Note that when the two areas overlap (which is most of the time) the overlap shows the green under the red as a different colour.
Red is partially transparent so you can see them both.
Thanks! It's a great idea, it will certainly help to new users still learning about the 5Nd!
As for the graphical representation, I think it would have been a bit more intuitive if it was just a green line above the graph. The way it is done now, the overlapping green and red create just another color, so a non-experienced user will see it as three different zones (even four zones if you take the white area). I guess this may cause more questions and confusion...