I added a dark-theme toggle to this blog about a month ago. Later, I saw Lea Verou’s post, The best dark mode toggle is probably none: However, my biggest insight from all of this is that while I stand by my original recommendation that in most cases, if you are going to have a dark mode toggle that is visible at all times, it should only have two states (system and opposite), I now think that for the vast majority of websites, you should not have such a toggle at all.