{
  description = "att_menu — a bottom desktop panel for wlroots compositors, built on Quickshell";

  inputs = {
    # Pinned to the current NixOS stable release.
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-26.05";
  };

  outputs =
    { self, nixpkgs }:
    let
      systems = [
        "x86_64-linux"
        "aarch64-linux"
      ];

      forAllSystems = fn: nixpkgs.lib.genAttrs systems (system: fn nixpkgs.legacyPackages.${system});
    in
    {
      packages = forAllSystems (pkgs: rec {
        default = att_menu;

        att_menu = pkgs.stdenvNoCC.mkDerivation {
          pname = "att_menu";
          version = "0.1.0";

          src = ./.;

          nativeBuildInputs = [ pkgs.makeWrapper ];

          dontConfigure = true;
          dontBuild = true;

          installPhase = ''
            runHook preInstall

            mkdir -p $out/share/att_menu
            cp -r shell.qml config components modules services $out/share/att_menu/

            makeWrapper ${pkgs.lib.getExe' pkgs.quickshell "qs"} $out/bin/att_menu \
              --add-flags "--path $out/share/att_menu" \
              --suffix PATH : ${
                pkgs.lib.makeBinPath [
                  # loginctl and systemctl back the default power actions. The
                  # session's own PATH is searched first, so a compositor's
                  # swaymsg/hyprctl/niri is still picked up for logging out.
                  pkgs.systemd
                ]
              } \
              --suffix XDG_DATA_DIRS : "${pkgs.adwaita-icon-theme}/share:${pkgs.hicolor-icon-theme}/share"

            runHook postInstall
          '';

          meta = {
            description = "Bottom desktop panel for wlroots compositors, built on Quickshell";
            mainProgram = "att_menu";
            platforms = pkgs.lib.platforms.linux;
          };
        };
      });

      apps = forAllSystems (pkgs: {
        default = {
          type = "app";
          program = pkgs.lib.getExe self.packages.${pkgs.stdenv.hostPlatform.system}.att_menu;
        };
      });

      devShells = forAllSystems (pkgs: {
        default = pkgs.mkShell {
          packages = [
            pkgs.quickshell
            # qmlls / qmlformat for editing the QML in place.
            pkgs.qt6.qtdeclarative
          ];

          shellHook = ''
            echo "att_menu dev shell — run the panel from the working tree with:"
            echo "  qs --path ."
          '';
        };
      });

      formatter = forAllSystems (pkgs: pkgs.nixfmt-tree);
    };
}