Could add clicker support (which I have done previously). Note however that clickers vary between Up/Down and PgUp/PgDown. Enabling the former was potentially annoying if you like to use the arrow keys to scroll, so I made that configurable. Alternatively you configure mappings per device outside the browser.

This is really cute!

I have a special spot in my heart for tools that do a good job of explaining themselves using their own outputs.

I wonder how hard it would be to add the cute old PowerPoint style transitions using CSS

I love it, but it was very disorienting to use `j` to move forward and `k` to move backward.

  (i = slide.nextElementSibling)?.className == "slidenote" ? i : slide
  ]),

An alternative approach:

  slide.querySelector(":scope+.slidenote") ?? slide

(|| would work just as well as ??, but ?? feels more appropriate.)