On Sat, 5 Nov 2016 00:28:06 -0500 Leslie Turriff jlturriff@mail.com wrote:
Because the easiest ways to deal with firefox is chrome/userChrome.css file in you firefox profile or "Theme Font & Size Changer" addon.
You appear to misunderstand my request. I'm not (as much) concerned with the content of web pages as the fonts used to display file pickers, configuration dialogs, menus, etc., components of Firefox itself.
Firefox GUI is written ix XUL and can be edited with css markup using that file (or addons)