this makes gtkgreet use the gtk theme (who would've thought)

hosts/niks/configuration.nix

@@ -174,7 +174,7 @@ in
             settings = {
                 default_session = {
                     command = "${pkgs.sway}/bin/sway --config ${swayConfig}";
-                    user = "greeter";
+                    user = "jacek";
                 };
             };
         };