True, I don’t have benchmarks, but there was a time period where shadow DOM was popularly disabled due to performance hits, but perhaps it was all the performance hit of polyfills and less efficient implementations in browsers. https://github.com/WICG/construct-stylesheets/blob/gh-pages/... is interesting, though Sass still looks unlikely to be added to the browser so we’ll always need some amount of CSS compilation if you want CSS nesting the way you expect it in Sass. Here’s more documentation on constructible stylesheets: https://developers.google.com/web/updates/2019/02/constructa...

I wasn’t aware of this because this stuff is being developed and released so dang quickly! (I do worry that APIs developed in relative haste might be replaced or iterated on in relative haste, especially if they aren’t adopted widely first...)