defaultFunc = tree.defaultFunc;
          if (thisSelectors && (selCnt = thisSelectors.length)) {
              selectors = [];
              defaultFunc.error({
                  type: "Syntax", 
                  message: "it is currently only allowed in parametric mixin guards," 
              });
              for (i = 0; i < selCnt; i++) {
                  selectors.push(thisSelectors[i].eval(env));
              }
              defaultFunc.reset();  
          }
  
          var rules = this.rules ? this.rules.slice(0) : null,
              ruleset = new(tree.Ruleset)(selectors, rules, this.strictImports),
              rule;
  
          ruleset.originalRuleset = this;
          ruleset.root = this.root;
          ruleset.firstRoot = this.firstRoot;
          ruleset.allowImports = this.allowImports;
  
          if(this.debugInfo) {
              ruleset.debugInfo = this.debugInfo;
          }
  
          // push the current ruleset to the frames stack
          var envFrames = env.frames;
          envFrames.unshift(ruleset);
  
          // currrent selectors
          var envSelectors = env.selectors;
          if (!envSelectors) {
              env.selectors = envSelectors = [];
          }
          envSelectors.unshift(this.selectors);
  
          // Evaluate imports
          if (ruleset.root || ruleset.allowImports || !ruleset.strictImports) {
              ruleset.evalImports(env);
          }
  
          // Store the frames around mixin definitions,
          // so they can be evaluated like closures when the time comes.
          var rsRules = ruleset.rules, rsRuleCnt = rsRules ? rsRules.length : 0;
          for (i = 0; i < rsRuleCnt; i++) {
              if (rsRules[i] instanceof tree.mixin.Definition) {
                  rsRules[i].frames = envFrames.slice(0);
              }
          }
  
          var mediaBlockCount = (env.mediaBlocks && env.mediaBlocks.length) || 0;
  
          // Evaluate mixin calls.
          for (i = 0; i < rsRuleCnt; i++) {
              if (rsRules[i] instanceof tree.mixin.Call) {
                  /*jshint loopfunc:true */
                  rules = rsRules[i].eval(env).filter(function(r) {
                      if ((r instanceof tree.Rule) && r.variable) {
                          // do not pollute the scope if the variable is
                          // already there. consider returning false here
                          // but we need a way to "return" variable from mixins
                          return !(ruleset.variable(r.name));
                      }
                      return true;
                  });
                  rsRules.splice.apply(rsRules, [i, 1].concat(rules));
                  rsRuleCnt += rules.length - 1;
                  i += rules.length-1;
                  ruleset.resetCache();
              }
          }
  
          // Evaluate everything else
          for (i = 0; i < rsRuleCnt; i++) {
              rule = rsRules[i];
              if (! (rule instanceof tree.mixin.Definition)) {
                  rsRules[i] = rule.eval ? rule.eval(env) : rule;
              }
          }
  
          // Pop the stack
          envFrames.shift();
          envSelectors.shift();
          
          if (env.mediaBlocks) {
              for (i = mediaBlockCount; i < env.mediaBlocks.length; i++) {
                  env.mediaBlocks[i].bubbleSelectors(selectors);
              }
          }
  
          return ruleset;
      },
      evalImports: function(env) {
          var rules = this.rules, i, importRules;
          if (!rules) { return; }
  
          for (i = 0; i < rules.length; i++) {
              if (rules[i] instanceof tree.Import) {
                  importRules = rules[i].eval(env);
                  if (importRules && importRules.length) {
                      rules.splice.apply(rules, [i, 1].concat(importRules));
                      i+= importRules.length-1;
                  } else {
                      rules.splice(i, 1, importRules);
                  }
                  this.resetCache();
              }
          }
      },
      makeImportant: function() {
          return new tree.Ruleset(this.selectors, this.rules.map(function (r) {
                      if (r.makeImportant) {
                          return r.makeImportant();
                      } else {
                          return r;
                      }
                  }), this.strictImports);
      },
      matchArgs: function (args) {
          return !args || args.length === 0;
      },
      matchCondition: function (args, env) {
          var lastSelector = this.selectors[this.selectors.length-1];
          if (lastSelector.condition &&
              !lastSelector.condition.eval(
                  new(tree.evalEnv)(env,
                      env.frames))) {
              return false;
          }
          return true;
      },
      resetCache: function () {
          this._rulesets = null;
          this._variables = null;
          this._lookups = {};
      },
      variables: function () {
          if (!this._variables) {
              this._variables = !this.rules ? {} : this.rules.reduce(function (hash, r) {
                  if (r instanceof tree.Rule && r.variable === true) {
                      hash[r.name] = r;
                  }
                  return hash;
              }, {});
          }
          return this._variables;
      },
      variable: function (name) {
          return this.variables()[name];
      },
      rulesets: function () {
          if (!this.rules) { return null; }
  
          var _Ruleset = tree.Ruleset, _MixinDefinition = tree.mixin.Definition,
              filtRules = [], rules = this.rules, cnt = rules.length,
              i, rule;
  
          for (i = 0; i < cnt; i++) {
              rule = rules[i];
              if ((rule instanceof _Ruleset) || (rule instanceof _MixinDefinition)) {
                  filtRules.push(rule);
              }
          }
  
          return filtRules;
      },
      prependRule: function (rule) {
          var rules = this.rules;
          if (rules) { rules.unshift(rule); } else { this.rules = [ rule ]; }
      },
      find: function (selector, self) {
          self = self || this;
          var rules = [], match,
              key = selector.toCSS();
  
          if (key in this._lookups) { return this._lookups[key]; }
  
          this.rulesets().forEach(function (rule) {
              if (rule !== self) {
                  for (var j = 0; j < rule.selectors.length; j++) {
                      match = selector.match(rule.selectors[j]);
                      if (match) {
                          if (selector.elements.length > match) {
                              Array.prototype.push.apply(rules, rule.find(
                                  new(tree.Selector)(selector.elements.slice(match)), self));
                          } else {
                              rules.push(rule);
                          }
                          break;
                      }
                  }
              }
          });
          this._lookups[key] = rules;
          return rules;
      },
      genCSS: function (env, output) {
          var i, j,
              ruleNodes = [],
              rulesetNodes = [],
              rulesetNodeCnt,
              debugInfo,     // Line number debugging
              rule,
              path;
  
          env.tabLevel = (env.tabLevel || 0);
  
          if (!this.root) {
              env.tabLevel++;
          }
  
          var tabRuleStr = env.compress ? '' : Array(env.tabLevel + 1).join("  "),
              tabSetStr = env.compress ? '' : Array(env.tabLevel).join("  "),
              sep;
  
          for (i = 0; i < this.rules.length; i++) {
              rule = this.rules[i];
              if (rule.rules || (rule instanceof tree.Media) || rule instanceof tree.Directive || (this.root && rule instanceof tree.Comment)) {
                  rulesetNodes.push(rule);
              } else {
                  ruleNodes.push(rule);
              }
          }
  
          // If this is the root node, we don't render
          // a selector, or {}.
          if (!this.root) {
              debugInfo = tree.debugInfo(env, this, tabSetStr);
  
              if (debugInfo) {
                  output.add(debugInfo);
                  output.add(tabSetStr);
              }
  
              var paths = this.paths, pathCnt = paths.length,
                  pathSubCnt;
  
              sep = env.compress ? ',' : (',\n' + tabSetStr);
  
              for (i = 0; i < pathCnt; i++) {
                  path = paths[i];
                  if (!(pathSubCnt = path.length)) { continue; }
                  if (i > 0) { output.add(sep); }
  
                  env.firstSelector = true;
                  path[0].genCSS(env, output);
  
                  env.firstSelector = false;
                  for (j = 1; j < pathSubCnt; j++) {
                      path[j].genCSS(env, output);
                  }
              }
  
              output.add((env.compress ? '{' : ' {\n') + tabRuleStr);
          }
  
          // Compile rules and rulesets
          for (i = 0; i < ruleNodes.length; i++) {
              rule = ruleNodes[i];
  
              // @page{ directive ends up with root elements inside it, a mix of rules and rulesets
              // In this instance we do not know whether it is the last property
              if (i + 1 === ruleNodes.length && (!this.root || rulesetNodes.length === 0 || this.firstRoot)) {
                  env.lastRule = true;
              }
  
              if (rule.genCSS) {
                  rule.genCSS(env, output);
              } else if (rule.value) {
                  output.add(rule.value.toString());
              }
  
              if (!env.lastRule) {
                  output.add(env.compress ? '' : ('\n' + tabRuleStr));
              } else {
                  env.lastRule = false;
              }
          }
  
          if (!this.root) {
              output.add((env.compress ? '}' : '\n' + tabSetStr + '}'));
              env.tabLevel--;
          }
  
          sep = (env.compress ? "" : "\n") + (this.root ? tabRuleStr : tabSetStr);
          rulesetNodeCnt = rulesetNodes.length;
          if (rulesetNodeCnt) {
              if (ruleNodes.length && sep) { output.add(sep); }
              rulesetNodes[0].genCSS(env, output);
              for (i = 1; i < rulesetNodeCnt; i++) {
                  if (sep) { output.add(sep); }
                  rulesetNodes[i].genCSS(env, output);
              }
          }
  
          if (!output.isEmpty() && !env.compress && this.firstRoot) {
              output.add('\n');
          }
      },
  
      toCSS: tree.toCSS,
  
      markReferenced: function () {
          for (var s = 0; s < this.selectors.length; s++) {
              this.selectors[s].markReferenced();
          }
      },
  
      joinSelectors: function (paths, context, selectors) {
          for (var s = 0; s < selectors.length; s++) {
              this.joinSelector(paths, context, selectors[s]);
          }
      },
  
      joinSelector: function (paths, context, selector) {
  
          var i, j, k, 
              hasParentSelector, newSelectors, el, sel, parentSel, 
              newSelectorPath, afterParentJoin, newJoinedSelector, 
              newJoinedSelectorEmpty, lastSelector, currentElements,
              selectorsMultiplied;
      
          for (i = 0; i < selector.elements.length; i++) {
              el = selector.elements[i];
              if (el.value === '&') {
                  hasParentSelector = true;
              }
          }
      
          if (!hasParentSelector) {
              if (context.length > 0) {
                  for (i = 0; i < context.length; i++) {
                      paths.push(context[i].concat(selector));
                  }
              }
              else {
                  paths.push([selector]);
              }
              return;
          }
  
          // The paths are [[Selector]]
          // The first list is a list of comma seperated selectors
          // The inner list is a list of inheritance seperated selectors
          // e.g.
          // .a, .b {
          //   .c {
          //   }
          // }
          // == [[.a] [.c]] [[.b] [.c]]
          //
  
          // the elements from the current selector so far
          currentElements = [];
          // the current list of new selectors to add to the path.
          // We will build it up. We initiate it with one empty selector as we "multiply" the new selectors
          // by the parents
          newSelectors = [[]];
  
          for (i = 0; i < selector.elements.length; i++) {
              el = selector.elements[i];
              // non parent reference elements just get added
              if (el.value !== "&") {
                  currentElements.push(el);
              } else {
                  // the new list of selectors to add
                  selectorsMultiplied = [];
  
                  // merge the current list of non parent selector elements
                  // on to the current list of selectors to add
                  if (currentElements.length > 0) {
                      this.mergeElementsOnToSelectors(currentElements, newSelectors);
                  }
  
                  // loop through our current selectors
                  for (j = 0; j < newSelectors.length; j++) {
                      sel = newSelectors[j];
                      // if we don't have any parent paths, the & might be in a mixin so that it can be used
                      // whether there are parents or not
                      if (context.length === 0) {
                          // the combinator used on el should now be applied to the next element instead so that
                          // it is not lost
                          if (sel.length > 0) {
                              sel[0].elements = sel[0].elements.slice(0);
                              sel[0].elements.push(new(tree.Element)(el.combinator, '', 0, el.index, el.currentFileInfo));
                          }
                          selectorsMultiplied.push(sel);
                      }
                      else {
                          // and the parent selectors
                          for (k = 0; k < context.length; k++) {
                              parentSel = context[k];
                              // We need to put the current selectors
                              // then join the last selector's elements on to the parents selectors
  
                              // our new selector path
                              newSelectorPath = [];
                              // selectors from the parent after the join
                              afterParentJoin = [];
                              newJoinedSelectorEmpty = true;
  
                              //construct the joined selector - if & is the first thing this will be empty,
                              // if not newJoinedSelector will be the last set of elements in the selector
                              if (sel.length > 0) {
                                  newSelectorPath = sel.slice(0);
                                  lastSelector = newSelectorPath.pop();
                                  newJoinedSelector = selector.createDerived(lastSelector.elements.slice(0));
                                  newJoinedSelectorEmpty = false;
                              }
                              else {
                                  newJoinedSelector = selector.createDerived([]);
                              }
  
                              //put together the parent selectors after the join
                              if (parentSel.length > 1) {
                                  afterParentJoin = afterParentJoin.concat(parentSel.slice(1));
                              }
  
                              if (parentSel.length > 0) {
                                  newJoinedSelectorEmpty = false;
  
                                  // join the elements so far with the first part of the parent
                                  newJoinedSelector.elements.push(new(tree.Element)(el.combinator, parentSel[0].elements[0].value, el.index, el.currentFileInfo));
                                  newJoinedSelector.elements = newJoinedSelector.elements.concat(parentSel[0].elements.slice(1));
                              }
  
                              if (!newJoinedSelectorEmpty) {
                                  // now add the joined selector
                                  newSelectorPath.push(newJoinedSelector);
                              }
  
                              // and the rest of the parent
                              newSelectorPath = newSelectorPath.concat(afterParentJoin);
  
                              // add that to our new set of selectors
                              selectorsMultiplied.push(newSelectorPath);
                          }
                      }
                  }
  
                  // our new selectors has been multiplied, so reset the state
                  newSelectors = selectorsMultiplied;
                  currentElements = [];
              }
          }
  
          // if we have any elements left over (e.g. .a& .b == .b)
          // add them on to all the current selectors
          if (currentElements.length > 0) {
              this.mergeElementsOnToSelectors(currentElements, newSelectors);
          }
  
          for (i = 0; i < newSelectors.length; i++) {
              if (newSelectors[i].length > 0) {
                  paths.push(newSelectors[i]);
              }
          }
      },
      
      mergeElementsOnToSelectors: function(elements, selectors) {
          var i, sel;
  
          if (selectors.length === 0) {
              selectors.push([ new(tree.Selector)(elements) ]);
              return;
          }
  
          for (i = 0; i < selectors.length; i++) {
              sel = selectors[i];
  
              // if the previous thing in sel is a parent this needs to join on to it
              if (sel.length > 0) {
                  sel[sel.length - 1] = sel[sel.length - 1].createDerived(sel[sel.length - 1].elements.concat(elements));
              }
              else {
                  sel.push(new(tree.Selector)(elements));
              }
          }
      }
  };
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Selector = function (elements, extendList, condition, index, currentFileInfo, isReferenced) {
      this.elements = elements;
      this.extendList = extendList;
      this.condition = condition;
      this.currentFileInfo = currentFileInfo || {};
      this.isReferenced = isReferenced;
      if (!condition) {
          this.evaldCondition = true;
      }
  };
  tree.Selector.prototype = {
      type: "Selector",
      accept: function (visitor) {
          if (this.elements) {
              this.elements = visitor.visitArray(this.elements);
          }
          if (this.extendList) {
              this.extendList = visitor.visitArray(this.extendList);
          }
          if (this.condition) {
              this.condition = visitor.visit(this.condition);
          }
      },
      createDerived: function(elements, extendList, evaldCondition) {
          evaldCondition = (evaldCondition != null) ? evaldCondition : this.evaldCondition;
          var newSelector = new(tree.Selector)(elements, extendList || this.extendList, this.condition, this.index, this.currentFileInfo, this.isReferenced);
          newSelector.evaldCondition = evaldCondition;
          return newSelector;
      },
      match: function (other) {
          var elements = this.elements,
              len = elements.length,
              oelements, olen, i;
              
          oelements = other.elements.map( function(v) {
              return v.combinator.value + (v.value.value || v.value);
          }).join("").match(/[,&#\.\w-]([\w-]|(\\.))*/g); 
          // ^ regexp could be more simple but see test/less/css-escapes.less:17, doh!
          
          if (!oelements) {
              return 0;
          }
  
          if (oelements[0] === "&") {
              oelements.shift();
          }
  
          olen = oelements.length;
          if (olen === 0 || len < olen) {
              return 0;
          } else {
              for (i = 0; i < olen; i++) {
                  if (elements[i].value !== oelements[i]) {
                      return 0;
                  }
              }
          }
          return olen; // return number of matched elements
      },
      eval: function (env) {
          var evaldCondition = this.condition && this.condition.eval(env),
              elements = this.elements, extendList = this.extendList;
  
          elements = elements && elements.map(function (e) { return e.eval(env); });
          extendList = extendList && extendList.map(function(extend) { return extend.eval(env); });
  
          return this.createDerived(elements, extendList, evaldCondition);
      },
      genCSS: function (env, output) {
          var i, element;
          if ((!env || !env.firstSelector) && this.elements[0].combinator.value === "") {
              output.add(' ', this.currentFileInfo, this.index);
          }
          if (!this._css) {
              //TODO caching? speed comparison?
              for(i = 0; i < this.elements.length; i++) {
                  element = this.elements[i];
                  element.genCSS(env, output);
              }
          }
      },
      toCSS: tree.toCSS,
      markReferenced: function () {
          this.isReferenced = true;
      },
      getIsReferenced: function() {
          return !this.currentFileInfo.reference || this.isReferenced;
      },
      getIsOutput: function() {
          return this.evaldCondition;
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.UnicodeDescriptor = function (value) {
      this.value = value;
  };
  tree.UnicodeDescriptor.prototype = {
      type: "UnicodeDescriptor",
      genCSS: function (env, output) {
          output.add(this.value);
      },
      toCSS: tree.toCSS,
      eval: function () { return this; }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.URL = function (val, currentFileInfo, isEvald) {
      this.value = val;
      this.currentFileInfo = currentFileInfo;
      this.isEvald = isEvald;
  };
  tree.URL.prototype = {
      type: "Url",
      accept: function (visitor) {
          this.value = visitor.visit(this.value);
      },
      genCSS: function (env, output) {
          output.add("url(");
          this.value.genCSS(env, output);
          output.add(")");
      },
      toCSS: tree.toCSS,
      eval: function (ctx) {
          var val = this.value.eval(ctx),
              rootpath;
  
          if (!this.isEvald) {
              // Add the base path if the URL is relative
              rootpath = this.currentFileInfo && this.currentFileInfo.rootpath;
              if (rootpath && typeof val.value === "string" && ctx.isPathRelative(val.value)) {
                  if (!val.quote) {
                      rootpath = rootpath.replace(/[\(\)'"\s]/g, function(match) { return "\\"+match; });
                  }
                  val.value = rootpath + val.value;
              }
              
              val.value = ctx.normalizePath(val.value);
          }
  
          return new(tree.URL)(val, this.currentFileInfo, true);
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Value = function (value) {
      this.value = value;
  };
  tree.Value.prototype = {
      type: "Value",
      accept: function (visitor) {
          if (this.value) {
              this.value = visitor.visitArray(this.value);
          }
      },
      eval: function (env) {
          if (this.value.length === 1) {
              return this.value[0].eval(env);
          } else {
              return new(tree.Value)(this.value.map(function (v) {
                  return v.eval(env);
              }));
          }
      },
      genCSS: function (env, output) {
          var i;
          for(i = 0; i < this.value.length; i++) {
              this.value[i].genCSS(env, output);
              if (i+1 < this.value.length) {
                  output.add((env && env.compress) ? ',' : ', ');
              }
          }
      },
      toCSS: tree.toCSS
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
  tree.Variable = function (name, index, currentFileInfo) {
      this.name = name;
      this.index = index;
      this.currentFileInfo = currentFileInfo || {};
  };
  tree.Variable.prototype = {
      type: "Variable",
      eval: function (env) {
          var variable, name = this.name;
  
          if (name.indexOf('@@') === 0) {
              name = '@' + new(tree.Variable)(name.slice(1)).eval(env).value;
          }
          
          if (this.evaluating) {
              throw { type: 'Name',
                      message: "Recursive variable definition for " + name,
                      filename: this.currentFileInfo.file,
                      index: this.index };
          }
          
          this.evaluating = true;
  
          variable = tree.find(env.frames, function (frame) {
              var v = frame.variable(name);
              if (v) {
                  return v.value.eval(env);
              }
          });
          if (variable) { 
              this.evaluating = false;
              return variable;
          } else {
              throw { type: 'Name',
                      message: "variable " + name + " is undefined",
                      filename: this.currentFileInfo.filename,
                      index: this.index };
          }
      }
  };
  
  })(require('../tree'));
  
  (function (tree) {
  
      var parseCopyProperties = [
          'paths',            // option - unmodified - paths to search for imports on
          'optimization',     // option - optimization level (for the chunker)
          'files',            // list of files that have been imported, used for import-once
          'contents',         // map - filename to contents of all the files
          'contentsIgnoredChars', // map - filename to lines at the begining of each file to ignore
          'relativeUrls',     // option - whether to adjust URL's to be relative
          'rootpath',         // option - rootpath to append to URL's
          'strictImports',    // option -
          'insecure',         // option - whether to allow imports from insecure ssl hosts
          'dumpLineNumbers',  // option - whether to dump line numbers
          'compress',         // option - whether to compress
          'processImports',   // option - whether to process imports. if false then imports will not be imported
          'syncImport',       // option - whether to import synchronously
          'javascriptEnabled',// option - whether JavaScript is enabled. if undefined, defaults to true
          'mime',             // browser only - mime type for sheet import
          'useFileCache',     // browser only - whether to use the per file session cache
          'currentFileInfo'   // information about the current file - for error reporting and importing and making urls relative etc.
      ];
  
