App Interface Guideline: Animation — Duration & Easing. Keywords: animation duration easing. Platform: iOS/Android/React Native. Description: Micro-interactions should be 150–300ms with native-like easing. Do: Use ease-out for enter/ease-in for exit. Don't: Use long or linear animations for core UI. Good Example: Animated.timing(..., { duration: 200, easing: Easing.out(Easing.quad) }). Bad Example: Animated.timing(..., { duration: 800, easing: Easing.linear }). Severity: Medium.