(3) Double-click layout.css.devPixelsPerPx and change its value to 1.25 and click OK, which corresponds to 125%
font size in Windows display settings. The toolbar area should enlarge after a few moments.

Too small? Try 1.5 and see whether that suits you better. And so on. If you are on Mac and use a Retina display,
anything below 2.0 may be smaller than what you started with, so start with 2.0.