Github Markdown Styles - Taken from devtool sources https://guides.github.com/features/mastering-markdown/

markdown.css

.markdown-body {
  font-size: 15px;
  line-height: 1.7;
  overflow: hidden; }
  .markdown-body > *:first-child {
    margin-top: 0 !important; }
  .markdown-body > *:last-child {
    margin-bottom: 0 !important; }
  .markdown-body a.absent {
    color: #c00; }
  .markdown-body a.anchor {
    display: block;
    padding-left: 30px;
    margin-left: -30px;
    cursor: pointer;
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0; }
  .markdown-body h1, .markdown-body h2, .markdown-body h3, .markdown-body h4, .markdown-body h5, .markdown-body h6 {
    margin: 1em 0 15px;
    padding: 0;
    font-weight: bold;
    line-height: 1.7;
    cursor: text;
    position: relative; }
    .markdown-body h1 .octicon-link, .markdown-body h2 .octicon-link, .markdown-body h3 .octicon-link, .markdown-body h4 .octicon-link, .markdown-body h5 .octicon-link, .markdown-body h6 .octicon-link {
      display: none;
      color: #000; }
    .markdown-body h1:hover a.anchor, .markdown-body h2:hover a.anchor, .markdown-body h3:hover a.anchor, .markdown-body h4:hover a.anchor, .markdown-body h5:hover a.anchor, .markdown-body h6:hover a.anchor {
      text-decoration: none;
      line-height: 1;
      padding-left: 0;
      margin-left: -22px;
      top: 15%; }
      .markdown-body h1:hover a.anchor .octicon-link, .markdown-body h2:hover a.anchor .octicon-link, .markdown-body h3:hover a.anchor .octicon-link, .markdown-body h4:hover a.anchor .octicon-link, .markdown-body h5:hover a.anchor .octicon-link, .markdown-body h6:hover a.anchor .octicon-link {
        display: inline-block; }
    .markdown-body h1 tt, .markdown-body h1 code, .markdown-body h2 tt, .markdown-body h2 code, .markdown-body h3 tt, .markdown-body h3 code, .markdown-body h4 tt, .markdown-body h4 code, .markdown-body h5 tt, .markdown-body h5 code, .markdown-body h6 tt, .markdown-body h6 code {
      font-size: inherit; }
  .markdown-body h1 {
    font-size: 2.5em;
    border-bottom: 1px solid #ddd; }
  .markdown-body h2 {
    font-size: 2em;
    border-bottom: 1px solid #eee; }
  .markdown-body h3 {
    font-size: 1.5em; }
  .markdown-body h4 {
    font-size: 1.2em; }
  .markdown-body h5 {
    font-size: 1em; }
  .markdown-body h6 {
    color: #777;
    font-size: 1em; }
  .markdown-body p,
  .markdown-body blockquote,
  .markdown-body ul, .markdown-body ol, .markdown-body dl,
  .markdown-body table,
  .markdown-body pre {
    margin: 15px 0; }
  .markdown-body hr {
    background: transparent;
    border: 0 none;
    color: #ccc;
    height: 4px;
    padding: 0;
    margin: 15px 0; }
  .markdown-body li p.first {
    display: inline-block; }
  .markdown-body ul, .markdown-body ol {
    padding-left: 30px; }
    .markdown-body ul.no-list, .markdown-body ol.no-list {
      list-style-type: none;
      padding: 0; }
  .markdown-body ul ul,
  .markdown-body ul ol,
  .markdown-body ol ol,
  .markdown-body ol ul {
    margin-top: 0;
    margin-bottom: 0; }
  .markdown-body dl {
    padding: 0; }
  .markdown-body dl dt {
    font-size: 14px;
    font-weight: bold;
    font-style: italic;
    padding: 0;
    margin-top: 15px; }
  .markdown-body dl dd {
    margin-bottom: 15px;
    padding: 0 15px; }
  .markdown-body blockquote {
    border-left: 4px solid #DDD;
    padding: 0 15px;
    color: #777; }
    .markdown-body blockquote > :first-child {
      margin-top: 0px; }
    .markdown-body blockquote > :last-child {
      margin-bottom: 0px; }
  .markdown-body table {
    width: 100%;
    overflow: auto;
    display: block;
    border-spacing: 0;
    border-collapse: collapse; }
    .markdown-body table th {
      font-weight: bold; }
    .markdown-body table th, .markdown-body table td {
      border: 1px solid #ddd;
      padding: 6px 13px; }
    .markdown-body table tr {
      border-top: 1px solid #ccc;
      background-color: #fff; }
      .markdown-body table tr:nth-child(2n) {
        background-color: #f8f8f8; }
  .markdown-body img {
    max-width: 100%;
    -moz-box-sizing: border-box;
    box-sizing: border-box; }
  .markdown-body span.frame {
    display: block;
    overflow: hidden; }
    .markdown-body span.frame > span {
      border: 1px solid #ddd;
      display: block;
      float: left;
      overflow: hidden;
      margin: 13px 0 0;
      padding: 7px;
      width: auto; }
    .markdown-body span.frame span img {
      display: block;
      float: left; }
    .markdown-body span.frame span span {
      clear: both;
      color: #333;
      display: block;
      padding: 5px 0 0; }
  .markdown-body span.align-center {
    display: block;
    overflow: hidden;
    clear: both; }
    .markdown-body span.align-center > span {
      display: block;
      overflow: hidden;
      margin: 13px auto 0;
      text-align: center; }
    .markdown-body span.align-center span img {
      margin: 0 auto;
      text-align: center; }
  .markdown-body span.align-right {
    display: block;
    overflow: hidden;
    clear: both; }
    .markdown-body span.align-right > span {
      display: block;
      overflow: hidden;
      margin: 13px 0 0;
      text-align: right; }
    .markdown-body span.align-right span img {
      margin: 0;
      text-align: right; }
  .markdown-body span.float-left {
    display: block;
    margin-right: 13px;
    overflow: hidden;
    float: left; }
    .markdown-body span.float-left span {
      margin: 13px 0 0; }
  .markdown-body span.float-right {
    display: block;
    margin-left: 13px;
    overflow: hidden;
    float: right; }
    .markdown-body span.float-right > span {
      display: block;
      overflow: hidden;
      margin: 13px auto 0;
      text-align: right; }
  .markdown-body code, .markdown-body tt {
    margin: 0 2px;
    padding: 0px 5px;
    border: 1px solid #ddd;
    background-color: #f8f8f8;
    border-radius: 3px; }
  .markdown-body code {
    white-space: nowrap; }
  .markdown-body pre > code {
    margin: 0;
    padding: 0;
    white-space: pre;
    border: none;
    background: transparent; }
  .markdown-body .highlight pre, .markdown-body pre {
    background-color: #f8f8f8;
    border: 1px solid #ddd;
    font-size: 13px;
    line-height: 19px;
    overflow: auto;
    padding: 6px 10px;
    border-radius: 3px; }
  .markdown-body pre code, .markdown-body pre tt {
    margin: 0;
    padding: 0;
    background-color: transparent;
    border: none; }