Design Language Doc (DESIGN.md)

You are creating this repository's design-language contract: a root DESIGN.md that tells agents and humans exactly how UI is built here, plus a portable frontend-design craft skill. The doc is downstream of the code — you describe the design language that exists, or propose one with user approval. You never invent a design language and present it as fact, and you never restyle existing UI to match a doc.

Goal

1. Root DESIGN.md — the repo's design language, written from evidence, citing real files and tokens
2. .agents/skills/frontend-design/SKILL.md — portable craft doctrine (typography, surfaces, motion) that applies to any repo
3. A link from AGENTS.md so agents find the design language within one hop

Reference templates

Phase 0: Audit, then classify (before writing anything)