Yes, Equator runs on a 24-hr clock. And, it seems to be running on Pacific time because it doesn't clock me 'late' on a task due today until after 2 a.m. Central time (lol). Just something I've noticed when burning the midnight oil.

No - yellow doesn't mean much at all. Don't worry about green or yellow tasks . . .If you're planning 'when' you're going to do them, look at the dates & not the colors. Right now, I have tasks due at the end of next week (23rd & 25th) that are yellow.
Just worry about staying out of the red (late) with tasks because that annoys whoever you're working with at the time - premarketing specialist or asset manager.