{ pkgs, ... }: {
  # ─────────────────────── Power & thermal ───────────────────────
  # Snapdragon 7c (sc7180) on a tablet form factor: aim for battery life. `schedutil` is the
  # right modern cpufreq governor on ARM (responsive + power-aware); use it instead of
  # `powersave` to avoid pinning the CPU at minimum frequency under interactive load.
  powerManagement.cpuFreqGovernor = "schedutil";
  powerManagement.enable = true;

  # ─────────────────────── logind: lid & power button ───────────────────────
  # Closing the lid suspends, even on AC — Duet 3 is a tablet, treat it like one.
  # Short press on power: suspend (matches ChromeOS/iOS); long press: poweroff.
  # The DMS bar power menu is the way to reboot / shut down explicitly.
  services.logind.settings.Login = {
    HandleLidSwitch = "suspend";
    HandleLidSwitchExternalPower = "suspend";
    HandleLidSwitchDocked = "ignore";
    HandlePowerKey = "suspend";
    HandlePowerKeyLongPress = "poweroff";
  };

  # ─────────────────────── Idle / suspend tuning ───────────────────────
  # Allow suspend-to-RAM but disable hibernate (ARM swap-resume is unreliable, and we don't
  # have a swap device by default anyway).
  systemd.sleep.settings.Sleep = {
    AllowHibernation = "no";
    AllowHybridSleep = "no";
    AllowSuspendThenHibernate = "no";
  };

  # upower picks the right battery percentages for low/critical out of the box; just make
  # sure the action on critical is hibernate-then-poweroff fallback (we disabled hibernate
  # so it'll go straight to poweroff). DMS reads upower for the bar widget.
  services.upower = {
    enable = true;
    criticalPowerAction = "PowerOff";
    percentageLow = 15;
    percentageCritical = 7;
    percentageAction = 3;
  };

  # ─────────────────────── Bluetooth audio quality of life ───────────────────────
  # Duet has limited mic/speaker hw — keep wpa_supplicant power-save off so audio doesn't crackle
  # over Bluetooth when CPU is idle. (Wi-Fi + BT share the chip; aggressive power-save = stutter.)
  networking.networkmanager.wifi.powersave = false;
}