I've found how to edit virtually every other piece of text through editing colours.css (root > styles > prosilver > theme > colours) but I can't locate where the font (colour) is for...
Your first forum
Description of your first forum.
Which is the first forum category when the forum gets created. That first line I found but the second line (the description) is eluding me, same as the Topics count, Posts count, the date in Last Post and I assume they'll all be the same edit.