Add ms.custom value to identify copilot highlight

Author: anandmeg

learn-pr/windows/get-started-with-web-development/4-css-basics.yml

@@ -4,10 +4,11 @@ uid: learn-windows.introduction-to-web-development.4-css-basics
 metadata:
   title: Exercise - Style your HTML with CSS
   description: Learn how to use CSS to apply styles to the HTML of your web app.
-  ms.date: 09/17/2024
+  ms.date: 02/26/2025
   author: kjo-msft
   ms.author: karinjohnson
   ms.topic: unit
+  ms.custom: copilot-scenario-highlight
 durationInMinutes: 10
 content: |
-    [!include[](includes/4-css-basics.md)]
+    [!include[](includes/4-css-basics.md)]