GTK3 Config Files
Add gtk.css and settings.ini to ~/.config/gtk-3.0/
Run GTK_DEBUG=interactive thunar to check classes on thunar, replace thunar with any gtk applicable app to debug it too
Add gtk.css and settings.ini to ~/.config/gtk-3.0/
Run GTK_DEBUG=interactive thunar to check classes on thunar, replace thunar with any gtk applicable app to debug it too