- Add CSS custom properties for surfaces, text, borders, accent, radius, font stacks
- Add JetBrains Mono via next/font/google alongside Inter (both as CSS variables)
- Upgrade cn() from naive filter/join to twMerge(clsx()) for proper Tailwind class merging
- Standardize marketing section containers from max-w-7xl to max-w-6xl
- Install tailwind-merge and clsx dependencies