[Flake] Move to 26.05

home-manager/features/linux-desktop.nix

@@ -71,8 +71,12 @@ in
     gtk3.extraConfig = {
       gtk-application-prefer-dark-theme = true;
     };
-    gtk4.extraConfig = {
-      gtk-application-prefer-dark-theme = true;
+    gtk4 = {
+      # Don't use GTK4 themes.  See https://stopthemingmy.app/
+      theme = null;
+      extraConfig = {
+        gtk-application-prefer-dark-theme = true;
+      };
     };
   };