Just so you know.
Offtopic but rewarding your article on Firefox on Android, there's a slight misalignment on the side. The left side gets cut off about 5-8 pixels, I'd say. It cuts off most of the first letter on every line.
It might be just my phone, of course. But I don't have any particular extensions installed or anything else.
I also think, like petemir, that it is a width issue. What model do you have?
Thank you for your comment! It is super helpful.
Ah, sorry for not answering sooner.
Admittedly it's not a hi-end phone. I use a Moto G7. Screen is 1080x2270 at 6.2 inches according to [ https://www.gsmarena.com/motorola_moto_g7-9357.php#eu ]
Trying it again to verify... You're right that it's the width. I get a small-ish horizontal scroll. But the problem is that no matter if I scroll it completely to that side the left still gets cut off.
fyi I tried on my Android phone with Firefox and I don't see the problem you mention. Perhaps some additional display specs may be useful? My screen is 6.67" with 1080x2400px (20:9, 395ppi).