Thinking about this as someone who teaches web dev: this shouldn't happen. As others have mentioned, this goes just far-enough past the scope of CSS to just lea

Thinking about this as someone who teaches web dev: this shouldn't happen. As others have mentioned, this goes just far-enough past the scope of CSS to just leave as a pre-processor feature. This will be an absolute nightmare for beginners and lead to a lot of messes/time wasted chasing bugs. If you can't get the as-is SCSS syntax natively without a bunch of hacks, it shouldn't be done (a bummer, as I'd love to have that natively). What could (should?) happen is codifying a pre-processor model into the standards track. Have a standard and then make some library the reference implementation.