CSS-Only Caret Test

This demonstrates the pure CSS caret implementation for VitePress sidebar items.

Features:

• ✅ CSS-only caret (no JavaScript needed)
• ✅ Caret positioned on the right side
• ✅ Smooth rotation animation when opened/closed
• ✅ Hover color changes
• ✅ No caret for simple links
• ✅ Native details/summary accessibility