Simple CSS transitions in Elm?

[romper]

The trick with max-height is not perfect at all, transition will consider if height is 500. So for the not known general case height solution should be more complicated, and probably implementing it with pure elm will be not trivial, is possible at all, one needs to calculate containing items heights and set it on the container element that will be transitioned. I’m not aware of other more simple solutions for this problem.