devdocs/assets/stylesheets/pages/_reactivex.scss

._reactivex {
  @extend %simple;

  img {
    max-width: 50%;
  }

  figure {
    margin: 0;
  }

  dfn {
    cursor: text;
    font-style: italic;
    text-decoration: none;
    border-bottom: none;
  }

  #tree {
    dt, dd {
      font-weight: normal;
    }

    dt {
      float: left;
      clear: left;

      margin-top: 0;

      &:before {
        content: "\2026";
      }
    }

    dd:not(.sub) {
      float: left;

      margin: 0 0 0 5px;
      padding: 0;
    }

    dl#outer > dt {
      font-weight: bold;
      margin-top: 5px;

      & + dd {
        margin-top: 5px;
      }
    }
  }
}