The majority of content on vBulletin pages is contained within an inner-block that starts at the end of the header template and finishes at the beginning of the footer template.
In the default vBulletin style, this can be seen as the white surround of the main page content.You may choose to have a blank value for the background color of this class. If you do so, the Page Background block will appear transparent, inheriting the background color of the Body class.Example of element using this class:
<div class="page" style="width:100%; text-align:left"> <!-- The DIV tag above uses this class --> </div>