Help/About: Revert subtle color to actually subtle color on Get Involved.

Props densinakum, courane01.
See #63025.



git-svn-id: https://develop.svn.wordpress.org/trunk@60136 602fd350-edb4-49c9-b593-d223f7449a82

Author: ryelle

src/wp-admin/css/about.css

@@ -22,7 +22,7 @@
 .about__container {
 	/* Section backgrounds */
 	--background: #f6f5f2;
-	--subtle-background: yellow;
+	--subtle-background: #eef0fd;
 
 	/* Main text color */
 	--text: #1e1e1e;