{ ... }:
{
  sane.programs.sysvol = {
    sandbox.method = "bwrap";
    sandbox.whitelistAudio = true;
    sandbox.whitelistWayland = true;

    fs.".config/sys64/volume.css".symlink.text = ''
      window {
        background: #000000B4;
        border-radius: 19px;
      }
      label {
        color: #FFFFFF;
      }
      image {
        margin-left: 9px;
        color: #FFFFFFD0;
      }

      /* optionally, replace with `scale.horizontal` and `scale.vertical` for specialization */
      scale {
        margin: 0px;
        padding: 0px;
        margin-right: 7px;
      }
      scale trough {
        border-radius: 12px;
        background: #00000000;
        border: none;
        margin-left: 12px;
        margin-right: 12px;
      }
      scale highlight {
        margin-bottom: 3px;
        margin-top: 3px;
        border-radius: 12px;
        background: #e1f0efdc;
      }
      scale slider {
        margin: 0px;
        margin-left: -12px;
        margin-right: -12px;
        padding: 0px;
        /* background: #e1f0efFF; */
        background: #f9fffc;
        box-shadow: none;
        min-height: 25px;
        min-width: 25px;
      }
    '';

    services."sysvol" = {
      description = "sysvol: volume monitor/notifier";
      depends = [ "sound" ];  #< specifically wireplumber-pulse
      partOf = [ "graphical-session" ];

      # options:
      # -p {0,1,2,3}  to attach to top/right/bottom/left screen edge
      # -t N          for the notifier to be dismissed after N seconds (integer only)
      # -m N          to set the indicator this many pixels in from the edge.
      #               it considers sway bars, but not window titles
      # -{H,W} N      to set the height/width of the notifier, in px.
      # -i N          to set the size of the volume icon
      # -P            to hide percentage text
      command = "sysvol -p 0 -t 1 -m 22 -H 39 -W 256 -i 32 -P";
    };
  };
}