devdocs/assets/stylesheets/pages/_crystal.scss

._crystal {
  @extend %simple;

  .signature { @extend %code; }
  a.signature, .superclass > a { @extend %label; }

  .entry-detail { margin-top: 1em; }
  .view-source { float: right; }

  .superclass-hierarchy {
    list-style: none;
    padding: 0;
    overflow: hidden;
  }

  li.superclass {
    float: left;
    margin: 0 .5em 0 0;
    padding: 0;
  }

  li.superclass + li.superclass:before {
    content: '<';
    margin-right: .5em;
  }
}