Mermaid Diagrams Support in Markdown (with Light/Dark Styling)

[guspatagonico]

Hi @satnaing !

First of all, congrats on the great work with Astro Paper. It's an outstanding theme, especially for developers and technical blogs. Really enjoying it!

I'm currently building my personal blog with Astro Paper (still a work in progress) and had an idea I'd love to share:

Adding support for Mermaid diagrams in Markdown, with automatic light/dark theme styling.

1. Specifically, I was thinking about integrating rehype-mermaid to handle rendering Mermaid diagrams.
2. Developing a small custom rehype plugin (or extend existing ones) to manage light/dark mode styles dynamically for diagrams, to keep them consistent with Astro Paper’s theme switching.

Would you be open to adding a feature like this?

I’d be happy to work on a PR to implement it if you're interested!

This would actually be my first GitHub contribution to an open-source project, so please forgive any rough edges. 😅

Thanks again for creating and maintaining such an awesome project!