Changing tab/stack colour in Mobile View

[RInfante]

Hello, 

If this question has been posed before I can't seem to find it, but is there any way to change the colors of the tab/stack selectors of a Dashboard when it's on its mobile view?

See the screenshot below. The blue does not conform to the brand colors I need, but can't seem to find any setting for it except the "Active tab border color" in the Theme settings; that one does apply the color to the desktop view but not the mobile one. 

Am I missing a setting somewhere or is this just not supported? This is in AGOL by the way.

Thanks!

[DarraghOSullivan]

I found to work via Theme -> Custom Theme -> Accent color