W3C Design System — complete local specimen

Implementation: Native W3C CSS and main.js, dated CDN snapshot; system font fallback and original content.

1. Extract this archive into its own directory.
2. Run: python3 -m http.server 8080
3. Open: http://localhost:8080/w3c.html

The HTML includes the document root, layout/theme overrides and initialization.
Its relative vendor directory includes the actual CSS, JavaScript module chain,
fonts and other packaged assets used by this specimen. Preserve this structure;
ES modules require HTTP rather than opening a file:// URL.

Dependencies included: w3c-2026-10-03
Official reference: https://design-system.w3.org/components/collapsible-containers.html

This is an original local demonstration, not an affiliated government service.
Actions have no external side effects. Retain supplied dependency licenses.
