<!DOCTYPE html>
<html>
<head>
<style type="text/css">
html {
 margin: 20px; padding: 0;
 background-color: green;
}
body {
 margin: 20px; padding: 0;
 background-color: blue;
 height: 20px;
}
</style>
</head>
<body>
</body>
</html>