Customizing Look and Feel - Need to Modify Notification bell Bubble Color(Self Service page)

I got a requirement to Modify the Notification Bell Bubble Color.

We are using the Oracle recommended way to do the changes we are not touching any source code or creating anything new. Please refer the Doc ID shared below in this please refer " 3. Modify custom.xss:" ( we are following the below way to customize).How to change the Look and Feel of Oracle Applications ( Doc ID 2470228.1 ).

We are trying to change the color of the notification bubble but even though we are trying to update the custom.xss file in correct way the changes are getting over ridden by original Color ( We are getting to know it is getting overridden using inspect elements styles from browser.)