The "smart" dark mode will essentially invert the colors of the actual document, not just them them of the app interface. Take a look at how CollaNote handles this on iPad, or how Outlook handles dark mode in emails. It's not a pure inversion of colors, rather, the background goes black and the colors you are using are adjusted to be more visible against a dark background. For example, if you are using a dark blue pen, on the dark-mode background it still shows as blue, but a much lighter blue. As opposed to inverting which would just make it yellow, and much less aesthetic and ergonomic