diff --git a/src/components/InteractiveCode.astro b/src/components/InteractiveCode.astro
index 2ccf905..d318ee8 100644
--- a/src/components/InteractiveCode.astro
+++ b/src/components/InteractiveCode.astro
@@ -1,15 +1,14 @@
 ---
+import { lex } from "../lexer/lexer";
 const {code} = Astro.props;
 
-let c = trimAndDedent(code);
-
 /** 
  * Performs the following:
  * - Removes the first & last line, if they are empty
  * - Picks the indentation level from the first non-white line
  * - Dedents the following lines
 */
-function trimAndDedent(input: string): string {
+function trimAndDedent(input: string): Array<string> {
     let lines = input.split("\n");
 
     // Remove empty lines at the start
@@ -70,16 +69,36 @@ function trimAndDedent(input: string): string {
         }
     }
 
-    return lines.join("\n");
+    return lines;
 }
 
-// TODO: Apply syntax highlighting
+function highlightCode(lines: Array<string>): string {
+    let outLines: Array<string> = [];
 
+    for (const line of lines) {
+        const tokens = lex(line);
+        const lineArray = [];
+        
+        for (const token of tokens) {
+            if (token.token_type !== "") {
+                lineArray.push(`<span class="token ${token.token_type}">${token.v}</span>`);
+            } else {
+                lineArray.push(token.v);
+            }
+        }
+
+        outLines.push(lineArray.join(""));
+    }
+
+    return outLines.join("\n");
+}
+
+const codeHtml = highlightCode(trimAndDedent(code));
 ---
 
 <div class="bg-black rounded">
     <span class="inline-block bg-[var(--code-theme-bg-acolor)] px-2 rounded-tl rounded-tr font-mono text-sm">thp code</span>
-    <pre class="language-thp" style="margin: 0; border-top-left-radius: 0;" data-disabled><code>{c}</code></pre>
+    <pre class="language-thp" style="margin: 0; border-top-left-radius: 0;" data-disabled><code set:html={codeHtml}></code></pre>
     <div class="grid grid-cols-2 font-mono text-sm">
         <div>
             <div class="p-1 border-b border-r border-white">stdout</div>
diff --git a/src/pages/learn/basics/hello-world.mdx b/src/pages/learn/basics/hello-world.mdx
index dd9b66c..19a5fae 100644
--- a/src/pages/learn/basics/hello-world.mdx
+++ b/src/pages/learn/basics/hello-world.mdx
@@ -16,6 +16,17 @@ Then run `thp hello.thp`
 
 ## Try
 
+```thp
+val x = 322
+val y = 322
+
+fun f(Int x, Int y) {
+    print("gaaaa {x} {y}")
+}
+
+f(x, y)
+```
+
 <InteractiveCode 
     code={`
     val x = 322