How do I change the font size of the address bar?

I use a 14px bitmap font as part of my system theme. It is set to display at 14px in my gtk theme which works for tabs, bookmarks, right-click menus, and other parts of Firefox UI, but the Firefox address bar doesn't seem to be the same size and is blurry.

How do I change the font size of the address bar? Is there an element I can target in userChrome?