<head>
<style>
.lager1 {
  position: absolute;
  top: 90px;
  left: 70px;
  width: 200px;
  height: 125px;
  background-color: yellow;
  z-index: 1;
}
div.lager2 {
  position: absolute;
  top: 100px;
  left: 50px;
  width: 200px;
  height: 125px;
  background-color: blue;
  z-index: -1;
}
div.lager3 {
  position: absolute;
  top: 120px;
  left: 30px;
  width: 200px;
  height: 100px;
  background-color:green
}
</style>
</head>