This might be a little OT, but just a little. If the brightness of the occassional website bothers your eyes (as it does mine) there is a little add-on for Firefox (and Firefox derivatives like Pale Moon) that can help. It's called "Page Colors & Fonts Buttons" and is available at Mozilla Add-ons. It puts a small icon on the address bar and if you click it it changes the background color to whatever you define it to in the browsers Options menu. In my case I have the color defined as light guy. A simple click and the backgound is light grey, another click and it's back to the website defined color. It's not the answer for those sites you spend a lot of time on, like this one, but for sites visited only occassionally where it's unlikey the host will change colors it can save you eye strain.