Add missing styles for the 04....-START.html

Author: jima-zillow

04 - CSS Grid Dev Tools/dev-tools-START.html

@@ -23,7 +23,10 @@
   </div>
 
   <style>
+    .container {
+      display: grid;
+    }
   </style>
 </body>
 
-</html>
+</html>