#cube {
	width: 200px;
	height: 150px;
	background-color: red;
	position: absolute;
	z-index: -1;
	/* position absolute posune prvek na jinou vrstvu*/
	/* z-index urcuje v jake vrstve je*/
	/* u absolute vzdy puzivat urceni pozice (top, left, bottom, right)*/
}
#cube_sec {
	width: 50px;
	height: 50px;
	background-color: blue;
	position: absolute;
	top: 20px;
	right: 20px;
	z-index: 10;
}