Fixed inconsistent abacus sizing in guide:
- Replaced aspect ratio containers with fixed dimensions
- Single-digit abacuses: 120px × 240px (consistent vertical layout)
- Multi-digit abacuses: 180px × 200px (horizontal layout)
- Added inner wrapper div for proper AbacusReact sizing
- Centered containers with mx: 'auto'
- Adjusted scale factors for better fit (0.7 and 0.8)
Also added with-fixed-nav class to guide page to prevent white bar
under navigation.
Fixes: Inconsistent abacus sizes in guide page screenshot
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Co-Authored-By: Claude <noreply@anthropic.com>
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