Can someone direct me where to change the default font size for the chat on the chatroom module without having to alter other portions of my site?

The reason is that I am inserting a chatroom using InsertNode into a block on my website such that visitors can ask have some admin interactivity while browsing. It would also be nice to turn off the author, date, and time stamp information.

The point is to have a simple chat box for a very limited degree of interactivity with site visitors.

I apologize for not chasing this further. I'm new to PHP and can't find the correct place to alter code in the css, js, or inc files.