<!DOCTYPE html>
<html>
<head>
    <title>Processing...</title>
    <style type="text/css">
		body {
			display: flex;
			align-items: center;
			justify-content: center;
			height: 100vh;
			margin: 0;
		}

		h1 {
			font-size: 2rem;
			font-weight: bold;
			text-align: center;
		}
	</style>
</head>
<body>
<h1>%s</h1>
</body>
</html>