System Design Interview Prep

Help me design [SYSTEM] for a system design interview. Walk through: 1) Requirements clarification (functional + non-functional), 2) Scale estimation (users, requests/sec, storage), 3) High-level architecture diagram description, 4) Database choice and schema, 5) API design, 6) Scaling strategies (caching, load balancing, sharding), 7) Bottlenecks and how to resolve them, 8) Trade-offs made. Interview-ready format.