diff --git a/index.html b/index.html
index 25b0d767d2da49ca6544b7666634b17fddc8865f..0aece4c81f49f2e9bd07ba0ceb5a7334c0c53a78 100644
--- a/index.html
+++ b/index.html
@@ -231,7 +231,7 @@
 					<p>
 						Additionally custom events can be triggered on a per slide basis by binding to the <code>data-state</code> name.
 					</p>
-					<pre><code data-trim contenteditable style="font-size: 18px; margin-top: 20px;">
+					<pre><code class="javascript" data-trim contenteditable style="font-size: 18px;">
 Reveal.addEventListener( 'customevent', function() {
 	console.log( '"customevent" has fired' );
 } );