GTK

• GKT is a widget toolkit for building GUI applications
• GTK will default to the Wayland backend
• Override it to Xwayland by modifying the environment variable: GDK_BACKEND=x11

Configuration

GTK3

# Force GTK3 dark mode using environment variable (not recommended)
GTK_THEME="Adwaita:dark" nautilus

# /etc/gtk-3.0/settings.ini
# ~/.config/gtk-3.0/settings.ini
[Settings]
gtk-application-prefer-dark-theme = true

GTK4

gsettings set \
  org.gnome.desktop.interface \
  color-scheme prefer-dark