diff --git a/home/profiles/base.nix b/home/profiles/base.nix
new file mode 100644
index 00000000..efe70297
--- /dev/null
+++ b/home/profiles/base.nix
@@ -0,0 +1,2 @@
+{ config, ... }: {
+}
diff --git a/nixos/modules/gnome.nix b/nixos/modules/gnome.nix
new file mode 100644
index 00000000..e29db84f
--- /dev/null
+++ b/nixos/modules/gnome.nix
@@ -0,0 +1,15 @@
+{ config, lib, pkgs, ... }: let
+  inherit (lib.modules) mkIf;
+in {
+  config = mkIf config.role.gnome {
+    services.xserver = {
+      desktopManager.gnome.enable = true;
+      displayManager.gdm.enable = true;
+    };
+
+    environment.systemPackages = with pkgs.gnomeExtensions; [
+      dash-to-dock
+      gsconnect
+    ];
+  };
+}
diff --git a/nixos/modules/home.nix b/nixos/modules/home.nix
new file mode 100644
index 00000000..85c5ef5b
--- /dev/null
+++ b/nixos/modules/home.nix
@@ -0,0 +1,14 @@
+{ config, tree, machine, ... }: {
+  home-manager = {
+    useGlobalPkgs = true;
+    useUserPackages = true;
+    sharedModules = [
+      tree.home.modules
+      tree.system.modules
+    ];
+    extraSpecialArgs = {
+      inherit tree machine;
+      nixos = config;
+    };
+  };
+}
diff --git a/nixos/modules/laptop.nix b/nixos/modules/laptop.nix
new file mode 100644
index 00000000..8d68baba
--- /dev/null
+++ b/nixos/modules/laptop.nix
@@ -0,0 +1,8 @@
+{ config, lib, ... }: let
+  inherit (lib.modules) mkIf mkDefault;
+in {
+  config = mkIf config.role.laptop {
+    powerManagement.cpuFreqGovernor = mkDefault "powersave";
+    programs.light.enable = true;
+  };
+}
diff --git a/nixos/modules/personal.nix b/nixos/modules/personal.nix
new file mode 100644
index 00000000..fe807146
--- /dev/null
+++ b/nixos/modules/personal.nix
@@ -0,0 +1,7 @@
+{ config, lib, ... }: let
+  inherit (lib.modules) mkIf;
+in {
+  config = mkIf config.role.personal {
+    services.fstrim.enable = true;
+  };
+}
diff --git a/nixos/modules/server.nix b/nixos/modules/server.nix
index 3717b7fb..931c630b 100644
--- a/nixos/modules/server.nix
+++ b/nixos/modules/server.nix
@@ -1,16 +1,7 @@
 { config, lib, ... }: let
-  inherit (lib.options) mkOption mdDoc;
   inherit (lib.modules) mkIf;
   inherit (lib.attrsets) mapAttrsToList;
-  inherit (lib.types) bool;
 in {
-  options = {
-    role.server = mkOption {
-      type = bool;
-      description = mdDoc "Is this system's role a server?";
-      default = false;
-    };
-  };
   config = mkIf config.role.server {
     # Prevent services from being automatically killed on log-out
     # https://wiki.archlinux.org/title/systemd/User#Automatic_start-up_of_systemd_user_instances
diff --git a/nixos/systems/koishi.nix b/nixos/systems/koishi.nix
index efe70297..9e2033ed 100644
--- a/nixos/systems/koishi.nix
+++ b/nixos/systems/koishi.nix
@@ -1,2 +1,51 @@
 { config, ... }: {
+  role = {
+    laptop = true;
+    personal = true;
+    gnome = true;
+  };
+
+  fileSystems = {
+    "/" = {
+      device = "/dev/disk/by-uuid/a664de0f-9883-420e-acc5-b9602a23e816";
+      fsType = "xfs";
+    };
+    "/boot" = {
+      device = "/dev/disk/by-uuid/DEBC-8F03";
+      fsType = "vfat";
+    };
+  };
+
+  swapDevices = [
+    { device = "/dev/disk/by-uuid/0d846453-95b4-46e1-8eaf-b910b4321ef0"; }
+  ];
+
+  boot = {
+    supportedFilesystems = [ "xfs" ];
+    initrd.luks.devices."cryptroot".device = "/dev/disk/by-uuid/f0ea08b4-6af7-4d90-a2ad-edd5672a2105";
+    loader = {
+      efi = {
+        canTouchEfiVariables = true;
+        efiSysMountPoint = "/boot";
+      };
+      grub = {
+        devices = [ "nodev" ];
