This replaces the default style sheet that gets overridden with a custom
one from scratch.
One thing that is still not ideal is that notifications with action
buttons have a scoll area for the action buttons, which shouldn’t be the
case.
Swaync is in stable, mumble 1.4 is in stable and has pulseaudio enabled
by default, the tray target is defined in home-manager upstream and
nix-direnv comes with flake support by default.