Revision Ledger

Prompt

You are a Senior Staff Engineer at a top-tier ed-tech lab. Your task is to architect and code the ultimate, single-file HTML/JS/CSS Progressive Web App (PWA) for a NEET 2027 Biology aspirant. I already have a working FSRS-based spaced repetition tracker, but it relies on chapter-level tracking. I need you to build its successor: an "NCERT Knowledge Graph Tracker." Here are the strict architectural requirements: 1. THE DATA MODEL (The Knowledge Graph) Do not use flat arrays for the syllabus. Implement a directed acyclic graph (DAG) structure. - Nodes represent specific NCERT sub-topics (e.g., `Node_LacOperon`, `Node_DNA_Replication`). - Edges represent prerequisites (e.g., failing `Node_LacOperon` should apply a 15% decay penalty to its parent `Node_GeneExpression`). 2. THE MATH ENGINE (Graph-FSRS) Implement an FSRS-lite mathematical model (Retrievability, Stability, Difficulty) applied at the NODE level, not the chapter level. - Write a function that calculates node decay based on time elapsed. - Write an error-propagation function: when a user logs a failure on a child node, the engine must recursively apply a fractional penalty to parent nodes. 3. THE UI (Zero-Friction Command Center) The app must run entirely client-side using IndexedDB for persistence. Use a minimalist, dark-mode CSS design (similar to GitHub or Vercel dashboards). - **The Dashboard:** A heatmap of the syllabus showing specific nodes turning from green to red as they decay over time or fail in tests. - **The Input (Surgical Logging):** A fuzzy-search bar where the user types a keyword (e.g., "wobble"), selects the matching NCERT node, and clicks "Failed in Mock" or "Revised." - **The Output (The Payload):** A "Generate Today's Run" button that outputs a highly specific, prioritized list of exactly which nodes (sub-topics) have dropped below an 85% retrievability threshold today. Output the complete, working, single-file code. Do not use external CSS/JS libraries besides Tailwind via CDN (if needed) and standard browser APIs. Prioritize the mathematical logic of the dependency decay and the IndexedDB schema.

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