Consistency, speed, quality. A Design System is not a static library: it’s a scaling strategy. We define tokens (colors, types, spacing), build accessible components, document clear guidelines, and establish light governance to evolve the system with the product. Goal: deliver faster with less ambiguity and reduce technical debt. On the UX side, the system guarantees journey coherence and interface readability. On the tech side, it accelerates development (front/back), simplifies CI/CD (stable builds, visual tests), and improves sustainable web performance (reducing unnecessary variety, shared assets). Regarding accessibility, it prevents regressions (contrast, focus, ARIA roles) and formalises acceptance criteria. Linked to branding-identity, it protects your uniqueness while staying lean. The Design System is also a tool for eco-design: fewer, better-thought-out components for clearer, faster screens. We connect documentation to your tools (Figma, Storybook), integrate system reviews into product governance rituals, and measure usage (adoption, debt). If an AI integration makes sense (variant generation, augmented documentation), we experiment without imposing it. Deliverables: tokens, key components, documentation, usage playbooks, adoption plans, accessibility checklist, performance conventions, maintenance.