      //currentFileInfo = {
      //  'relativeUrls' - option - whether to adjust URL's to be relative
      //  'filename' - full resolved filename of current file
      //  'rootpath' - path to append to normal URLs for this node
      //  'currentDirectory' - path to the current file, absolute
      //  'rootFilename' - filename of the base file
      //  'entryPath' - absolute path to the entry file
      //  'reference' - whether the file should not be output and only output parts that are referenced
  
      tree.parseEnv = function(options) {
          copyFromOriginal(options, this, parseCopyProperties);
  
          if (!this.contents) { this.contents = {}; }
          if (!this.contentsIgnoredChars) { this.contentsIgnoredChars = {}; }
          if (!this.files) { this.files = {}; }
  
          if (!this.currentFileInfo) {
              var filename = (options && options.filename) || "input";
              var entryPath = filename.replace(/[^\/\\]*$/, "");
              if (options) {
                  options.filename = null;
              }
              this.currentFileInfo = {
                  filename: filename,
                  relativeUrls: this.relativeUrls,
                  rootpath: (options && options.rootpath) || "",
                  currentDirectory: entryPath,
                  entryPath: entryPath,
                  rootFilename: filename
              };
          }
      };
  
      var evalCopyProperties = [
          'silent',      // whether to swallow errors and warnings
          'verbose',     // whether to log more activity
          'compress',    // whether to compress
          'yuicompress', // whether to compress with the outside tool yui compressor
          'ieCompat',    // whether to enforce IE compatibility (IE8 data-uri)
          'strictMath',  // whether math has to be within parenthesis
          'strictUnits', // whether units need to evaluate correctly
          'cleancss',    // whether to compress with clean-css
          'sourceMap',   // whether to output a source map
          'importMultiple'// whether we are currently importing multiple copies
          ];
  
      tree.evalEnv = function(options, frames) {
          copyFromOriginal(options, this, evalCopyProperties);
  
          this.frames = frames || [];
      };
  
      tree.evalEnv.prototype.inParenthesis = function () {
          if (!this.parensStack) {
              this.parensStack = [];
          }
          this.parensStack.push(true);
      };
  
      tree.evalEnv.prototype.outOfParenthesis = function () {
          this.parensStack.pop();
      };
  
      tree.evalEnv.prototype.isMathOn = function () {
          return this.strictMath ? (this.parensStack && this.parensStack.length) : true;
      };
  
      tree.evalEnv.prototype.isPathRelative = function (path) {
          return !/^(?:[a-z-]+:|\/)/.test(path);
      };
  
      tree.evalEnv.prototype.normalizePath = function( path ) {
          var
            segments = path.split("/").reverse(),
            segment;
  
          path = [];
          while (segments.length !== 0 ) {
              segment = segments.pop();
              switch( segment ) {
                  case ".":
                      break;
                  case "..":
                      if ((path.length === 0) || (path[path.length - 1] === "..")) {
                          path.push( segment );
                      } else {
                          path.pop();
                      }
                      break;
                  default:
                      path.push( segment );
                      break;
              }
          }
  
          return path.join("/");
      };
  
      //todo - do the same for the toCSS env
      //tree.toCSSEnv = function (options) {
      //};
  
      var copyFromOriginal = function(original, destination, propertiesToCopy) {
          if (!original) { return; }
  
          for(var i = 0; i < propertiesToCopy.length; i++) {
              if (original.hasOwnProperty(propertiesToCopy[i])) {
                  destination[propertiesToCopy[i]] = original[propertiesToCopy[i]];
              }
          }
      };
  
  })(require('./tree'));
  
  (function (tree) {
  
      var _visitArgs = { visitDeeper: true },
          _hasIndexed = false;
  
      function _noop(node) {
          return node;
      }
  
      function indexNodeTypes(parent, ticker) {
          // add .typeIndex to tree node types for lookup table
          var key, child;
          for (key in parent) {
              child = parent[key];
              switch (typeof child) {
                  case "function":
                      // ignore bound functions directly on tree which do not have a prototype
                      // or aren't nodes
                      if (child.prototype && child.prototype.type) {
                          child.prototype.typeIndex = ticker++;
                      }
                      break;
                  case "object":
                      ticker = indexNodeTypes(child, ticker);
                      break;
              }
          }
          return ticker;
      }
  
      tree.visitor = function(implementation) {
          this._implementation = implementation;
          this._visitFnCache = [];
  
          if (!_hasIndexed) {
              indexNodeTypes(tree, 1);
              _hasIndexed = true;
          }
      };
  
      tree.visitor.prototype = {
          visit: function(node) {
              if (!node) {
                  return node;
              }
  
              var nodeTypeIndex = node.typeIndex;
              if (!nodeTypeIndex) {
                  return node;
              }
  
              var visitFnCache = this._visitFnCache,
                  impl = this._implementation,
                  aryIndx = nodeTypeIndex << 1,
                  outAryIndex = aryIndx | 1,
                  func = visitFnCache[aryIndx],
                  funcOut = visitFnCache[outAryIndex],
                  visitArgs = _visitArgs,
                  fnName;
  
              visitArgs.visitDeeper = true;
  
              if (!func) {
                  fnName = "visit" + node.type;
                  func = impl[fnName] || _noop;
                  funcOut = impl[fnName + "Out"] || _noop;
                  visitFnCache[aryIndx] = func;
                  visitFnCache[outAryIndex] = funcOut;
              }
  
              if (func !== _noop) {
                  var newNode = func.call(impl, node, visitArgs);
                  if (impl.isReplacing) {
                      node = newNode;
                  }
              }
  
              if (visitArgs.visitDeeper && node && node.accept) {
                  node.accept(this);
              }
  
              if (funcOut != _noop) {
                  funcOut.call(impl, node);
              }
  
              return node;
          },
          visitArray: function(nodes, nonReplacing) {
              if (!nodes) {
                  return nodes;
              }
  
              var cnt = nodes.length, i;
  
              // Non-replacing
              if (nonReplacing || !this._implementation.isReplacing) {
                  for (i = 0; i < cnt; i++) {
                      this.visit(nodes[i]);
                  }
                  return nodes;
              }
  
              // Replacing
              var out = [];
              for (i = 0; i < cnt; i++) {
                  var evald = this.visit(nodes[i]);
                  if (!evald.splice) {
                      out.push(evald);
                  } else if (evald.length) {
                      this.flatten(evald, out);
                  }
              }
              return out;
          },
          flatten: function(arr, out) {
              if (!out) {
                  out = [];
              }
  
              var cnt, i, item,
                  nestedCnt, j, nestedItem;
  
              for (i = 0, cnt = arr.length; i < cnt; i++) {
                  item = arr[i];
                  if (!item.splice) {
                      out.push(item);
                      continue;
                  }
  
                  for (j = 0, nestedCnt = item.length; j < nestedCnt; j++) {
                      nestedItem = item[j];
                      if (!nestedItem.splice) {
                          out.push(nestedItem);
                      } else if (nestedItem.length) {
                          this.flatten(nestedItem, out);
                      }
                  }
              }
  
              return out;
          }
      };
  
  })(require('./tree'));
  (function (tree) {
      tree.importVisitor = function(importer, finish, evalEnv) {
          this._visitor = new tree.visitor(this);
          this._importer = importer;
          this._finish = finish;
          this.env = evalEnv || new tree.evalEnv();
          this.importCount = 0;
      };
  
      tree.importVisitor.prototype = {
          isReplacing: true,
          run: function (root) {
              var error;
              try {
                  // process the contents
                  this._visitor.visit(root);
              }
              catch(e) {
                  error = e;
              }
  
              this.isFinished = true;
  
              if (this.importCount === 0) {
                  this._finish(error);
              }
          },
          visitImport: function (importNode, visitArgs) {
              var importVisitor = this,
                  evaldImportNode,
                  inlineCSS = importNode.options.inline;
  
              if (!importNode.css || inlineCSS) {
  
                  try {
                      evaldImportNode = importNode.evalForImport(this.env);
                  } catch(e){
                      if (!e.filename) { e.index = importNode.index; e.filename = importNode.currentFileInfo.filename; }
                      // attempt to eval properly and treat as css
                      importNode.css = true;
                      // if that fails, this error will be thrown
                      importNode.error = e;
                  }
  
                  if (evaldImportNode && (!evaldImportNode.css || inlineCSS)) {
                      importNode = evaldImportNode;
                      this.importCount++;
                      var env = new tree.evalEnv(this.env, this.env.frames.slice(0));
  
                      if (importNode.options.multiple) {
                          env.importMultiple = true;
                      }
  
                      this._importer.push(importNode.getPath(), importNode.currentFileInfo, importNode.options, function (e, root, imported, fullPath) {
                          if (e && !e.filename) { e.index = importNode.index; e.filename = importNode.currentFileInfo.filename; }
  
                          if (imported && !env.importMultiple) { importNode.skip = imported; }
  
                          var subFinish = function(e) {
                              importVisitor.importCount--;
  
                              if (importVisitor.importCount === 0 && importVisitor.isFinished) {
                                  importVisitor._finish(e);
                              }
                          };
  
                          if (root) {
                              importNode.root = root;
                              importNode.importedFilename = fullPath;
                              if (!inlineCSS && !importNode.skip) {
                                  new(tree.importVisitor)(importVisitor._importer, subFinish, env)
                                      .run(root);
                                  return;
                              }
                          }
  
                          subFinish();
                      });
                  }
              }
              visitArgs.visitDeeper = false;
              return importNode;
          },
          visitRule: function (ruleNode, visitArgs) {
              visitArgs.visitDeeper = false;
              return ruleNode;
          },
          visitDirective: function (directiveNode, visitArgs) {
              this.env.frames.unshift(directiveNode);
              return directiveNode;
          },
          visitDirectiveOut: function (directiveNode) {
              this.env.frames.shift();
          },
          visitMixinDefinition: function (mixinDefinitionNode, visitArgs) {
              this.env.frames.unshift(mixinDefinitionNode);
              return mixinDefinitionNode;
          },
          visitMixinDefinitionOut: function (mixinDefinitionNode) {
              this.env.frames.shift();
          },
          visitRuleset: function (rulesetNode, visitArgs) {
              this.env.frames.unshift(rulesetNode);
              return rulesetNode;
          },
          visitRulesetOut: function (rulesetNode) {
              this.env.frames.shift();
          },
          visitMedia: function (mediaNode, visitArgs) {
              this.env.frames.unshift(mediaNode.ruleset);
              return mediaNode;
          },
          visitMediaOut: function (mediaNode) {
              this.env.frames.shift();
          }
      };
  
  })(require('./tree'));
  (function (tree) {
      tree.joinSelectorVisitor = function() {
          this.contexts = [[]];
          this._visitor = new tree.visitor(this);
      };
  
      tree.joinSelectorVisitor.prototype = {
          run: function (root) {
              return this._visitor.visit(root);
          },
          visitRule: function (ruleNode, visitArgs) {
              visitArgs.visitDeeper = false;
          },
          visitMixinDefinition: function (mixinDefinitionNode, visitArgs) {
              visitArgs.visitDeeper = false;
          },
  
          visitRuleset: function (rulesetNode, visitArgs) {
              var context = this.contexts[this.contexts.length - 1],
                  paths = [], selectors;
  
              this.contexts.push(paths);
  
              if (! rulesetNode.root) {
                  selectors = rulesetNode.selectors;
                  if (selectors) {
                      selectors = selectors.filter(function(selector) { return selector.getIsOutput(); });
                      rulesetNode.selectors = selectors.length ? selectors : (selectors = null);
                      if (selectors) { rulesetNode.joinSelectors(paths, context, selectors); }
                  }
                  if (!selectors) { rulesetNode.rules = null; }
                  rulesetNode.paths = paths;
              }
          },
          visitRulesetOut: function (rulesetNode) {
              this.contexts.length = this.contexts.length - 1;
          },
          visitMedia: function (mediaNode, visitArgs) {
              var context = this.contexts[this.contexts.length - 1];
              mediaNode.rules[0].root = (context.length === 0 || context[0].multiMedia);
          }
      };
  
  })(require('./tree'));
  (function (tree) {
      tree.toCSSVisitor = function(env) {
          this._visitor = new tree.visitor(this);
          this._env = env;
      };
  
      tree.toCSSVisitor.prototype = {
          isReplacing: true,
          run: function (root) {
              return this._visitor.visit(root);
          },
  
          visitRule: function (ruleNode, visitArgs) {
              if (ruleNode.variable) {
                  return [];
              }
              return ruleNode;
          },
  
          visitMixinDefinition: function (mixinNode, visitArgs) {
              return [];
          },
  
          visitExtend: function (extendNode, visitArgs) {
              return [];
          },
  
          visitComment: function (commentNode, visitArgs) {
              if (commentNode.isSilent(this._env)) {
                  return [];
              }
              return commentNode;
          },
  
          visitMedia: function(mediaNode, visitArgs) {
              mediaNode.accept(this._visitor);
              visitArgs.visitDeeper = false;
  
              if (!mediaNode.rules.length) {
                  return [];
              }
              return mediaNode;
          },
  
          visitDirective: function(directiveNode, visitArgs) {
              if (directiveNode.currentFileInfo.reference && !directiveNode.isReferenced) {
                  return [];
              }
              if (directiveNode.name === "@charset") {
                  // Only output the debug info together with subsequent @charset definitions
                  // a comment (or @media statement) before the actual @charset directive would
                  // be considered illegal css as it has to be on the first line
                  if (this.charset) {
                      if (directiveNode.debugInfo) {
                          var comment = new tree.Comment("/* " + directiveNode.toCSS(this._env).replace(/\n/g, "")+" */\n");
                          comment.debugInfo = directiveNode.debugInfo;
                          return this._visitor.visit(comment);
                      }
                      return [];
                  }
                  this.charset = true;
              }
              return directiveNode;
          },
  
          checkPropertiesInRoot: function(rules) {
              var ruleNode;
              for(var i = 0; i < rules.length; i++) {
                  ruleNode = rules[i];
                  if (ruleNode instanceof tree.Rule && !ruleNode.variable) {
                      throw { message: "properties must be inside selector blocks, they cannot be in the root.",
                          index: ruleNode.index, filename: ruleNode.currentFileInfo ? ruleNode.currentFileInfo.filename : null};
                  }
              }
          },
  
          visitRuleset: function (rulesetNode, visitArgs) {
              var rule, rulesets = [];
              if (rulesetNode.firstRoot) {
                  this.checkPropertiesInRoot(rulesetNode.rules);
              }
              if (! rulesetNode.root) {
                  if (rulesetNode.paths) {
                      rulesetNode.paths = rulesetNode.paths
                          .filter(function(p) {
                              var i;
                              if (p[0].elements[0].combinator.value === ' ') {
                                  p[0].elements[0].combinator = new(tree.Combinator)('');
                              }
                              for(i = 0; i < p.length; i++) {
                                  if (p[i].getIsReferenced() && p[i].getIsOutput()) {
                                      return true;
                                  }
                              }
                              return false;
                          });
                  }
  
                  // Compile rules and rulesets
                  var nodeRules = rulesetNode.rules, nodeRuleCnt = nodeRules ? nodeRules.length : 0;
                  for (var i = 0; i < nodeRuleCnt; ) {
                      rule = nodeRules[i];
                      if (rule && rule.rules) {
                          // visit because we are moving them out from being a child
                          rulesets.push(this._visitor.visit(rule));
                          nodeRules.splice(i, 1);
                          nodeRuleCnt--;
                          continue;
                      }
                      i++;
                  }
                  // accept the visitor to remove rules and refactor itself
                  // then we can decide now whether we want it or not
                  if (nodeRuleCnt > 0) {
                      rulesetNode.accept(this._visitor);
                  } else {
                      rulesetNode.rules = null;
                  }
                  visitArgs.visitDeeper = false;
  
                  nodeRules = rulesetNode.rules;
                  if (nodeRules) {
                      this._mergeRules(nodeRules);
                      nodeRules = rulesetNode.rules;
                  }
                  if (nodeRules) {
                      this._removeDuplicateRules(nodeRules);
                      nodeRules = rulesetNode.rules;
                  }
  
                  // now decide whether we keep the ruleset
                  if (nodeRules && nodeRules.length > 0 && rulesetNode.paths.length > 0) {
                      rulesets.splice(0, 0, rulesetNode);
                  }
              } else {
                  rulesetNode.accept(this._visitor);
                  visitArgs.visitDeeper = false;
                  if (rulesetNode.firstRoot || (rulesetNode.rules && rulesetNode.rules.length > 0)) {
                      rulesets.splice(0, 0, rulesetNode);
                  }
              }
              if (rulesets.length === 1) {
                  return rulesets[0];
              }
              return rulesets;
          },
  
          _removeDuplicateRules: function(rules) {
              if (!rules) { return; }
  
              // remove duplicates
              var ruleCache = {},
                  ruleList, rule, i;
  
              for(i = rules.length - 1; i >= 0 ; i--) {
                  rule = rules[i];
                  if (rule instanceof tree.Rule) {
                      if (!ruleCache[rule.name]) {
                          ruleCache[rule.name] = rule;
                      } else {
                          ruleList = ruleCache[rule.name];
                          if (ruleList instanceof tree.Rule) {
                              ruleList = ruleCache[rule.name] = [ruleCache[rule.name].toCSS(this._env)];
                          }
                          var ruleCSS = rule.toCSS(this._env);
                          if (ruleList.indexOf(ruleCSS) !== -1) {
                              rules.splice(i, 1);
                          } else {
                              ruleList.push(ruleCSS);
                          }
                      }
                  }
              }
          },
  
          _mergeRules: function (rules) {
              if (!rules) { return; }
  
              var groups = {},
                  parts,
                  rule,
                  key;
  
              for (var i = 0; i < rules.length; i++) {
                  rule = rules[i];
  
                  if ((rule instanceof tree.Rule) && rule.merge) {
                      key = [rule.name,
                          rule.important ? "!" : ""].join(",");
  
                      if (!groups[key]) {
                          groups[key] = [];
                      } else {
                          rules.splice(i--, 1);
                      }
  
                      groups[key].push(rule);
                  }
              }
  
              Object.keys(groups).map(function (k) {
                  parts = groups[k];
  
                  if (parts.length > 1) {
                      rule = parts[0];
  
                      rule.value = new (tree.Value)(parts.map(function (p) {
                          return p.value;
                      }));
                  }
              });
          }
      };
  
  })(require('./tree'));
  (function (tree) {
      /*jshint loopfunc:true */
  
      tree.extendFinderVisitor = function() {
          this._visitor = new tree.visitor(this);
          this.contexts = [];
          this.allExtendsStack = [[]];
      };
  
      tree.extendFinderVisitor.prototype = {
          run: function (root) {
              root = this._visitor.visit(root);
              root.allExtends = this.allExtendsStack[0];
              return root;
          },
          visitRule: function (ruleNode, visitArgs) {
              visitArgs.visitDeeper = false;
          },
          visitMixinDefinition: function (mixinDefinitionNode, visitArgs) {
              visitArgs.visitDeeper = false;
          },
          visitRuleset: function (rulesetNode, visitArgs) {
              if (rulesetNode.root) {
                  return;
              }
  
              var i, j, extend, allSelectorsExtendList = [], extendList;
  
              // get &:extend(.a); rules which apply to all selectors in this ruleset
              var rules = rulesetNode.rules, ruleCnt = rules ? rules.length : 0;
              for(i = 0; i < ruleCnt; i++) {
                  if (rulesetNode.rules[i] instanceof tree.Extend) {
                      allSelectorsExtendList.push(rules[i]);
                      rulesetNode.extendOnEveryPath = true;
                  }
              }
  
              // now find every selector and apply the extends that apply to all extends
              // and the ones which apply to an individual extend
              var paths = rulesetNode.paths;
              for(i = 0; i < paths.length; i++) {
                  var selectorPath = paths[i],
                      selector = selectorPath[selectorPath.length - 1],
                      selExtendList = selector.extendList;
  
                  extendList = selExtendList ? selExtendList.slice(0).concat(allSelectorsExtendList)
                                             : allSelectorsExtendList;
  
                  if (extendList) {
                      extendList = extendList.map(function(allSelectorsExtend) {
                          return allSelectorsExtend.clone();
                      });
                  }
  
                  for(j = 0; j < extendList.length; j++) {
                      this.foundExtends = true;
                      extend = extendList[j];
                      extend.findSelfSelectors(selectorPath);
                      extend.ruleset = rulesetNode;
                      if (j === 0) { extend.firstExtendOnThisSelectorPath = true; }
                      this.allExtendsStack[this.allExtendsStack.length-1].push(extend);
                  }
              }
  
              this.contexts.push(rulesetNode.selectors);
          },
          visitRulesetOut: function (rulesetNode) {
              if (!rulesetNode.root) {
                  this.contexts.length = this.contexts.length - 1;
              }
          },
          visitMedia: function (mediaNode, visitArgs) {
              mediaNode.allExtends = [];
              this.allExtendsStack.push(mediaNode.allExtends);
          },
          visitMediaOut: function (mediaNode) {
              this.allExtendsStack.length = this.allExtendsStack.length - 1;
          },
          visitDirective: function (directiveNode, visitArgs) {
              directiveNode.allExtends = [];
              this.allExtendsStack.push(directiveNode.allExtends);
          },
          visitDirectiveOut: function (directiveNode) {
              this.allExtendsStack.length = this.allExtendsStack.length - 1;
          }
      };
  
      tree.processExtendsVisitor = function() {
          this._visitor = new tree.visitor(this);
      };
  
      tree.processExtendsVisitor.prototype = {
          run: function(root) {
              var extendFinder = new tree.extendFinderVisitor();
              extendFinder.run(root);
              if (!extendFinder.foundExtends) { return root; }
              root.allExtends = root.allExtends.concat(this.doExtendChaining(root.allExtends, root.allExtends));
              this.allExtendsStack = [root.allExtends];
              return this._visitor.visit(root);
          },
          doExtendChaining: function (extendsList, extendsListTarget, iterationCount) {
              //
              // chaining is different from normal extension.. if we extend an extend then we are not just copying, altering and pasting
              // the selector we would do normally, but we are also adding an extend with the same target selector
              // this means this new extend can then go and alter other extends
              //
              // this method deals with all the chaining work - without it, extend is flat and doesn't work on other extend selectors
              // this is also the most expensive.. and a match on one selector can cause an extension of a selector we had already processed if
              // we look at each selector at a time, as is done in visitRuleset
  
              var extendIndex, targetExtendIndex, matches, extendsToAdd = [], newSelector, extendVisitor = this, selectorPath, extend, targetExtend, newExtend;
  
              iterationCount = iterationCount || 0;
  
