diff --git a/flake.lock b/flake.lock
index a2abe0d..e8e9285 100644
--- a/flake.lock
+++ b/flake.lock
@@ -43,6 +43,23 @@
         "type": "gitlab"
       }
     },
+    "brew-src": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1751910772,
+        "narHash": "sha256-jQNdIkq2iRDNWskd5f8kX6q9BO/CBSXhMH41WNRft8E=",
+        "owner": "Homebrew",
+        "repo": "brew",
+        "rev": "700d67a85e0129ab8a893ff69246943479e33df1",
+        "type": "github"
+      },
+      "original": {
+        "owner": "Homebrew",
+        "ref": "4.5.9",
+        "repo": "brew",
+        "type": "github"
+      }
+    },
     "crash": {
       "inputs": {
         "nixpkgs": [
@@ -248,6 +265,38 @@
         "type": "github"
       }
     },
+    "homebrew-cask": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1753968895,
+        "narHash": "sha256-q8loYa7TQFtxs0gAKUGs+arGusXkaNTnMYJdOSLLups=",
+        "owner": "homebrew",
+        "repo": "homebrew-cask",
+        "rev": "d3cc45a4ab90edca625bb040823edac3c09feb11",
+        "type": "github"
+      },
+      "original": {
+        "owner": "homebrew",
+        "repo": "homebrew-cask",
+        "type": "github"
+      }
+    },
+    "homebrew-core": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1753967820,
+        "narHash": "sha256-KPrAcjKW3dXbCt0b8i+bgMwNSnpGgnAnYZS6tgX0IVs=",
+        "owner": "homebrew",
+        "repo": "homebrew-core",
+        "rev": "e64e128c3acca63c8cbb25a7e6896b78e214092c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "homebrew",
+        "repo": "homebrew-core",
+        "type": "github"
+      }
+    },
     "nil": {
       "inputs": {
         "nixpkgs": "nixpkgs_2"
@@ -308,6 +357,24 @@
         "type": "github"
       }
     },
+    "nix-homebrew": {
+      "inputs": {
+        "brew-src": "brew-src"
+      },
+      "locked": {
+        "lastModified": 1752160973,
+        "narHash": "sha256-BCC8KB7TEtwv7vZN1WDu870tRbXtzUcmF9xNr6ws5Wc=",
+        "owner": "zhaofengli",
+        "repo": "nix-homebrew",
+        "rev": "69c1aa2f136f3c3326d9b6770e0eb54f12832971",
+        "type": "github"
+      },
+      "original": {
+        "owner": "zhaofengli",
+        "repo": "nix-homebrew",
+        "type": "github"
+      }
+    },
     "nixos-mailserver": {
       "inputs": {
         "blobs": "blobs",
@@ -450,9 +517,12 @@
         "fenix": "fenix",
         "github2forgejo": "github2forgejo",
         "home-manager": "home-manager",
+        "homebrew-cask": "homebrew-cask",
+        "homebrew-core": "homebrew-core",
         "nil": "nil",
         "nix": "nix",
         "nix-darwin": "nix-darwin",
+        "nix-homebrew": "nix-homebrew",
         "nixos-mailserver": "nixos-mailserver",
         "nixpkgs": "nixpkgs_4",
         "themes": "themes"
diff --git a/flake.nix b/flake.nix
index 7e4fc13..ef8c264 100644
--- a/flake.nix
+++ b/flake.nix
@@ -44,6 +44,18 @@
       inputs.nixpkgs.follows = "nixpkgs";
     };
 
+    nix-homebrew.url = "github:zhaofengli/nix-homebrew";
+    homebrew-core    = {
+      url = "github:homebrew/homebrew-core";
+
+      flake = false;
+    };
+    homebrew-cask    = {
+      url = "github:homebrew/homebrew-cask";
+
+      flake = false;
+    };
+
     home-manager = {
       url = "github:nix-community/home-manager";
 
diff --git a/modules/common/agenix.nix b/modules/common/agenix.nix
index 3c7b95e..8b142f2 100644
--- a/modules/common/agenix.nix
+++ b/modules/common/agenix.nix
@@ -1,5 +1,5 @@
 { config, lib, pkgs, ... }: let
-  inherit (lib) attrNames filterAttrs hasPrefix head mkAliasOptionModule mkIf;
+  inherit (lib) mkAliasOptionModule mkIf;
 in {
   imports = [(mkAliasOptionModule [ "secrets" ] [ "age" "secrets" ])];
 
@@ -7,7 +7,7 @@ in {
     (if config.isLinux then
       "/root/.ssh/id"
     else
-      "/Users/${head <| attrNames <| filterAttrs (_: value: value.home != null && hasPrefix "/Users/" value.home) config.users.users}/.ssh/id")
+      "/Users/${config.system.primaryUser}/.ssh/id")
   ];
 
   environment = mkIf config.isDesktop {
diff --git a/modules/darwin/ghostty.nix b/modules/darwin/ghostty.nix
new file mode 100644
index 0000000..ad488fd
--- /dev/null
+++ b/modules/darwin/ghostty.nix
@@ -0,0 +1,3 @@
+{
+  homebrew.casks = [ "ghostty" ];
+}
diff --git a/modules/darwin/homebrew.nix b/modules/darwin/homebrew.nix
new file mode 100644
index 0000000..19dba2e
--- /dev/null
+++ b/modules/darwin/homebrew.nix
@@ -0,0 +1,16 @@
+{ nix-homebrew, homebrew-core, homebrew-cask, config, lib, ... }: let
+  inherit (lib) enabled;
+in {
+  imports = [ nix-homebrew.darwinModules.nix-homebrew ];
+
+  homebrew = enabled;
+
+  nix-homebrew = enabled {
+    user = config.system.primaryUser;
+
+    taps."homebrew/homebrew-core" = homebrew-core;
+    taps."homebrew/homebrew-cask" = homebrew-cask;
+
+    mutableTaps = false;
+  };
+}
diff --git a/modules/darwin/karabiner.nix b/modules/darwin/karabiner.nix
index 5e55403..4724306 100644
--- a/modules/darwin/karabiner.nix
+++ b/modules/darwin/karabiner.nix
@@ -129,21 +129,7 @@
     }
   ];
 in {
-  # TODO: Install using Nix. Currently I'm doing it manually.
-
-  # nixpkgs.overlays = [(self: super: {
-  #   karabiner-elements = super.karabiner-elements.overrideAttrs (old: {
-  #     version = "14.13.0";
-
-  #     src = super.fetchurl {
-  #       inherit (old.src) url;
-
-  #       hash = "sha256-gmJwoht/Tfm5qMecmq1N6PSAIfWOqsvuHU8VDJY8bLw=";
-  #     };
-  #   });
-  # })];
-
-  # services.karabiner-elements = enabled;
+  homebrew.casks = [ "karabiner-elements" ];
 
   home-manager.sharedModules = [{
     xdg.configFile."karabiner/karabiner.json".text = toJSON {