I installed Lollipop on a Nexus 4 and I noticed some differences from the videos and images of stock Lollipop that I've seen before. Mainly the status/notification and navigational bars are black (they should be transparent). Also, the design of the folders on the home screen is different (my folders have a black background while it should be white). You can see some examples in the images.
"Black bars" / "Black Folder" (click images for larger variants)
Does anyone know where's the problem?