Senior Next.js / TypeScript Front-End Developer

I'm a digital agency owner managing a contract for a large agricultural intelligence platform. I need a senior front-end developer to handle the core build of a reusable component library and page-assembly framework. This is real enterprise work — not a marketing site. The client is organized, has a detailed SOW, and expects clean, documented, production-quality code. TECH STACK: - Next.js 14 (App Router) - TypeScript (required — not optional) - CSS Modules - Storybook or equivalent component documentation tool WHAT YOU'LL BUILD: - Full component library: page shell, nav/header, KPI strip, card grids, filter bar, tabbed nav, slide-over drawer, tables, badges - Design token system (color, typography, spacing, breakpoints) as JSON/CSS variables - 2–3 assembled layout templates populated with mock data - Storybook documentation for every component (props, variants, responsive behavior) - Country configuration schema — a JSON-driven system that lets a junior dev populate a new country page without touching the UI code - Architecture handoff document (5–10 pages) written for an internal dev team WHAT I'M PROVIDING: - Screenshots and written design spec (colors, typography, spacing, breakpoints) - Mock JSON data schema - Access to an isolated sandbox Git repository - Clear milestone structure with defined deliverables WHAT I NEED FROM YOU: - Portfolio showing enterprise-level React/Next.js component library work - Strong TypeScript — you're designing the type contracts, not just adding types - Experience building for handoff to other developers, not just for yourself - Clean, readable, well-commented code - Availability to start within 2 weeks HOW TO APPLY: Don't send a generic proposal. Tell me specifically: what's the most complex component library or design system you've built, what stack did you use, and what was the hardest part of the architecture. If your proposal doesn't answer that, I won't respond. This is a fixed-price milestone contract. I'll share full scope and rate expectations after a short screening call.