This repository is a production-grade Next.js application (v14 with App Router) that serves as the official web eco-design best practices reference (Référentiel d'écoconception web) by GreenIT.fr. It provides a multi-language (French, English, Spanish) content site with a headless CMS (TinaCMS) for editing, a REST API for programmatic access, and a client-side search (Pagefind). The core content is a structured collection of 115+ best practice sheets (fiches) with frontmatter metadata including lifecycle stages, environmental impact, validation rules, and version tracking. The site is deployed on Vercel and uses MongoDB for TinaCMS indexing. While the primary purpose is an application, the underlying content is a well-structured, versioned dataset that could be used independently for compliance checking or analytical purposes, giving the repo a hybrid character. The application code is well-organized with reusable patterns for MDX rendering, glossary tooltips, content validation, and multi-referential configuration.