compact icon picker

Pick system and change the appearance in macOS System Settings with this page open: it follows, live. A toggle that stored a boolean would have stopped listening the moment it was first pressed.

Everything on this site is wired to it. The tokens item carries both halves, so an item that reads them has nothing to switch: only the handful of components with a palette of their own (the terminal's phosphor, Telegram's client colours) ever name a theme at all.