This seems like a reduction in readability from either declaring properties in an order such that browsers which don't support the syntax will still have a fall

This seems like a reduction in readability from either declaring properties in an order such that browsers which don't support the syntax will still have a fallback declaration: .foobar { background: red; /* fallback declaration */ background: poorly-supported; /* preferred declaration */ } or using platform-specific property prefixes. Personally, I'd rather see the entire definition block for a selector in one place than have to consult multiple conditional declarations.