diff --git a/configuration.nix b/configuration.nix
index e6f1443..07e0ed4 100644
--- a/configuration.nix
+++ b/configuration.nix
@@ -9,7 +9,14 @@
     ./hardware-configuration.nix
   ];
 
-  nixpkgs.config.allowUnfree = true;
+  nixpkgs = {
+    config.allowUnfree = true;
+    overlays = [
+      (self: super: {
+        hyprland = inputs.hyprland-git.packages."x86_64-linux".hyprland;
+      })
+    ];
+  };
   nix.settings.experimental-features = ["nix-command" "flakes"];
 
   # Use the systemd-boot EFI boot loader.
@@ -45,11 +52,20 @@
       tree
     ];
   };
+  home-manager = {
+    useGlobalPkgs = true;
+    useUserPackages = true;
+    extraSpecialArgs = {inherit inputs;};
+
+    users.ashley = import ./home.nix;
+  };
 
   services = {
-    displayManager.sddm = {
-      enable = true;
-      wayland.enable = true;
+    displayManager = {
+      sddm = {
+        enable = true;
+        wayland.enable = ! config.services.xserver.enable; # experimental
+      };
       defaultSession = "hyprland";
     };
 
@@ -68,15 +84,22 @@
   programs = {
     hyprland = {
       enable = true;
-      package = inputs.hyprland-git.packages."x86_64-linux".hyprland;
+      withUWSM = true; # Universal Wayland Session Manager
+      xwayland.enable = true;
     };
 
+    gamemode.enable = true;
     steam = {
       enable = true;
-      remotePlay.openFirewall = true; # optional
-      dedicatedServer.openFirewall = true; # optional
-      localNetworkGameTransfers.openFirewall = true; # optional
-      gamescopeSession.enable = true; # optional
+      gamescopeSession.enable = true; # .desktop entry for gamescope
+
+      remotePlay.openFirewall = true;
+      dedicatedServer.openFirewall = true;
+      localNetworkGameTransfers.openFirewall = true;
+
+      # extraCompatPackages = with pkgs; [
+      #   proton-ge-bin
+      # ];
     };
 
     silentSDDM = {
@@ -104,9 +127,12 @@
     };
 
     # nvidia drivers
-    nvidia = rec {
+    nvidia = {
       package = config.boot.kernelPackages.nvidiaPackages.stable;
-      open = lib.mkOverride 990 (package ? open && package ? firmware);
+
+      # WARNING: whether to use open-source or proprietary kernel modules
+      # open = lib.mkOverride 990 (package ? open && package ? firmware);
+      open = true;
 
       nvidiaSettings = true;
       modesetting.enable = true;
@@ -122,6 +148,12 @@
   };
 
   environment = {
+    # NOTE: loaded earlier than `environment.variables`
+    sessionVariables = {
+      # Hint Electrons apps to use Wayland
+      NIXOS_OZONE_WL = "1";
+    };
+
     variables = {
       EDITOR = "nvim";
     };
@@ -132,6 +164,8 @@
       git
       neovim
       wget
+
+      steamcmd
     ];
   };
 