              //loop through comparing every extend with every target extend.
              // a target extend is the one on the ruleset we are looking at copy/edit/pasting in place
              // e.g.  .a:extend(.b) {}  and .b:extend(.c) {} then the first extend extends the second one
              // and the second is the target.
              // the seperation into two lists allows us to process a subset of chains with a bigger set, as is the
              // case when processing media queries
              for(extendIndex = 0; extendIndex < extendsList.length; extendIndex++){
                  for(targetExtendIndex = 0; targetExtendIndex < extendsListTarget.length; targetExtendIndex++){
  
                      extend = extendsList[extendIndex];
                      targetExtend = extendsListTarget[targetExtendIndex];
  
                      // look for circular references
                      if( extend.parent_ids.indexOf( targetExtend.object_id ) >= 0 ){ continue; }
  
                      // find a match in the target extends self selector (the bit before :extend)
                      selectorPath = [targetExtend.selfSelectors[0]];
                      matches = extendVisitor.findMatch(extend, selectorPath);
  
                      if (matches.length) {
  
                          // we found a match, so for each self selector..
                          extend.selfSelectors.forEach(function(selfSelector) {
  
                              // process the extend as usual
                              newSelector = extendVisitor.extendSelector(matches, selectorPath, selfSelector);
  
                              // but now we create a new extend from it
                              newExtend = new(tree.Extend)(targetExtend.selector, targetExtend.option, 0);
                              newExtend.selfSelectors = newSelector;
  
                              // add the extend onto the list of extends for that selector
                              newSelector[newSelector.length-1].extendList = [newExtend];
  
                              // record that we need to add it.
                              extendsToAdd.push(newExtend);
                              newExtend.ruleset = targetExtend.ruleset;
  
                              //remember its parents for circular references
                              newExtend.parent_ids = newExtend.parent_ids.concat(targetExtend.parent_ids, extend.parent_ids);
  
                              // only process the selector once.. if we have :extend(.a,.b) then multiple
                              // extends will look at the same selector path, so when extending
                              // we know that any others will be duplicates in terms of what is added to the css
                              if (targetExtend.firstExtendOnThisSelectorPath) {
                                  newExtend.firstExtendOnThisSelectorPath = true;
                                  targetExtend.ruleset.paths.push(newSelector);
                              }
                          });
                      }
                  }
              }
  
              if (extendsToAdd.length) {
                  // try to detect circular references to stop a stack overflow.
                  // may no longer be needed.
                  this.extendChainCount++;
                  if (iterationCount > 100) {
                      var selectorOne = "{unable to calculate}";
                      var selectorTwo = "{unable to calculate}";
                      try
                      {
                          selectorOne = extendsToAdd[0].selfSelectors[0].toCSS();
                          selectorTwo = extendsToAdd[0].selector.toCSS();
                      }
                      catch(e) {}
                      throw {message: "extend circular reference detected. One of the circular extends is currently:"+selectorOne+":extend(" + selectorTwo+")"};
                  }
  
                  // now process the new extends on the existing rules so that we can handle a extending b extending c ectending d extending e...
                  return extendsToAdd.concat(extendVisitor.doExtendChaining(extendsToAdd, extendsListTarget, iterationCount+1));
              } else {
                  return extendsToAdd;
              }
          },
          visitRule: function (ruleNode, visitArgs) {
              visitArgs.visitDeeper = false;
          },
          visitMixinDefinition: function (mixinDefinitionNode, visitArgs) {
              visitArgs.visitDeeper = false;
          },
          visitSelector: function (selectorNode, visitArgs) {
              visitArgs.visitDeeper = false;
          },
          visitRuleset: function (rulesetNode, visitArgs) {
              if (rulesetNode.root) {
                  return;
              }
              var matches, pathIndex, extendIndex, allExtends = this.allExtendsStack[this.allExtendsStack.length-1], selectorsToAdd = [], extendVisitor = this, selectorPath;
  
              // look at each selector path in the ruleset, find any extend matches and then copy, find and replace
  
              for(extendIndex = 0; extendIndex < allExtends.length; extendIndex++) {
                  for(pathIndex = 0; pathIndex < rulesetNode.paths.length; pathIndex++) {
                      selectorPath = rulesetNode.paths[pathIndex];
  
                      // extending extends happens initially, before the main pass
                      if (rulesetNode.extendOnEveryPath) { continue; }
                      var extendList = selectorPath[selectorPath.length-1].extendList;
                      if (extendList && extendList.length) { continue; }
  
                      matches = this.findMatch(allExtends[extendIndex], selectorPath);
  
                      if (matches.length) {
  
                          allExtends[extendIndex].selfSelectors.forEach(function(selfSelector) {
                              selectorsToAdd.push(extendVisitor.extendSelector(matches, selectorPath, selfSelector));
                          });
                      }
                  }
              }
              rulesetNode.paths = rulesetNode.paths.concat(selectorsToAdd);
          },
          findMatch: function (extend, haystackSelectorPath) {
              //
              // look through the haystack selector path to try and find the needle - extend.selector
              // returns an array of selector matches that can then be replaced
              //
              var haystackSelectorIndex, hackstackSelector, hackstackElementIndex, haystackElement,
                  targetCombinator, i,
                  extendVisitor = this,
                  needleElements = extend.selector.elements,
                  potentialMatches = [], potentialMatch, matches = [];
  
              // loop through the haystack elements
              for(haystackSelectorIndex = 0; haystackSelectorIndex < haystackSelectorPath.length; haystackSelectorIndex++) {
                  hackstackSelector = haystackSelectorPath[haystackSelectorIndex];
  
                  for(hackstackElementIndex = 0; hackstackElementIndex < hackstackSelector.elements.length; hackstackElementIndex++) {
  
                      haystackElement = hackstackSelector.elements[hackstackElementIndex];
  
                      // if we allow elements before our match we can add a potential match every time. otherwise only at the first element.
                      if (extend.allowBefore || (haystackSelectorIndex === 0 && hackstackElementIndex === 0)) {
                          potentialMatches.push({pathIndex: haystackSelectorIndex, index: hackstackElementIndex, matched: 0, initialCombinator: haystackElement.combinator});
                      }
  
                      for(i = 0; i < potentialMatches.length; i++) {
                          potentialMatch = potentialMatches[i];
  
                          // selectors add " " onto the first element. When we use & it joins the selectors together, but if we don't
                          // then each selector in haystackSelectorPath has a space before it added in the toCSS phase. so we need to work out
                          // what the resulting combinator will be
                          targetCombinator = haystackElement.combinator.value;
                          if (targetCombinator === '' && hackstackElementIndex === 0) {
                              targetCombinator = ' ';
                          }
  
                          // if we don't match, null our match to indicate failure
                          if (!extendVisitor.isElementValuesEqual(needleElements[potentialMatch.matched].value, haystackElement.value) ||
                              (potentialMatch.matched > 0 && needleElements[potentialMatch.matched].combinator.value !== targetCombinator)) {
                              potentialMatch = null;
                          } else {
                              potentialMatch.matched++;
                          }
  
                          // if we are still valid and have finished, test whether we have elements after and whether these are allowed
                          if (potentialMatch) {
                              potentialMatch.finished = potentialMatch.matched === needleElements.length;
                              if (potentialMatch.finished &&
                                  (!extend.allowAfter && (hackstackElementIndex+1 < hackstackSelector.elements.length || haystackSelectorIndex+1 < haystackSelectorPath.length))) {
                                  potentialMatch = null;
                              }
                          }
                          // if null we remove, if not, we are still valid, so either push as a valid match or continue
                          if (potentialMatch) {
                              if (potentialMatch.finished) {
                                  potentialMatch.length = needleElements.length;
                                  potentialMatch.endPathIndex = haystackSelectorIndex;
                                  potentialMatch.endPathElementIndex = hackstackElementIndex + 1; // index after end of match
                                  potentialMatches.length = 0; // we don't allow matches to overlap, so start matching again
                                  matches.push(potentialMatch);
                              }
                          } else {
                              potentialMatches.splice(i, 1);
                              i--;
                          }
                      }
                  }
              }
              return matches;
          },
          isElementValuesEqual: function(elementValue1, elementValue2) {
              if (typeof elementValue1 === "string" || typeof elementValue2 === "string") {
                  return elementValue1 === elementValue2;
              }
              if (elementValue1 instanceof tree.Attribute) {
                  if (elementValue1.op !== elementValue2.op || elementValue1.key !== elementValue2.key) {
                      return false;
                  }
                  if (!elementValue1.value || !elementValue2.value) {
                      if (elementValue1.value || elementValue2.value) {
                          return false;
                      }
                      return true;
                  }
                  elementValue1 = elementValue1.value.value || elementValue1.value;
                  elementValue2 = elementValue2.value.value || elementValue2.value;
                  return elementValue1 === elementValue2;
              }
              elementValue1 = elementValue1.value;
              elementValue2 = elementValue2.value;
              if (elementValue1 instanceof tree.Selector) {
                  if (!(elementValue2 instanceof tree.Selector) || elementValue1.elements.length !== elementValue2.elements.length) {
                      return false;
                  }
                  for(var i = 0; i <elementValue1.elements.length; i++) {
                      if (elementValue1.elements[i].combinator.value !== elementValue2.elements[i].combinator.value) {
                          if (i !== 0 || (elementValue1.elements[i].combinator.value || ' ') !== (elementValue2.elements[i].combinator.value || ' ')) {
                              return false;
                          }
                      }
                      if (!this.isElementValuesEqual(elementValue1.elements[i].value, elementValue2.elements[i].value)) {
                          return false;
                      }
                  }
                  return true;
              }
              return false;
          },
          extendSelector:function (matches, selectorPath, replacementSelector) {
  
              //for a set of matches, replace each match with the replacement selector
  
              var currentSelectorPathIndex = 0,
                  currentSelectorPathElementIndex = 0,
                  path = [],
                  matchIndex,
                  selector,
                  firstElement,
                  match,
                  newElements;
  
              for (matchIndex = 0; matchIndex < matches.length; matchIndex++) {
                  match = matches[matchIndex];
                  selector = selectorPath[match.pathIndex];
                  firstElement = new tree.Element(
                      match.initialCombinator,
                      replacementSelector.elements[0].value,
                      replacementSelector.elements[0].index,
                      replacementSelector.elements[0].currentFileInfo
                  );
  
                  if (match.pathIndex > currentSelectorPathIndex && currentSelectorPathElementIndex > 0) {
                      path[path.length - 1].elements = path[path.length - 1].elements.concat(selectorPath[currentSelectorPathIndex].elements.slice(currentSelectorPathElementIndex));
                      currentSelectorPathElementIndex = 0;
                      currentSelectorPathIndex++;
                  }
  
                  newElements = selector.elements
                      .slice(currentSelectorPathElementIndex, match.index)
                      .concat([firstElement])
                      .concat(replacementSelector.elements.slice(1));
  
                  if (currentSelectorPathIndex === match.pathIndex && matchIndex > 0) {
                      path[path.length - 1].elements =
                          path[path.length - 1].elements.concat(newElements);
                  } else {
                      path = path.concat(selectorPath.slice(currentSelectorPathIndex, match.pathIndex));
  
                      path.push(new tree.Selector(
                          newElements
                      ));
                  }
                  currentSelectorPathIndex = match.endPathIndex;
                  currentSelectorPathElementIndex = match.endPathElementIndex;
                  if (currentSelectorPathElementIndex >= selectorPath[currentSelectorPathIndex].elements.length) {
                      currentSelectorPathElementIndex = 0;
                      currentSelectorPathIndex++;
                  }
              }
  
              if (currentSelectorPathIndex < selectorPath.length && currentSelectorPathElementIndex > 0) {
                  path[path.length - 1].elements = path[path.length - 1].elements.concat(selectorPath[currentSelectorPathIndex].elements.slice(currentSelectorPathElementIndex));
                  currentSelectorPathIndex++;
              }
  
              path = path.concat(selectorPath.slice(currentSelectorPathIndex, selectorPath.length));
  
              return path;
          },
          visitRulesetOut: function (rulesetNode) {
          },
          visitMedia: function (mediaNode, visitArgs) {
              var newAllExtends = mediaNode.allExtends.concat(this.allExtendsStack[this.allExtendsStack.length-1]);
              newAllExtends = newAllExtends.concat(this.doExtendChaining(newAllExtends, mediaNode.allExtends));
              this.allExtendsStack.push(newAllExtends);
          },
          visitMediaOut: function (mediaNode) {
              this.allExtendsStack.length = this.allExtendsStack.length - 1;
          },
          visitDirective: function (directiveNode, visitArgs) {
              var newAllExtends = directiveNode.allExtends.concat(this.allExtendsStack[this.allExtendsStack.length-1]);
              newAllExtends = newAllExtends.concat(this.doExtendChaining(newAllExtends, directiveNode.allExtends));
              this.allExtendsStack.push(newAllExtends);
          },
          visitDirectiveOut: function (directiveNode) {
              this.allExtendsStack.length = this.allExtendsStack.length - 1;
          }
      };
  
  })(require('./tree'));
  
  (function (tree) {
  
      tree.sourceMapOutput = function (options) {
          this._css = [];
          this._rootNode = options.rootNode;
          this._writeSourceMap = options.writeSourceMap;
          this._contentsMap = options.contentsMap;
          this._contentsIgnoredCharsMap = options.contentsIgnoredCharsMap;
          this._sourceMapFilename = options.sourceMapFilename;
          this._outputFilename = options.outputFilename;
          this._sourceMapURL = options.sourceMapURL;
          if (options.sourceMapBasepath) {
              this._sourceMapBasepath = options.sourceMapBasepath.replace(/\\/g, '/');
          }
          this._sourceMapRootpath = options.sourceMapRootpath;
          this._outputSourceFiles = options.outputSourceFiles;
          this._sourceMapGeneratorConstructor = options.sourceMapGenerator || require("source-map").SourceMapGenerator;
  
          if (this._sourceMapRootpath && this._sourceMapRootpath.charAt(this._sourceMapRootpath.length-1) !== '/') {
              this._sourceMapRootpath += '/';
          }
  
          this._lineNumber = 0;
          this._column = 0;
      };
  
      tree.sourceMapOutput.prototype.normalizeFilename = function(filename) {
          filename = filename.replace(/\\/g, '/');
  
          if (this._sourceMapBasepath && filename.indexOf(this._sourceMapBasepath) === 0) {
              filename = filename.substring(this._sourceMapBasepath.length);
              if (filename.charAt(0) === '\\' || filename.charAt(0) === '/') {
                 filename = filename.substring(1);
              }
          }
          return (this._sourceMapRootpath || "") + filename;
      };
  
      tree.sourceMapOutput.prototype.add = function(chunk, fileInfo, index, mapLines) {
  
          //ignore adding empty strings
          if (!chunk) {
              return;
          }
  
          var lines,
              sourceLines,
              columns,
              sourceColumns,
              i;
  
          if (fileInfo) {
              var inputSource = this._contentsMap[fileInfo.filename];
              
              // remove vars/banner added to the top of the file
              if (this._contentsIgnoredCharsMap[fileInfo.filename]) {
                  // adjust the index
                  index -= this._contentsIgnoredCharsMap[fileInfo.filename];
                  if (index < 0) { index = 0; }
                  // adjust the source
                  inputSource = inputSource.slice(this._contentsIgnoredCharsMap[fileInfo.filename]);
              }
              inputSource = inputSource.substring(0, index);
              sourceLines = inputSource.split("\n");
              sourceColumns = sourceLines[sourceLines.length-1];
          }
  
          lines = chunk.split("\n");
          columns = lines[lines.length-1];
  
          if (fileInfo) {
              if (!mapLines) {
                  this._sourceMapGenerator.addMapping({ generated: { line: this._lineNumber + 1, column: this._column},
                      original: { line: sourceLines.length, column: sourceColumns.length},
                      source: this.normalizeFilename(fileInfo.filename)});
              } else {
                  for(i = 0; i < lines.length; i++) {
                      this._sourceMapGenerator.addMapping({ generated: { line: this._lineNumber + i + 1, column: i === 0 ? this._column : 0},
                          original: { line: sourceLines.length + i, column: i === 0 ? sourceColumns.length : 0},
                          source: this.normalizeFilename(fileInfo.filename)});
                  }
              }
          }
  
          if (lines.length === 1) {
              this._column += columns.length;
          } else {
              this._lineNumber += lines.length - 1;
              this._column = columns.length;
          }
  
          this._css.push(chunk);
      };
  
      tree.sourceMapOutput.prototype.isEmpty = function() {
          return this._css.length === 0;
      };
  
      tree.sourceMapOutput.prototype.toCSS = function(env) {
          this._sourceMapGenerator = new this._sourceMapGeneratorConstructor({ file: this._outputFilename, sourceRoot: null });
  
          if (this._outputSourceFiles) {
              for(var filename in this._contentsMap) {
                  var source = this._contentsMap[filename];
                  if (this._contentsIgnoredCharsMap[filename]) {
                      source = source.slice(this._contentsIgnoredCharsMap[filename]);
                  }
                  this._sourceMapGenerator.setSourceContent(this.normalizeFilename(filename), source);
              }
          }
  
          this._rootNode.genCSS(env, this);
  
          if (this._css.length > 0) {
              var sourceMapURL,
                  sourceMapContent = JSON.stringify(this._sourceMapGenerator.toJSON());
  
              if (this._sourceMapURL) {
                  sourceMapURL = this._sourceMapURL;
              } else if (this._sourceMapFilename) {
                  sourceMapURL = this.normalizeFilename(this._sourceMapFilename);
              }
  
              if (this._writeSourceMap) {
                  this._writeSourceMap(sourceMapContent);
              } else {
                  sourceMapURL = "data:application/json," + encodeURIComponent(sourceMapContent);
              }
  
              if (sourceMapURL) {
                  this._css.push("/*# sourceMappingURL=" + sourceMapURL + " */");
              }
          }
  
          return this._css.join('');
      };
  
  })(require('./tree'));
  
  //
  // browser.js - client-side engine
  //
  /*global less, window, document, XMLHttpRequest, location */
  
  var isFileProtocol = /^(file|chrome(-extension)?|resource|qrc|app):/.test(location.protocol);
  
  less.env = less.env || (location.hostname == '127.0.0.1' ||
                          location.hostname == '0.0.0.0'   ||
                          location.hostname == 'localhost' ||
                          (location.port &&
                            location.port.length > 0)      ||
                          isFileProtocol                   ? 'development'
                                                           : 'production');
  
  var logLevel = {
      info: 2,
      errors: 1,
      none: 0
  };
  
  // The amount of logging in the javascript console.
  // 2 - Information and errors
  // 1 - Errors
  // 0 - None
  // Defaults to 2
  less.logLevel = typeof(less.logLevel) != 'undefined' ? less.logLevel : logLevel.info;
  
  // Load styles asynchronously (default: false)
  //
  // This is set to `false` by default, so that the body
  // doesn't start loading before the stylesheets are parsed.
  // Setting this to `true` can result in flickering.
  //
  less.async = less.async || false;
  less.fileAsync = less.fileAsync || false;
  
  // Interval between watch polls
  less.poll = less.poll || (isFileProtocol ? 1000 : 1500);
  
  //Setup user functions
  if (less.functions) {
      for(var func in less.functions) {
          less.tree.functions[func] = less.functions[func];
     }
  }
  
  var dumpLineNumbers = /!dumpLineNumbers:(comments|mediaquery|all)/.exec(location.hash);
  if (dumpLineNumbers) {
      less.dumpLineNumbers = dumpLineNumbers[1];
  }
  
  var typePattern = /^text\/(x-)?less$/;
  var cache = null;
  var fileCache = {};
  
  function log(str, level) {
      if (less.env == 'development' && typeof(console) !== 'undefined' && less.logLevel >= level) {
          console.log('less: ' + str);
      }
  }
  
  function extractId(href) {
      return href.replace(/^[a-z-]+:\/+?[^\/]+/, '' )  // Remove protocol & domain
          .replace(/^\//,                 '' )  // Remove root /
          .replace(/\.[a-zA-Z]+$/,        '' )  // Remove simple extension
          .replace(/[^\.\w-]+/g,          '-')  // Replace illegal characters
          .replace(/\./g,                 ':'); // Replace dots with colons(for valid id)
  }
  
  function errorConsole(e, rootHref) {
      var template = '{line} {content}';
      var filename = e.filename || rootHref;
      var errors = [];
      var content = (e.type || "Syntax") + "Error: " + (e.message || 'There is an error in your .less file') +
          " in " + filename + " ";
  
      var errorline = function (e, i, classname) {
          if (e.extract[i] !== undefined) {
              errors.push(template.replace(/\{line\}/, (parseInt(e.line, 10) || 0) + (i - 1))
                  .replace(/\{class\}/, classname)
                  .replace(/\{content\}/, e.extract[i]));
          }
      };
  
      if (e.extract) {
          errorline(e, 0, '');
          errorline(e, 1, 'line');
          errorline(e, 2, '');
          content += 'on line ' + e.line + ', column ' + (e.column + 1) + ':\n' +
              errors.join('\n');
      } else if (e.stack) {
          content += e.stack;
      }
      log(content, logLevel.errors);
  }
  
  function createCSS(styles, sheet, lastModified) {
      // Strip the query-string
      var href = sheet.href || '';
  
