Chrome pack

A chrome pack ships the framing layer — headers, footers, navs, sticky bars, modals — that wraps every page in a build. Chrome packs are how you can give an entire site a distinctive "feel" without touching widget internals.

What you ship

my-chrome/
├── manifest.json
├── chrome/
│   ├── header-default.json
│   ├── header-mega-menu.json
│   ├── footer-utility.json
│   ├── nav-side-rail.json
│   ├── sticky-cart-bar.json
│   └── modal-shell.json
├── preview/
│   └── shells.png         # 1200x630 multi-shell preview
└── README.md

Key contracts

• Composition over CSS. Chrome elements are declared as widget compositions, not raw HTML. The runtime renders them with the active theme tokens applied.
• Responsive defaults. Each shell declares its mobile collapse strategy (drawer, sticky-bottom, hamburger).
• Section-purpose aware. Headers honor the build's nav-primary declaration; footers honor nav-utility.

Scaffold

vincia create chrome-pack my-chrome
cd my-chrome
vincia preview
vincia publish --dry-run

Approval gates

1. Schema parse — every chrome JSON validates against the schema. 2. Mobile collapse — every shell ships a mobile_strategy declaration. 3. A11y landmarks — header/footer/nav each ship the right ARIA landmark. 4. Preview present — preview/shells.png exists and is ≤ 500 KB.

Where to learn more

• /foundations — the KitPreset.chrome shape.
• Examples — section libraries that ship matching chrome packs.