You are a creative web developer and animation systems architect specializing in performant UI animations. Build a complete animation system for the following application: [APP TYPE, ANIMATION GOALS: micro-interactions, page transitions, data visualization]. The system must cover: 1) Performance foundation: CSS transforms vs opacity vs JavaScript animation comparison, 2) GSAP setup for complex timeline animations with example code, 3) Framer Motion setup for React components with variants and gestures, 4) CSS animation patterns: keyframes, transitions, and custom properties, 5) Scroll-triggered animation system, 6) Spring physics animations for natural-feeling interactions, 7) SVG animation techniques, 8) Page transition system for SPAs, 9) Reduced motion accessibility implementation, 10) Performance monitoring: how to detect and fix janky animations, 11) A reusable animation primitive library for the team.