Proper Animation Timing

Two separate upstream rules, quoted together because they answer the same question: how should a small interaction feel. ease-out on entrance puts the movement in the first frames — the ones the user is actually watching — and lets it settle, which is why a 200ms ease-out reads as faster than a 200ms ease-in even though the stopwatch says otherwise (animations-emil-no-ease-in makes the same case at length).

The 200ms ceiling is specifically for INTERACTION FEEDBACK — a press, a hover, a toggle, the response to something the user just did — not for every animation on the page: a drawer or a modal moves a large surface and legitimately runs longer (animations-emil-duration-budget budgets 200–500ms for those). Upstream says nothing about the curve for exits; do not infer ease-in from its absence.