gtk4.md

This theme is a GTK-3 theme. Some apps use GTK-4 but not libadwaita. If you want these apps to use the libadwaita theme you'll have to extract it from source. First you will need to install dependencies, on Fedora 36+ this can be done with the following:

sudo dnf install git vala gobject-introspection-devel sassc meson gtk4-devel cmake ninja-build

on ubuntu 22.04+ or debian 12+:

sudo apt install git libvala-dev gobject-introspection sassc meson libgtk-4-dev cmake ninja-build valac gettext

on Arch and Arch based distros:

sudo pacman -S git vala gobject-introspection sassc meson gtk4 cmake ninja

Next build libadwaita

git clone https://gitlab.gnome.org/GNOME/libadwaita.git
cd libadwaita
meson . _build
ninja -C _build

1. Copy all the CSS files in _build/src/stylesheet/ to ~/.local/share/themes/adw-gtk3/gtk-4.0 (or adw-gtk3-dark/gtk-4.0).
2. Rename base.css to gtk.css.
3. Open gtk.css in a text editor and at the top add the line: @import 'defaults-light.css'; (or @import 'defaults-dark.css'; depending on your color theme preference). Save and exit.

If the non-libadwaita GTK-4 app is a flatpak application you must set permissions: flatpak override --filesystem=~/.local/share/themes