[Feature Request] Update Docs Site

[kaihiroi]

Problem

Current documentation site uses the default Docusaurus theme, making it look generic and unprofessional. This reduces our library's credibility and makes it harder for users to navigate through documentation.

Solution

• Implement custom theme with modern UI styling
• Improve navigation and search functionality
• Update custom landing page
• Update document structure & contents
• Update NatSpec documentation

Alternatives

1. Switch to other documentation frameworks (VitePress, MkDocs)
2. Use pre-made Docusaurus themes

Both options would limit our customization ability and may not meet our specific needs.

Additional context

Currently using Docusaurus v3. Looking to reference modern documentation sites like Vocs and VitePress for inspiration.