3.3.2

Let dialogs close the way they open

Two separate faults with the same cause: the animation was in the wrong
place.

Opening faded the whole modal by animating its opacity. An element with
animating opacity becomes its own compositing layer, and the
backdrop-filter inside has nothing to sample until that layer settles —
so the window slid in clear and the blur landed afterwards, in one step.

Closing set `display: none`, which cannot be animated at all. Window
and blur went together, mid-frame, with nothing in between.

Neither animates the modal now. The overlay fades and un-blurs on its
own curve, the panel moves on its own, and the modal itself only stops
taking clicks — its visibility switch is delayed past the transition so
both children are still on screen while they leave. Measured on the way
in and out: blur and panel travel together, 0 to 7px and back over
240ms.