CSS: How to except the "overlay" that seems to be universal to websites? [closed]

I'm trying to do a quick and dirty userstyle edit to make some websites more OLED friendly. When I select * to reduce the brightness of every element slightly then any website turns into a grayish mess:

*{filter: brightness(85%);}

When I only select links, for example, then it works just fine and reduces the brightness of the letters a bit:

* a{filter: brightness(85%);}

How could I select everything except for whatever causes this? Excepting html, body, div, etc. doesn't seem to do it. As I already mentioned, I'm not looking for a perfect dedicated solution, just a simple "universal" blacklist approach to turn all elements a bit less bright.