feat: add rehype-prism-plus and docs

css/tailwind.css

@@ -14,6 +14,19 @@
   @apply hidden;
 }
 
+.code-line {
+  @apply pl-4 -mx-4 border-l-4 border-gray-800;
+}
+
+.highlight-line {
+  @apply -mx-4 bg-gray-700 bg-opacity-50 border-l-4 border-primary-500;
+}
+
+.line-number::before {
+  @apply pr-4 -ml-2 text-gray-400;
+  content: attr(line);
+}
+
 html {
   scroll-behavior: smooth;
 }