This is a MacDown rendering style to reduce the precived effect of flickering when the preview pane updates if you are using DarkMode on your Mac.

GitHub2 Darkified.css

/* ----------------------------------------------------------------------------------------------------------
    File: GitHub2 Darkified.css

    This is a modified version of the Github2.css included with MacDown to reduce the precived effect
    of flickering when the preview pane updates if you are using DarkMode on your Mac.

    To Use this:
      Open MacDown > Preferences > Rendering.

      Click reveal next the CSS option

      Create new file called GitHub2 Darkified.css

      Paste the contents of this Gist, save it.

      Select "GitHub2 Darkified" as the CSS style in MacDown preferences

      Optional:
        I think the Syntax highlight theme of "Okaidia" works well this

        You can edit the background-color value below (notice the comment above the line)
        to better match your editor background color

---------------------------------------------------------------------------------------------------------- */

body {
  font-family: Helvetica, arial, sans-serif;
  color: rgba(255, 255, 255, 0.91);
  font-size: 14px;
  line-height: 1.6;
  padding-top: 10px;
  padding-bottom: 10px;
  /*            Modify this background color to match, or closely match your editor color to reduce flashing.       */
  background-color: #2d2d2d;
  padding: 30px; }

body > *:first-child {
  margin-top: 0 !important; }
body > *:last-child {
  margin-bottom: 0 !important; }

a {
  color: #4ba5ff; }
a.absent {
  color: #cc0000; }
a.anchor {
  display: block;
  padding-left: 30px;
  margin-left: -30px;
  cursor: pointer;
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0; }

h1, h2, h3, h4, h5, h6 {
  margin: 20px 0 10px;
  padding: 0;
  font-weight: bold;
  color: white;
  -webkit-font-smoothing: antialiased;
  cursor: text;
  position: relative; }

h1:hover a.anchor, h2:hover a.anchor, h3:hover a.anchor, h4:hover a.anchor, h5:hover a.anchor, h6:hover a.anchor {
  background: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAA09pVFh0WE1MOmNvbS5hZG9iZS54bXAAAAAAADw/eHBhY2tldCBiZWdpbj0i77u/IiBpZD0iVzVNME1wQ2VoaUh6cmVTek5UY3prYzlkIj8+IDx4OnhtcG1ldGEgeG1sbnM6eD0iYWRvYmU6bnM6bWV0YS8iIHg6eG1wdGs9IkFkb2JlIFhNUCBDb3JlIDUuMy1jMDExIDY2LjE0NTY2MSwgMjAxMi8wMi8wNi0xNDo1NjoyNyAgICAgICAgIj4gPHJkZjpSREYgeG1sbnM6cmRmPSJodHRwOi8vd3d3LnczLm9yZy8xOTk5LzAyLzIyLXJkZi1zeW50YXgtbnMjIj4gPHJkZjpEZXNjcmlwdGlvbiByZGY6YWJvdXQ9IiIgeG1sbnM6eG1wPSJodHRwOi8vbnMuYWRvYmUuY29tL3hhcC8xLjAvIiB4bWxuczp4bXBNTT0iaHR0cDovL25zLmFkb2JlLmNvbS94YXAvMS4wL21tLyIgeG1sbnM6c3RSZWY9Imh0dHA6Ly9ucy5hZG9iZS5jb20veGFwLzEuMC9zVHlwZS9SZXNvdXJjZVJlZiMiIHhtcDpDcmVhdG9yVG9vbD0iQWRvYmUgUGhvdG9zaG9wIENTNiAoMTMuMCAyMDEyMDMwNS5tLjQxNSAyMDEyLzAzLzA1OjIxOjAwOjAwKSAgKE1hY2ludG9zaCkiIHhtcE1NOkluc3RhbmNlSUQ9InhtcC5paWQ6OUM2NjlDQjI4ODBGMTFFMTg1ODlEODNERDJBRjUwQTQiIHhtcE1NOkRvY3VtZW50SUQ9InhtcC5kaWQ6OUM2NjlDQjM4ODBGMTFFMTg1ODlEODNERDJBRjUwQTQiPiA8eG1wTU06RGVyaXZlZEZyb20gc3RSZWY6aW5zdGFuY2VJRD0ieG1wLmlpZDo5QzY2OUNCMDg4MEYxMUUxODU4OUQ4M0REMkFGNTBBNCIgc3RSZWY6ZG9jdW1lbnRJRD0ieG1wLmRpZDo5QzY2OUNCMTg4MEYxMUUxODU4OUQ4M0REMkFGNTBBNCIvPiA8L3JkZjpEZXNjcmlwdGlvbj4gPC9yZGY6UkRGPiA8L3g6eG1wbWV0YT4gPD94cGFja2V0IGVuZD0iciI/PsQhXeAAAABfSURBVHjaYvz//z8DJYCRUgMYQAbAMBQIAvEqkBQWXI6sHqwHiwG70TTBxGaiWwjCTGgOUgJiF1J8wMRAIUA34B4Q76HUBelAfJYSA0CuMIEaRP8wGIkGMA54bgQIMACAmkXJi0hKJQAAAABJRU5ErkJggg==) no-repeat 10px center;
  text-decoration: none; }

h1 tt, h1 code {
  font-size: inherit; }

h2 tt, h2 code {
  font-size: inherit; }

h3 tt, h3 code {
  font-size: inherit; }

h4 tt, h4 code {
  font-size: inherit; }

h5 tt, h5 code {
  font-size: inherit; }

h6 tt, h6 code {
  font-size: inherit; }

h1 {
  font-size: 28px;
  color: #94d9ff; }

h2 {
  font-size: 24px;
  border-bottom: 1px solid #cccccc;
  color: #94d9ff; }

h3 {
  font-size: 18px; }

h4 {
  font-size: 16px; }

h5 {
  font-size: 14px; }

h6 {
  color: #777777;
  font-size: 14px; }

p, blockquote, ul, ol, dl, li, table, pre {
  margin: 15px 0; }

hr {
  background: transparent url(data:image/png;base64,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) repeat-x 0 0;
  border: 0 none;
  color: #cccccc;
  height: 4px;
  padding: 0;
}

