[theme: twenty eleven] full screen nav bar

Setting One Column max width to 100% will work for you if you remove the padding from the body like –

.one-column #page {
    max-width: 100%;
}

Body padding should be 0 like –

body {
    padding: 0;
}

Thanks! That was way too easy. Originally I wanted the feature image to have some padding around it with a dashed boarder but full width looks way better.