devdocs/assets/stylesheets/pages/_rxjs.scss

._rxjs {
  @extend %simple;

  .pre-title { @extend %pre-heading; }

  .breadcrumbs { @extend %note; }
  .banner { @extend %note-green; }
  code.stable { @extend %label-green; }
  code.experimental { @extend %label-orange; }
  code.deprecated { @extend %label-red; }
  .alert.is-important { @extend %note-red; }
  .alert.is-helpful, .breadcrumbs { @extend %note-blue; }

  .breadcrumbs { padding-left: 2em; }

  img { margin: 1em 0; }

  .location-badge {
    font-style: italic;
    text-align: right;
  }

  td h3 { margin: 0 !important; }
}