This extension was recommended to me as a way to force dark text on light background on websites. Well, I tried. None of the sliders in extension config appear to do anything; the predefined themes only have "and add some ridiculous tint all over" takes on "light mode". I thought, perhaps I could make a copy of some "light" theme and try to adjust that? Nope, you can only rename predefined themes, not make duplicates. Ok, then maybe I could export a theme, edit the exported file, and import that back as a new theme? NOPE. "Color schemes import from files is not supported in Firefox." Why is that "import" button even there then?