public function onlineIndicator(bool $online) : string
{
$state = $online ? 'on' : 'off';
$icon = $online ? 'circle' : 'circle-o';
$title = $online ? 'Online' : 'Offline';
return el("span.status.-{$state}", ['title' => $title], el("i.fa.fa-{$icon}"));
}