      // If there is no title set, use the filename, minus the extension
      var id = 'less:' + (sheet.title || extractId(href));
  
      // If this has already been inserted into the DOM, we may need to replace it
      var oldCss = document.getElementById(id);
      var keepOldCss = false;
  
      // Create a new stylesheet node for insertion or (if necessary) replacement
      var css = document.createElement('style');
      css.setAttribute('type', 'text/css');
      if (sheet.media) {
          css.setAttribute('media', sheet.media);
      }
      css.id = id;
  
      if (css.styleSheet) { // IE
          try {
              css.styleSheet.cssText = styles;
          } catch (e) {
              throw new(Error)("Couldn't reassign styleSheet.cssText.");
          }
      } else {
          css.appendChild(document.createTextNode(styles));
  
          // If new contents match contents of oldCss, don't replace oldCss
          keepOldCss = (oldCss !== null && oldCss.childNodes.length > 0 && css.childNodes.length > 0 &&
              oldCss.firstChild.nodeValue === css.firstChild.nodeValue);
      }
  
      var head = document.getElementsByTagName('head')[0];
  
      // If there is no oldCss, just append; otherwise, only append if we need
      // to replace oldCss with an updated stylesheet
      if (oldCss === null || keepOldCss === false) {
          var nextEl = sheet && sheet.nextSibling || null;
          if (nextEl) {
              nextEl.parentNode.insertBefore(css, nextEl);
          } else {
              head.appendChild(css);
          }
      }
      if (oldCss && keepOldCss === false) {
          oldCss.parentNode.removeChild(oldCss);
      }
  
      // Don't update the local store if the file wasn't modified
      if (lastModified && cache) {
          log('saving ' + href + ' to cache.', logLevel.info);
          try {
              cache.setItem(href, styles);
              cache.setItem(href + ':timestamp', lastModified);
          } catch(e) {
              //TODO - could do with adding more robust error handling
              log('failed to save', logLevel.errors);
          }
      }
  }
  
  function errorHTML(e, rootHref) {
      var id = 'less-error-message:' + extractId(rootHref || "");
      var template = '<li><label>{line}</label><pre class="{class}">{content}</pre></li>';
      var elem = document.createElement('div'), timer, content, errors = [];
      var filename = e.filename || rootHref;
      var filenameNoPath = filename.match(/([^\/]+(\?.*)?)$/)[1];
  
      elem.id        = id;
      elem.className = "less-error-message";
  
      content = '<h3>'  + (e.type || "Syntax") + "Error: " + (e.message || 'There is an error in your .less file') +
          '</h3>' + '<p>in <a href="' + filename   + '">' + filenameNoPath + "</a> ";
  
      var errorline = function (e, i, classname) {
          if (e.extract[i] !== undefined) {
              errors.push(template.replace(/\{line\}/, (parseInt(e.line, 10) || 0) + (i - 1))
                  .replace(/\{class\}/, classname)
                  .replace(/\{content\}/, e.extract[i]));
          }
      };
  
      if (e.extract) {
          errorline(e, 0, '');
          errorline(e, 1, 'line');
          errorline(e, 2, '');
          content += 'on line ' + e.line + ', column ' + (e.column + 1) + ':</p>' +
              '<ul>' + errors.join('') + '</ul>';
      } else if (e.stack) {
          content += '<br/>' + e.stack.split('\n').slice(1).join('<br/>');
      }
      elem.innerHTML = content;
  
      // CSS for error messages
      createCSS([
          '.less-error-message ul, .less-error-message li {',
          'list-style-type: none;',
          'margin-right: 15px;',
          'padding: 4px 0;',
          'margin: 0;',
          '}',
          '.less-error-message label {',
          'font-size: 12px;',
          'margin-right: 15px;',
          'padding: 4px 0;',
          'color: #cc7777;',
          '}',
          '.less-error-message pre {',
          'color: #dd6666;',
          'padding: 4px 0;',
          'margin: 0;',
          'display: inline-block;',
          '}',
          '.less-error-message pre.line {',
          'color: #ff0000;',
          '}',
          '.less-error-message h3 {',
          'font-size: 20px;',
          'font-weight: bold;',
          'padding: 15px 0 5px 0;',
          'margin: 0;',
          '}',
          '.less-error-message a {',
          'color: #10a',
          '}',
          '.less-error-message .error {',
          'color: red;',
          'font-weight: bold;',
          'padding-bottom: 2px;',
          'border-bottom: 1px dashed red;',
          '}'
      ].join('\n'), { title: 'error-message' });
  
      elem.style.cssText = [
          "font-family: Arial, sans-serif",
          "border: 1px solid #e00",
          "background-color: #eee",
          "border-radius: 5px",
          "-webkit-border-radius: 5px",
          "-moz-border-radius: 5px",
          "color: #e00",
          "padding: 15px",
          "margin-bottom: 15px"
      ].join(';');
  
      if (less.env == 'development') {
          timer = setInterval(function () {
              if (document.body) {
                  if (document.getElementById(id)) {
                      document.body.replaceChild(elem, document.getElementById(id));
                  } else {
                      document.body.insertBefore(elem, document.body.firstChild);
                  }
                  clearInterval(timer);
              }
          }, 10);
      }
  }
  
  function error(e, rootHref) {
      if (!less.errorReporting || less.errorReporting === "html") {
          errorHTML(e, rootHref);
      } else if (less.errorReporting === "console") {
          errorConsole(e, rootHref);
      } else if (typeof less.errorReporting === 'function') {
          less.errorReporting("add", e, rootHref);
      }
  }
  
  function removeErrorHTML(path) {
      var node = document.getElementById('less-error-message:' + extractId(path));
      if (node) {
          node.parentNode.removeChild(node);
      }
  }
  
  function removeErrorConsole(path) {
      //no action
  }
  
  function removeError(path) {
      if (!less.errorReporting || less.errorReporting === "html") {
          removeErrorHTML(path);
      } else if (less.errorReporting === "console") {
          removeErrorConsole(path);
      } else if (typeof less.errorReporting === 'function') {
          less.errorReporting("remove", path);
      }
  }
  
  function loadStyles(modifyVars) {
      var styles = document.getElementsByTagName('style'),
          style;
      for (var i = 0; i < styles.length; i++) {
          style = styles[i];
          if (style.type.match(typePattern)) {
              var env = new less.tree.parseEnv(less),
                  lessText = style.innerHTML || '';
              env.filename = document.location.href.replace(/#.*$/, '');
  
              if (modifyVars || less.globalVars) {
                  env.useFileCache = true;
              }
  
              /*jshint loopfunc:true */
              // use closure to store current value of i
              var callback = (function(style) {
                  return function (e, cssAST) {
                      if (e) {
                          return error(e, "inline");
                      }
                      var css = cssAST.toCSS(less);
                      style.type = 'text/css';
                      if (style.styleSheet) {
                          style.styleSheet.cssText = css;
                      } else {
                          style.innerHTML = css;
                      }
                  };
              })(style);
              new(less.Parser)(env).parse(lessText, callback, {globalVars: less.globalVars, modifyVars: modifyVars});
          }
      }
  }
  
  function extractUrlParts(url, baseUrl) {
      // urlParts[1] = protocol&hostname || /
      // urlParts[2] = / if path relative to host base
      // urlParts[3] = directories
      // urlParts[4] = filename
      // urlParts[5] = parameters
  
      var urlPartsRegex = /^((?:[a-z-]+:)?\/+?(?:[^\/\?#]*\/)|([\/\\]))?((?:[^\/\\\?#]*[\/\\])*)([^\/\\\?#]*)([#\?].*)?$/i,
          urlParts = url.match(urlPartsRegex),
          returner = {}, directories = [], i, baseUrlParts;
  
      if (!urlParts) {
          throw new Error("Could not parse sheet href - '"+url+"'");
      }
  
      // Stylesheets in IE don't always return the full path
      if (!urlParts[1] || urlParts[2]) {
          baseUrlParts = baseUrl.match(urlPartsRegex);
          if (!baseUrlParts) {
              throw new Error("Could not parse page url - '"+baseUrl+"'");
          }
          urlParts[1] = urlParts[1] || baseUrlParts[1] || "";
          if (!urlParts[2]) {
              urlParts[3] = baseUrlParts[3] + urlParts[3];
          }
      }
  
      if (urlParts[3]) {
          directories = urlParts[3].replace(/\\/g, "/").split("/");
  
          // extract out . before .. so .. doesn't absorb a non-directory
          for(i = 0; i < directories.length; i++) {
              if (directories[i] === ".") {
                  directories.splice(i, 1);
                  i -= 1;
              }
          }
  
          for(i = 0; i < directories.length; i++) {
              if (directories[i] === ".." && i > 0) {
                  directories.splice(i-1, 2);
                  i -= 2;
              }
          }
      }
  
      returner.hostPart = urlParts[1];
      returner.directories = directories;
      returner.path = urlParts[1] + directories.join("/");
      returner.fileUrl = returner.path + (urlParts[4] || "");
      returner.url = returner.fileUrl + (urlParts[5] || "");
      return returner;
  }
  
  function pathDiff(url, baseUrl) {
      // diff between two paths to create a relative path
  
      var urlParts = extractUrlParts(url),
          baseUrlParts = extractUrlParts(baseUrl),
          i, max, urlDirectories, baseUrlDirectories, diff = "";
      if (urlParts.hostPart !== baseUrlParts.hostPart) {
          return "";
      }
      max = Math.max(baseUrlParts.directories.length, urlParts.directories.length);
      for(i = 0; i < max; i++) {
          if (baseUrlParts.directories[i] !== urlParts.directories[i]) { break; }
      }
      baseUrlDirectories = baseUrlParts.directories.slice(i);
      urlDirectories = urlParts.directories.slice(i);
      for(i = 0; i < baseUrlDirectories.length-1; i++) {
          diff += "../";
      }
      for(i = 0; i < urlDirectories.length-1; i++) {
          diff += urlDirectories[i] + "/";
      }
      return diff;
  }
  
  function getXMLHttpRequest() {
      if (window.XMLHttpRequest) {
          return new XMLHttpRequest();
      } else {
          try {
              /*global ActiveXObject */
              return new ActiveXObject("MSXML2.XMLHTTP.3.0");
          } catch (e) {
              log("browser doesn't support AJAX.", logLevel.errors);
              return null;
          }
      }
  }
  
  function doXHR(url, type, callback, errback) {
      var xhr = getXMLHttpRequest();
      var async = isFileProtocol ? less.fileAsync : less.async;
  
      if (typeof(xhr.overrideMimeType) === 'function') {
          xhr.overrideMimeType('text/css');
      }
      log("XHR: Getting '" + url + "'", logLevel.info);
      xhr.open('GET', url, async);
      xhr.setRequestHeader('Accept', type || 'text/x-less, text/css; q=0.9, */*; q=0.5');
      xhr.send(null);
  
      function handleResponse(xhr, callback, errback) {
          if (xhr.status >= 200 && xhr.status < 300) {
              callback(xhr.responseText,
                  xhr.getResponseHeader("Last-Modified"));
          } else if (typeof(errback) === 'function') {
              errback(xhr.status, url);
          }
      }
  
      if (isFileProtocol && !less.fileAsync) {
          if (xhr.status === 0 || (xhr.status >= 200 && xhr.status < 300)) {
              callback(xhr.responseText);
          } else {
              errback(xhr.status, url);
          }
      } else if (async) {
          xhr.onreadystatechange = function () {
              if (xhr.readyState == 4) {
                  handleResponse(xhr, callback, errback);
              }
          };
      } else {
          handleResponse(xhr, callback, errback);
      }
  }
  
  function loadFile(originalHref, currentFileInfo, callback, env, modifyVars) {
  
      if (currentFileInfo && currentFileInfo.currentDirectory && !/^([a-z-]+:)?\//.test(originalHref)) {
          originalHref = currentFileInfo.currentDirectory + originalHref;
      }
  
      // sheet may be set to the stylesheet for the initial load or a collection of properties including
      // some env variables for imports
      var hrefParts = extractUrlParts(originalHref, window.location.href);
      var href      = hrefParts.url;
      var newFileInfo = {
          currentDirectory: hrefParts.path,
          filename: href
      };
  
      if (currentFileInfo) {
          newFileInfo.entryPath = currentFileInfo.entryPath;
          newFileInfo.rootpath = currentFileInfo.rootpath;
          newFileInfo.rootFilename = currentFileInfo.rootFilename;
          newFileInfo.relativeUrls = currentFileInfo.relativeUrls;
      } else {
          newFileInfo.entryPath = hrefParts.path;
          newFileInfo.rootpath = less.rootpath || hrefParts.path;
          newFileInfo.rootFilename = href;
          newFileInfo.relativeUrls = env.relativeUrls;
      }
  
      if (newFileInfo.relativeUrls) {
          if (env.rootpath) {
              newFileInfo.rootpath = extractUrlParts(env.rootpath + pathDiff(hrefParts.path, newFileInfo.entryPath)).path;
          } else {
              newFileInfo.rootpath = hrefParts.path;
          }
      }
  
      if (env.useFileCache && fileCache[href]) {
          try {
              var lessText = fileCache[href];
              callback(null, lessText, href, newFileInfo, { lastModified: new Date() });
          } catch (e) {
              callback(e, null, href);
          }
          return;
      }
  
      doXHR(href, env.mime, function (data, lastModified) {
          // per file cache
          fileCache[href] = data;
  
          // Use remote copy (re-parse)
          try {
              callback(null, data, href, newFileInfo, { lastModified: lastModified });
          } catch (e) {
              callback(e, null, href);
          }
      }, function (status, url) {
          callback({ type: 'File', message: "'" + url + "' wasn't found (" + status + ")" }, null, href);
      });
  }
  
  function loadStyleSheet(sheet, callback, reload, remaining, modifyVars) {
  
      var env = new less.tree.parseEnv(less);
      env.mime = sheet.type;
  
      if (modifyVars || less.globalVars) {
          env.useFileCache = true;
      }
  
      loadFile(sheet.href, null, function(e, data, path, newFileInfo, webInfo) {
  
          if (webInfo) {
              webInfo.remaining = remaining;
  
              var css       = cache && cache.getItem(path),
                  timestamp = cache && cache.getItem(path + ':timestamp');
  
              if (!reload && timestamp && webInfo.lastModified &&
                  (new(Date)(webInfo.lastModified).valueOf() ===
                      new(Date)(timestamp).valueOf())) {
                  // Use local copy
                  createCSS(css, sheet);
                  webInfo.local = true;
                  callback(null, null, data, sheet, webInfo, path);
                  return;
              }
          }
  
          //TODO add tests around how this behaves when reloading
          removeError(path);
  
          if (data) {
              env.currentFileInfo = newFileInfo;
              new(less.Parser)(env).parse(data, function (e, root) {
                  if (e) { return callback(e, null, null, sheet); }
                  try {
                      callback(e, root, data, sheet, webInfo, path);
                  } catch (e) {
                      callback(e, null, null, sheet);
                  }
              }, {modifyVars: modifyVars, globalVars: less.globalVars});
          } else {
              callback(e, null, null, sheet, webInfo, path);
          }
      }, env, modifyVars);
  }
  
  function loadStyleSheets(callback, reload, modifyVars) {
      for (var i = 0; i < less.sheets.length; i++) {
          loadStyleSheet(less.sheets[i], callback, reload, less.sheets.length - (i + 1), modifyVars);
      }
  }
  
  function initRunningMode(){
      if (less.env === 'development') {
          less.optimization = 0;
          less.watchTimer = setInterval(function () {
              if (less.watchMode) {
                  loadStyleSheets(function (e, root, _, sheet, env) {
                      if (e) {
                          error(e, sheet.href);
                      } else if (root) {
                          createCSS(root.toCSS(less), sheet, env.lastModified);
                      }
                  });
              }
          }, less.poll);
      } else {
          less.optimization = 3;
      }
  }
  
  
  
  //
  // Watch mode
  //
  less.watch   = function () {
      if (!less.watchMode ){
          less.env = 'development';
           initRunningMode();
      }
      this.watchMode = true;
      return true;
  };
  
  less.unwatch = function () {clearInterval(less.watchTimer); this.watchMode = false; return false; };
  
  if (/!watch/.test(location.hash)) {
      less.watch();
  }
  
  if (less.env != 'development') {
      try {
          cache = (typeof(window.localStorage) === 'undefined') ? null : window.localStorage;
      } catch (_) {}
  }
  
  //
  // Get all <link> tags with the 'rel' attribute set to "stylesheet/less"
  //
  var links = document.getElementsByTagName('link');
  
  less.sheets = [];
  
  for (var i = 0; i < links.length; i++) {
      if (links[i].rel === 'stylesheet/less' || (links[i].rel.match(/stylesheet/) &&
         (links[i].type.match(typePattern)))) {
          less.sheets.push(links[i]);
      }
  }
  
  //
  // With this function, it's possible to alter variables and re-render
  // CSS without reloading less-files
  //
  less.modifyVars = function(record) {
      less.refresh(false, record);
  };
  
  less.refresh = function (reload, modifyVars) {
      var startTime, endTime;
      startTime = endTime = new Date();
  
      loadStyleSheets(function (e, root, _, sheet, env) {
          if (e) {
              return error(e, sheet.href);
          }
          if (env.local) {
              log("loading " + sheet.href + " from cache.", logLevel.info);
          } else {
              log("parsed " + sheet.href + " successfully.", logLevel.info);
              createCSS(root.toCSS(less), sheet, env.lastModified);
          }
          log("css for " + sheet.href + " generated in " + (new Date() - endTime) + 'ms', logLevel.info);
          if (env.remaining === 0) {
              log("css generated in " + (new Date() - startTime) + 'ms', logLevel.info);
          }
          endTime = new Date();
      }, reload, modifyVars);
  
      loadStyles(modifyVars);
  };
  
  less.refreshStyles = loadStyles;
  
  less.Parser.fileLoader = loadFile;
  
  less.refresh(less.env === 'development');
  
  // amd.js
  //
  // Define Less as an AMD module.
  if (typeof define === "function" && define.amd) {
      define(function () { return less; } );
  }
  
  })(window);
  ;!function(exports, undefined) {
  
    var isArray = Array.isArray ? Array.isArray : function _isArray(obj) {
      return Object.prototype.toString.call(obj) === "[object Array]";
    };
    var defaultMaxListeners = 10;
  
    function init() {
      this._events = {};
      if (this._conf) {
        configure.call(this, this._conf);
      }
    }
  
    function configure(conf) {
      if (conf) {
  
        this._conf = conf;
  
        conf.delimiter && (this.delimiter = conf.delimiter);
        conf.maxListeners && (this._events.maxListeners = conf.maxListeners);
        conf.wildcard && (this.wildcard = conf.wildcard);
        conf.newListener && (this.newListener = conf.newListener);
  
        if (this.wildcard) {
          this.listenerTree = {};
        }
      }
    }
  
    function EventEmitter(conf) {
      this._events = {};
      this.newListener = false;
      configure.call(this, conf);
    }
  
    //
    // Attention, function return type now is array, always !
    // It has zero elements if no any matches found and one or more
    // elements (leafs) if there are matches
    //
    function searchListenerTree(handlers, type, tree, i) {
      if (!tree) {
        return [];
      }
      var listeners=[], leaf, len, branch, xTree, xxTree, isolatedBranch, endReached,
          typeLength = type.length, currentType = type[i], nextType = type[i+1];
      if (i === typeLength && tree._listeners) {
        //
        // If at the end of the event(s) list and the tree has listeners
        // invoke those listeners.
        //
        if (typeof tree._listeners === 'function') {
          handlers && handlers.push(tree._listeners);
          return [tree];
        } else {
          for (leaf = 0, len = tree._listeners.length; leaf < len; leaf++) {
            handlers && handlers.push(tree._listeners[leaf]);
          }
          return [tree];
        }
      }
  
      if ((currentType === '*' || currentType === '**') || tree[currentType]) {
        //
        // If the event emitted is '*' at this part
        // or there is a concrete match at this patch
        //
        if (currentType === '*') {
          for (branch in tree) {
            if (branch !== '_listeners' && tree.hasOwnProperty(branch)) {
              listeners = listeners.concat(searchListenerTree(handlers, type, tree[branch], i+1));
            }
          }
          return listeners;
        } else if(currentType === '**') {
          endReached = (i+1 === typeLength || (i+2 === typeLength && nextType === '*'));
          if(endReached && tree._listeners) {
            // The next element has a _listeners, add it to the handlers.
            listeners = listeners.concat(searchListenerTree(handlers, type, tree, typeLength));
          }
  
          for (branch in tree) {
            if (branch !== '_listeners' && tree.hasOwnProperty(branch)) {
              if(branch === '*' || branch === '**') {
                if(tree[branch]._listeners && !endReached) {
                  listeners = listeners.concat(searchListenerTree(handlers, type, tree[branch], typeLength));
                }
                listeners = listeners.concat(searchListenerTree(handlers, type, tree[branch], i));
              } else if(branch === nextType) {
                listeners = listeners.concat(searchListenerTree(handlers, type, tree[branch], i+2));
              } else {
                // No match on this one, shift into the tree but not in the type array.
                listeners = listeners.concat(searchListenerTree(handlers, type, tree[branch], i));
              }
            }
          }
          return listeners;
        }
  
        listeners = listeners.concat(searchListenerTree(handlers, type, tree[currentType], i+1));
      }
  
      xTree = tree['*'];
      if (xTree) {
        //
        // If the listener tree will allow any match for this part,
        // then recursively explore all branches of the tree
        //
        searchListenerTree(handlers, type, xTree, i+1);
      }
  
      xxTree = tree['**'];
      if(xxTree) {
        if(i < typeLength) {
          if(xxTree._listeners) {
            // If we have a listener on a '**', it will catch all, so add its handler.
            searchListenerTree(handlers, type, xxTree, typeLength);
          }
  
          // Build arrays of matching next branches and others.
          for(branch in xxTree) {
            if(branch !== '_listeners' && xxTree.hasOwnProperty(branch)) {
              if(branch === nextType) {
                // We know the next element will match, so jump twice.
                searchListenerTree(handlers, type, xxTree[branch], i+2);
              } else if(branch === currentType) {
                // Current node matches, move into the tree.
                searchListenerTree(handlers, type, xxTree[branch], i+1);
              } else {
                isolatedBranch = {};
                isolatedBranch[branch] = xxTree[branch];
                searchListenerTree(handlers, type, { '**': isolatedBranch }, i+1);
              }
            }
          }
        } else if(xxTree._listeners) {
          // We have reached the end and still on a '**'
          searchListenerTree(handlers, type, xxTree, typeLength);
        } else if(xxTree['*'] && xxTree['*']._listeners) {
          searchListenerTree(handlers, type, xxTree['*'], typeLength);
        }
      }
  
      return listeners;
    }
  
    function growListenerTree(type, listener) {
  
      type = typeof type === 'string' ? type.split(this.delimiter) : type.slice();
  
      //
      // Looks for two consecutive '**', if so, don't add the event at all.
      //
      for(var i = 0, len = type.length; i+1 < len; i++) {
        if(type[i] === '**' && type[i+1] === '**') {
          return;
        }
      }
  
      var tree = this.listenerTree;
      var name = type.shift();
  
      while (name) {
  
        if (!tree[name]) {
          tree[name] = {};
        }
  
        tree = tree[name];
  
        if (type.length === 0) {
  
          if (!tree._listeners) {
            tree._listeners = listener;
          }
          else if(typeof tree._listeners === 'function') {
            tree._listeners = [tree._listeners, listener];
          }
          else if (isArray(tree._listeners)) {
  
            tree._listeners.push(listener);
  
            if (!tree._listeners.warned) {
  
              var m = defaultMaxListeners;
  
              if (typeof this._events.maxListeners !== 'undefined') {
                m = this._events.maxListeners;
              }
  
              if (m > 0 && tree._listeners.length > m) {
  
                tree._listeners.warned = true;
                console.error('(node) warning: possible EventEmitter memory ' +
                              'leak detected. %d listeners added. ' +
                              'Use emitter.setMaxListeners() to increase limit.',
                              tree._listeners.length);
                console.trace();
              }
            }
          }
          return true;
        }
        name = type.shift();
      }
      return true;
    }
  
    // By default EventEmitters will print a warning if more than
    // 10 listeners are added to it. This is a useful default which
    // helps finding memory leaks.
    //
    // Obviously not all Emitters should be limited to 10. This function allows
    // that to be increased. Set to zero for unlimited.
  
