Design Google Docs.

Focus on the core functionalities that make Google Docs a collaborative word processing tool. Consider user needs such as real-time editing, commenting, and version history. Think about how to integrate features that enhance collaboration, like chat and notifications, while ensuring a seamless user experience. Discuss the technical architecture that would support scalability and performance, including cloud storage and data synchronization. Be prepared to address potential challenges, such as handling conflicts during simultaneous edits and maintaining document security.