nostr:npub1jpp36eeycvlkkdy4d4l4lgswvf8jtdare5vly0w0sk7rc39pzgrqlyu59l Thank you, that's very helpful. But this makes me realize my issue isn't with & but the fact that div .foo {...} is different from div.foo {...} 

That's even MORE obscure! 

BTW, I want to stress that I'm NOT a professional CSS author. Just someone that is trying to not drown when reading it.