Shell Right Pane Color

Hi

I have a shell on my screen and RIGHT VERTICAL PANE BAR where you have FEED PEOPLE items, I want to change the background color of this to blue.

The code is below and is not changing the color :

.sapUiUx3ShellPaneBarRight {    background-color: aliceblue;    top: 0;    padding-top: 80px;
}

Please advise what is wrong here.

Thank you.