> Critically, the item's in-flow position doesn't change.
This is the main problem with animations in CSS: they work as long as you don't have to reflow the document, and `transform: translate` is very good for that.
But try to slide a new item into a list (or animate as it's being removed), and you're in for a nasty surprise especially if you don't know the height of the element beforehand.
Always pop stuff out with position absolute. It sucks to have to know top, bottom positioning, but it’s the only way to get smoother animations (pop it out of the document flow).
This is the main problem with animations in CSS: they work as long as you don't have to reflow the document, and `transform: translate` is very good for that.
But try to slide a new item into a list (or animate as it's being removed), and you're in for a nasty surprise especially if you don't know the height of the element beforehand.