XF 2.3 Font size

add to extra.less
13 is the current size (stock xf). increase as desired.

Thanks buddy, and one last question. In the attached image, where would I change the gradient background behind "board control" "discussion boards" etc etc?

I'm used to looking at a css file, the theme/style editor on Xenforo is a whole new thing for me. I'm stuck in the early 2000s as a forum admin!!!