<!DOCTYPE html>
<html>
    <head>
        <style type="text/css">
            body {
                margin: 0;
            }
            .red {
                background-color: red;
            }
            .green {
                background-color: green;
            }
            .d1 {
                position: absolute;
                width: 400px;
                height: 400px;
            }
            .d2 {
                position: absolute;
                left: 400px;
                top: 80px;
                width: 300px;
                height: 300px;
            }
        </style>
    </head>
    <body>
        <div class="d1 red"></div>
        <div class="d2 green"></div>
    </body>
</html>