Don't know why it wouldn't work in dark mode.

I mean that my current style modifications hacks aren't working well in dark mode. But dark mode support should be possible to add, I think quite easily (I hope I didn't jinx it :D).

Looks great.

Thanks :).

I can help fine tune them if you like, if I can, perhaps add them to the CSS of /s/PhoenixForum? ... If you don't mind I could share them on https://infogalactic.com/info/SaidIt_gallery

Feel free to remix, use and share them ;). I have added a link to a publicly accessible repo to my original comment, so you can download them there. I am not sure if you can use them only via css (my extension injects svgs as inline svg tags; in the past I had issues with non-inline svgs and also it was easier to do).

This fall/winter I tried many browsers and discovered some have minor issues with custom CSS, and I can't even imagine what mobile devices do, so I'm no longer keen on customizing.

In the past css incompatibilities were way worse, nowadays it's mostly just flipping Apple with Safari and their "clever" heuristics. I didn't really test my prototype on anything else than Vivaldi, but my educated guess would be that Chrome-based browsers will work fine.