@Howard-Brown
@peterjones has given you the necessary information to get back the default DarkMode settings, so you should learn from this issue and do what I did, and make your own DarkMode settings by copying that file, and giving it a different name. I called mine MyDarkModeDefault to avoid the confusion, and played with it to my hearts content. Doing this trick, even with your new default version, you can make another copy and continue to fine tune what you need to, without damaging the default, or your own new default versions. Call it MyExperimentalDarkMode, and have fun without worrying. As @peterjones and many of us around here always say, “back up what you don’t want to lose or recreate” - though that is paraphrasing. :-)