changing the background

Hi.

I have a problem with setting the ultimate FAQ. I am using this plug-in with SiteOrigin theme. For my page I have a picture in the background, but I would like the questions and answers from FAQ to be boxed with white background. I’m using the free version of the plug-in and I have a problem with CSS that would enable me this. First of all I would like to ask if it it even possible to do that (I am quite new in all this), and if so some hints on css would be very welcome.