title: MVC4 bundling: Minification failed because of css3-feature?
body: <p>I want to use MVC4 bundling and minification, but I always get this error message as comment in my not minified css file:</p>
  
  <pre><code>/* Minification failed. Returning unminified contents.
  (534,29): run-time error CSS1019: Unexpected token, found ' '
  (534,29): run-time error CSS1019: Unexpected token, found ' '
  (534,29): run-time error CSS1042: Expected function, found ' '
  (534,29): run-time error CSS1062: Expected semicolon or closing curly-brace, found ' '
  (535,26): run-time error CSS1019: Unexpected token, found ' '
  (535,26): run-time error CSS1019: Unexpected token, found ' '
  (535,26): run-time error CSS1042: Expected function, found ' '
  (535,26): run-time error CSS1062: Expected semicolon or closing curly-brace, found ' '
  (536,25): run-time error CSS1019: Unexpected token, found ' '
  (536,25): run-time error CSS1019: Unexpected token, found ' '
  (536,25): run-time error CSS1042: Expected function, found ' '
  (536,25): run-time error CSS1062: Expected semicolon or closing curly-brace, found ' '
  (537,24): run-time error CSS1019: Unexpected token, found ' '
  (537,24): run-time error CSS1019: Unexpected token, found ' '
  (537,24): run-time error CSS1042: Expected function, found ' '
  (537,24): run-time error CSS1062: Expected semicolon or closing curly-brace, found ' '
   */
  </code></pre>
  
  <p>The corresponding lines in CSS are:</p>
  
  <pre><code>width: -webkit-calc(100% - 0.5em);
  width: -moz-calc(100% - 0.5em);
  width: -ms-calc(100% - 0.5em);
  width: -o-calc(100% - 0.5em);
  </code></pre>
  
  <p>What can I do for minification to work with css3's calc feature?</p>