split everything into modules and update nixpkgs

system/bootloader.nix

@@ -0,0 +1,12 @@
+{
+  boot.loader = {
+    systemd-boot.enable = false;
+    grub = {
+      enable = true;
+      efiSupport = true;
+      useOSProber = true;
+      devices = [ "nodev" ];
+    };
+    efi.canTouchEfiVariables = true;
+  };
+}

system/configuration.nix

@@ -0,0 +1,25 @@
+{
+  time.timeZone = "Asia/Kolkata";
+
+  i18n.defaultLocale = "en_IN";
+  i18n.extraLocaleSettings = {
+    LC_ADDRESS = "en_IN";
+    LC_IDENTIFICATION = "en_IN";
+    LC_MEASUREMENT = "en_IN";
+    LC_MONETARY = "en_IN";
+    LC_NAME = "en_IN";
+    LC_NUMERIC = "en_IN";
+    LC_PAPER = "en_IN";
+    LC_TELEPHONE = "en_IN";
+    LC_TIME = "en_IN";
+  };
+
+  nixpkgs.config.allowUnfree = true;
+
+  nix.settings.experimental-features = [
+    "nix-command"
+    "flakes"
+  ];
+
+  system.stateVersion = "25.11";
+}

system/default.nix

@@ -1,7 +1,8 @@
-{ ... }:
-
 {
   imports = [
+    ./bootloader.nix
+    ./networking.nix
+    ./configuration.nix
     ./overlays.nix
   ];
 }

system/networking.nix

@@ -0,0 +1,4 @@
+{
+  networking.hostName = "nixos";
+  networking.networkmanager.enable = true;
+}