I do reduce often, but this makes everything else on my desktop too dark so I can't read it. So I have a keyboard shortcuts that run xrandr --brightness <intensity> that I use frequently, but it is not the ideal solution for everyone. Better solution of this problem would be if websites detected brightness+contrast preference set up in browsers, like they detect language or browser window size, and changed their CSS accordingly. It would be great accessibility and UX improvement of the Web. We should make some standard for that and push it up into browser projects. Anybody experienced with such a task?