Bump version to 0.3.1

docs: update screenshots for pine forest theme

feat: update typography to IBM Plex Mono and refactor CSS architecture

- Switch from IBM Plex Sans to IBM Plex Mono for consistent monospace design
- Refactor CSS with improved organization and maintainability
- Add comprehensive CSS custom properties system
- Introduce standardized spacing scale and design tokens
- Remove tooltip functionality for cleaner UX
- Update README with design philosophy and customization guide
- Bump version to 0.2.4

bump: version 0.2.3

chore: gem update

chore: update gem

feat: updated gem, action

Update dependencies and bump version webrick, 0.1.7