diff --git a/flake.lock b/flake.lock
index 012d233..4b1ad8b 100644
--- a/flake.lock
+++ b/flake.lock
@@ -161,7 +161,9 @@
         "hyprutils": "hyprutils",
         "hyprwayland-scanner": "hyprwayland-scanner",
         "hyprwire": "hyprwire",
-        "nixpkgs": "nixpkgs",
+        "nixpkgs": [
+          "nixpkgs"
+        ],
         "pre-commit-hooks": "pre-commit-hooks",
         "systems": "systems",
         "xdph": "xdph"
@@ -428,22 +430,6 @@
       }
     },
     "nixpkgs": {
-      "locked": {
-        "lastModified": 1766070988,
-        "narHash": "sha256-G/WVghka6c4bAzMhTwT2vjLccg/awmHkdKSd2JrycLc=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "c6245e83d836d0433170a16eb185cefe0572f8b8",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixos-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "nixpkgs_2": {
       "locked": {
         "lastModified": 1771369470,
         "narHash": "sha256-0NBlEBKkN3lufyvFegY4TYv5mCNHbi5OmBDrzihbBMQ=",
@@ -487,7 +473,7 @@
         "home-manager": "home-manager",
         "hyprland-git": "hyprland-git",
         "nixcats": "nixcats",
-        "nixpkgs": "nixpkgs_2",
+        "nixpkgs": "nixpkgs",
         "silentSDDM": "silentSDDM"
       }
     },
diff --git a/flake.nix b/flake.nix
index a5c86b2..2177a33 100644
--- a/flake.nix
+++ b/flake.nix
@@ -3,6 +3,7 @@
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+
     # home-manager, used for managing user configuration
     home-manager = {
       url = "github:nix-community/home-manager/master";
@@ -12,6 +13,7 @@
       # to avoid problems caused by different versions of nixpkgs.
       inputs.nixpkgs.follows = "nixpkgs";
     };
+
     silentSDDM = {
       url = "github:uiriansan/SilentSDDM";
       inputs.nixpkgs.follows = "nixpkgs";
@@ -21,13 +23,14 @@
 
     hyprland-git = {
       url = "github:hyprwm/Hyprland/25250527793eb04bb60f103abe7f06370b9f6e1c";
+      inputs.nixpkgs.follows = "nixpkgs";
     };
   };
 
   outputs = inputs @ {
     nixpkgs,
     home-manager,
-    nixcats,
+    silentSDDM,
     ...
   }: {
     nixosConfigurations = {
@@ -35,21 +38,10 @@
         specialArgs = {inherit inputs;};
         modules = [
           ./configuration.nix
-          inputs.silentSDDM.nixosModules.default
-
           # make home-manager as a module of nixos
           # so that home-manager configuration will be deployed automatically when executing `nixos-rebuild switch`
           home-manager.nixosModules.home-manager
-          {
-            home-manager.useGlobalPkgs = true;
-            home-manager.useUserPackages = true;
-
-            home-manager.extraSpecialArgs = {inherit inputs;};
-
-            home-manager.users.ashley = import ./home.nix;
-
-            # Optionally, use home-manager.extraSpecialArgs to pass arguments to home.nix
-          }
+          silentSDDM.nixosModules.default
         ];
       };
     };
diff --git a/home.nix b/home.nix
index cff5e13..9aff559 100644
--- a/home.nix
+++ b/home.nix
@@ -40,5 +40,29 @@
     };
   };
 
+  services.kanshi = {
+    enable = true;
+    systemdTarget = "hyprland-session.target";
+
+    settings = [
+      {
+        # laptop screen
+        output.criteria = "eDP-1"; # XXX: TODO
+        output.mode = "1920x1080@240.00Hz";
+        output.scale = 1.0;
+        output.adaptiveSync = false; # Variable Refresh Rate
+      }
+      {
+        profile.name = "girlCore";
+        profile.outputs = [
+          {
+            criteria = "eDP-1"; # laptop screen
+            position = "0,0";
+          }
+        ];
+      }
+    ];
+  };
+
   home.stateVersion = "25.11";
 }
diff --git a/modules/neovim/nixcats.nix b/modules/neovim/nixcats.nix
index 2a1aa78..f9c2650 100644
--- a/modules/neovim/nixcats.nix
+++ b/modules/neovim/nixcats.nix
@@ -1,16 +1,10 @@
-{
-  inputs,
-  config,
-  pkgs,
-  ...
-}: let
+{inputs, ...}: let
   utils = inputs.nixcats.utils;
 in {
-
   imports = [
     inputs.nixcats.homeModule
   ];
-  
+
   config = {
     # this value, nixCats is the defaultPackageName you pass to mkNixosModules
     # it will be the namespace for your options.