public/500.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Výpadok</title>
<style>
#container {display:block; float:none; overflow:hidden; width:600px; height:448px; background:url(/assets/robot_error_page.png) no-repeat; position:absolute; top:50%; left:50%; margin:-224px -300px;}
</style>
</head>
<body>
<div id="container"></div>
</body>
</html>