flake.nix

@@ -90,6 +90,7 @@
           { nixpkgs.pkgs = pkgs; }
           ./system/configuration.nix
           ./system/secrets.nix
+          ./system/specialisation.nix
           ./system/greetd.nix
           { login-manager.greetd.enable = desktop == "sway"; }
 

system/specialisation.nix

@@ -0,0 +1,21 @@
+{ pkgs, ... }:
+{
+  specialisation.dark-theme.configuration = {
+    nixpkgs.overlays = [ (final: prev: { uservars = prev.uservars; }) ];
+  };
+  specialisation.light-theme.configuration = {
+    nixpkgs.overlays = [
+      (final: prev: {
+        uservars = prev.uservars // rec {
+          theme = prev.uservars.themes.light;
+          color = theme.color;
+        };
+      })
+    ];
+  };
+  environment.systemPackages = [
+    (pkgs.writeShellScriptBin "theme" ''
+      sudo "/nix/var/nix/profiles/system/specialisation/$1-theme/bin/switch-to-configuration" test
+    '')
+  ];
+}

user/vscode/default.nix

@@ -3,7 +3,7 @@
 
   programs.vscode = {
     enable = true;
-    package = pkgs.vscodium-fhs;
+    package = pkgs.vscodium;
     extensions = with pkgs.vscode-extensions; [
       jnoortheen.nix-ide
       github.github-vscode-theme