I'm pretty sure firefox has this feature.

the problem is no website offer custom css.

for an example: https://stackoverflow.com/questions/48227413/what-is-the-pur...

Seems Firefox doesn't remember the CSS you have selected (i.e. per page? per domain?)

I can think of some uses for this if it were sticky - high contrast and dark mode versions for websites

You can detect css changes and remember/enforce it yourself but yeah, it does remember permission per page so adding this should have been/be easy.

Oh wow. Does this only work on FF?

I doubt it would work well but you could put a theme in user.css (on Firefox) and block all .css files (with uBlock, say). Not sure if uBlock will block <style> tags, but I think it can.

I think user.css automatically overrides any remote CSS, doesn't it?—so no need for blocking.

Yes, I suppose if you use a css reset then you wouldn't need to block .css files; but you could save a little bandwidth if you did.

Yeah, that is how it should have worked.

HN is pretty vanilla. I use it with https://userstyles.org/styles/92693/dark-hacker-news-solariz...

Not the standardized approach that we should have had long ago but better than nothing.