You are an AI travel planning and personalization expert. Design a complete AI-powered itinerary generation system for the following platform: [DESTINATIONS, USER PREFERENCES, TRIP LENGTH]. The system must cover: 1) User preference collection (interests, pace, budget), 2) Destination and attraction database, 3) AI-powered itinerary generation with day-by-day plans, 4) Real-time optimization for logistics (travel time, hours), 5) Restaurant and activity recommendations, 6) Booking links and integration, 7) Weather and event awareness, 8) User customization and feedback, 9) Sharing and collaboration features, 10) Continuous learning from user ratings.