Horizontal Column Accordion

Build a "Horizontal Column Accordion" React component.

CONCEPT: A horizontal accordion for a portfolio: five columns, like book spines on a shelf. The active one grows wide to show a project title, year and short blurb.

LAYOUT & CONTENT:
- Columns alternate colors: paper, charcoal, terracotta, cobalt, paper-2. Collapsed columns show a vertical rotated title and a mono index.
- Expanded column shows index, title at 2rem, year, one-line blurb, and an arrow link.

INTERACTIONS & MOTION:
- Animate flex-grow (1 → 5) with spring stiffness 260 damping 30 on hover and on focus (keyboard).
- Rotated label fades out while expanded content fades in with a 100ms delay.
- On mobile (<640px) switch to vertical stacking with height instead of width.

DESIGN SYSTEM (non-negotiable):
- Palette: paper background #FAF9F6, deep charcoal #121212 for text and 1px borders, ONE warm accent: cobalt #1D4ED8 or terracotta #D9534F. Secondary surface #F2EFE8.
- Typography: Swiss / editorial. A tight grotesk for UI (Instrument Sans, Inter Tight or similar) with negative tracking on display sizes; an italic serif (Instrument Serif) used sparingly for one emphasized word.
- NO dark-mode neon, NO glow, NO glassmorphism, NO backdrop blur, NO purple-to-blue gradients, NO emoji icons. Solid fills, hairline rules, honest shadows (hard offset or none).
- Motion: Framer Motion with spring physics (type: "spring", stiffness 300-500, damping 20-35). Animate transform and opacity only. Respect prefers-reduced-motion via useReducedMotion().
- Icons: lucide-react, 1.5px stroke.
- Accessibility: real <button>/<a>/<label> elements, visible focus ring (2px cobalt, 3px offset), keyboard operable, aria attributes where state changes.

OUTPUT: one self-contained React component file (Tailwind CSS v4 utility classes, framer-motion, lucide-react), no external images, default export, ready to paste into a Next.js App Router page with "use client".