feat(design): adjust prismjs theme colors

Author: julie-ng

static/styles/prism.scss

@@ -7,7 +7,7 @@
 
 code[class*="language-"],
 pre[class*="language-"] {
-	color: black;
+	color: #333;
 	background: none;
 	// text-shadow: 0 1px white;
 	font-family: Consolas, Monaco, 'Andale Mono', 'Ubuntu Mono', monospace;
@@ -82,23 +82,26 @@ pre[class*="language-"] {
 	opacity: .7;
 }
 
-.token.property,
-.token.tag,
-.token.boolean,
-.token.number,
 .token.constant,
 .token.symbol,
 .token.deleted {
 	color: #905;
 }
 
+.token.property,
+.token.tag,
+.token.boolean,
+.token.number {
+	color: #9b59b6;
+}
+
 .token.selector,
 .token.attr-name,
 .token.string,
 .token.char,
 .token.builtin,
 .token.inserted {
-	color: #690;
+	color: #16a085; // green
 }
 
 .token.operator,
@@ -117,7 +120,7 @@ pre[class*="language-"] {
 }
 
 .token.function {
-	color: #DD4A68;
+	color: #c0392b;
 }
 
 .token.regex,