mdx-js/mdx ? reverse-engineered prompt

Build me a markdown tool that lets people write normal markdown files, but also drop in JSX style components right inside the content.

I want it to feel like a modern content format for docs, blogs, and interactive pages, so someone can import a component, use variables, and mix text with things like charts, alerts, or other UI pieces in the same file. It should compile that content into JavaScript and work well in React, and ideally be flexible enough to fit with other frameworks too.

Please also make a simple playground or demo page where I can type MDX and see it render, plus clear getting started docs so someone can understand how to use it in a real project. If you need to look up current docs online while building, go ahead.