csd: initial theming for CSD windows decorations
csd: initial theming for CSD windows decorations

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