{
  description = "My system configuration";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
    nixgl = {
      url = "github:nix-community/nixGL";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };
  outputs =
    {
      nixpkgs,
      nixgl,
      ...
    }:
    let
      forAllSystems = nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed;
      castrum = import ./util/castrum;
    in
    {
      packages = forAllSystems (
        system:
        let
          pkgs = import nixpkgs {
            inherit system;
            overlays = [ nixgl.overlay ];
          };
        in
        {
          profile = castrum.lib.castrumSystem {
            inherit pkgs;
            # Specifies things to pin in the flake registry and in NIX_PATH.
            pinned = {
              nixpkgs = toString nixpkgs;
            };

            modules = [
              # { nixpkgs.overlays = [ nixgl.overlay ]; }
              # impermanence.homeManagerModules.impermanence
              ./hosts/deck
              ./configuration.nix
            ];
            specialArgs = {
              inherit nixgl;
              inherit nixpkgs;
            };
          };
        }
      );
    };
}