Dark Mode, first introduced in Mojave (my current macOS) is helpful and I’ve always preferred to read white text on a black background whenever I could make a choice of colors: much easier on my eyes.
However, Dark Mode does nothing to change the white background and dark lettering of browser windows (at least those of Safari, Waterfox and Chrome). Is there some way to get this eye relief, for example to dim considerably the background and turn lettering from black to white, or choose a darker color for the background and a contrasting one for the text? Changing the background color to some more eye-soothing than bright white used to be possible in older versions of Windows, but it is gone now, at least from Windows 7 after installing some patches quite while ago. The way it worked was that a background color could be chosen for all windows, including those of browsers, not just for the ones of the OS or related application software, as with Dark Mode.
One could always dim the screen, but that does little to help, because reading black lettering on a darker background is also stressful to the eyes.
Ex-Windows user (Win. 98, XP, 7); since mid-2017 using also macOS. Presently on Monterey 12.15 & sometimes running also Linux (Mint).
MacBook Pro circa mid-2015, 15" display, with 16GB 1600 GHz DDR3 RAM, 1 TB SSD, a Haswell architecture Intel CPU with 4 Cores and 8 Threads model i7-4870HQ @ 2.50GHz.
Intel Iris Pro GPU with Built-in Bus, VRAM 1.5 GB, Display 2880 x 1800 Retina, 24-Bit color.
macOS Monterey; browsers: Waterfox "Current", Vivaldi and (now and then) Chrome; security apps. Intego AV