How do I increase font size in Pidgin's buddy list?

I realize this question is extremely old (over a year) but I had the same question the other day and after a little bit of testing, figured out the answer.

Instead of this:

<offline_text font="Verdana [14.0]"/> 

You should do this:

<offline_text font="Verdana, 14.0"/> 

A simple change, but it seems to work.