Design System
IO uses Apple's easing curves for all transitions.
--ease-io cubic-bezier(0.25, 0.46, 0.45, 0.94), --ease-io-spring cubic-bezier(0.34, 1.56, 0.64, 1)
--duration-fast (150ms hover/micro), --duration-base (300ms transitions), --duration-slow (500ms scroll animations)
Add .io-animate to any element — fades up when entering viewport. Delay modifiers: .io-animate-delay-1 through .io-animate-delay-5 (100-500ms). All respect prefers-reduced-motion.