[pmontra]

Check these links: I managed to reduce the padding of those huge menus.

https://blog.samalik.com/make-your-gnome-title-bars-smaller/

https://blog.samalik.com/make-your-gnome-title-bar-smaller-f...

https://stackoverflow.com/questions/36869701/decrease-the-ta...

Your CSS must go to ~/.config/gtk-3.0/gtk.css