Opacity and Background Color

[broyuken]

I'm trying to get the background color of the selected menu item on the left side of the main HA interface to use in a label card but I can't figure it out. HA seems to use the following to color it.

background-color: var(--sidebar-selected-icon-color);
opacity: 0.12;

How can I set the opacity of just the background without changing the text as well? I believe I can use the rgba, but I don't think I can use that in conjunction with the variable.

Thanks in advance!

[broyuken]

bueller?

[RomRider]

You can do that in supported browser: background-color: color-mix(in srgb, var(--sidebar-selected-icon-color) 50%, transparent) (50% is the transparency here)