{
  description = "NixOS configuration";

  inputs = {
    # NixOS official package source
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.05";
    home-manager = {
      url = "github:nix-community/home-manager/release-25.05";
      # The `follows` keyword in inputs is used for inheritance.
      # Here, `inputs.nixpkgs` of home-manager is kept consistent with
      # the `inputs.nixpkgs` of the current flake,
      # to avoid problems caused by different versions of nixpkgs.
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = { self, nixpkgs, home-manager, ... }@inputs: {
    nixosConfigurations.case = nixpkgs.lib.nixosSystem {
      system = "x86_64-linux";

      specialArgs = { inherit inputs; };
      modules = [
        # Import the previous configuration.nix we used,
        # so the old configuration file still takes effect
        ./configuration.nix

	# make home-manager as a module of nixos so that home-manager
	# configuration will be deployed automatically when executing
	# `nixos-rebuild switch`
        home-manager.nixosModules.home-manager
        {
          home-manager.useGlobalPkgs = true;
          home-manager.useUserPackages = true;

          home-manager.users.alex = import ./home.nix;

	  # Optionally, use home-manager.extraSpecialArgs to pass arguments to
	  # home.nix
        }
      ];
    };
  };
}