the implementation is actually interesting:
- it takes effect instantly as you're editing the CSS. this makes such a huge difference!
- it shows up as a "user agent" stylesheet, which is quite similar to if it was actually in the "user" origin defined in the css-cascade spec. this does mean it's weaker than author styles (unless combined with `!important`).
it pierces shadow boundaries automatically :0
normally, this would be really tricky to do in the author origin.
@mayank Hadn't played with Zen until now; enjoying this on aarch64 Linux.
@mayank hmm if it's in the user agent stylesheet layer does that mean you accidentally break stuff? Thinking of stuff like overlay on popovers? (Bad example as Firefox doesn't have that yet...)
@Lukew hmm, i'm not sure how you'd *accidentally* break stuff (you're writing the styles yourself, as a user, and per-site), but that's an interesting case indeed — one could set `overlay: none`, which is normally not allowed.
are there any other UA-controlled properties that i could test today?
@mayank none that I'm aware of but there could be Mozilla specific stuff. I guess also that you'd be able to make use of any -internal properties, that validate they're parsing in a UA context, they might have, I know chromium and servo has that concept but idk if Mozilla really does.