diff --git a/modules/desktop/gnome.nix b/modules/desktop/gnome.nix
index c5d6643..efdf080 100644
--- a/modules/desktop/gnome.nix
+++ b/modules/desktop/gnome.nix
@@ -17,7 +17,7 @@ in {
         desktopManager.gnome.enable = true;
         displayManager = {
           gdm.enable = true;
-                  };
+        };
       };
 
       displayManager.defaultSession = "gnome";
diff --git a/modules/desktop/printing.nix b/modules/desktop/printing.nix
index e4ab50d..ba73ac9 100644
--- a/modules/desktop/printing.nix
+++ b/modules/desktop/printing.nix
@@ -12,7 +12,7 @@ in {
     services = {
       # Enable CUPS to print documents.
       printing.enable = true;
-      
+
       avahi = {
         enable = true; # runs the Avahi daemon
         nssmdns4 = true; # enables the mDNS NSS plug-in
diff --git a/modules/nixpkgs.nix b/modules/nixpkgs.nix
index 761d1ae..a1444df 100644
--- a/modules/nixpkgs.nix
+++ b/modules/nixpkgs.nix
@@ -15,7 +15,8 @@ in {
   imports = [
     # this switches the nix implementation to lix everywhere, but means recompiling lix every build.
     # https://lix.systems/add-to-config/
-    (let
+    (
+      let
         module = fetchTarball {
           name = "source";
           url = "https://git.lix.systems/lix-project/nixos-module/archive/2.90.0.tar.gz";
@@ -26,7 +27,8 @@ in {
           url = "https://git.lix.systems/lix-project/lix/archive/2.90.0.tar.gz";
           sha256 = "sha256-f8k+BezKdJfmE+k7zgBJiohtS3VkkriycdXYsKOm3sc=";
         };
-        in import "${module}/module.nix" { lix = lixSrc; }
+      in
+        import "${module}/module.nix" {lix = lixSrc;}
     )
   ];
 
@@ -51,6 +53,11 @@ in {
         substituters = ["https://nix-community.cachix.org" "https://cache.nixos.org/"];
         trusted-public-keys = ["nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="];
       };
+      gc = {
+        automatic = true;
+        dates = "daily";
+        options = "--delete-older-than 7d";
+      };
     };
 
     system = {
@@ -62,12 +69,6 @@ in {
       };
     };
 
-    nix.gc = {
-      automatic = true;
-      dates = "daily";
-      options = "--delete-older-than 7d";
-    };
-
     documentation = {
       enable = true; # documentation of packages
       nixos.enable = false; # nixos documentation