.titlebar, headerbar {
min-height: 0px;
padding: 0px;
margin: 0px;
}
headerbar entry,
headerbar spinbutton,
headerbar button,
headerbar separator {
min-height: 0px;
padding: 0px;
margin: 1px;
}
/*
more or less normal
write this in ~\.config\gtk-3.0\gtk.css
use slashes instead of backslashes
slashes just terrifyin my nano (:
*/
Как сказал пользователь Фредди:
You don't have a US keyboard, try ? and shift + » for -/+ (the keys between 0 and backspace).
Это решило мою проблему!