Install gnome-themes
This package contains the Adwaita-dark theme.
sudo pacman -S gnome-themes-extra
Set the following env vars to apply the theme:
GTK_THEME=Adwaita:dark
GTK2_RC_FILES=/usr/share/themes/Adwaita-dark/gtk-2.0/gtkrc
QT_QPA_PLATFORMTHEME=gtk3
Possible alternative to QT_QPA_PLATFORMTHEME, if the packages adwaita-qt5 and adwaita-qt6 are installed from the AUR:
QT_STYLE_OVERRIDE=adwaita-dark
Note that adwaita-qt is not maintained anymore: https://github.com/FedoraQt/adwaita-qt?tab=readme-ov-file#adwaita-qt-project-is-unmaintained-a-no-longer-actively-developed
Make sure gtk3 apps pick up the theme:
~/.config/gtk-3.0/settings.ini:
[Settings]
gtk-icon-theme-name = Adwaita
gtk-theme-name = Adwaita
gtk-application-prefer-dark-theme = true
Hide minimize, maximize and close buttons for all windows
gsettings set org.gnome.desktop.wm.preferences button-layout :
To restore them
gsettings set org.gnome.desktop.wm.preferences button-layout 'icons:minimize,maximize,close'