cls

An optional CSS class to apply to the main rendering element of the Window widget.
The properties in this class will override any control and theme-specific properties.

<div id="window" />

<style>
    .pink { background-color:pink; }
</style>

<script type="text/javascript">
    jQuery(function($) {
          $("#window").shieldWindow({
                 cls: 'pink'
           });
    });
</script>