bwhahahaha I gotta share this insane hack. I just used a little bit of reagent to implement a floating top navbar from scratch without changing more than a single CSS property. The strategy is just to hook an event listener on scroll that updates a ratom containing the y-axis position, and then make the position property of the div containing the navbar depend on that. Which is nutty, and makes the navbar appear to jump around a teensy bit, but is so so so so much nicer than having to fight with css to get the elements under the navbar positions correctly with respect to it.

https://gist.github.com/paultopia/e67da7899cdf52a677169de0edcd5d87