diff --git a/index.html b/index.html
index b8f4271..cface13 100644
--- a/index.html
+++ b/index.html
@@ -224,6 +224,8 @@
   </div>
 
   <script>
+    "use strict";
+
     const __cube = document.querySelector(".cube");
 
     class Vec3 {
@@ -363,4 +365,4 @@
   </script>
 </body>
 
-</html>
\ No newline at end of file
+</html>