How to change color to sidebar panels background?

[ta1kun]

i would like to change color to button/panel background. i cant find the class to do it. i use vertical bar with only icons

[shazzap]

I think that is the --toolbar-bg value.

That can be easily modified in the Sidebery settings.

Go to the Style Editor section, look under General and scroll down a bit to "Toolbar background" and set a color.