Design the backend architecture for a global real-time collaborative document editing platform similar to Google Docs. Requirements: 99.99% availability, strong consistency for text content, eventual consistency for presence indicators, and support for 10 million concurrent active users. Describe your choice of database technologies, conflict resolution strategies (e.g., CRDTs vs OT), load balancing approach, and partitioning scheme. Justify your trade-offs regarding the CAP theorem.