Show HN: An AI interface to zoom in and out of epubs (www.kerns.ai)

Show HN: Kerns — a new AI-powered reader that lets you "zoom" through EPUBs at multiple granularities (book, chapter, page, paragraph, sentence) using an AI interface for summaries, expansion, and conversational Q&A. The demo pitches itself as "the modern way to read," enabling semantic navigation of long-form text so you can quickly get high-level overviews or dive into fine-grained passages without losing context. Technically the app is implemented as a React/Next.js web client (the page includes auth, conversation and analytics providers), which suggests a chat-style UI backed by server or API-based model calls. The approach implies EPUB parsing plus hierarchical chunking/indexing and on-demand model queries so the system can produce multi-scale summaries, answer questions grounded in the source, and surface related passages. For the AI/ML community this matters because it packages common building blocks — document chunking, hierarchical context windows, and conversational retrieval — into a user-facing product for long-form content, highlighting opportunities and challenges around latency, context-window management, embedding/index design, and privacy when handling entire books.