Bad background color in GIMP sliders with ZorinBlue-Dark

[pizzzzza]

The text became totally unreadable in GIMP with the default ZorinBlue-Dark theme, like these on the sliders.

How could I change the background colors of these sliders to a darker one? Should I modify the GTK theme?

I still want to use zorin gtk theme instead of the default gimp one because it's truly fluent.

GIMP2.10 and 3.0-RC1 had the same problem

Thanks a lot.

[Storm]

You need to modify its GTK2 .css file or GTK3 .css file for RC.

[pizzzzza]

I changed this in gtk-3.0/gtk.css [line 2388]:
@define-color theme_selected_bg_color #323e44;

#323e44 worked better than the original #add3e6 in GIMP.

Now it looks well.

I copied the theme into ~/.themes/ folder and modified its name to ZorinBlue-Dark-GIMP and changed the thing. I managed to use Flatseal to add a parameter GTK_THEME=ZorinBlue-Dark-GIMP to let gimp use this theme. So it won't affect any other apps other than GIMP.