+        efiSupport = true;
+        enable = true;
+        extraEntries = ''
+          menuentry "Windows" {
+            insmod part_gpt
+              insmod fat
+              insmod search_fs_uuid
+              insmod chain
+              search --fs-uuid --set=root DEBC-8F03
+              chainloader /EFI/Microsoft/Boot/bootmgfw.efi
+          }
+        '';
+        version = 2;
+      };
+    };
+  };
+
+  system.stateVersion = "21.11";
 }
diff --git a/nixos/users/kat.nix b/nixos/users/kat.nix
index 4f4b3843..e963974b 100644
--- a/nixos/users/kat.nix
+++ b/nixos/users/kat.nix
@@ -1,6 +1,4 @@
-{ tree, config, ... }: with lib;
-
-{
+{ tree, config, ... }: {
   users.users.kat = {
     uid = 1000;
     isNormalUser = true;
@@ -10,6 +8,13 @@
       "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAII74JrgGsDQ6r7tD7+k3ykxXV7DpeeFRscPMxrBsDPhz kat@goliath"
     ];
     shell = pkgs.zsh;
-    extraGroups = [ "wheel" "video" "systemd-journal" "plugdev" "bird2" "vfio" "input" "uinput" ];
+    extraGroups = [
+      "wheel"
+      "video"
+      "systemd-journal"
+      "plugdev"
+      "input"
+      "uinput"
+    ];
   };
 }
diff --git a/outputs.nix b/outputs.nix
index 5740f6a3..66b1cd48 100644
--- a/outputs.nix
+++ b/outputs.nix
@@ -9,6 +9,11 @@
           "default"
         ];
       };
+      "system/modules" = {
+        functor = {
+          enable = true;
+        };
+      };
       "nixos/modules" = {
         functor = {
           enable = true;
@@ -27,14 +32,11 @@
           ];
         };
       };
-      "home".evaluateDefault = true;
-      "home/*" = {
-        functor.enable = true;
-      };
     };
   }).impure;
   lib = inputs.nixpkgs.lib;
   inherit (lib.attrsets) mapAttrs;
+  inherit (builtins) removeAttrs;
   inherit (lib.lists) singleton;
 in utils.lib.mkFlake {
   inherit self inputs;
@@ -43,6 +45,9 @@ in utils.lib.mkFlake {
 
   hostDefaults = {
     system = "x86_64-linux";
+    modules = [
+      tree.system.modules
+    ];
     extraArgs = {
       inherit inputs tree;
     };
@@ -96,18 +101,14 @@ in utils.lib.mkFlake {
       extraSpecialArgs = {
         inherit inputs tree;
         machine = name;
+        nixos = {};
       };
       modules = [
-        ({ config, ... }: {
-          home = {
-            username = "kat";
-            stateVersion = "22.11";
-            homeDirectory = "/home/kat";
-          };
-        })
+        tree.system.modules
+        tree.home.common
         path
       ];
-    }) tree.home;
+    }) tree.home.profiles;
 
     inherit tree;
   };
diff --git a/system/modules/roles.nix b/system/modules/roles.nix
new file mode 100644
index 00000000..9c238811
--- /dev/null
+++ b/system/modules/roles.nix
@@ -0,0 +1,30 @@
+{ config, lib, ... }: let
+  inherit (lib.options) mkOption mdDoc;
+  inherit (lib.modules) mkIf mkDefault;
+  inherit (lib.types) bool;
+in {
+  options = {
+    role = {
+      server = mkOption {
+        type = bool;
+        description = mdDoc "Is this system's role as a server?";
+        default = false;
+      };
+      personal = mkOption {
+        type = bool;
+        description = mdDoc "Is this system's role as a personal device?";
+        default = false;
+      };
+      laptop = mkOption {
+        type = bool;
+        description = mdDoc "Is this system's role as a laptop?";
+        default = false;
+      };
+      gnome = mkOption {
+        type = bool;
+        description = mdDoc "Does this system's role include running GNOME?";
+        default = false;
+      };
+    };
+  };
+}