    EventEmitter.prototype.delimiter = '.';
  
    EventEmitter.prototype.setMaxListeners = function(n) {
      this._events || init.call(this);
      this._events.maxListeners = n;
      if (!this._conf) this._conf = {};
      this._conf.maxListeners = n;
    };
  
    EventEmitter.prototype.event = '';
  
    EventEmitter.prototype.once = function(event, fn) {
      this.many(event, 1, fn);
      return this;
    };
  
    EventEmitter.prototype.many = function(event, ttl, fn) {
      var self = this;
  
      if (typeof fn !== 'function') {
        throw new Error('many only accepts instances of Function');
      }
  
      function listener() {
        if (--ttl === 0) {
          self.off(event, listener);
        }
        fn.apply(this, arguments);
      }
  
      listener._origin = fn;
  
      this.on(event, listener);
  
      return self;
    };
  
    EventEmitter.prototype.emit = function() {
  
      this._events || init.call(this);
  
      var type = arguments[0];
  
      if (type === 'newListener' && !this.newListener) {
        if (!this._events.newListener) { return false; }
      }
  
      // Loop through the *_all* functions and invoke them.
      if (this._all) {
        var l = arguments.length;
        var args = new Array(l - 1);
        for (var i = 1; i < l; i++) args[i - 1] = arguments[i];
        for (i = 0, l = this._all.length; i < l; i++) {
          this.event = type;
          this._all[i].apply(this, args);
        }
      }
  
      // If there is no 'error' event listener then throw.
      if (type === 'error') {
  
        if (!this._all &&
          !this._events.error &&
          !(this.wildcard && this.listenerTree.error)) {
  
          if (arguments[1] instanceof Error) {
            throw arguments[1]; // Unhandled 'error' event
          } else {
            throw new Error("Uncaught, unspecified 'error' event.");
          }
          return false;
        }
      }
  
      var handler;
  
      if(this.wildcard) {
        handler = [];
        var ns = typeof type === 'string' ? type.split(this.delimiter) : type.slice();
        searchListenerTree.call(this, handler, ns, this.listenerTree, 0);
      }
      else {
        handler = this._events[type];
      }
  
      if (typeof handler === 'function') {
        this.event = type;
        if (arguments.length === 1) {
          handler.call(this);
        }
        else if (arguments.length > 1)
          switch (arguments.length) {
            case 2:
              handler.call(this, arguments[1]);
              break;
            case 3:
              handler.call(this, arguments[1], arguments[2]);
              break;
            // slower
            default:
              var l = arguments.length;
              var args = new Array(l - 1);
              for (var i = 1; i < l; i++) args[i - 1] = arguments[i];
              handler.apply(this, args);
          }
        return true;
      }
      else if (handler) {
        var l = arguments.length;
        var args = new Array(l - 1);
        for (var i = 1; i < l; i++) args[i - 1] = arguments[i];
  
        var listeners = handler.slice();
        for (var i = 0, l = listeners.length; i < l; i++) {
          this.event = type;
          listeners[i].apply(this, args);
        }
        return (listeners.length > 0) || this._all;
      }
      else {
        return this._all;
      }
  
    };
  
    EventEmitter.prototype.on = function(type, listener) {
  
      if (typeof type === 'function') {
        this.onAny(type);
        return this;
      }
  
      if (typeof listener !== 'function') {
        throw new Error('on only accepts instances of Function');
      }
      this._events || init.call(this);
  
      // To avoid recursion in the case that type == "newListeners"! Before
      // adding it to the listeners, first emit "newListeners".
      this.emit('newListener', type, listener);
  
      if(this.wildcard) {
        growListenerTree.call(this, type, listener);
        return this;
      }
  
      if (!this._events[type]) {
        // Optimize the case of one listener. Don't need the extra array object.
        this._events[type] = listener;
      }
      else if(typeof this._events[type] === 'function') {
        // Adding the second element, need to change to array.
        this._events[type] = [this._events[type], listener];
      }
      else if (isArray(this._events[type])) {
        // If we've already got an array, just append.
        this._events[type].push(listener);
  
        // Check for listener leak
        if (!this._events[type].warned) {
  
          var m = defaultMaxListeners;
  
          if (typeof this._events.maxListeners !== 'undefined') {
            m = this._events.maxListeners;
          }
  
          if (m > 0 && this._events[type].length > m) {
  
            this._events[type].warned = true;
            console.error('(node) warning: possible EventEmitter memory ' +
                          'leak detected. %d listeners added. ' +
                          'Use emitter.setMaxListeners() to increase limit.',
                          this._events[type].length);
            console.trace();
          }
        }
      }
      return this;
    };
  
    EventEmitter.prototype.onAny = function(fn) {
  
      if(!this._all) {
        this._all = [];
      }
  
      if (typeof fn !== 'function') {
        throw new Error('onAny only accepts instances of Function');
      }
  
      // Add the function to the event listener collection.
      this._all.push(fn);
      return this;
    };
  
    EventEmitter.prototype.addListener = EventEmitter.prototype.on;
  
    EventEmitter.prototype.off = function(type, listener) {
      if (typeof listener !== 'function') {
        throw new Error('removeListener only takes instances of Function');
      }
  
      var handlers,leafs=[];
  
      if(this.wildcard) {
        var ns = typeof type === 'string' ? type.split(this.delimiter) : type.slice();
        leafs = searchListenerTree.call(this, null, ns, this.listenerTree, 0);
      }
      else {
        // does not use listeners(), so no side effect of creating _events[type]
        if (!this._events[type]) return this;
        handlers = this._events[type];
        leafs.push({_listeners:handlers});
      }
  
      for (var iLeaf=0; iLeaf<leafs.length; iLeaf++) {
        var leaf = leafs[iLeaf];
        handlers = leaf._listeners;
        if (isArray(handlers)) {
  
          var position = -1;
  
          for (var i = 0, length = handlers.length; i < length; i++) {
            if (handlers[i] === listener ||
              (handlers[i].listener && handlers[i].listener === listener) ||
              (handlers[i]._origin && handlers[i]._origin === listener)) {
              position = i;
              break;
            }
          }
  
          if (position < 0) {
            continue;
          }
  
          if(this.wildcard) {
            leaf._listeners.splice(position, 1);
          }
          else {
            this._events[type].splice(position, 1);
          }
  
          if (handlers.length === 0) {
            if(this.wildcard) {
              delete leaf._listeners;
            }
            else {
              delete this._events[type];
            }
          }
          return this;
        }
        else if (handlers === listener ||
          (handlers.listener && handlers.listener === listener) ||
          (handlers._origin && handlers._origin === listener)) {
          if(this.wildcard) {
            delete leaf._listeners;
          }
          else {
            delete this._events[type];
          }
        }
      }
  
      return this;
    };
  
    EventEmitter.prototype.offAny = function(fn) {
      var i = 0, l = 0, fns;
      if (fn && this._all && this._all.length > 0) {
        fns = this._all;
        for(i = 0, l = fns.length; i < l; i++) {
          if(fn === fns[i]) {
            fns.splice(i, 1);
            return this;
          }
        }
      } else {
        this._all = [];
      }
      return this;
    };
  
    EventEmitter.prototype.removeListener = EventEmitter.prototype.off;
  
    EventEmitter.prototype.removeAllListeners = function(type) {
      if (arguments.length === 0) {
        !this._events || init.call(this);
        return this;
      }
  
      if(this.wildcard) {
        var ns = typeof type === 'string' ? type.split(this.delimiter) : type.slice();
        var leafs = searchListenerTree.call(this, null, ns, this.listenerTree, 0);
  
        for (var iLeaf=0; iLeaf<leafs.length; iLeaf++) {
          var leaf = leafs[iLeaf];
          leaf._listeners = null;
        }
      }
      else {
        if (!this._events[type]) return this;
        this._events[type] = null;
      }
      return this;
    };
  
    EventEmitter.prototype.listeners = function(type) {
      if(this.wildcard) {
        var handlers = [];
        var ns = typeof type === 'string' ? type.split(this.delimiter) : type.slice();
        searchListenerTree.call(this, handlers, ns, this.listenerTree, 0);
        return handlers;
      }
  
      this._events || init.call(this);
  
      if (!this._events[type]) this._events[type] = [];
      if (!isArray(this._events[type])) {
        this._events[type] = [this._events[type]];
      }
      return this._events[type];
    };
  
    EventEmitter.prototype.listenersAny = function() {
  
      if(this._all) {
        return this._all;
      }
      else {
        return [];
      }
  
    };
  
    if (typeof define === 'function' && define.amd) {
      define(function() {
        return EventEmitter;
      });
    } else {
      exports.EventEmitter2 = EventEmitter;
    }
  
  }(typeof process !== 'undefined' && typeof process.title !== 'undefined' && typeof exports !== 'undefined' ? exports : window);
  
  (function(window) {
    'use strict';
  
    // Public: Create a new SelectorSet.
    function SelectorSet() {
      // Construct new SelectorSet if called as a function.
      if (!(this instanceof SelectorSet)) {
        return new SelectorSet();
      }
  
      // Public: Number of selectors added to the set
      this.size = 0;
  
      // Internal: Incrementing ID counter
      this.uid = 0;
  
      // Internal: Array of String selectors in the set
      this.selectors = [];
  
      // Internal: All Object index String names mapping to Index objects.
      this.indexes = Object.create(this.indexes);
  
      // Internal: Used Object index String names mapping to Index objects.
      this.activeIndexes = [];
    }
  
    // Detect prefixed Element#matches function.
    var docElem = window.document.documentElement;
    var matches = (docElem.webkitMatchesSelector ||
                    docElem.mozMatchesSelector ||
                    docElem.oMatchesSelector ||
                    docElem.msMatchesSelector);
  
    // Public: Check if element matches selector.
    //
    // Maybe overridden with custom Element.matches function.
    //
    // el       - An Element
    // selector - String CSS selector
    //
    // Returns true or false.
    SelectorSet.prototype.matchesSelector = function(el, selector) {
      return matches.call(el, selector);
    };
  
    // Public: Find all elements in the context that match the selector.
    //
    // Maybe overridden with custom querySelectorAll function.
    //
    // selectors - String CSS selectors.
    // context   - Element context
    //
    // Returns non-live list of Elements.
    SelectorSet.prototype.querySelectorAll = function(selectors, context) {
      return context.querySelectorAll(selectors);
    };
  
  
    // Public: Array of indexes.
    //
    // name     - Unique String name
    // selector - Function that takes a String selector and returns a String key
    //            or undefined if it can't be used by the index.
    // element  - Function that takes an Element and returns an Array of String
    //            keys that point to indexed values.
    //
    SelectorSet.prototype.indexes = [];
  
    // Index by element id
    var idRe = /^#((?:[\w\u00c0-\uFFFF\-]|\\.)+)/g;
    SelectorSet.prototype.indexes.push({
      name: 'ID',
      selector: function matchIdSelector(sel) {
        var m;
        if (m = sel.match(idRe)) {
          return m[0].slice(1);
        }
      },
      element: function getElementId(el) {
        if (el.id) {
          return [el.id];
        }
      }
    });
  
    // Index by all of its class names
    var classRe = /^\.((?:[\w\u00c0-\uFFFF\-]|\\.)+)/g;
    SelectorSet.prototype.indexes.push({
      name: 'CLASS',
      selector: function matchClassSelector(sel) {
        var m;
        if (m = sel.match(classRe)) {
          return m[0].slice(1);
        }
      },
      element: function getElementClassNames(el) {
        var className = el.className;
        if (className) {
          if (typeof className === 'string') {
            return className.split(/\s/);
          } else if (typeof className === 'object' && 'baseVal' in className) {
            // className is a SVGAnimatedString
            // global SVGAnimatedString is not an exposed global in Opera 12
            return className.baseVal.split(/\s/);
          }
        }
      }
    });
  
    // Index by tag/node name: `DIV`, `FORM`, `A`
    var tagRe = /^((?:[\w\u00c0-\uFFFF\-]|\\.)+)/g;
    SelectorSet.prototype.indexes.push({
      name: 'TAG',
      selector: function matchTagSelector(sel) {
        var m;
        if (m = sel.match(tagRe)) {
          return m[0].toUpperCase();
        }
      },
      element: function getElementTagName(el) {
        return [el.nodeName.toUpperCase()];
      }
    });
  
    // Default index just contains a single array of elements.
    SelectorSet.prototype.indexes['default'] = {
      name: 'UNIVERSAL',
      selector: function() {
        return true;
      },
      element: function() {
        return [true];
      }
    };
  
  
    // Use ES Maps when supported
    var Map;
    if (typeof window.Map === 'function') {
      Map = window.Map;
    } else {
      Map = (function() {
        function Map() {
          this.map = {};
        }
        Map.prototype.get = function(key) {
          return this.map[key + ' '];
        };
        Map.prototype.set = function(key, value) {
          this.map[key + ' '] = value;
        };
        return Map;
      })();
    }
  
  
    // Regexps adopted from Sizzle
    //   https://github.com/jquery/sizzle/blob/1.7/sizzle.js
    //
    var chunker = /((?:\((?:\([^()]+\)|[^()]+)+\)|\[(?:\[[^\[\]]*\]|['"][^'"]*['"]|[^\[\]'"]+)+\]|\\.|[^ >+~,(\[\\]+)+|[>+~])(\s*,\s*)?((?:.|\r|\n)*)/g;
  
    // Internal: Get indexes for selector.
    //
    // selector - String CSS selector
    //
    // Returns Array of {index, key}.
    function parseSelectorIndexes(allIndexes, selector) {
      allIndexes = allIndexes.slice(0).concat(allIndexes['default']);
  
      var allIndexesLen = allIndexes.length,
          i, j, m, dup, rest = selector,
          key, index, indexes = [];
  
      do {
        chunker.exec('');
        if (m = chunker.exec(rest)) {
          rest = m[3];
          if (m[2] || !rest) {
            for (i = 0; i < allIndexesLen; i++) {
              index = allIndexes[i];
              if (key = index.selector(m[1])) {
                j = indexes.length;
                dup = false;
                while (j--) {
                  if (indexes[j].index === index && indexes[j].key === key) {
                    dup = true;
                    break;
                  }
                }
                if (!dup) {
                  indexes.push({index: index, key: key});
                }
                break;
              }
            }
          }
        }
      } while (m);
  
      return indexes;
    }
  
    // Internal: Find first item in Array that is a prototype of `proto`.
    //
    // ary   - Array of objects
    // proto - Prototype of expected item in `ary`
    //
    // Returns object from `ary` if found. Otherwise returns undefined.
    function findByPrototype(ary, proto) {
      var i, len, item;
      for (i = 0, len = ary.length; i < len; i++) {
        item = ary[i];
        if (proto.isPrototypeOf(item)) {
          return item;
        }
      }
    }
  
    // Public: Log when added selector falls under the default index.
    //
    // This API should not be considered stable. May change between
    // minor versions.
    //
    // obj - {selector, data} Object
    //
    //   SelectorSet.prototype.logDefaultIndexUsed = function(obj) {
    //     console.warn(obj.selector, "could not be indexed");
    //   };
    //
    // Returns nothing.
    SelectorSet.prototype.logDefaultIndexUsed = function() {};
  
    // Public: Add selector to set.
    //
    // selector - String CSS selector
    // data     - Optional data Object (default: undefined)
    //
    // Returns nothing.
    SelectorSet.prototype.add = function(selector, data) {
      var obj, i, indexProto, key, index, objs,
          selectorIndexes, selectorIndex,
          indexes = this.activeIndexes,
          selectors = this.selectors;
  
      if (typeof selector !== 'string') {
        return;
      }
  
      obj = {
        id: this.uid++,
        selector: selector,
        data: data
      };
  
      selectorIndexes = parseSelectorIndexes(this.indexes, selector);
      for (i = 0; i < selectorIndexes.length; i++) {
        selectorIndex = selectorIndexes[i];
        key = selectorIndex.key;
        indexProto = selectorIndex.index;
  
        index = findByPrototype(indexes, indexProto);
        if (!index) {
          index = Object.create(indexProto);
          index.map = new Map();
          indexes.push(index);
        }
  
        if (indexProto === this.indexes['default']) {
          this.logDefaultIndexUsed(obj);
        }
        objs = index.map.get(key);
        if (!objs) {
          objs = [];
          index.map.set(key, objs);
        }
        objs.push(obj);
      }
  
      this.size++;
      selectors.push(selector);
    };
  
    // Public: Remove selector from set.
    //
    // selector - String CSS selector
    // data     - Optional data Object (default: undefined)
    //
    // Returns nothing.
    SelectorSet.prototype.remove = function(selector, data) {
      if (typeof selector !== 'string') {
        return;
      }
  
      var selectorIndexes, selectorIndex, i, j, k, selIndex, objs, obj;
      var indexes = this.activeIndexes;
      var removedIds = {};
      var removeAll = arguments.length === 1;
  
      selectorIndexes = parseSelectorIndexes(this.indexes, selector);
      for (i = 0; i < selectorIndexes.length; i++) {
        selectorIndex = selectorIndexes[i];
  
        j = indexes.length;
        while (j--) {
          selIndex = indexes[j];
          if (selectorIndex.index.isPrototypeOf(selIndex)) {
            objs = selIndex.map.get(selectorIndex.key);
            if (objs) {
              k = objs.length;
              while (k--) {
                obj = objs[k];
                if (obj.selector === selector && (removeAll || obj.data === data)) {
                  objs.splice(k, 1);
                  removedIds[obj.id] = true;
                }
              }
            }
            break;
          }
        }
      }
  
      this.size -= Object.keys(removedIds).length;
    };
  
    // Sort by id property handler.
    //
    // a - Selector obj.
    // b - Selector obj.
    //
    // Returns Number.
    function sortById(a, b) {
      return a.id - b.id;
    }
  
    // Public: Find all matching decendants of the context element.
    //
    // context - An Element
    //
    // Returns Array of {selector, data, elements} matches.
    SelectorSet.prototype.queryAll = function(context) {
      if (!this.selectors.length) {
        return [];
      }
  
      var matches = {}, results = [];
      var els = this.querySelectorAll(this.selectors.join(', '), context);
  
      var i, j, len, len2, el, m, match, obj;
      for (i = 0, len = els.length; i < len; i++) {
        el = els[i];
        m = this.matches(el);
        for (j = 0, len2 = m.length; j < len2; j++) {
          obj = m[j];
          if (!matches[obj.id]) {
            match = {
              id: obj.id,
              selector: obj.selector,
              data: obj.data,
              elements: []
            };
            matches[obj.id] = match;
            results.push(match);
          } else {
            match = matches[obj.id];
          }
          match.elements.push(el);
        }
      }
  
      return results.sort(sortById);
    };
  
