Foundations
Motion
Atlas feels instant. 120–150ms fades on background-color are the only standard transition. Everything else is immediate — devtools respect your attention.
Interactive states
Hover a button to see the transition.
Rules
120ms ease-out — default for hover/press.
150ms ease-out — popover open, toast enter.
Never animate
color or opacity on icons — causes visible jitter.No springs, no bounces, no overshoot. Ease-out or linear only.