Honestly, I hate this on the phone. But I get it. I had that initial cognitive disruption when FF did this. But once that was gone (idk, like 30 minutes?) I realized it was a lot nicer because I could actually reach the address bar and tabs without needing to stretch my hand. Or if I have a bigger phone, use a second hand. I mean there's a reason navigation buttons on the phones (for the OS) were always on the bottom. It's just easier. But yeah, you gotta get through the initial cognitive disruption. But you know what? I also got used to when Android switched the time from being at the top right to top left and I'm willing to bet most people did too and don't really think about it anymore. As for the dark mode... well you got a point there. Though dark reader was one of the first add-ons on FF mobile. Though as much as I love dark mode, some websites are just unreadable with it and it drives me nuts. Specifically anything with a transparent background...