    // Public: Match element against all selectors in set.
    //
    // el - An Element
    //
    // Returns Array of {selector, data} matches.
    SelectorSet.prototype.matches = function(el) {
      if (!el) {
        return [];
      }
  
      var i, j, k, len, len2, len3, index, keys, objs, obj, id;
      var indexes = this.activeIndexes, matchedIds = {}, matches = [];
  
      for (i = 0, len = indexes.length; i < len; i++) {
        index = indexes[i];
        keys = index.element(el);
        if (keys) {
          for (j = 0, len2 = keys.length; j < len2; j++) {
            if (objs = index.map.get(keys[j])) {
              for (k = 0, len3 = objs.length; k < len3; k++) {
                obj = objs[k];
                id = obj.id;
                if (!matchedIds[id] && this.matchesSelector(el, obj.selector)) {
                  matchedIds[id] = true;
                  matches.push(obj);
                }
              }
            }
          }
        }
      }
  
      return matches.sort(sortById);
    };
  
    // Public: Expose SelectorSet as a global on window.
    window.SelectorSet = SelectorSet;
  })(window);
  
  (function() {
    var MODULES;
  
    MODULES = {
      underscore: this._,
      sizzle: this.Sizzle,
      less: this.less,
      eventemitter2: this.EventEmitter2,
      'selector-set': this.SelectorSet
    };
  
    this._ = this.__polyfills_originalGlobals['underscore'];
  
    this.less = this.__polyfills_originalGlobals['less'];
  
    this.EventEmitter2 = this.__polyfills_originalGlobals['eventemitter2'];
  
    this.define = function(moduleName, deps, callback) {
      var args, depName, first, second, val;
      args = (function() {
        var _i, _len, _ref, _results;
        _results = [];
        for (_i = 0, _len = deps.length; _i < _len; _i++) {
          depName = deps[_i];
          _ref = depName.split('!'), first = _ref[0], second = _ref[1];
          depName = second || first;
          if (!MODULES[depName]) {
            throw new Error('Files are not concatenated based on their dependencies');
          }
          _results.push(MODULES[depName]);
        }
        return _results;
      })();
      val = callback.apply(this, args);
      MODULES[moduleName] = val;
      return val;
    };
  
  }).call(this);
  
  (function() {
    var __slice = [].slice;
  
    define('polyfill-path/selector-tree', [], function() {
      var CHUNKIFY, SelectorTree, chunker;
      chunker = /((?:\((?:\([^()]+\)|[^()]+)+\)|\[(?:\[[^\[\]]*\]|['"][^'"]*['"]|[^\[\]'"]+)+\]|\\.|[^ >+~,(\[\\]+)+|[>+~])(\s*,\s*)?((?:.|\r|\n)*)/g;
      CHUNKIFY = function(selector) {
        var chunks, m, rest;
        rest = selector;
        chunks = [];
        while (true) {
          chunker.exec('');
          if (m = chunker.exec(rest)) {
            rest = m[3];
            chunks.push(m[1]);
            if (m[2] || !rest) {
              break;
            }
          }
          if (!m) {
            break;
          }
        }
        return chunks;
      };
      return SelectorTree = (function() {
        function SelectorTree(children, data) {
          this.children = children != null ? children : {};
          this.data = data != null ? data : [];
        }
  
        SelectorTree.prototype._add = function(chunks, datum) {
          var first, rest;
          if (chunks.length === 0) {
            return this.data.push(datum);
          } else {
            first = chunks[0], rest = 2 <= chunks.length ? __slice.call(chunks, 1) : [];
            if (!this.children[first]) {
              this.children[first] = new SelectorTree();
            }
            return this.children[first]._add(rest, datum);
          }
        };
  
        SelectorTree.prototype.clear = function() {
          this.children = {};
          return this.data = [];
        };
  
        SelectorTree.prototype.add = function(selector, datum) {
          var sel, selectors, _i, _len, _results;
          selectors = selector.split(',');
          _results = [];
          for (_i = 0, _len = selectors.length; _i < _len; _i++) {
            sel = selectors[_i];
            _results.push(this._add(CHUNKIFY(sel), datum));
          }
          return _results;
        };
  
        SelectorTree.prototype.findMatches = function(rootEl, acc, selectorFirst) {
          var els, selector, selectorSnippet, tree, _ref;
          if (acc == null) {
            acc = {};
          }
          if (selectorFirst == null) {
            selectorFirst = '';
          }
          _ref = this.children;
          for (selectorSnippet in _ref) {
            tree = _ref[selectorSnippet];
            selector = "" + selectorFirst + " " + selectorSnippet;
            if (tree.data.length > 0) {
              console.log("KLASDJFKLAJF Querying " + selector);
              els = rootEl.querySelectorAll(selector);
              acc[selector] = {
                els: els,
                data: tree.data
              };
            } else {
              tree.findMatches(rootEl, acc, selector);
            }
          }
          return acc;
        };
  
        SelectorTree.prototype.getSelectors = function(acc, selectorFirst) {
          var selector, selectorSnippet, tree, _ref;
          if (acc == null) {
            acc = {};
          }
          if (selectorFirst == null) {
            selectorFirst = '';
          }
          _ref = this.children;
          for (selectorSnippet in _ref) {
            tree = _ref[selectorSnippet];
            selector = "" + selectorFirst + " " + selectorSnippet;
            if (tree.data.length > 0) {
              acc[selector] = tree.data;
            } else {
              tree.getSelector(acc, selector);
            }
          }
          return acc;
        };
  
        SelectorTree.prototype._get = function(chunks) {
          var child, first;
          if (chunks.length) {
            first = chunks.shift();
            child = this.children[first];
            if (child) {
              return child._get(chunks);
            } else {
              return [];
            }
          } else {
            return this.data;
          }
        };
  
        SelectorTree.prototype.get = function(selector) {
          var chunks;
          chunks = CHUNKIFY(selector);
          return this._get(chunks);
        };
  
        return SelectorTree;
  
      })();
    });
  
  }).call(this);
  
  (function() {
    var __slice = [].slice,
      __hasProp = {}.hasOwnProperty,
      __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; };
  
    define('polyfill-path/fixed-point-runner', ['underscore', 'less', 'eventemitter2', 'selector-set'], function(_, less, EventEmitter, SelectorSet) {
      var CSS_FUNCTION_WRAPPER, CSS_SELECTIVITY_COMPARATOR, FixedPointRunner, IMPORTANT_COMPARATOR, IMPORTANT_FIXER, SPECIFICITY_SORT;
      CSS_SELECTIVITY_COMPARATOR = function(cls1, cls2) {
        var compare, elements1, elements2, isClassOrAttrib, isElementOrPseudo, isIdAttrib;
        elements1 = cls1.elements;
        elements2 = cls2.elements;
        if (!(elements1 || elements2)) {
          console.error('BUG: Selectivity Comparator has null elements');
        }
        compare = function(iterator, els1, els2) {
          var x1, x2;
          x1 = _.reduce(elements1, iterator, 0);
          x2 = _.reduce(elements2, iterator, 0);
          if (x1 < x2) {
            return -1;
          }
          if (x1 > x2) {
            return 1;
          }
          return 0;
        };
        isIdAttrib = function(n, el) {
          var _ref, _ref1;
          return (_ref = '#' === ((_ref1 = el.value) != null ? _ref1[0] : void 0)) != null ? _ref : n + {
            1: n
          };
        };
        isClassOrAttrib = function(n, el) {
          if ('.' === el.value[0] || '[' === el.value[0]) {
            return n + 1;
          }
          return n;
        };
        isElementOrPseudo = function(n, el) {
          if ((el.value instanceof less.tree.Attribute) || ':' === el.value[0] || /^[a-zA-Z]/.test(el.value)) {
            return n + 1;
          }
          return n;
        };
        return compare(isIdAttrib) || compare(isClassOrAttrib) || compare(isElementOrPseudo);
      };
      SPECIFICITY_SORT = function(autogenClasses) {
        var autogenClass, foundDisplayRule, i, newRules, rule, _i, _j, _len, _len1, _ref;
        newRules = [];
        autogenClasses.sort(CSS_SELECTIVITY_COMPARATOR);
        for (_i = 0, _len = autogenClasses.length; _i < _len; _i++) {
          autogenClass = autogenClasses[_i];
          _ref = autogenClass.rules;
          for (_j = 0, _len1 = _ref.length; _j < _len1; _j++) {
            rule = _ref[_j];
            newRules.push(rule);
          }
        }
        foundDisplayRule = false;
        newRules.reverse();
        i = 0;
        while (i < newRules.length) {
          if ('display' === newRules[i].name) {
            if (foundDisplayRule) {
              newRules.splice(i, 1);
              continue;
            } else {
              foundDisplayRule = true;
            }
          }
          i += 1;
        }
        return newRules;
      };
      IMPORTANT_FIXER = function(autogenRules) {
        var r, v, _i, _len, _ref, _results;
        _results = [];
        for (_i = 0, _len = autogenRules.length; _i < _len; _i++) {
          r = autogenRules[_i];
          if (!r.important) {
            v = (_ref = r.value.value) != null ? _ref[0] : void 0;
            if (v instanceof less.tree.Anonymous && /\!important$/.test(v.value)) {
              r.important = ' !important';
              _results.push(v.value = v.value.replace(/\s+\!important$/, ''));
            } else {
              _results.push(void 0);
            }
          } else {
            _results.push(void 0);
          }
        }
        return _results;
      };
      IMPORTANT_COMPARATOR = function(a, b) {
        if (a.important && b.important) {
          return 0;
        }
        if (a.important) {
          return -1;
        }
        if (b.important) {
          return 1;
        }
        return 0;
      };
      CSS_FUNCTION_WRAPPER = function(funcName, func) {
        return function() {
          var ret;
          ret = func.apply(this, [this.env].concat(__slice.call(arguments)));
          if (ret == null) {
            return new less.tree.Call(funcName, _.toArray(arguments));
          } else if (ret.toCSS) {
            return ret;
          } else if (ret instanceof Array) {
            return new less.tree.ArrayTreeNode(ret);
          } else if (_.isString(ret)) {
            return new less.tree.Quoted("'" + ret + "'", ret);
          } else if (_.isNumber(ret)) {
            return new less.tree.Dimension(ret);
          } else {
            return new less.tree.Anonymous(ret);
          }
        };
      };
      return FixedPointRunner = (function(_super) {
        __extends(FixedPointRunner, _super);
  
        function FixedPointRunner(rootNode, plugins, set, removeAutogenClasses) {
          var func, funcName, plugin, ruleFunc, ruleName, _i, _len, _ref, _ref1, _ref2;
          this.rootNode = rootNode;
          this.plugins = plugins;
          this.set = set;
          this.removeAutogenClasses = removeAutogenClasses;
          FixedPointRunner.__super__.constructor.call(this, {
            wildcard: true
          });
          this.squirreledEnv = {};
          this.functions = {};
          this.lookupClasses = {};
          this.lookupCounter = 0;
          this.rules = [];
          _ref = this.plugins;
          for (_i = 0, _len = _ref.length; _i < _len; _i++) {
            plugin = _ref[_i];
            _ref1 = plugin.functions;
            for (funcName in _ref1) {
              func = _ref1[funcName];
              this.functions[funcName] = func.bind(plugin);
            }
            _ref2 = plugin.rules;
            for (ruleName in _ref2) {
              ruleFunc = _ref2[ruleName];
              this.rules.push({
                name: ruleName,
                func: ruleFunc.bind(plugin)
              });
            }
          }
        }
  
        FixedPointRunner.prototype.lookupAutogenClasses = function(domnode) {
          var classes, cls, foundClasses, _i, _len;
          if (domnode.className) {
            if ('string' === typeof domnode.className) {
              classes = domnode.className;
            } else {
              classes = domnode.className.baseVal;
            }
            classes = classes.split(' ');
            foundClasses = [];
            for (_i = 0, _len = classes.length; _i < _len; _i++) {
              cls = classes[_i];
              if (/^js-polyfill-autoclass-/.test(cls)) {
                foundClasses = foundClasses.concat(this.set.get("." + cls));
              }
            }
            return foundClasses;
          } else {
            return [];
          }
        };
  
        FixedPointRunner.prototype.tick = function(interestingNodes) {
          var domnode, env, _i, _len,
            _this = this;
          this.emit('tick.start', interestingNodes.length);
          this.somethingChanged = 0;
          env = new less.tree.evalEnv();
          env.state = {};
          env.helpers = {
            interestingByHref: function(href) {
              var id;
              if ('#' !== href[0]) {
                console.error('ERROR: href must start with a # character');
              }
              id = href.substring(1);
              if (!_this.squirreledEnv[id]) {
                console.error('BUG: id was not marked and squirreled before being looked up');
              }
              return _this.squirreledEnv[id];
            },
            markInterestingByHref: function(href) {
              var id, target, wasAlreadyMarked;
              if ('#' !== href[0]) {
                console.error('ERROR: href must start with a # character');
              }
              id = href.substring(1);
              wasAlreadyMarked = !!_this.squirreledEnv[id];
              if (!wasAlreadyMarked) {
                target = document.getElementById(id);
                if (target) {
                  _this.somethingChanged += 1;
                  target.classList.add('js-polyfill-interesting');
                  target.classList.add('js-polyfill-target');
                } else {
                  console.warn("ERROR: Invalid target id: #" + id);
                }
              }
              return !wasAlreadyMarked;
            },
            didSomthingNonIdempotent: function(msg) {
              return _this.somethingChanged += 1;
            }
          };
          for (_i = 0, _len = interestingNodes.length; _i < _len; _i++) {
            domnode = interestingNodes[_i];
            this.evalNode(env, domnode);
          }
          this.emit('tick.end', this.somethingChanged);
          return this.somethingChanged;
        };
  
        FixedPointRunner.prototype.pullRulesFromCache = function(domnode) {
          var autogenClasses, autogenRule, autogenRules, filteredRules, id, name, _i, _len;
          if (domnode.jsPolyfillId) {
            filteredRules = this.lookupClasses[domnode.jsPolyfillId];
            if (filteredRules) {
              return filteredRules;
            }
          }
          id = this.lookupCounter += 1;
          autogenClasses = this.lookupAutogenClasses(domnode);
          autogenRules = SPECIFICITY_SORT(autogenClasses);
          IMPORTANT_FIXER(autogenRules);
          autogenRules.sort(IMPORTANT_COMPARATOR);
          filteredRules = {};
          for (_i = 0, _len = autogenRules.length; _i < _len; _i++) {
            autogenRule = autogenRules[_i];
            name = autogenRule.name;
            if (name instanceof Array) {
              name = name.join('');
            }
            if (filteredRules[name] == null) {
              filteredRules[name] = [];
            }
            filteredRules[name].push(autogenRule);
          }
          this.lookupClasses[id] = filteredRules;
          domnode.jsPolyfillId = id;
          return filteredRules;
        };
  
        FixedPointRunner.prototype.evalNode = function(env, domnode) {
          var autogenRule, autogenRules, beforeSomethingChanged, filteredRules, i, pluginRule, rule, ruleName, ruleValNode, rules, somethingNotCompleted, targetEnv, understood, understoodRules, unused, _i, _j, _k, _len, _len1, _len2, _ref;
          this.emit('tick.node', domnode);
          somethingNotCompleted = false;
          if (domnode.compareDocumentPosition(document.body) & Node.DOCUMENT_POSITION_DISCONNECTED) {
            return;
          }
          env.helpers.contextNode = domnode;
          autogenRules = this.pullRulesFromCache(domnode);
          _ref = this.rules;
          for (_i = 0, _len = _ref.length; _i < _len; _i++) {
            pluginRule = _ref[_i];
            if ('*' === pluginRule.name) {
              filteredRules = [];
              for (unused in autogenRules) {
                rules = autogenRules[unused];
                for (_j = 0, _len1 = rules.length; _j < _len1; _j++) {
                  rule = rules[_j];
                  filteredRules.push(rule);
                }
              }
            } else {
              filteredRules = autogenRules[pluginRule.name];
            }
            understoodRules = {};
            if (filteredRules) {
              for (i = _k = 0, _len2 = filteredRules.length; _k < _len2; i = ++_k) {
                autogenRule = filteredRules[i];
                ruleName = autogenRule.name;
                if (ruleName instanceof Array) {
                  ruleName = ruleName.join('');
                }
                ruleValNode = autogenRule.value;
                if (!ruleName) {
                  continue;
                }
                if (ruleName in understoodRules) {
                  continue;
                }
                if ('completed' === domnode.getAttribute("data-js-polyfill-rule-" + ruleName)) {
                  continue;
                }
                beforeSomethingChanged = this.somethingChanged;
                if ('*' === pluginRule.name) {
                  understood = pluginRule.func(env, ruleName, ruleValNode);
                } else {
                  understood = pluginRule.func(env, ruleValNode);
                }
                somethingNotCompleted = true;
                if (understood) {
                  understoodRules[ruleName] = true;
                  domnode.setAttribute("data-js-polyfill-rule-" + ruleName, 'evaluated');
                  if (understood === 'RULE_COMPLETED') {
                    this.somethingChanged += 1;
                    domnode.setAttribute("data-js-polyfill-rule-" + ruleName, 'completed');
                  } else if (understood === 'NODE_REMOVED') {
                    if (domnode.jsPolyfillId) {
                      delete this.lookupClasses[domnode.jsPolyfillId];
                    }
                    return;
                  }
                  break;
                }
                if (beforeSomethingChanged !== this.somethingChanged) {
                  break;
                }
              }
            }
          }
          if (domnode.classList.contains('js-polyfill-target')) {
            targetEnv = {
              helpers: _.clone(env.helpers),
              state: JSON.parse(JSON.stringify(_.omit(env.state, 'buckets')))
            };
            targetEnv.helpers.contextNode = domnode;
            return this.squirreledEnv[domnode.id] = targetEnv;
          } else if (!somethingNotCompleted) {
            domnode.classList.remove('js-polyfill-interesting');
            if (domnode.jsPolyfillId) {
              return delete this.lookupClasses[domnode.jsPolyfillId];
            }
          }
        };
  
        FixedPointRunner.prototype.setUp = function() {
          var func, funcName, _ref, _results;
          this.emit('runner.start');
          _ref = this.functions;
          _results = [];
          for (funcName in _ref) {
            func = _ref[funcName];
            _results.push(less.tree.functions[funcName] = CSS_FUNCTION_WRAPPER(funcName, func));
          }
          return _results;
        };
  
        FixedPointRunner.prototype.done = function() {
          var className, classes, discardedClasses, el, funcName, node, nonPolyfillClasses, _i, _j, _k, _l, _len, _len1, _len2, _len3, _ref, _ref1;
          for (funcName in this.functions) {
            delete less.tree.functions[funcName];
          }
          discardedClasses = ['js-polyfill-evaluated', 'js-polyfill-interesting', 'js-polyfill-target'];
          for (_i = 0, _len = discardedClasses.length; _i < _len; _i++) {
            className = discardedClasses[_i];
            _ref = this.rootNode.querySelectorAll("." + className);
            for (_j = 0, _len1 = _ref.length; _j < _len1; _j++) {
              el = _ref[_j];
              el.classList.remove(className);
            }
          }
          _ref1 = this.rootNode.querySelectorAll('.js-polyfill-autoclass:not(.js-polyfill-autoclass-keep), .js-polyfill-pseudo');
          for (_k = 0, _len2 = _ref1.length; _k < _len2; _k++) {
            node = _ref1[_k];
            if (node.classList) {
              if ('string' === typeof node.className) {
                classes = node.className;
              } else {
                classes = node.className.baseVal;
              }
              classes = classes.split(' ');
              nonPolyfillClasses = [];
              for (_l = 0, _len3 = classes.length; _l < _len3; _l++) {
                className = classes[_l];
                if (!/^js-polyfill-/.test(className)) {
                  nonPolyfillClasses.push(className);
                }
                if (!this.removeAutogenClasses) {
                  if (/^js-polyfill-autoclass-/.test(className)) {
                    nonPolyfillClasses.push(className);
                  }
                }
              }
              if (nonPolyfillClasses.length > 0) {
                node.className = nonPolyfillClasses.join(' ');
              } else {
                node.removeAttribute('class');
              }
            }
          }
          return this.emit('runner.end');
        };
  
        FixedPointRunner.prototype.run = function() {
          var changes, interestingNodes;
          this.setUp();
          interestingNodes = this.rootNode.querySelectorAll('.js-polyfill-interesting');
          while (changes = this.tick(interestingNodes)) {
            interestingNodes = this.rootNode.querySelectorAll('.js-polyfill-interesting');
          }
          return this.done();
        };
  
        return FixedPointRunner;
  
      })(EventEmitter);
    });
  
  }).call(this);
  
  (function() {
    var __hasProp = {}.hasOwnProperty,
      __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; },
      __indexOf = [].indexOf || function(item) { for (var i = 0, l = this.length; i < l; i++) { if (i in this && this[i] === item) return i; } return -1; };
  
    define('polyfill-path/selector-visitor', ['underscore', 'less', 'sizzle', 'eventemitter2'], function(_, less, Sizzle, EventEmitter) {
      var AbstractSelectorVisitor, LessVisitor, PSEUDO_CLASSES, _ref;
      LessVisitor = (function(_super) {
        __extends(LessVisitor, _super);
  
        function LessVisitor(rootNode) {
          this.rootNode = rootNode;
          this._visitor = new less.tree.visitor(this);
          this._frames = [];
        }
  
        LessVisitor.prototype.run = function(root) {
          return this._visitor.visit(root);
        };
  
        LessVisitor.prototype.peek = function() {
          return this._frames[this._frames.length - 1];
        };
  
        LessVisitor.prototype.push = function(val) {
          return this._frames.push(val);
        };
  
        LessVisitor.prototype.pop = function() {
          return this._frames.pop();
        };
  
        return LessVisitor;
  
