I hope they make Container Tabs work on Android Firefox soon, it’s the one Add-on I can’t make work with the Android Firefox Nightly workaround.

There’s no need to go JavaScript route for theming, Stylus is an add-on that injects CSS instead. I wrote a style here, which increases width of Lemmy instances for wide screens, and also respects your browser light or dark theme if set to follow system:
https://userstyles.world/style/10233/zettajon-1440p-and-darkmode-supported-lemmy

And yet: https://www.newsweek.com/republicans-plan-cut-free-school-lunches-1807361