const char HTTP_HEAD_STYLE_ZIGBEE[] PROGMEM =
  ".bt{box-sizing:border-box;position:relative;display:inline-block;width:20px;height:12px;border:2px solid;border-radius:3px;margin-left:-3px}"
  ".bt::after,.bt::before{content:\"\";display:block;box-sizing:border-box;position:absolute;height:6px;background:currentColor;top:1px}"
  ".bt::before{right:-4px;border-radius:3px;width:4px}"
  ".bt::after{width:var(--bl,14px);left:1px}";