{
  description = "star — native Lightspeed LiveView on Mist";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
  };

  outputs =
    { self, nixpkgs }:
    let
      systems = [
        "x86_64-linux"
        "aarch64-linux"
        "x86_64-darwin"
        "aarch64-darwin"
      ];
      forAllSystems = nixpkgs.lib.genAttrs systems;
    in
    {
      devShells = forAllSystems (
        system:
        let
          pkgs = nixpkgs.legacyPackages.${system};
        in
        {
          default = pkgs.mkShell {
            packages = [
              pkgs.gleam
              pkgs.beamPackages.erlang
              pkgs.rebar3
            ];

            shellHook = ''
              echo "star dev shell"
              echo "  gleam run   # http://localhost:8080/"
              echo "  gleam test"
            '';
          };
        }
      );

      # `nix run` → gleam run (from the current working directory).
      apps = forAllSystems (
        system:
        let
          pkgs = nixpkgs.legacyPackages.${system};
          star = pkgs.writeShellApplication {
            name = "star";
            runtimeInputs = [
              pkgs.gleam
              pkgs.beamPackages.erlang
              pkgs.rebar3
            ];
            text = ''
              exec gleam run "$@"
            '';
          };
        in
        {
          default = {
            type = "app";
            program = "${star}/bin/star";
          };
        }
      );

      formatter = forAllSystems (system: nixpkgs.legacyPackages.${system}.nixfmt);
    };
}