Dark theme support in GTK 3 apps

Some old applications, like Rhythmbox, do not support the GTK 4 / Adwaita theme on modern distributions like Fedora.

Even though there are many solutions available,

I'm using this simple fix that requires just an application restart after making the change:

[Settings]
gtk-application-prefer-dark-theme=1

Integrations

CSS patch for i3wm

Also, found this file in my backup folder, so let's keep it here, as it may be needed elsewhere (suppose in i3wm case)

.window-frame {
    box-shadow: none;
    margin: 0;
}

Adwaita theme port

Personally, I'm not using it, but it would be helpful at some point: