discourse/app/assets/stylesheets/application/code_highlighting.css.scss

// github.com style (c) Vasily Polovnyov <vast@whiteants.net>

pre {
  code {
    display: block;
    padding: 5px 10px;
    color: #333333;
    background: #f1f1ff;
    font-size: 14px;
    font-family: Consolas, Menlo, Monaco, Lucida Console, Liberation Mono, DejaVu Sans Mono, Bitstream Vera Sans Mono, Courier New, monospace, serif;
  }
  .comment, .template_comment, .diff .header, .javadoc {
    color: #999988;
    font-style: italic;
  }
  .keyword, .css .keyword, .winutils, .javascript .title, .nginx .title, .subst, .request, .status {
    color: #333333;
    font-weight: bold;
  }
  .number, .hexcolor, .ruby .constant {
    color: #009999;
  }
  .string, .tag .value, .phpdoc, .tex .formula {
    color: #dd1144;
  }
  .title, .id {
    color: #990000;
    font-weight: bold;
  }
  .javascript .title, .lisp .title, .clojure .title, .subst {
    font-weight: normal;
  }
  .class .title, .haskell .type, .vhdl .literal, .tex .command {
    color: #445588;
    font-weight: bold;
  }
  .tag {
    color: navy;
    font-weight: normal;
    .title {
      color: navy;
      font-weight: normal;
    }
  }
  .rules .property, .django .keyword {
    color: navy;
    font-weight: normal;
  }
  .attribute, .variable, .lisp .body {
    color: teal;
  }
  .regexp {
    color: #009926;
  }
  .class {
    color: #445588;
    font-weight: bold;
  }
  .symbol, .ruby .string, .lisp .keyword, .tex .special, .input_number {
    color: #990073;
  }
  .built_in, .lisp .title, .clojure .built_in {
    color: #0086b3;
  }
  .preprocessor, .pi, .doctype, .shebang, .cdata {
    color: #999999;
    font-weight: bold;
  }
  .deletion {
    background: #ffdddd;
  }
  .addition {
    background: #ddffdd;
  }
  .diff .change {
    background: #0086b3;
  }
  .chunk {
    color: #aaaaaa;
  }
  .tex .formula {
    opacity: 0.5;
  }
}

p > code {
  margin: 0px 2px;
  padding: 2px 5px;
  background-color: #f1f1ff;
  border-radius: 3px 3px 3px 3px;
}