<!DOCTYPE html>
<style>
body, html {
    margin: 0;
    padding: 0;
}
</style>
<div style="background: red;   position: absolute; height: 40px; width: 40px; top: 10px; left: 10px;"></div>
<div style="background: green; position: absolute; height: 40px; width: 40px; top: 20px; left: 20px;"></div>
