Barleywine
Your browser may have an option to help with that. In Mozilla Firefox, for instance, I can go to the View menu and choose Page Style > No Style. The page then appears as black text on a white background. And it's easy to reverse when you leave the page.
Worked like a charm. Thanks! If I had remembered to enable the Menu toolbar I might have found that on my own I especially like the Mantegna Renaissance tarot deck (colored by Raven) shown on that site.