add and configure gtklock

sys/modules/default.nix

@@ -15,6 +15,7 @@
     ./bluetooth.nix
     ./net.nix
     ./steam.nix
+    ./gtklock.nix
   ];
 
   fonts.packages = with pkgs; [

sys/modules/gtklock.nix

@@ -0,0 +1,84 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+with lib; let
+  cfg = config.local.sys.gtklock;
+in {
+  options.local.sys.gtklock = {
+    enable = mkEnableOption "gtklock settings";
+  };
+  config = mkIf cfg.enable {
+    programs.gtklock = {
+      enable = true;
+      config = {
+        main = {
+          idle-hide = true;
+          idle-timeout = 1;
+          time-format = "%H:%M:%S";
+          start-hidden = true;
+        };
+      };
+      style = ''
+        /* Main lockscreen window */
+        window {
+          background-color: rgba(20, 20, 20, 0.9); /* dark, slightly translucent */
+          color: #eaeaea;
+          font-family: "JetBrains Mono", monospace;
+          font-size: 14px;
+        }
+
+        /* Container for clock + prompt */
+        #main-box {
+          background: transparent;
+          border: none;
+          border-radius: 0;
+          padding: 0;
+          margin: 0;
+        }
+
+        /* Clock text */
+        #clock {
+          font-size: 32px;
+          font-weight: bold;
+          color: #ffffff;
+          margin-bottom: 12px;
+        }
+
+        /* Date text */
+        #date {
+          font-size: 14px;
+          color: #aaaaaa;
+          margin-bottom: 24px;
+        }
+
+        /* Password entry */
+        entry {
+          background-color: rgba(0, 0, 0, 0.5);
+          color: #ffffff;
+          border: none;
+          border-radius: 0;
+          padding: 6px 8px;
+          font-family: "JetBrains Mono", monospace;
+          font-size: 12px;
+        }
+
+        /* Hide any extra icons in the entry */
+        entry image {
+          opacity: 0;
+          width: 0;
+          height: 0;
+        }
+
+        /* Wrong password feedback */
+        #auth-failure {
+          color: #ff6666;
+          font-size: 12px;
+          margin-top: 6px;
+        }
+      '';
+    };
+  };
+}

sys/platforms/posixlycorrect/default.nix

@@ -20,6 +20,7 @@
     virtualisation.enable = true;
     androidSupport.enable = true;
     steam.enable = true;
+    gtklock.enable = true;
 
     users = {
       fabian = {