diff --git a/site/src/components/viewer/script.js b/site/src/components/viewer/script.js
index ad9e6f9..948adc1 100644
--- a/site/src/components/viewer/script.js
+++ b/site/src/components/viewer/script.js
@@ -13,6 +13,11 @@ export default
 
     computed:
     {
+        extension()
+        {
+            return this.$store.state.files.current.data.extension
+        },
+
         version()
         {
             return this.$store.state.files.currentVersion
diff --git a/site/src/components/viewer/template.html b/site/src/components/viewer/template.html
index 4863a04..e2c5ce9 100644
--- a/site/src/components/viewer/template.html
+++ b/site/src/components/viewer/template.html
@@ -1,5 +1,5 @@
 <div class="viewer" v-if="version">
-    <pre v-highlightjs="version.content" contenteditable @keydown="onCodeKeyDown($event)"><code></code></pre>
+    <pre v-highlightjs="version.content" contenteditable @keydown="onCodeKeyDown($event)"><code :class="[ extension ]"></code></pre>
     <div class="lines">
         <div class="line" v-for="i in linesCount">{{ i }}</div>
     </div>