Pdfcn is a free, open-source library of customizable PDF components for React built on Takumi and Forme frameworks. It offers zero-config setup, live previews, full customization, and compatibility with shadcn/ui, allowing developers to create documents like tables, forms, charts, and invoices through composable React components.
Article outlines a four-level component hierarchy for UI development: headless components handling core behavior, design system components like shadcn/ui adding styles, layout components for common patterns, and consumer components building the final UI. Five rules emphasize using shadcn/ui as a foundation, maintaining design system consistency, organizing components by level, and leveraging composition patterns to avoid poorly designed interfaces.