<!DOCTYPE html>
<html>
<head>
<style type="text/css" media="screen">
body {
margin: 0;
}
.box {
height: 200px;
width: 200px;
}
</style>
</head>
<body>
<div class="box" style="background-color: red;"></div>
<div class="box" style="background-color: green;"></div>
</body>
</html>