[Русский] Content Duo: How We Mix New Lessons, Reviews, and Challenges for Every Child

# Content Duo: How We Mix New Lessons, Reviews, and Challenges for Every Child [Russian content] ## Content Duo: How We Mix New Lessons, Reviews, and Challenges for Every Child Content Duo is Amal's adaptive lesson engine that generates personalized learning sessions by mixing three types of content: new material the child hasn't seen, review items due for spaced repetition, and stretch challenges slightly above the child's current level. The mix ratio adapts in real-time based on the child's persona (beginner/intermediate/advanced) and session performance. ### How Content Duo Works **The Virtual Content Byte System** Content Duo is a special generator, not a pre-created content byte: ``` User taps "Play" on Content Duo ↓ API endpoint: POST /user/{user_id}/content_bytes/play ↓ Backend ContentDuo generator: 1. Fetch user's persona (beginner/intermediate/advanced) 2. Fetch all concepts due for review (from HLR scheduling) 3. Fetch next-level new concepts (from curriculum progression) 4. Fetch challenge concepts (1-2 levels above current) 5. Mix into a personal