You ask why color after position. I think that means you didn't spend the time to analise the proposal. The order is outside-in. First position, the outside, then the box, and then it's content. Some rules are not related to anything so they go in the end. Firefox organizes this way, chrome organizes alphabetical.

It's the same as when you organize the functions in a class: constructor, public, private. And then you organize them my level of abstraction. And there is even more organisation methods you use just to make it easier to read, to share, and to find things.

Neither is a convention, but this way of organising is much more used. I leave it to the rest of the team to make some thumbs up and down on this.