anchor.diff:  .your-class-name { @include alert(#ff6c3c); }
   ', :css %>
   
  -<div class="alert-base">
  +<div data-alert class="alert-base">
   This is a default alert.
   <a href="#" class="close">&times;</a>
   </div>
   
  -<div class="alert-base custom-bg">
  +<div data-alert class="alert-base custom-bg">
   This is an alert with a custom background set.
   <a href="#" class="close">&times;</a>
   </div>
  
positive.code:   @include radius($radius);
  }', :css %>
  
  <div class="alert-base bg radius success">
  This is base, bg and radius mixins.
  <a href="" class="close">&times;</a>
  </div>
  
negative.code:     <p>Then, you'll need to add a data-attribute to make the JS work properly on that element. That looks like:</p>
  
  <%= code_example '
  <div data-alert class="alert-box" data-alert>
    <!-- Your content goes here -->
    <a href="#" class="close">&times;</a>
  </div>
  