body { overflow: hidden; }

.overlapper {
	position: absolute;
	height: 100vh;
	width: 100%;
	top: 0;
	bottom: 0;
	left: 0;
	right: 0;
}

audio { display: none; }

video { 
	position: fixed;
	top: 50%;
	left: 50%;
	min-width: 100%;
	min-height: 100%;
	width: auto;
	height: auto;
	z-index: -100;
	transform: translateX(-50%) translateY(-50%);
	background-size: cover;
	transition: 1s opacity;
}

video.constrained {
	top: 0;
	bottom: 0;
	left: 0;
	right: 0;
	max-width: 100%;
	max-height: 100vh;
	transform: none;
}