vigo: update CATALOG.md — description field, removed redundant h1/blockquote/contents

CATALOG.md

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+---
+title: "OpenCD"
+description: "Physical CD jewel case CSS framework — web design driven by ISO 15727 packaging specifications"
+status: prototype
+state: published
+created: 2026-05-26
+tags:
+  - prototype
+  - framework
+  - css
+  - design
+repo: trentuna/opencd
+authors:
+  - name: Ludo
+    role: Author
+  - name: Vigo
+    role: Maintainer
+---
+
+## Context
+
+Physical objects have measurable dimensions. A CD jewel case is 142×125 mm. A CD leaflet is 120×120 mm. A disc is 120 mm in diameter. These are not arbitrary numbers — they are ISO 15727 specifications, the result of decades of industrial design refinement.
+
+OpenCD maps these measurements directly to CSS custom properties at 2× scale. Built on Open Props v2 and following the Agentic Semantic Web philosophy of semantic HTML plus zero-classes styling, OpenCD is a study in how physical media constraints can inform and enrich digital design.
+
+The framework ships seven components, each a CSS module mapping to a physical CD packaging element: jewel case, spine, leaflet, disc, tray, booklet, and back insert.
+
+
+
+## Related
+
+- [Agentic Semantic Web](./../projects/asw/CATALOG.md) — shared philosophy: semantic HTML, zero classes, data-attribute selectors
+- [Human Advisory](./../projects/human-advisory/CATALOG.md) — shares the display typography and monochrome aesthetic
+- [Essay: On the Craft of Invisible Systems](./../essays/2026-02-01_invisible-systems.md) — the principle of systems that recede
+
+## Credits
+
+- **Ludo** — Author, concept, design
+- **Vigo** — Maintainer, distribution
+- **A-Team** — Built via autonomous agent missions