turns out it was the wrong selector, the intent was to style the sidebar.
turns out it was the wrong selector, the intent was to style the sidebar.

DoctorJellyface/gnome-themes-standard,rgcjonas/adwaita-semidark,ChrisCummins/gnome-themes-standard,rgcjonas/adwaita-semidark,DoctorJellyface/gnome-themes-standard,cosimoc/gnome-themes-standard,ChrisCummins/gnome-themes-standard,cosimoc/gnome-themes-standard,magcius/gnome-themes-standard,magcius/gnome-themes-standard,cosimoc/gnome-themes-standard,cosimoc/gnome-themes-standard,Distrotech/gnome-themes-standard,Distrotech/gnome-themes-standard,ChrisCummins/gnome-themes-standard,rgcjonas/adwaita-semidark,ChrisCummins/gnome-themes-standard,rgcjonas/adwaita-semidark,magcius/gnome-themes-standard,ChrisCummins/gnome-themes-standard