One of the three required output functions for gpEasy CMS themes is the GetContent, <?php $page->GetContent() ?>, that calls the page's main content. The page's content is the main body of your gpEasy web page.
This output function wraps the content with the following DIVs: <div id="gpx_content"><div class="GPAREA">. This gives us two classes to work with: .gpx_content and .GPAREA.
However, it is rare not to have the <?php $page->GetContent() ?> output function wrapped by another div within the theme and styled mainly by that div's class or id. Nonetheless, you now have that two classes that can be utilized together to style any page's main content area. Though it is generally best to combine the .gpx_content with the class or id of the div that wraps the GetContent output function. This way you won't cause styling problems with other pages such as the galleries.