📝 Solved by CSS Scroll-Driven Animations: hide a header when scrolling down, show it again only when scrolling up again.
By adding a long transition-delay to a CSS property under certain conditions (which you can do using a Style Query), you can persist its value.
🔗 https://brm.us/scroll-driven-header
Demo by @fcalderan.
@bramus @fcalderan I find this to be an anti-pattern for usability. Often times when I'm reading a site that uses this, I feel like I have to fight with the site and produce a scroll pattern "just right" so that I can again access the site header. I wish it would either be sticky or not.