It seems a bit odd to me that the same user would choose to change the color of his or her background or the color of his or her screen. But this is the closest you’ll get to it. The solution to this problem appears to be to use the background color in a way that it is not really a problem at all.
It can be really hard to use CSS to change the background color of a webpage, because if you want to change the background color on a webpage then you have to make sure the colors you are changing are actually in the same color space than the background color. If you can’t be sure you can’t change the background color then the only other option is to alter everything you can see on the page, which means changing the colors of your text, borders, images, and fonts.
The first few times I tried to get my background color to change on my website it wouldn’t work. So I ended up creating an image that was set to the background color but then I’d have to use CSS to adjust the color to the desired color. That works great if you have a background image set. But if you don’t then you can’t use the background color.