There's a really specific behaviour that iOS has with its collapsible top bars that I've been trying off and on to nail with CSS for ages as a little puzzle, but for some reason it's always not quite right. As you scroll down or up, the bar remains perfectly in place and only starts moving up once it's fully revealed or down once it's fully gone. There should be a way to do it with `position: sticky` but whether you use some javascript or not, it's always slightly jerky or wrong, especially on safari. Apple really does pay attention to these little things in ways others don't.
And then they go and release that recent photos app update and make me seriously want to leave their ecosystem completely.