http://mackhankins.com Prism JS Syntax Highlighter Gist Theme
Jun 28, 2016  

I hacked together a Prism syntax highlighter Gist theme. I mostly work with PHP, but you could go on to extend the prism.css to match up with any set of languages you wanted. I simply compiled it from their download page with the line numbers plugin.

I decided to extend it with Clipboard.js instead of going for the "view raw" approach. I'm also using Bootstrap, JQuery, and Font-Awesome, so you'll need to customize it to fit your needs.

Prism.css

/****
PrismJS Gist Theme
*****/

code[class*="language-"],
pre[class*="language-"] {
    color: black;
    background: none;
    font-family: Consolas, "Liberation Mono", Menlo, Courier, monospace;
    font-size: 12px;
    text-align: left;
    white-space: pre;
    word-spacing: normal;
    word-break: normal;
    word-wrap: normal;
    line-height: 1.5;

    -moz-tab-size: 4;
    -o-tab-size: 4;
    tab-size: 4;

    -webkit-hyphens: none;
    -moz-hyphens: none;
    -ms-hyphens: none;
    hyphens: none;
}

/* Code blocks */
pre[class*="language-"] {
    position: relative;
    margin: .5em 0;
    border: 1px solid #dddddd;
    background-color: #ffffff;
    overflow: visible;
    padding: 0;
}

code[class*="language"] {
    max-height: inherit;
    height: 100%;
    padding: 0 1em;
    display: block;
    overflow: auto;
}

/* Margin bottom to accomodate shadow */
:not(pre) > code[class*="language-"],
pre[class*="language-"] {
    background-color: #ffffff;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
    margin-bottom: 1em;
}

/* Inline code */
:not(pre) > code[class*="language-"] {
    position: relative;
    padding: .2em;
    -webkit-border-radius: 0.3em;
    -moz-border-radius: 0.3em;
    -ms-border-radius: 0.3em;
    -o-border-radius: 0.3em;
    border-radius: 0.3em;
    color: #c92c2c;
    border: 1px solid rgba(0, 0, 0, 0.1);
    display: inline;
    white-space: normal;
}

pre[class*="language-"]:before,
pre[class*="language-"]:after {
    content: '';
    z-index: -2;
    display: block;
    position: absolute;
    bottom: 0.75em;
    left: 0.18em;
    width: 40%;
    height: 20%;
    max-height: 13em;
    -webkit-box-shadow: 0px 13px 8px #979797;
    -moz-box-shadow: 0px 13px 8px #979797;
    box-shadow: 0px 13px 8px #979797;
    -webkit-transform: rotate(-2deg);
    -moz-transform: rotate(-2deg);
    -ms-transform: rotate(-2deg);
    -o-transform: rotate(-2deg);
    transform: rotate(-2deg);
}

:not(pre) > code[class*="language-"]:after,
pre[class*="language-"]:after {
    right: 0.75em;
    left: auto;
    -webkit-transform: rotate(2deg);
    -moz-transform: rotate(2deg);
    -ms-transform: rotate(2deg);
    -o-transform: rotate(2deg);
    transform: rotate(2deg);
}

.token.comment,
.token.block-comment,
.token.prolog,
.token.doctype,
.token.cdata {
    color: #969896;
}

.token.punctuation {
    color: #969896;
}

.token.string,
.token.attr-value {
    color: #183691;
}

.token.keyword,
.token.property,
.token.boolean,
.token.number,
.token.function-name,
.token.constant,
.token.symbol,
.token.deleted {
    color: #c92c2c;
}

.token.tag {
    color: #63a35c;
}

.token.selector,
.token.char,
.token.function,
.token.builtin,
.token.inserted,
.token.class-name,
.token.attr-name {
    color: #795da3;
}

.token.operator,
.token.entity,
.token.url,
.token.variable {
    color: #333333;
    background: rgba(255, 255, 255, 0.5);
}

.token.atrule {
    color: #a71d5d;
}

.token.regex,
.token.important {
    color: #e90;
}

.language-css .token.string,
.style .token.string {
    color: #333333;
    background: rgba(255, 255, 255, 0.5);
}

.token.important {
    font-weight: normal;
}

.token.bold {
    font-weight: bold;
}

.token.italic {
    font-style: italic;
}

.token.entity {
    cursor: help;
}

.namespace {
    opacity: .7;
}

@media screen and (max-width: 767px) {
    pre[class*="language-"]:before,
    pre[class*="language-"]:after {
        bottom: 14px;
        -webkit-box-shadow: none;
        -moz-box-shadow: none;
        box-shadow: none;
    }

}

/* Plugin styles */
.token.tab:not(:empty):before,
.token.cr:before,
.token.lf:before {
    color: #e0d7d1;
}

/* Plugin styles: Line Numbers */
pre[class*="language-"].line-numbers {
    padding-left: 0;
}

pre[class*="language-"].line-numbers code {
    padding-left: 3.8em;
}

pre[class*="language-"].line-numbers .line-numbers-rows {
    left: 0;
}

/* Plugin styles: Line Highlight */
pre[class*="language-"][data-line] {
    padding-top: 0;
    padding-bottom: 0;
    padding-left: 0;
}

pre[data-line] code {
    position: relative;
    padding-left: 4em;
}

pre .line-highlight {
    margin-top: 0;
}

pre.line-numbers {
    position: relative;
    padding-left: 3.8em;
    counter-reset: linenumber;
}

pre.line-numbers > code {
    position: relative;
}

.line-numbers .line-numbers-rows {
    position: absolute;
    pointer-events: none;
    top: 0;
    font-size: 100%;
    left: -3.8em;
    width: 3em; /* works for line-numbers below 1000 lines */
    letter-spacing: -1px;
    border-right: 1px solid #dddddd;

    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;

}

.line-numbers-rows > span {
    pointer-events: none;
    display: block;
    counter-increment: linenumber;
}

.line-numbers-rows > span:before {
    content: counter(linenumber);
    color: #dddddd;
    display: block;
    padding-right: 0.8em;
    text-align: right;
}

Meta (div)

I just dropped this in my _typography.scss, but feel free to go your own route.

.meta {
  display: block;
  position: relative;
  padding: 10px;
  overflow: hidden;
  font-family: Consolas, "Liberation Mono", Menlo, Courier, monospace;
  font-size: 12px;
  color: #767676;
  background-color: #f7f7f7;
  border-top: 1px solid #dddddd;
  border-radius: 0 0 2px 2px;
  width: 100%;
  margin: 0 auto !important;

  > span {
    color: black;

    > a, a:link, a:visited, a:hover, a:active {
      color: black !important;
      font-weight: bold;
    }

    > .fa {
      color: red !important;
    }

  }

}

Some Javascript

    <script>
        $( document ).ready(function () {
            $('pre').addClass('line-numbers');
            $('pre').append('<div class="meta">' +
                    '<span class="pull-left"><i class="fa fa-heart"></i> mackhankins.com</span>' +
                    '<span class="pull-right">' +
                    '<a href="javascript:;" id="clippy" title="copy to clipboard"><i class="fa fa-clipboard"></i></a>' +
                    '</span>' +
                    '</div>');
        });

        new Clipboard("#clippy", {
            text: function(trigger) {
                var code = $(trigger).closest('pre').find('code').text();
                return code;
            }
        });
    </script>