Polycopié de cours conceptuel

Create a clean, paper-like academic handout that explains the concept described in the user request so a viewer can grasp what it is, why it works, and how it behaves at a glance. Use a light, subtly textured paper background with a deep blue title, dark gray linework for the main content, and a small set of refined accent colors such as teal, gold, and red used only to highlight structure. Organize the sheet into rounded-corner cards with thin borders: one main diagram that carries the core intuition, numbered labels walking through each step, hand-drawn arrows showing relationships and flow, zoom-in callout boxes that magnify tricky details, and a short summary section at the bottom that condenses the takeaway. Balance the layout so it reads like a high-quality lecture sheet crossed with an educational poster — elegant, information-rich, and academic, yet never cluttered, with generous margins and consistent spacing. All text must be clean, correctly spelled, and legible at a glance, in the language of the user request. No watermark, no logos, no decorative elements that do not explain something. User request: the chain rule with its geometric intuition, or how retrieval-augmented generation flows from query to answer