The faces, palette and glyphs Margin and Margin Docs both draw from. It is the one copy of the decisions the two apps have to agree on: which six fonts they offer, what their named pairings are, the 35 design tokens they share, and the title bar icon paths.

No build step and no dependencies. Both apps resolve the TypeScript source directly through their bundler, so an edit here is live in both on the next dev server restart.

Margin consumes it as "margin-shared": "file:./shared". Margin Docs, which lives in a separate repository, uses a relative path to this directory; see its package.json.

The font binaries in fonts/ are the source of truth, and each app keeps a vendored copy under public/fonts because its Rust PDF exporter reads them with include_bytes! before any npm install has run. Run pnpm fonts:sync in an app to refresh that copy and pnpm fonts:check to verify it.