{
  description = "NixOS configuration";

  inputs = {
    # NixOS official package source
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.11";
    nixpkgs-unstable.url = "github:NixOS/nixpkgs/nixos-unstable";
    home-manager = {
      url = "github:nix-community/home-manager/release-25.11";
      # 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";
    };
    locutus.url = "git+https://git.figtree.dev/alex/locutus";
  };

  outputs = { self, nixpkgs, home-manager, ... }@inputs:
  let
    # Shared Home Manager configuration function
    mkHomeManagerConfig = { extraModules ? [] }: {
      home-manager.useGlobalPkgs = true;
      home-manager.useUserPackages = true;
      home-manager.backupFileExtension = "backup";
      home-manager.users.alex = {
        imports = [ ./alex/core.nix ] ++ extraModules;
      };
      home-manager.extraSpecialArgs = { inherit inputs; };
    };
  in {
    nixosConfigurations = {
      case = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        specialArgs = { inherit inputs; };
        modules = [
          ./hosts/case/configuration.nix
          home-manager.nixosModules.home-manager
          (mkHomeManagerConfig { extraModules = [ ./alex/desktop.nix ./alex/personal.nix ]; })
        ];
      };

      count = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        specialArgs = { inherit inputs; };
        modules = [
          ./hosts/count/configuration.nix
          home-manager.nixosModules.home-manager
          (mkHomeManagerConfig { extraModules = [ ./alex/desktop.nix ./alex/personal.nix ]; })
        ];
      };

      armitage = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        specialArgs = { inherit inputs; };
        modules = [
          ./hosts/armitage/configuration.nix
          home-manager.nixosModules.home-manager
          (mkHomeManagerConfig { extraModules = [ ./alex/desktop.nix ]; })
        ];
      };

      alt = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        specialArgs = { inherit inputs; };
        modules = [
          ./hosts/alt/configuration.nix
          home-manager.nixosModules.home-manager
          (mkHomeManagerConfig {})
        ];
      };

      nightcity = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        specialArgs = { inherit inputs; };
        modules = [
          ./hosts/nightcity/configuration.nix
          home-manager.nixosModules.home-manager
          (mkHomeManagerConfig {})
        ];
      };
      # other hosts...
    };
  };
}