feat: enhance visibility of syntax blocks in docs

[cofin]

Summary

Migrates custom documentation styling from hardcoded colors to Shibuya theme's native CSS variable system. This ensures consistent theming across light/dark modes and leverages the configured accent_color: "amber" setting.

Changes

Theme Color Integration

• custom.css: Replaced all hardcoded colors (#202235, #edb641, #ffd480) with Shibuya CSS variables
  • Uses --accent-* variables (1-12) for brand colors
  • Uses --accent-a* variables for transparent/glow effects
  • Uses --sy-c-text and --sy-c-heading for text colors
  • Uses --gray-* variables for neutral colors

Syntax Highlighting

• syntax-highlighting.css: New file integrating code syntax highlighting with amber accent color
  • Decorators, attributes use --accent-11 in light mode
  • Functions, classes use --accent-11 in dark mode
  • Highlighted lines use --accent-a2 (light) and --accent-a4 (dark)
  • All colors respect current theme mode

Logo Styling

• Dark mode: White text (var(--sy-c-text)) with soft gold glow
• Light mode: Heading color with amber glow

Badge Container

• Removed box styling (padding, border, background)
• Clean flex layout with gap spacing

Configuration

• Added syntax-highlighting.css to codespell skip list (prevents false positives on CSS class abbreviations like .nd for Name.Decorator)

Visual Impact

Before: Hardcoded colors inconsistent with theme system
After: All colors dynamically use Shibuya's amber accent palette

• Light mode: Clean amber accents throughout
• Dark mode: White text with soft gold glow, amber highlights
• Both modes: Consistent theming, proper contrast ratios

Testing

• ✅ Documentation builds successfully
• ✅ Light mode verified
• ✅ Dark mode verified
• ✅ Logo glow effect preserved
• ✅ Syntax highlighting integrates with theme
• ✅ All linting passes

Files Changed

• docs/_static/custom.css - Theme variable migration
• docs/_static/syntax-highlighting.css - New syntax highlighting integration
• docs/conf.py - Added syntax-highlighting.css to html_css_files
• pyproject.toml - Added codespell skip rule
• Minor documentation fixes in guides (unrelated formatting)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Documentation preview will be available shortly at https://litestar-org.github.io/advanced-alchemy-docs-preview/570