Use prism as smaller nicer code highlighting library

app/assets/stylesheets/application.css.scss

@@ -28,7 +28,7 @@ $weight-bold: 400;
 
 @import "checkmark-icon";
 @import 'demo';
-@import 'highlight';
+@import 'prism';
 
 .field_with_errors input {
   border-color: $red;

app/assets/stylesheets/highlight.css.scss

@@ -1,5 +0,0 @@
-code.html .hljs-tag:first-child .hljs-attr, code.html .hljs-tag:first-child .hljs-string {
-  font-weight: bold;
-  font-size: 1.2em;
-}
-

app/assets/stylesheets/prism.css.scss

@@ -0,0 +1,131 @@
+/* PrismJS 1.20.0
+https://prismjs.com/download.html#themes=prism-okaidia&languages=markup+css+clike+javascript&plugins=custom-class */
+/**
+ * okaidia theme for JavaScript, CSS and HTML
+ * Loosely based on Monokai textmate theme by http://www.monokai.nl/
+ * @author ocodia
+ */
+
+code.language-html > .prism-tag:first-child {
+  font-weight: bold;
+  font-size: 1.1em;
+}
+
+code[class*="language-"],
+pre[class*="language-"] {
+	color: #f8f8f2;
+	background: none;
+	text-shadow: 0 1px rgba(0, 0, 0, 0.3);
+	font-family: Consolas, Monaco, 'Andale Mono', 'Ubuntu Mono', monospace;
+	font-size: 1em;
+	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-"] {
+	padding: 1em;
+	margin: .5em 0;
+	overflow: auto;
+	border-radius: 0.3em;
+}
+
+:not(pre) > code[class*="language-"],
+pre[class*="language-"] {
+	background: #272822;
+}
+
+/* Inline code */
+:not(pre) > code[class*="language-"] {
+	padding: .1em;
+	border-radius: .3em;
+	white-space: normal;
+}
+
+.prism-token.prism-comment,
+.prism-token.prism-prolog,
+.prism-token.prism-doctype,
+.prism-token.prism-cdata {
+	color: slategray;
+}
+
+.prism-token.prism-punctuation {
+	color: #f8f8f2;
+}
+
+.prism-token.prism-namespace {
+	opacity: .7;
+}
+
+.prism-token.prism-property,
+.prism-token.prism-tag,
+.prism-token.prism-constant,
+.prism-token.prism-symbol,
+.prism-token.prism-deleted {
+	color: #f92672;
+}
+
+.prism-token.prism-boolean,
+.prism-token.prism-number {
+	color: #ae81ff;
+}
+
+.prism-token.prism-selector,
+.prism-token.prism-attr-name,
+.prism-token.prism-string,
+.prism-token.prism-char,
+.prism-token.prism-builtin,
+.prism-token.prism-inserted {
+	color: #a6e22e;
+}
+
+.prism-token.prism-operator,
+.prism-token.prism-entity,
+.prism-token.prism-url,
+.prism-language-css .prism-token.prism-string,
+.prism-style .prism-token.prism-string,
+.prism-token.prism-variable {
+	color: #f8f8f2;
+}
+
+.prism-token.prism-atrule,
+.prism-token.prism-attr-value,
+.prism-token.prism-function,
+.prism-token.prism-class-name {
+	color: #e6db74;
+}
+
+.prism-token.prism-keyword {
+	color: #66d9ef;
+}
+
+.prism-token.prism-regex,
+.token.important {
+	color: #fd971f;
+}
+
+.prism-token.prism-important,
+.prism-token.prism-bold {
+	font-weight: bold;
+}
+.prism-token.prism-italic {
+	font-style: italic;
+}
+
+.prism-token.prism-entity {
+	cursor: help;
+}
+