div.loader {
	position: fixed;
	width: 100%;
	height: 100%;
	left: 0;
	top: 0;
	background-color: #000000;
	opacity: 0.5;
}

div.loader::after {
	content: '';
	display: block;
	position: fixed;
	border: 16px solid #f3f3f3;
	border-top: 16px solid #3498db;
	border-radius: 50%;
	width: 5em;
	height: 5em;
	left: 0;
	right: 0;
	top: 0;
	bottom: 0;
	margin: auto;
	animation: spin 2s linear infinite;
}

@keyframes spin {
	0% { transform: rotate(0deg); }
	100% { transform: rotate(360deg); }
}