meta/astryx ? reverse-engineered prompt

Build me an open source design system called Astryx for React 19 apps.

I want a polished package that gives me lots of accessible UI components, a theme system with a few ready made themes, and a simple way to use it without any weird build setup. It should feel easy for both people and coding agents to work with, so keep the component APIs consistent and well documented, and make the CLI useful for exploring, scaffolding, and customizing components.

Please include the docs site, a Storybook style component explorer, and a sandbox so I can try things out quickly. The system should support dark mode, full theming through CSS custom properties, and easy overrides with normal CSS or class names. Use TypeScript throughout, and make sure the package structure supports core components, CLI tooling, build helpers, and themes.

If you need current setup details or library docs, look them up online first.