I'm running Linux, and I use Firefox Extended Support Release, 52.6.0, because I depend on certain accessibility/usability extensions which don't work in Firefox Quantum.
I have a small laptop screen with somewhat high resolution, which makes the default Firefox UI font unreadable for me.
I figured out that I can change the UI font size of most applications with an
This works for things like Gedit and i3, but for some reason Firefox ignores it.
I tried another workaround I found on support.mozilla.org, changing
layout.css.devPixelsPerPx to 1.25 in about:config. On my version of Firefox this changes the size of pretty much everything but the UI text font.
Another suggestion from support.mozilla.org is to use an extension called "Theme and Font Size Changer". However, since the release of Firefox Quantum this extension seems to have been modified to no longer support changing font sizes (it only allows me to change the colors!).
I tried halving my screen resolution with
xrandr (to 640x400), but this breaks many things, for instance various dialog boxes such as print dialogs no longer fit on the screen.
Is there a better solution?