      })(EventEmitter);
      PSEUDO_CLASSES = ['before', 'after', 'outside', 'footnote-call', 'footnote-marker', 'deferred'];
      return AbstractSelectorVisitor = (function(_super) {
        __extends(AbstractSelectorVisitor, _super);
  
        function AbstractSelectorVisitor() {
          _ref = AbstractSelectorVisitor.__super__.constructor.apply(this, arguments);
          return _ref;
        }
  
        AbstractSelectorVisitor.prototype.isPreEvalVisitor = false;
  
        AbstractSelectorVisitor.prototype.isPreVisitor = false;
  
        AbstractSelectorVisitor.prototype.isReplacing = false;
  
        AbstractSelectorVisitor.prototype.operateOnElements = function(frame, nodes, ruleSet, domSelector, pseudoSelector, originalSelector) {};
  
        AbstractSelectorVisitor.prototype.doSelector = function(node, visitArgs) {
          var element, i, isPseudo, sliceIndex, _i, _len, _ref1;
          isPseudo = function(name) {
            var _ref1;
            return _.isString(name) && /^:/.test(name) && (_ref1 = name.replace(/:/g, ''), __indexOf.call(PSEUDO_CLASSES, _ref1) >= 0);
          };
          sliceIndex = node.elements.length;
          _ref1 = node.elements;
          for (i = _i = 0, _len = _ref1.length; _i < _len; i = ++_i) {
            element = _ref1[i];
            if (isPseudo(element.value)) {
              sliceIndex = i;
              break;
            }
          }
          return {
            originalSelector: node,
            domSelector: node.createDerived(node.elements.slice(0, sliceIndex)),
            pseudoSelector: node.createDerived(node.elements.slice(sliceIndex))
          };
        };
  
        AbstractSelectorVisitor.prototype.getNodes = function(selectorStr) {
          var err;
          try {
            return this.rootNode.querySelectorAll(selectorStr);
          } catch (_error) {
            err = _error;
            return Sizzle(selectorStr, this.rootNode);
          }
        };
  
        AbstractSelectorVisitor.prototype.visitRuleset = function(node) {
          var context, el, path, sel, selector, selectorStr, _i, _j, _k, _len, _len1, _len2, _ref1, _ref2, _results,
            _this = this;
          if (node.root) {
            return;
          }
          _ref1 = node.paths;
          _results = [];
          for (_i = 0, _len = _ref1.length; _i < _len; _i++) {
            path = _ref1[_i];
            context = [];
            for (_j = 0, _len1 = path.length; _j < _len1; _j++) {
              sel = path[_j];
              selector = this.doSelector(sel);
              selectorStr = [];
              _ref2 = selector.domSelector.elements;
              for (_k = 0, _len2 = _ref2.length; _k < _len2; _k++) {
                el = _ref2[_k];
                selectorStr.push(el.toCSS({}));
                if (/^[\*]/.test(el.value)) {
                  selectorStr.push(':not(.js-polyfill-pseudo)');
                }
              }
              selectorStr = selectorStr.join('');
              context.push(selectorStr);
            }
            selectorStr = context.join('');
            this.emit('selector.start', selectorStr, node.debugInfo);
            this.emit('selector.end', selectorStr, node.debugInfo, function() {
              return _this.getNodes(selectorStr);
            });
            if (__indexOf.call(selectorStr, '@') >= 0 || __indexOf.call(selectorStr, '|') >= 0) {
  
            } else {
              this.operateOnElements(null, node, selector.domSelector, selector.pseudoSelector, selector.originalSelector, selectorStr);
            }
            _results.push(context.pop());
          }
          return _results;
        };
  
        return AbstractSelectorVisitor;
  
      })(LessVisitor);
    });
  
  }).call(this);
  
  (function() {
    define('polyfill-path/extras', ['underscore', 'sizzle', 'less'], function(_, Sizzle, less) {
      var ElementExtras, pseudo, uniqueId, uniqueIdCount, _base, _base1, _base2, _i, _len, _ref;
      uniqueIdCount = 0;
      uniqueId = function() {
        return "id-added-via-x-ensure-id-" + (uniqueIdCount++);
      };
      _ref = ['deferred', 'pass', 'match'];
      for (_i = 0, _len = _ref.length; _i < _len; _i++) {
        pseudo = _ref[_i];
        if ((_base = Sizzle.selectors.match)[pseudo] == null) {
          _base[pseudo] = RegExp(":?" + pseudo);
        }
        if ((_base1 = Sizzle.selectors.find)[pseudo] == null) {
          _base1[pseudo] = function(match, context, isXML) {
            return context;
          };
        }
        if ((_base2 = Sizzle.selectors.pseudos)[pseudo] == null) {
          _base2[pseudo] = function(elem) {
            return elem;
          };
        }
      }
      ElementExtras = (function() {
        function ElementExtras() {}
  
        ElementExtras.prototype.functions = {
          'x-selector': function(env, selectorNode) {
            if (!(selectorNode instanceof less.tree.Quoted)) {
              console.warn("ERROR: x-selector(): expects a Quoted");
            }
            return selectorNode.value;
          },
          'x-sort': function(env, bucketElementsNode, sortBySelector) {
            var domAry, sorted,
              _this = this;
            if (sortBySelector == null) {
              sortBySelector = null;
            }
            domAry = bucketElementsNode["eval"](env).values;
            sorted = _.clone(domAry).sort(function(a, b) {
              if (sortBySelector) {
                a = a.querySelector(sortBySelector.value);
                if (!a) {
                  console.error('ERROR: Attempting to sort but cannot find selector');
                }
                a = a != null ? a.textContent.trim() : void 0;
                b = b.querySelector(sortBySelector.value);
                if (!b) {
                  console.error('ERROR: Attempting to sort but cannot find selector');
                }
                b = b != null ? b.textContent.trim() : void 0;
              } else {
                a = a.textContent.trim();
                b = b.textContent.trim();
              }
              if (a < b) {
                return -1;
              }
              if (a > b) {
                return 1;
              }
              return 0;
            });
            return sorted;
          },
          'x-target-is': function(env, targetIdNode, selectorNode) {
            var context, href, targetEnv;
            if (selectorNode == null) {
              selectorNode = null;
            }
            href = targetIdNode["eval"](env).value;
            selectorNode = selectorNode["eval"](env);
            if (!(selectorNode instanceof less.tree.Quoted)) {
              console.warn("ERROR: x-target-is() expects a Quoted");
            }
            if (!env.helpers.markInterestingByHref(href)) {
              targetEnv = env.helpers.interestingByHref(href);
              context = targetEnv.helpers.contextNode;
              if (Sizzle.matchesSelector(context, selectorNode.value)) {
                return '';
              } else {
                return null;
              }
            }
            return null;
          }
        };
  
        ElementExtras.prototype.rules = {
          'x-tag-name': function(env, tagNameNode) {
            var child, context, newEl, oldTagName, tagName, _j, _len1, _ref1;
            tagNameNode = tagNameNode["eval"](env);
            if (!(tagNameNode instanceof less.tree.Quoted)) {
              console.warn("ERROR: move-to: expects a Quoted");
            }
            context = env.helpers.contextNode;
            oldTagName = context.tagName.toLowerCase();
            tagName = tagNameNode.value.toLowerCase();
            if (oldTagName !== tagName) {
              newEl = document.createElement(tagName);
              newEl.className = context.className;
              newEl.setAttribute('data-js-polyfill-tagname-orig', oldTagName);
              _ref1 = context.childNodes;
              for (_j = 0, _len1 = _ref1.length; _j < _len1; _j++) {
                child = _ref1[_j];
                newEl.appendChild(child);
              }
              context.parentNode.replaceChild(newEl, context);
              env.helpers.contextNode = newEl;
              env.helpers.didSomthingNonIdempotent('x-tag-name');
              return 'RULE_COMPLETED';
            }
            return false;
          },
          'x-ensure-id': function(env, attributeNameNode) {
            attributeNameNode = attributeNameNode["eval"](env);
            if (!(attributeNameNode instanceof less.tree.Quoted)) {
              console.warn("ERROR: x-ensure-id: expects a Quoted");
            }
            if (!env.helpers.contextNode.getAttribute(attributeNameNode.value)) {
              env.helpers.contextNode.setAttribute(attributeNameNode.value, uniqueId());
              env.helpers.didSomthingNonIdempotent('x-ensure-id');
              return 'RULE_COMPLETED';
            }
            return false;
          },
          'x-attr': function(env, attrsAndVals) {
            var setAttr, v, _j, _len1, _ref1, _results,
              _this = this;
            attrsAndVals = attrsAndVals["eval"](env);
            setAttr = function(val) {
              var arg, args, attrName, str, _j, _len1;
              attrName = _.first(val.value).value;
              args = _.rest(val.value);
              str = [];
              for (_j = 0, _len1 = args.length; _j < _len1; _j++) {
                arg = args[_j];
                if (arg instanceof less.tree.Quoted) {
                  str.push(arg.value);
                } else if (arg instanceof less.tree.Call) {
                  if ('content' === arg.name) {
                    arg.name = 'x-string-set-content';
                    val = arg["eval"](env);
                    if (val instanceof less.tree.Call) {
                      return null;
                    }
                    str.push(val.value);
                    arg.name = 'content';
                  } else {
                    return null;
                  }
                } else {
                  str.push(arg.value);
                }
              }
              return env.helpers.contextNode.setAttribute(attrName, str.join(''));
            };
            if (attrsAndVals instanceof less.tree.Expression) {
              return setAttr(attrsAndVals);
            } else if (attrsAndVals instanceof less.tree.Value) {
              _ref1 = attrsAndVals.value;
              _results = [];
              for (_j = 0, _len1 = _ref1.length; _j < _len1; _j++) {
                v = _ref1[_j];
                _results.push(setAttr(v));
              }
              return _results;
            } else {
              return console.warn('ERROR: invalid arguments given to "x-attr:"');
            }
          }
        };
  
        return ElementExtras;
  
      })();
      return {
        ElementExtras: ElementExtras
      };
    });
  
  }).call(this);
  
  (function() {
    define('polyfill-path/plugins', ['underscore', 'sizzle', 'less'], function(_, Sizzle, less) {
      var ArrayTreeNode, ContentSet, DisplayNone, MoveTo, StringSet, TargetCounter, TargetText, contentsFuncBuilder;
      less.tree.ArrayTreeNode = ArrayTreeNode = (function() {
        function ArrayTreeNode(values) {
          this.values = values;
        }
  
        ArrayTreeNode.prototype["eval"] = function() {
          return this;
        };
  
        return ArrayTreeNode;
  
      })();
      MoveTo = (function() {
        function MoveTo() {}
  
        MoveTo.prototype.functions = {
          'pending': function(env, bucketNameNode) {
            var domAry, footnote, node, pendingPseudo, _i, _j, _len, _len1, _ref;
            bucketNameNode = bucketNameNode["eval"](env);
            if (!(bucketNameNode instanceof less.tree.Keyword)) {
              console.warn("ERROR: pending(): expects a Keyword");
            }
            domAry = ((_ref = env.state.buckets) != null ? _ref[bucketNameNode.value] : void 0) || [];
            for (_i = 0, _len = domAry.length; _i < _len; _i++) {
              node = domAry[_i];
              pendingPseudo = node.querySelector('.js-polyfill-pseudo[data-js-polyfill-rule-content="pending"]');
              if (pendingPseudo) {
                return null;
              }
            }
            for (_j = 0, _len1 = domAry.length; _j < _len1; _j++) {
              node = domAry[_j];
              footnote = node.querySelector('.js-polyfill-pseudo-footnote-call');
              if (footnote) {
                if (node.nextSibling) {
                  node.parentNode.insertBefore(footnote, node.nextSibling);
                } else {
                  node.parentNode.append(footnote);
                }
              }
            }
            if (env.state.buckets) {
              delete env.state.buckets[bucketNameNode.value];
            }
            return domAry || [];
          }
        };
  
        MoveTo.prototype.rules = {
          'move-to': function(env, bucketNameNode) {
            var bucketName, domnode, ruleName, _base, _base1;
            bucketNameNode = bucketNameNode["eval"](env);
            if (!(bucketNameNode instanceof less.tree.Keyword)) {
              console.warn("ERROR: move-to: expects a Keyword");
            }
            ruleName = 'move-to';
            domnode = env.helpers.contextNode;
            if ('pending' === domnode.getAttribute('data-js-polyfill-rule-content') || domnode.querySelector("[data-js-polyfill-rule-content='pending']")) {
              return false;
            }
            bucketName = bucketNameNode.value;
            if ((_base = env.state).buckets == null) {
              _base.buckets = {};
            }
            if ((_base1 = env.state.buckets)[bucketName] == null) {
              _base1[bucketName] = [];
            }
            env.state.buckets[bucketName].push(env.helpers.contextNode);
            return 'RULE_COMPLETED';
          }
        };
  
        return MoveTo;
  
      })();
      DisplayNone = (function() {
        function DisplayNone() {}
  
        DisplayNone.prototype.rules = {
          'display': function(env, valNode) {
            var context;
            valNode = valNode["eval"](env);
            if (!(valNode instanceof less.tree.Anonymous)) {
              return;
            }
            if ('none' === valNode.value) {
              context = env.helpers.contextNode;
              context.parentNode.removeChild(context);
              env.helpers.didSomthingNonIdempotent('display:none');
              return 'NODE_REMOVED';
            }
            return true;
          }
        };
  
        return DisplayNone;
  
      })();
      TargetCounter = (function() {
        function TargetCounter() {}
  
        TargetCounter.prototype.functions = {
          'x-parent': function(env, valNode) {
            var context;
            context = env.helpers.contextNode;
            env.helpers.contextNode = context.parentNode;
            valNode = valNode["eval"](env);
            env.helpers.contextNode = context;
            return valNode;
          },
          'attr': function(env, attrNameNode) {
            var context, val;
            attrNameNode = attrNameNode["eval"](env);
            if (!(attrNameNode instanceof less.tree.Keyword)) {
              console.warn("ERROR: attr(): expects a Keyword");
            }
            context = env.helpers.contextNode;
            val = context.getAttribute(attrNameNode.value);
            if (val && !isNaN(val)) {
              val = parseInt(val);
            }
            if (!val) {
              if (context.classList.contains('js-polyfill-pseudo')) {
                if (context.classList.contains('js-polyfill-pseudo-outside')) {
                  context = context.querySelector(':not(.js-polyfill-pseudo)');
                } else {
                  if (context.parentNode) {
                    context = context.parentNode;
                    while (context.classList.contains('js-polyfill-pseudo')) {
                      context = context.parentNode;
                      if (!context) {
                        break;
                      }
                    }
                  }
                }
                val = context.getAttribute(attrNameNode.value);
                if (val && !isNaN(val)) {
                  val = parseInt(val);
                }
              }
            }
            return val;
          },
          'counter': function(env, counterNameNode, counterType) {
            var _ref;
            if (counterType == null) {
              counterType = null;
            }
            counterNameNode = counterNameNode["eval"](env);
            if (!(counterNameNode instanceof less.tree.Keyword)) {
              console.warn("ERROR: counter(): expects a Keyword");
            }
            return this.numberingStyle((_ref = env.state.counters) != null ? _ref[counterNameNode.value] : void 0, counterType != null ? counterType["eval"](env).value : void 0);
          },
          'target-counter': function(env, targetIdNode, counterNameNode, counterType) {
            var counterName, href, targetEnv, _ref;
            if (counterType == null) {
              counterType = null;
            }
            if (!counterNameNode) {
              console.error("ERROR: target-counter(): expects a 2nd argument");
              return;
            }
            counterNameNode = counterNameNode["eval"](env);
            if (!(counterNameNode instanceof less.tree.Keyword)) {
              console.warn("ERROR: target-counter(): expects a Keyword");
            }
            href = targetIdNode["eval"](env).value;
            counterName = counterNameNode.value;
            if (!href || href[0] !== '#' || href.length < 2) {
              return null;
            }
            if (!env.helpers.markInterestingByHref(href)) {
              targetEnv = env.helpers.interestingByHref(href);
              return this.numberingStyle((_ref = targetEnv.state.counters) != null ? _ref[counterName] : void 0, counterType != null ? counterType["eval"](env).value : void 0);
            }
            return null;
          }
        };
  
        TargetCounter.prototype.rules = {
          'counter-increment': function(env, valNode) {
            var counterName, counterValue, counters, countersAndNumbers, _base, _base1;
            countersAndNumbers = valNode["eval"](env);
            counters = this.parseCounters(countersAndNumbers, 1);
            if ((_base = env.state).counters == null) {
              _base.counters = {};
            }
            for (counterName in counters) {
              counterValue = counters[counterName];
              if ((_base1 = env.state.counters)[counterName] == null) {
                _base1[counterName] = 0;
              }
              env.state.counters[counterName] += counterValue;
            }
            return true;
          },
          'counter-reset': function(env, valNode) {
            var counterName, counterValue, counters, countersAndNumbers, _base;
            countersAndNumbers = valNode["eval"](env);
            counters = this.parseCounters(countersAndNumbers, 0);
            if ((_base = env.state).counters == null) {
              _base.counters = {};
            }
            for (counterName in counters) {
              counterValue = counters[counterName];
              env.state.counters[counterName] = counterValue;
            }
            return true;
          }
        };
  
        TargetCounter.prototype.parseCounters = function(val, defaultNum) {
          var counters, cssStr, i, name, tokens;
          cssStr = val.toCSS({});
          tokens = cssStr.split(' ');
          counters = {};
          if ('none' === tokens[0]) {
            return counters;
          }
          i = 0;
          while (i < tokens.length) {
            name = tokens[i];
            if (i === tokens.length - 1) {
              val = defaultNum;
            } else if (isNaN(parseInt(tokens[i + 1]))) {
              val = defaultNum;
            } else {
              val = parseInt(tokens[i + 1]);
              i++;
            }
            counters[name] = val;
            i++;
          }
          return counters;
        };
  
        TargetCounter.prototype.numberingStyle = function(num, style) {
          if (num == null) {
            num = 0;
          }
          if (style == null) {
            style = 'decimal';
          }
          switch (style) {
            case 'decimal-leading-zero':
              if (num < 10) {
                return "0" + num;
              } else {
                return num;
              }
              break;
            case 'lower-roman':
              return this.toRoman(num).toLowerCase();
            case 'upper-roman':
              return this.toRoman(num);
            case 'lower-latin':
              if (!((1 <= num && num <= 26))) {
                console.warn('ERROR: number out of range (must be 1...26)');
                return num;
              } else {
                return String.fromCharCode(num + 96);
              }
              break;
            case 'upper-latin':
              if (!((1 <= num && num <= 26))) {
                console.warn('ERROR: number out of range (must be 1...26)');
                return num;
              } else {
                return String.fromCharCode(num + 64);
              }
              break;
            case 'decimal':
              return num;
            default:
              console.warn("ERROR: Counter numbering not supported for list type " + style + ". Using decimal.");
              return num;
          }
        };
  
        TargetCounter.prototype.toRoman = function(num) {
          var integer, numeral, result, romanNumeralMap, _i, _len, _ref;
          romanNumeralMap = [['M', 1000], ['CM', 900], ['D', 500], ['CD', 400], ['C', 100], ['XC', 90], ['L', 50], ['XL', 40], ['X', 10], ['IX', 9], ['V', 5], ['IV', 4], ['I', 1]];
          if (!((0 < num && num < 5000))) {
            console.warn('ERROR: number out of range (must be 1..4999)');
            return "" + num;
          }
          result = '';
          for (_i = 0, _len = romanNumeralMap.length; _i < _len; _i++) {
            _ref = romanNumeralMap[_i], numeral = _ref[0], integer = _ref[1];
            while (num >= integer) {
              result += numeral;
              num -= integer;
            }
          }
          return result;
        };
  
        return TargetCounter;
  
      })();
      contentsFuncBuilder = function(defaultType) {
        return function(env, typeNode) {
          var child, el, els, evaluated, getContents, selector, text, type, val, _i, _j, _k, _l, _len, _len1, _len2, _len3, _ref, _ref1, _ref2, _ref3, _ref4, _ref5, _ref6,
            _this = this;
          typeNode = typeNode != null ? typeNode["eval"](env) : void 0;
          if ((!typeNode) || typeNode instanceof less.tree.Keyword) {
            getContents = function() {
              var child, el, _i, _len, _ref, _ref1;
              el = env.helpers.contextNode.cloneNode(true);
              _ref = _.toArray(el.children);
              for (_i = 0, _len = _ref.length; _i < _len; _i++) {
                child = _ref[_i];
                if ((_ref1 = child.classList) != null ? _ref1.contains('js-polyfill-pseudo') : void 0) {
                  el.removeChild(child);
                }
              }
              return el.textContent;
            };
            type = (typeNode != null ? typeNode.value : void 0) || defaultType;
            switch (type) {
              case 'contents':
                val = getContents();
                break;
              case 'first-letter':
                val = (_ref = getContents()) != null ? _ref.trim()[0] : void 0;
                break;
              case 'before':
                text = [];
                _ref1 = env.helpers.contextNode.children;
                for (_i = 0, _len = _ref1.length; _i < _len; _i++) {
                  child = _ref1[_i];
                  if ((_ref2 = child.classList) != null ? _ref2.contains('js-polyfill-pseudo-before') : void 0) {
                    text.push(child.textContent);
                  }
                }
                evaluated = false;
                _ref3 = env.helpers.contextNode.children;
                for (_j = 0, _len1 = _ref3.length; _j < _len1; _j++) {
                  child = _ref3[_j];
                  if (child.classList.contains('js-polyfill-evaluated')) {
                    evaluated = true;
                  }
                }
                if (evaluated) {
                  val = text.join('');
                }
                break;
              case 'after':
                text = [];
                _ref4 = env.helpers.contextNode.children;
                for (_k = 0, _len2 = _ref4.length; _k < _len2; _k++) {
                  child = _ref4[_k];
                  if ((_ref5 = child.classList) != null ? _ref5.contains('js-polyfill-pseudo-after') : void 0) {
                    text.push(child.textContent);
                  }
                }
                evaluated = false;
                _ref6 = env.helpers.contextNode.children;
                for (_l = 0, _len3 = _ref6.length; _l < _len3; _l++) {
                  child = _ref6[_l];
                  if (child.classList.contains('js-polyfill-evaluated')) {
                    evaluated = true;
                  }
                }
                if (evaluated) {
                  val = text.join('');
                }
                break;
              default:
                val = typeNode.toCSS({});
                console.error("ERROR: invalid argument to content(). argument=[" + val + "]");
                val = '';
            }
            return val;
          } else if (typeNode instanceof less.tree.Quoted) {
            selector = typeNode.value;
            els = Sizzle(selector, env.helpers.contextNode);
            if (!els[0]) {
              return;
            }
            text = (function() {
              var _len4, _m, _results;
              _results = [];
              for (_m = 0, _len4 = els.length; _m < _len4; _m++) {
                el = els[_m];
                _results.push(el.textContent);
              }
              return _results;
            })();
            return text.join('');
          } else {
            return console.warn("ERROR: content(): expects a Keyword or a Selector String");
          }
        };
      };
      TargetText = (function() {
        function TargetText() {}
  
