html, body
{
    margin: 0;
    padding: 0;
}

body
{
    width: 100%;
    background: red;
}

header, nav, article, footer
{
    width: 1000px;
    margin: 0 auto;
    color: white;
}

header
{
    height: 100px;
    background: green;
    color: black !important;
    margin-bottom: 50px;
}

nav
{
    position: relative;
    height: 50px;
    background: blue;
    margin: -50px auto 0;
}

article
{
    height: 50px;
    background: yellow;
}

footer
{
    height: 50px;
    background: purple;
}