Untitled

<html>
    <head>
        <style type="text/css">

            div.wrap {

                padding: 5px;
            }

            header {

                max-width:600px;
                margin: 100px auto 5px;
                border: 1px solid blue;
            }

            main {

                max-width: 600px;
                margin: 5px auto;
                border:1px solid red;
            }

            h1 {

                margin: 0 auto;
                text-align: center;
            }

            footer {

                max-width: 600px;
                margin: 5px auto;
                border: 1px solid green;
            }

        </style>
    </head>
    <body>
        <div class="wrap">
            <header>
                <h1>header</h1>
            </header>
            <main>
                <h1>main</h1>
            </main>
            <footer>
                <h1>footer</h1>
            </footer>
        </div>

    </body>
</html>