Hello Aya,
Thank you for getting in touch with us. All layers of the file are endeed in the same color (for us is black instead of white), but the elements in each of them are properly grouped on our end. The “streets” layer really contain the streets, the “building” layer really contains the buildings, and so on.
Here is a screenshot with all layers on:
And here one with only the buildings layer on, as an example:
