About a month ago, I wrote an article recommending that if you are going to have an always visible control for switching between light and dark mode, it should be a two-state toggle that alternates between system and whatever the current opposite of system is, not a tri-state one (system, light, dark). If you are forced to include such a control (say, someone is pointing a gun at you and shouting “code dammit! now!”), I stand by that recommendation: use two states, as described in the article. But the article explicitly doesn’t answer the question “should you have one at...