A wrapper with fixed margin and expandable width

The following is fixed width layout.

        <pre data-sub="prettyprint:_">
        div#container
        {
        width:800px;
        margin:0px auto;
        }
        </pre>


        The following is fluid layout with fluid margin.

        <pre data-sub="prettyprint:_">
        div#container
        {
        width:80%;
        margin:0px auto;
        }
        </pre>



        <pre data-sub="prettyprint:_">
        {
        width:800px;
        margin:0px auto;
        }
        </pre>


        The following is fluid layout with fixed margin.

        <pre data-sub="prettyprint:_">
        div#container
        {
        margin:0px 20px;
        overflow:auto;

        }
        </pre>