* {
	margin: 0;
	padding: 0;
	background: #000000;
}

#curtain{
	z-index: 11;
	background: #ff0000;
}

#rabbit-hole {
	position: relative;
	z-index: 10;
}

div {
	position: absolute;
	border-radius: 1em;
}

div.A {
}
div.B {
}
div.C {
}
div.D {
}