        TargetText.prototype.functions = {
          'x-target-text-content': contentsFuncBuilder('before'),
          'target-text': function(env, targetIdNode, contentTypeNode) {
            var contents, href, targetEnv;
            if (contentTypeNode == null) {
              contentTypeNode = null;
            }
            href = targetIdNode["eval"](env).value;
            if (!env.helpers.markInterestingByHref(href)) {
              targetEnv = env.helpers.interestingByHref(href);
              if (!(contentTypeNode instanceof less.tree.Call)) {
                console.warn("ERROR: target-text() expects a function Call");
              }
              if ('content' !== contentTypeNode.name) {
                console.warn("ERROR: target-text() expects a Call to content()");
              }
              contentTypeNode.name = 'x-target-text-content';
              contents = contentTypeNode["eval"](targetEnv).value;
              contentTypeNode.name = 'content';
              return contents;
            }
            return null;
          }
        };
  
        return TargetText;
  
      })();
      StringSet = (function() {
        function StringSet() {}
  
        StringSet.prototype.functions = {
          'x-string-set-content': contentsFuncBuilder('contents'),
          'string': function(env, stringNameNode) {
            var str, _ref;
            stringNameNode = stringNameNode["eval"](env);
            if (!(stringNameNode instanceof less.tree.Keyword)) {
              console.warn("ERROR: string(): expects a Keyword");
            }
            str = (_ref = env.state.strings) != null ? _ref[stringNameNode.value] : void 0;
            return str;
          }
        };
  
        StringSet.prototype.rules = {
          'string-set': function(env, stringsAndVals) {
            var setString, v, _i, _len, _ref,
              _this = this;
            stringsAndVals = stringsAndVals["eval"](env);
            setString = function(val) {
              var arg, args, str, stringName, _base, _i, _len;
              stringName = _.first(val.value).value;
              args = _.rest(val.value);
              str = [];
              for (_i = 0, _len = args.length; _i < _len; _i++) {
                arg = args[_i];
                if (arg instanceof less.tree.Quoted) {
                  str.push(arg.value);
                } else if (arg instanceof less.tree.Call) {
                  if ('content' === arg.name) {
                    arg.name = 'x-string-set-content';
                    val = arg["eval"](env);
                    if (val instanceof less.tree.Call) {
                      return null;
                    }
                    str.push(val.value);
                    arg.name = 'content';
                  } else {
                    console.warn("ERROR: invalid function used. only content() is acceptable. name=[" + arg.name + "]");
                  }
                } else {
                  str.push(arg.value);
                }
              }
              if ((_base = env.state).strings == null) {
                _base.strings = {};
              }
              return env.state.strings[stringName] = str.join('');
            };
            if (stringsAndVals instanceof less.tree.Expression) {
              setString(stringsAndVals);
            } else if (stringsAndVals instanceof less.tree.Value) {
              _ref = stringsAndVals.value;
              for (_i = 0, _len = _ref.length; _i < _len; _i++) {
                v = _ref[_i];
                setString(v);
              }
            } else {
              console.warn('ERROR: invalid arguments given to string-set');
              return false;
            }
            return true;
          }
        };
  
        return StringSet;
  
      })();
      ContentSet = (function() {
        function ContentSet() {}
  
        ContentSet.prototype.rules = {
          'content': function(env, valNode) {
            var child, domnode, pseudoAfter, val, values, _i, _j, _len, _len1, _ref, _ref1;
            valNode = valNode["eval"](env);
            values = this.evaluateValNode(valNode);
            if (values) {
              domnode = env.helpers.contextNode;
              _ref = _.toArray(domnode.childNodes);
              for (_i = 0, _len = _ref.length; _i < _len; _i++) {
                child = _ref[_i];
                if (!((_ref1 = child.classList) != null ? _ref1.contains('js-polyfill-pseudo') : void 0)) {
                  domnode.removeChild(child);
                }
              }
              pseudoAfter = domnode.querySelector('.js-polyfill-pseudo-after');
              for (_j = 0, _len1 = values.length; _j < _len1; _j++) {
                val = values[_j];
                switch (typeof val) {
                  case 'string':
                    val = document.createTextNode(val);
                    break;
                  case 'number':
                    val = document.createTextNode(val);
                    break;
                  default:
                    if (val.ELEMENT_NODE) {
  
                    } else {
                      throw new Error('BUG: content rule only supports string, number, and DOM Node objects');
                    }
                }
                if (pseudoAfter) {
                  domnode.insertBefore(val, pseudoAfter);
                } else {
                  domnode.appendChild(val);
                }
              }
              domnode.classList.add('js-polyfill-evaluated');
              return 'RULE_COMPLETED';
            }
            return false;
          }
        };
  
        ContentSet.prototype.evaluateValNode = function(valNode) {
          var el, r, ret, val, vals, _i, _j, _len, _len1, _ref;
          ret = [];
          if (valNode instanceof less.tree.Expression) {
            vals = valNode.value;
          } else {
            vals = [valNode];
          }
          for (_i = 0, _len = vals.length; _i < _len; _i++) {
            val = vals[_i];
            if (val instanceof less.tree.Expression) {
              r = this.evaluateValNode(val);
              if (r === null) {
                return null;
              }
              ret = ret.concat(r);
            } else if (val instanceof less.tree.Quoted) {
              ret.push(val.value);
            } else if (val instanceof less.tree.Dimension) {
              ret.push(val.value);
            } else if (val instanceof less.tree.ArrayTreeNode) {
              _ref = val.values;
              for (_j = 0, _len1 = _ref.length; _j < _len1; _j++) {
                el = _ref[_j];
                ret.push(el);
              }
            } else if (val instanceof less.tree.Call) {
              return null;
            } else if (val instanceof less.tree.URL) {
              return null;
            } else if (val instanceof less.tree.Comment) {
              ret.push('');
            } else {
              console.warn("BUG: Attempting to set content: to something unknown. [" + val.value + "]");
              console.warn(JSON.stringify(val));
              return null;
            }
          }
          return ret;
        };
  
        return ContentSet;
  
      })();
      return {
        MoveTo: MoveTo,
        DisplayNone: DisplayNone,
        TargetCounter: TargetCounter,
        TargetText: TargetText,
        StringSet: StringSet,
        ContentSet: ContentSet
      };
    });
  
  }).call(this);
  
  (function() {
    var __hasProp = {}.hasOwnProperty,
      __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; };
  
    define('polyfill-path/less-converters', ['underscore', 'sizzle', 'cs!polyfill-path/selector-visitor'], function(_, Sizzle, AbstractSelectorVisitor) {
      var AutogenClass, PSEUDO_CLASSES, PseudoExpander, freshClass, freshClassIdCounter, slugify;
      PSEUDO_CLASSES = ['before', 'after', 'outside', 'footnote-call', 'footnote-marker', 'running', 'deferred'];
      slugify = function(str) {
        str = str.replace(/\ +/g, ' ');
        str = str.replace(/[^A-Za-z0-9>\[\]\(\)\.]/g, '-');
        str = str.replace(/[\[\]\(\)]/g, '_');
        str = str.replace(/-+/g, '-');
        str = str.replace(/>/g, '-child-');
        str = str.replace(/\./g, '-dot-');
        str = str.replace(/-+/g, '-');
        str = str.replace(/^-|-$/g, '');
        return str;
      };
      freshClassIdCounter = 0;
      freshClass = function(selectorStr) {
        selectorStr = slugify(selectorStr);
        return "js-polyfill-autoclass-" + (freshClassIdCounter++) + "-" + selectorStr;
      };
      AutogenClass = (function() {
        function AutogenClass(selectorStr, elements, rules) {
          this.selectorStr = selectorStr;
          this.elements = elements;
          this.rules = rules;
        }
  
        return AutogenClass;
  
      })();
      PseudoExpander = (function(_super) {
        var selectorTestNode;
  
        __extends(PseudoExpander, _super);
  
        PseudoExpander.prototype.PSEUDO_ELEMENT_NAME = 'span';
  
        selectorTestNode = document.createElement('span');
  
        function PseudoExpander(root, set, interestingSet, plugins) {
          var plugin, ruleName, _i, _len;
          this.set = set;
          this.interestingSet = interestingSet;
          PseudoExpander.__super__.constructor.apply(this, arguments);
          this.interestingRules = [];
          for (_i = 0, _len = plugins.length; _i < _len; _i++) {
            plugin = plugins[_i];
            for (ruleName in plugin.rules || {}) {
              this.interestingRules[ruleName] = true;
            }
          }
        }
  
        PseudoExpander.prototype.hasInterestingRules = function(ruleSet) {
          var rule, _i, _len, _ref;
          if (this.interestingRules['*']) {
            return true;
          }
          _ref = ruleSet.rules;
          for (_i = 0, _len = _ref.length; _i < _len; _i++) {
            rule = _ref[_i];
            if (rule.name in this.interestingRules) {
              return true;
            }
          }
        };
  
        PseudoExpander.prototype.operateOnElements = function(frame, ruleSet, domSelector, pseudoSelector, originalSelector, selectorStr) {
          var autoClass, className, cls, context, e, hasInterestingRules, isBrowserSelector, newClassName, newContexts, node, op, originalContext, outside, pseudoName, pseudoNode, simpleExpand, _i, _j, _len, _len1, _ref;
          if (!pseudoSelector.elements.length) {
            try {
              selectorTestNode.querySelector(selectorStr);
              isBrowserSelector = true;
            } catch (_error) {
              e = _error;
              isBrowserSelector = false;
            }
            if (isBrowserSelector) {
              autoClass = new AutogenClass(selectorStr, originalSelector.elements, ruleSet.rules);
              this.set.add(selectorStr, autoClass);
            }
            hasInterestingRules = this.hasInterestingRules(ruleSet);
            if (!isBrowserSelector || hasInterestingRules) {
              className = freshClass(selectorStr);
              _ref = this.getNodes(selectorStr);
              for (_i = 0, _len = _ref.length; _i < _len; _i++) {
                node = _ref[_i];
                if (node.className == null) {
                  node.className = '';
                }
                if (node.classList) {
                  if (!isBrowserSelector) {
                    node.classList.add('js-polyfill-autoclass-keep');
                  }
                  node.classList.add('js-polyfill-autoclass');
                  node.classList.add('js-polyfill-interesting');
                  node.classList.add(className);
                }
              }
              selectorStr = "." + className;
              autoClass = new AutogenClass(selectorStr, originalSelector.elements, ruleSet.rules);
              this.interestingSet.add(selectorStr, autoClass);
              if (!isBrowserSelector && !hasInterestingRules) {
                return this.set.add(selectorStr, autoClass);
              }
            }
          } else {
            newContexts = (function() {
              var _j, _k, _len1, _len2, _ref1, _ref2, _results,
                _this = this;
              _ref1 = this.getNodes(selectorStr);
              _results = [];
              for (_j = 0, _len1 = _ref1.length; _j < _len1; _j++) {
                originalContext = _ref1[_j];
                context = originalContext;
                _ref2 = pseudoSelector.elements;
                for (_k = 0, _len2 = _ref2.length; _k < _len2; _k++) {
                  pseudoNode = _ref2[_k];
                  pseudoName = pseudoNode.value.replace('::', ':');
                  simpleExpand = function(op, pseudoName) {
                    var cls, pseudo;
                    cls = "js-polyfill-pseudo-" + pseudoName;
                    pseudo = Sizzle(" > ." + cls + ", > .js-polyfill-pseudo-outside > ." + cls, context)[0];
                    if (pseudo) {
                      return context = pseudo;
                    } else {
                      pseudo = document.createElement(_this.PSEUDO_ELEMENT_NAME);
                      pseudo.classList.add('js-polyfill-pseudo');
                      pseudo.classList.add(cls);
                      switch (op) {
                        case 'append':
                          context.appendChild(pseudo);
                          break;
                        case 'prepend':
                          context.insertBefore(pseudo, context.firstChild);
                      }
                      return context = pseudo;
                    }
                  };
                  selectorStr += pseudoName;
                  switch (pseudoName) {
                    case ':before':
                      simpleExpand('prepend', 'before');
                      break;
                    case ':after':
                      simpleExpand('append', 'after');
                      break;
                    case ':footnote-marker':
                      simpleExpand('prepend', 'footnote-marker');
                      break;
                    case ':footnote-call':
                      simpleExpand('append', 'footnote-call');
                      break;
                    case ':running':
                      simpleExpand('append', 'footnote-call');
                      break;
                    case ':outside':
                      op = 'wrap';
                      pseudoName = 'outside';
                      cls = "js-polyfill-pseudo-" + pseudoName;
                      if (context.parentNode.classList.contains(cls)) {
                        context = context.parentNode;
                      } else {
                        outside = document.createElement(this.PSEUDO_ELEMENT_NAME);
                        outside.classList.add('js-polyfill-pseudo');
                        outside.classList.add(cls);
                        context.parentNode.replaceChild(outside, context);
                        outside.appendChild(context);
                        context = outside;
                      }
                      break;
                    case ':deferred':
                      break;
                    default:
                      console.error("ERROR: Attempted to expand unsupported pseudo element " + pseudoName);
                  }
                }
                _results.push(context);
              }
              return _results;
            }).call(this);
            newClassName = freshClass(selectorStr);
            for (_j = 0, _len1 = newContexts.length; _j < _len1; _j++) {
              context = newContexts[_j];
              context.classList.add('js-polyfill-autoclass');
              context.classList.add('js-polyfill-interesting');
              context.classList.add(newClassName);
            }
            autoClass = new AutogenClass(selectorStr, pseudoSelector.elements, ruleSet.rules, this.hasInterestingRules(ruleSet));
            selectorStr = "." + newClassName;
            this.set.add(selectorStr, autoClass);
            if (this.hasInterestingRules(ruleSet)) {
              return this.interestingSet.add(selectorStr, autoClass);
            }
          }
        };
  
        return PseudoExpander;
  
      })(AbstractSelectorVisitor);
      return {
        PseudoExpander: PseudoExpander
      };
    });
  
  }).call(this);
  
  (function() {
    var __hasProp = {}.hasOwnProperty,
      __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; },
      __slice = [].slice;
  
    define('polyfill-path/index', ['underscore', 'less', 'eventemitter2', 'selector-set', 'cs!polyfill-path/selector-tree', 'cs!polyfill-path/less-converters', 'cs!polyfill-path/plugins', 'cs!polyfill-path/extras', 'cs!polyfill-path/fixed-point-runner', 'cs!polyfill-path/selector-visitor'], function(_, less, EventEmitter, SelectorSet, SelectorTree, LESS_CONVERTERS, PLUGINS, EXTRAS, FixedPointRunner, AbstractSelectorVisitor) {
      var CSSPolyfills, ContentSet, DisplayNone, ElementExtras, MoveTo, PseudoExpander, StringSet, TargetCounter, TargetText;
      PseudoExpander = LESS_CONVERTERS.PseudoExpander;
      MoveTo = PLUGINS.MoveTo;
      DisplayNone = PLUGINS.DisplayNone;
      TargetCounter = PLUGINS.TargetCounter;
      TargetText = PLUGINS.TargetText;
      StringSet = PLUGINS.StringSet;
      ContentSet = PLUGINS.ContentSet;
      ElementExtras = EXTRAS.ElementExtras;
      CSSPolyfills = (function(_super) {
        __extends(CSSPolyfills, _super);
  
        CSSPolyfills.DEFAULT_PLUGINS = [new MoveTo(), new DisplayNone(), new TargetCounter(), new TargetText(), new StringSet(), new ElementExtras(), new ContentSet()];
  
        function CSSPolyfills(config) {
          if (config == null) {
            config = {};
          }
          _.extend(this, config);
          _.defaults(this, {
            plugins: [],
            lessPlugins: [],
            pseudoExpanderClass: PseudoExpander,
            doNotIncludeDefaultPlugins: false,
            removeAutogenClasses: true
          });
          if (!this.doNotIncludeDefaultPlugins) {
            this.plugins = this.plugins.concat(CSSPolyfills.DEFAULT_PLUGINS);
          }
        }
  
        CSSPolyfills.prototype.runTree = function(rootNode, lessTree, cb) {
          var SelectorSet_add, allSet, bindAll, changeLessTree, interestingSet, outputRulesetsToString, pseudoExpander, runFixedPoint,
            _this = this;
          if (cb == null) {
            cb = null;
          }
          this.emit('start');
          if (rootNode.jquery) {
            rootNode = rootNode[0];
          }
          bindAll = function(emitter, eventNames) {
            return _.each(eventNames, function(name) {
              return emitter.on(name, function() {
                return _this.emit.apply(_this, [name].concat(__slice.call(arguments)));
              });
            });
          };
          SelectorSet_add = SelectorSet.prototype.add;
          SelectorSet.prototype.add = function(sel, data) {
            SelectorSet_add.apply(this, arguments);
            if (this.addedSelectors == null) {
              this.addedSelectors = [];
            }
            return this.addedSelectors.push({
              selector: sel,
              data: data
            });
          };
          outputRulesetsToString = function(outputRulesets) {
            var allSelectors, autogenClass, comment, cssStrs, env, originalSelectorStr, rule, rules, selector, selectorStr, start, _i, _j, _len, _len1, _ref;
            cssStrs = [];
            env = new less.tree.evalEnv();
            env.compress = false;
            env.dumpLineNumbers = 'all';
            start = new Date();
            allSelectors = outputRulesets.addedSelectors || [];
            for (_i = 0, _len = allSelectors.length; _i < _len; _i++) {
              _ref = allSelectors[_i], selectorStr = _ref.selector, autogenClass = _ref.data;
              rules = autogenClass.rules, selector = autogenClass.selector;
              originalSelectorStr = selector;
              if (originalSelectorStr === selectorStr) {
                comment = '';
              } else {
                comment = "/* BASED_ON: " + originalSelectorStr + " */";
              }
              cssStrs.push("" + selectorStr + " { " + comment);
              for (_j = 0, _len1 = rules.length; _j < _len1; _j++) {
                rule = rules[_j];
                cssStrs.push("  " + (rule.toCSS(env)));
              }
              cssStrs.push("}");
            }
            return cssStrs.join('\n');
          };
          allSet = new SelectorSet();
          interestingSet = new SelectorTree();
          changeLessTree = function(plugins) {
            var env;
            env = new less.tree.evalEnv();
            env.compress = false;
            env.dumpLineNumbers = 'all';
            env.plugins = plugins;
            return lessTree.toCSS(env);
          };
          runFixedPoint = function(plugins) {
            var fixedPointRunner;
            fixedPointRunner = new FixedPointRunner(rootNode, plugins, interestingSet, _this.removeAutogenClasses);
            bindAll(fixedPointRunner, ['runner.start', 'runner.end', 'tick.start', 'tick.node', 'tick.end']);
            fixedPointRunner.run();
            return fixedPointRunner;
          };
          if (this.pseudoExpanderClass) {
            pseudoExpander = new this.pseudoExpanderClass(rootNode, allSet, interestingSet, this.plugins);
            bindAll(pseudoExpander, ['selector.start', 'selector.end']);
            this.lessPlugins.push(pseudoExpander);
          }
          changeLessTree(this.lessPlugins);
          runFixedPoint(this.plugins);
          if (typeof cb === "function") {
            cb(null, outputRulesetsToString(allSet));
          }
          return this.emit('end');
        };
  
        CSSPolyfills.prototype.run = function(rootNode, cssStyle, filename, cb) {
          var _this = this;
          return this.parse(cssStyle, filename, function(err, lessTree) {
            if (err) {
              return typeof cb === "function" ? cb(err, lessTree) : void 0;
            }
            return _this.runTree(rootNode, lessTree, cb);
          });
        };
  
        CSSPolyfills.prototype.parse = function(cssStyle, filename, cb) {
          var env, parser;
          env = {
            compress: false,
            dumpLineNumbers: 'all',
            filename: filename
          };
          parser = new less.Parser(env);
          return parser.parse(cssStyle, cb);
        };
  
        return CSSPolyfills;
  
      })(EventEmitter);
      CSSPolyfills.less = less;
      CSSPolyfills.AbstractSelectorVisitor = AbstractSelectorVisitor;
      if (typeof window !== "undefined" && window !== null) {
        window.CSSPolyfills = CSSPolyfills;
      }
      return CSSPolyfills;
    });
  
  }).call(this);
  
  (function() {
    this.define = this.__polyfills_originalGlobals['define'];
  
    if (typeof this.define === "function") {
      this.define('polyfill-path/index', function() {
        return this.CSSPolyfills;
      });
    }
  
    this.__polyfills_originalGlobals = void 0;
  
  }).call(this);
  