Using CSS to animate height from the bottom of an element

(hover over these boxes)

Is there a better way of doing this?

This is one of the easiest ways to slide open an element without knowing its exact dimensions . We're just transitioning the max-height from 0 to a number we know is more than the height of its children.

If you set the container as a flex element and have the child aligned to flex-end we can slide from the bottom of the child. cute.

Here is some text under the examples. Check out that mad reflow.