Witam
<!DOCTYPE html>
<html lang="pl">
<head>
<title>O mnie</title>
<meta charset="utf-8">
<style>
body{
background-color: black;
}
.jeden{
width: 200px;
height: 200px;
position: relative;
background: #0099e5;
z-index: 1;
}
.dwa{
width: 180px;
height: 180px;
position: absolute;
z-index: 3;
top: 10px;
left: 10px;
background: #ff4c4c;
}
.trzy{
width: 190px;
height: 190px;
position: absolute;
z-index: 2;
top: 5px;
left: 5px;
background: #34bf49;
}
</style>
</head>
<body>
<div class="jeden">
<div class="dwa"></div>
<div class="trzy"></div>
</div>
</body>
</html>