---
id: S03
parent: M016
milestone: M016
provides:
  - favicon.svg and PNG assets in frontend/public/
  - OG/Twitter meta tags in index.html
  - Inline SVG logo mark in header brand area
requires:
  []
affects:
  - S06
key_files:
  - frontend/public/favicon.svg
  - frontend/public/favicon-32.png
  - frontend/public/apple-touch-icon.png
  - frontend/public/og-image.png
  - frontend/index.html
  - frontend/src/App.tsx
  - frontend/src/App.css
key_decisions:
  - Generated PNG assets programmatically using Python stdlib to avoid external image tool dependencies
  - Used favicon mark without background rect for inline header logo — decorative with aria-hidden
patterns_established:
  - Brand assets in frontend/public/ with SVG primary + PNG fallback pattern
  - Inline SVG logo mark with aria-hidden for decorative header elements
observability_surfaces:
  - none
drill_down_paths:
  - .gsd/milestones/M016/slices/S03/tasks/T01-SUMMARY.md
  - .gsd/milestones/M016/slices/S03/tasks/T02-SUMMARY.md
duration: ""
verification_result: passed
completed_at: 2026-04-03T05:48:09.839Z
blocker_discovered: false
---

# S03: Brand Minimum (Favicon, OG Tags, Logo)

**Added favicon (SVG + PNG fallback), apple-touch-icon, OG/Twitter social meta tags, and inline SVG logo mark in header.**

## What Happened

Two tasks delivered the full brand minimum. T01 created four static assets in frontend/public/ — an SVG favicon (stylized C arc + dot in #22d3ee on dark background), a 32px PNG fallback, a 180px apple-touch-icon, and a 1200×630 OG social image. All PNGs were generated programmatically using Python stdlib (struct + zlib) to avoid external image tool dependencies. index.html was updated with favicon link tags, OG meta tags (title, description, image, type), Twitter card tags (summary_large_image), and a description meta tag. T02 added the same arc+dot mark as an inline SVG in the header brand area (App.tsx), wrapped in a .app-header__logo span with aria-hidden for decorative semantics. The .app-header__brand container was updated to flex layout with gap for clean logo/text alignment at 24px height. Build passes cleanly (57 modules, 915ms). All assets copy to dist/ and all meta tags appear in the built index.html.

## Verification

Ran npm run build (exit 0, 915ms). Verified all 4 assets exist in dist/ (favicon.svg, favicon-32.png, apple-touch-icon.png, og-image.png). Grepped dist/index.html for all required patterns: rel="icon", og:title, og:description, og:image, twitter:card, name="description" — all present. Confirmed app-header__logo class in App.tsx and App.css, inline SVG present in App.tsx, and #22d3ee accent color in favicon.svg.

## Requirements Advanced

- R039 — Favicon, OG tags, Twitter card tags, description meta, and inline SVG logo all delivered and verified in build output.

## Requirements Validated

- R039 — Build produces favicon.svg, favicon-32.png, apple-touch-icon.png, og-image.png in dist/. index.html contains rel=icon, og:title, og:description, og:image, og:type, twitter:card, twitter:title, twitter:description, twitter:image, and meta description. Header shows inline SVG logo mark.

## New Requirements Surfaced

None.

## Requirements Invalidated or Re-scoped

None.

## Deviations

T01 switched from flat-list pixel generation to scanline-based with bounding-box culling for large PNG generation (OG image) after initial approach timed out.

## Known Limitations

OG image uses programmatically generated shapes rather than rendered text — social previews show the brand colors and mark but not the "Chrysopedia" wordmark. Adequate for initial brand presence; can be replaced with a designed asset later.

## Follow-ups

Replace programmatic PNGs with professionally designed assets when brand identity matures. Add per-page OG tags (technique pages should have unique og:title/og:description).

## Files Created/Modified

- `frontend/public/favicon.svg` — New: SVG favicon with stylized C arc + dot in #22d3ee
- `frontend/public/favicon-32.png` — New: 32px PNG favicon fallback
- `frontend/public/apple-touch-icon.png` — New: 180px Apple touch icon
- `frontend/public/og-image.png` — New: 1200x630 OG social sharing image
- `frontend/index.html` — Added favicon links, OG tags, Twitter card tags, description meta
- `frontend/src/App.tsx` — Added inline SVG logo mark in header brand area
- `frontend/src/App.css` — Added .app-header__logo styles, updated .app-header__brand to flex
