Turn down the brightness of your screen when you are on GT.
I don't really see this as being any brighter.
It's not so much that the page colour is brighter, to me it appears a soft eggshell shade, but the actual text areas are wider, I think, and that increases the overall page brightness. If I recall, the page background showed a good inch on either side of message and text areas... now it appears less than a quarter-inch. But that's more an apparent style of thing, and will be perceived differently.
I do use the brightness and contrast controls on my monitor; some full-screen games and applications are a bit bright, whilst certain 'websites of a questionable nature' require full brightness. So's I can see. Ahem. Most of 'em are amateurs, after all. Giggity.
I find just adjusting the contrast will do the trick for different comfort viewing pages on different websites.
Yes thank you that is it. And also, the turning down the brightness of my screen? Worked wonders.