have you tried to use the shift key?

While there is no way I know of to do it in Firefox for iOS, you can increase the font size for all apps in your iphone settings. For more information, visit https://support.apple.com/HT202828

Is Shift key an iphone app? I can't find it. ( other than the keyboard shift key. . Chris.. thanks for the suggestion.. HOWEVER, I already tried that. I already have those (mainly works with iphone Menu) fonts increased.. but not FireFox. argggg