feat: replace default Astro favicon with atom + neural network design

[CaesiumY]

Custom SVG favicon combining electron orbits with neural network nodes,
reflecting the blog's AI + science identity. Uses blue (#3B82F6) and
amber (#F59E0B) colors with dark mode support.

https://claude.ai/code/session_017Tjprqh8Cu22nLxED6Jz8E

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a new, custom SVG favicon to replace the generic default Astro icon. The updated favicon is designed to visually communicate the blog's core themes of AI and science by integrating atomic and neural network motifs, enhancing the site's unique branding and providing a more tailored visual identity for users across different display modes.

Highlights

• Custom Favicon Design: Replaced the default Astro favicon with a custom SVG that visually represents an atom and a neural network.
• Thematic Representation: The new design combines electron orbits with neural network nodes, aligning with the blog's AI and science identity.
• Color Scheme & Dark Mode Support: Implemented a blue (#3B82F6) and amber (#F59E0B) color scheme, with specific color adjustments for dark mode preference.

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[gemini-code-assist]

Code Review

This pull request replaces the default Astro favicon with a new custom SVG icon that represents the blog's theme of AI and science. The new SVG is well-structured, using CSS classes for styling and providing support for dark mode. My feedback focuses on improving the conciseness of the CSS within the SVG.

[gemini-code-assist]

The CSS styles for light mode are defined separately from the base styles, leading to redundancy. You can combine the base styles and the light mode styles into a single set of rules for better conciseness and maintainability. The styles within the @media (prefers-color-scheme: dark) block will correctly override them for dark mode.

      /* Default (Light mode) styles */
      .orbit { fill: none; stroke-width: 1.5; opacity: 0.5; stroke: #3B82F6; }
      .node-outer { opacity: 0.9; fill: #3B82F6; }
      .node-inner { opacity: 0.85; fill: #F59E0B; }
      .link { stroke-width: 1.2; opacity: 0.4; stroke: #3B82F6; }
      .core { fill: #F59E0B; }
      .core-ring { fill: none; stroke-width: 2; stroke: #3B82F6; }

[claude]

Code Review PR 18 - Custom Favicon SVG. Issues: 1) Empty .core rule can be removed. 2) Duplicate CSS class declarations - structural and color props split across two rule blocks for the same classes; should be merged. 3) Inner accent nodes at (40,52) etc are placed by approximation not calculated orbit positions. Positives: dark mode correctly implemented, CSS classes used for theme-switching, colors consistent, no other files changed, commit follows Conventional Commits. Verdict: minor style issues only, no bugs, safe to merge.

[claude]

Code Review

Summary

This PR replaces the default Astro favicon with a terminal prompt (>) + cursor design. The concept is clean and developer-appropriate.

---

Issues Found

1. SVG text element is not recommended for favicons

Severity: High

Using a <text> element with font-family in an SVG favicon is unreliable across rendering contexts:

• Fonts may not render correctly in browser tab favicons, bookmarks, or OS-level icon caches — the system font stack varies per platform
• The monospace, 'Courier New' fallback may render inconsistently between Windows, macOS, and Linux
• Many favicon processors and PWA manifest generators rasterize SVGs without system font access, resulting in an invisible or broken > symbol

Recommendation: Convert the > glyph to an SVG <path> for guaranteed cross-platform rendering. Example:

<path class="prompt" d="M20 30 L70 64 L20 98"
  stroke-width="14" stroke-linecap="round"
  stroke-linejoin="round" fill="none" stroke="currentColor"/>

2. Inconsistent PR title vs. final implementation

Severity: Low

The PR title says "atom + neural network design" but the second commit switched to a terminal prompt design. The PR title should be updated to reflect the final state.

---

Code Quality Notes

• Dark mode support via prefers-color-scheme is correctly implemented ✅
• viewBox="0 0 128 128" is appropriate for a favicon ✅
• HTML entity > is the correct escape for > in SVG/XML ✅
• rx="3" on the cursor rectangle is a nice subtle detail ✅
• fill="none" was correctly removed from the root <svg> element ✅

---

Recommendation

Before merging, address the font reliability issue by converting the > text to a <path>. This ensures the favicon renders correctly at 16x16/32x32 in all browsers and OSes without depending on system font availability.

[claude]

Code Review

Summary: Replaces the default Astro favicon with a terminal prompt design (chevron + cursor bar). Implementation is clean and functional.

Issue: PR Title/Description Mismatch — The title and description reference an atom+neural-network design with amber colors, but the final implementation is a terminal prompt. Title and body should be updated to match reality.

Positives

• Dark mode via prefers-color-scheme with appropriate light/dark color variants
• No font dependencies: the > symbol is an SVG path for consistent cross-platform rendering
• Semantic CSS class names (.prompt, .cursor)
• Lightweight and minimal SVG

Minor Suggestions

1. Move the style element to be a direct child of svg rather than inside defs (both are valid SVG, but placing style directly under svg is more conventional)
2. Colors #1e293b and #f1f5f9 map to Tailwind slate-800/slate-100 — worth checking alignment with any site-wide color tokens in src/config.ts
3. The original root svg had fill=none; omitting it here is fine since child elements define their own fills, just noting for awareness

No concerns on performance (tiny file, no external resources), security (no scripts or external refs), or accessibility (favicons do not require alt text)