Adding a back end WYSIWYG to chat plug in

I am trying to restyle the chat to fit more with my theme. I was wondering if you had thought of adding a style WUSIWYG to the plug in to allow people to style a bit differently from the Standard Facebook Style.

That leads to my next question if i do restyle it using the CSS will it break the plug in?
All I am wanting to do is round out the corners a bit and a bit more fun to the look of it.