{
  description = "A Wayland status bar for Sway, built with Quickshell";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    # Upstream Quickshell, tracked directly so we get layer-surface fixes
    # (e.g. clean buffers on output transform / rotation) ahead of nixpkgs.
    quickshell = {
      url = "git+https://git.outfoxxed.me/quickshell/quickshell";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = { self, nixpkgs, quickshell }:
    let
      systems = [ "x86_64-linux" "aarch64-linux" ];
      forAllSystems = f:
        nixpkgs.lib.genAttrs systems (system: f nixpkgs.legacyPackages.${system});
    in
    {
      packages = forAllSystems (pkgs:
        let
          # Quickshell from the upstream flake rather than nixpkgs.
          qsPkg = quickshell.packages.${pkgs.stdenv.hostPlatform.system}.default;

          # Runtime tools the bar relies on: discover.sh (one-shot hardware
          # probe), the periodic `df` for disk usage, and `ss` (iproute2) for
          # the per-process network drawer (topnet.sh). Everything else is read
          # from /proc and /sys directly in QML.
          runtimeInputs = [
            qsPkg
            pkgs.bash
            pkgs.coreutils # df, cat
            pkgs.iproute2  # ss, for topnet.sh per-process network usage
          ];

          # Self-contained font set so Nerd Font glyphs always render,
          # regardless of the host's installed fonts.
          fontsConf = pkgs.makeFontsConf {
            fontDirectories = [
              pkgs.nerd-fonts.jetbrains-mono
              pkgs.nerd-fonts.symbols-only
              pkgs.inter
            ];
          };

          bar = pkgs.writeShellApplication {
            name = "quickshell-bar";
            inherit runtimeInputs;
            text = ''
              export FONTCONFIG_FILE=${fontsConf}
              # Force the Wayland QPA plugin: Qt defaults to xcb (X11) on Linux,
              # so without this the bar comes up under XWayland. Honour an
              # explicit override if the caller already set one.
              export QT_QPA_PLATFORM="''${QT_QPA_PLATFORM:-wayland}"
              exec quickshell --path ${self} "$@"
            '';
          };
        in
        {
          default = bar;
          quickshell-bar = bar;
        });

      apps = forAllSystems (pkgs: {
        default = {
          type = "app";
          program = "${self.packages.${pkgs.stdenv.hostPlatform.system}.default}/bin/quickshell-bar";
        };
      });

      devShells = forAllSystems (pkgs: {
        default = pkgs.mkShell {
          packages = [
            quickshell.packages.${pkgs.stdenv.hostPlatform.system}.default
            pkgs.bash
            pkgs.coreutils
            pkgs.iproute2 # ss, for topnet.sh
            pkgs.nerd-fonts.jetbrains-mono
            pkgs.inter
            pkgs.qt6.qtdeclarative # qmlls / qmlformat for editing
          ];
          shellHook = ''
            echo "quickshell $(quickshell --version 2>/dev/null | head -1)"
            echo "Run the bar with:  quickshell --path ."
          '';
        };
      });

      formatter = forAllSystems (pkgs: pkgs.nixpkgs-fmt);
    };
}