Firefox generates a white line at the bottom when it is in dark mode and the windows bar is at the top, which is annoying, other browsers like chrome do not show this defect
Same problem here. I'm on Windows and when I have the taskbar set to auto-hide, there's a thin white bar on the bottom. I have an OLED display, so this might cause some burn-in over time. I don't know if this is a Firefox or Windows issue, but I hope it gets resolved.