As an outside-the-box tip, a lot of laptops and monitors offer a simple key-combo for brightness.

If you don't like light backgrounds (especially noticed when you're in a dark room), you can press something like Control-Down (well it's Function-Down on my laptop), and it dims the screen brightness. This really helps take the edge off light backgrounds, and make them tolerable.

By the same token if you're on a dark website, you can possibly increase the brightness (Function-Up on my laptop) to make the letters & words pop out more.

I hit those keys constantly going from site to site, and going from daytime to nighttime screen viewing. Can't imagine how some people can stand the same brightness level all the time.