accordion content style

Hi,
I have converted my splitpanel that is was using to an accordion. The accordion contains 2 tabs which are Forms. Now, when using the splitpanel, i was able to keep my general style (blue background for instance) within the Forms, but now, when using the accordion, it is just white.
Is there any way to set the contents of the accordion to have the same style as the other components in my Window? Something similar to setting the stylename to ‘light’ when using a Panel?

Thanks!
Jan