Q&A: integrating Q&A with my styles

OK I have installed Q&A but I'm not quite sure how to start integrating it with my style sheet so that it looks integrated with the rest of my site.

http://rosacea-support.org/questions is my installation.

You can see that I need to wrap the Q&A column in a div element that matches my style.

Do I do this by updating say qa-page-wrapper ? or do I add another div around that with the name of the left-hand div from my existing stylesheet ?