Is there any particular reason why we separate some statements with commas, but not others? for example, when transforming elements?

Answer 1

It appears that the commas are when you have multiple instances of the same effect (like 2 shadows on top of each other { box-shadow: shadow1, shadow2} ) but with these transform properties are done as complex descriptions of a single transform ( x component and y component) which doesn't use a comma.

Answer 2

Ah, thank you! I was starting to think that, but never checked lol

Answer 3

The answer that @Matt Beck Gave probably makes the most sense as to why.