responsive.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div class="header-part">
        asdfghjkl
    </div>

    <div class="body-part">
            asdfghjkladf
    </div>

    <div class="footer-part">
            asdfghjkllhhhh
    </div>

</body>
</html>