Wyze Vacuum map floor coloring meaning?

Can anyone make sense of the floor coloring the vac gives a room on the map. There is a light and dark color but I’m not sure what the difference means. From what I can tell after a room is scanned the whole room is dark, but then when the vac returns to clean it changes to light coloring. Also, my vac won’t go anywhere where the ground is colored dark. I have some areas that are wide open carpet and they’ve been colored dark, hence the vac avoids them instead of going all the way to a wall for example