body > h2:first-child {
  margin-top: 0;
  padding-top: 0; }
body > h1:first-child {
  margin-top: 0;
  padding-top: 0; }
  body > h1:first-child + h2 {
    margin-top: 0;
    padding-top: 0; }
body > h3:first-child, body > h4:first-child, body > h5:first-child, body > h6:first-child {
  margin-top: 0;
  padding-top: 0; }

a:first-child h1, a:first-child h2, a:first-child h3, a:first-child h4, a:first-child h5, a:first-child h6 {
  margin-top: 0;
  padding-top: 0; }

h1 p, h2 p, h3 p, h4 p, h5 p, h6 p {
  margin-top: 0; }

li p.first {
  display: inline-block; }
li {
  margin: 0; }
ul, ol {
  padding-left: 30px; }

ul :first-child, ol :first-child {
  margin-top: 0; }

dl {
  padding: 0; }
  dl dt {
    font-size: 14px;
    font-weight: bold;
    font-style: italic;
    padding: 0;
    margin: 15px 0 5px; }
    dl dt:first-child {
      padding: 0; }
    dl dt > :first-child {
      margin-top: 0; }
    dl dt > :last-child {
      margin-bottom: 0; }
  dl dd {
    margin: 0 0 15px;
    padding: 0 15px; }
    dl dd > :first-child {
      margin-top: 0; }
    dl dd > :last-child {
      margin-bottom: 0; }

blockquote {
  border-left: 4px solid #dddddd;
  padding: 0 15px;
  color: #777777; }
  blockquote > :first-child {
    margin-top: 0; }
  blockquote > :last-child {
    margin-bottom: 0; }

table {
  padding: 0;border-collapse: collapse; }
  table tr {
    border-top: 1px solid #cccccc;
    background-color: rgba(0, 0, 0, 0.11);
    margin: 0;
    padding: 0; }
    table tr:nth-child(2n) {
      background-color: rgba(0, 0, 0, 0.26); }
    table tr th {
      font-weight: bold;
      border: 1px solid #cccccc;
      margin: 0;
      padding: 6px 13px; }
    table tr td {
      border: 1px solid #cccccc;
      margin: 0;
      padding: 6px 13px; }
    table tr th :first-child, table tr td :first-child {
      margin-top: 0; }
    table tr th :last-child, table tr td :last-child {
      margin-bottom: 0; }

img {
  max-width: 100%; }

span.frame {
  display: block;
  overflow: hidden; }
  span.frame > span {
    border: 1px solid #dddddd;
    display: block;
    float: left;
    overflow: hidden;
    margin: 13px 0 0;
    padding: 7px;
    width: auto; }
  span.frame span img {
    display: block;
    float: left; }
  span.frame span span {
    clear: both;
    color: #333333;
    display: block;
    padding: 5px 0 0; }
span.align-center {
  display: block;
  overflow: hidden;
  clear: both; }
  span.align-center > span {
    display: block;
    overflow: hidden;
    margin: 13px auto 0;
    text-align: center; }
  span.align-center span img {
    margin: 0 auto;
    text-align: center; }
span.align-right {
  display: block;
  overflow: hidden;
  clear: both; }
  span.align-right > span {
    display: block;
    overflow: hidden;
    margin: 13px 0 0;
    text-align: right; }
  span.align-right span img {
    margin: 0;
    text-align: right; }
span.float-left {
  display: block;
  margin-right: 13px;
  overflow: hidden;
  float: left; }
  span.float-left span {
    margin: 13px 0 0; }
span.float-right {
  display: block;
  margin-left: 13px;
  overflow: hidden;
  float: right; }
  span.float-right > span {
    display: block;
    overflow: hidden;
    margin: 13px auto 0;
    text-align: right; }

code, tt {
  margin: 0 2px;
  padding: 0 5px;
  white-space: nowrap;
  border: 1px solid rgba(235, 235, 235, 0.3);
  background-color: #252525;
  border-radius: 3px; }

pre code {
  margin: 0;
  padding: 0;
  white-space: pre;
  border: none;
  background: transparent; }

.highlight pre {
  background-color: #641111;
  border: 1px solid #f2f2f2;
  font-size: 13px;
  line-height: 19px;
  overflow: auto;
  padding: 6px 10px;
  border-radius: 3px; }

pre {
  background-color: #393939;
  border: 1px solid rgba(235, 235, 235, 0.3);
  font-size: 13px;
  line-height: 19px;
  overflow: auto;
  padding: 6px 10px;
  border-radius: 3px; }
  pre code, pre tt {
    background-color: transparent;
    border: none; }

sup {
    font-size: 0.83em;
    vertical-align: super;
    line-height: 0;
}

kbd {
  display: inline-block;
  padding: 3px 5px;
  font-size: 11px;
  line-height: 10px;
  color: #555;
  vertical-align: middle;
  background-color: #3c3b3b;
  border: solid 1px #ccc;
  border-bottom-color: #bbb;
  border-radius: 3px;
  box-shadow: inset 0 -1px 0 #bbb
}

* {
	-webkit-print-color-adjust: exact;
}
@media screen and (min-width: 914px) {
    body {
        width: 854px;
        margin:0 auto;
    }
}
@media print {
	table, pre {
		page-break-inside: avoid;
	}
	pre {
		word-wrap: break-word;
	}
  body {
    padding: 2cm;
  }
}