Does the legend not match the actual colors used on the map, or is the entire surface of the planet light polluted? I don't see a single area on the Earth that's as dark as the three darkest colors on the legend.
The legend isn't a perfect match - there is an opacity on the color overlays that makes the black side of the legends instead be lighter shades of grey when on the map.
Sorry to reply on this thread but I wasn't sure how to contact you otherwise. Thank you for your comments regarding my landing page copy. I think you are right, and I was assuming my bad experiences were what others would experience. I revised my page based on your feedback. So thanks.
If you switch the map to full opacity (slider underneath the full screen button at the top right), the colors match the legend. There are areas in the darkest categories-- look in Nevada, for example, or just about anywhere in central Africa or Siberia.