How to change Firefox GUI font WHEN not allowing webpages to use their own fonts?

mzso

Создано: 15.01.2018

Hi!

This CSS doesn't work to change the gui font when I don't allow websites to use their on font settings in FF56:

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

* {

    font-family:"Comic Sans MS" !important;


}

The GUI will use the font specified for websites... Apparently it's because of a firefox bug starting with FF41.

Since CSS seems to fail, is there any way I can override the GUI fonts used in this case, via a userscript?