Your help please with css

Hi could anyone help me out with this problem, i have created a template for my forum by editing the main.tpl file within the templates directory.

However everything text wise has gone very very very small,

http://www.phpauctionsites.com/forum/index.php to see what i mean.

Where / which file do i edit and what css style do alter to correct this??

I added div#punwrap p {font-size: 12px} and this has made all the forum posted text readable at 12px but i cant find how to fix the rest??

Would appreciate the help thanks

Roger