I always use Windows High Contrast mode, but I do not want to use High Contrast mode on the web. So, I changed color settings and set "browser.display.use_system_colors" in "about:config" to false to disable high contrast mode in Firefox.
In Firefox 121, setting "browser.display.use_system_colors" to false with Windows High Contrast mode enabled forces the color scheme to Light.
Firefox 120 does not have this issue.
