RelaxedJS/ReLaXed ? reverse-engineered prompt

I want to build a command-line tool that lets people create polished PDF documents using web technologies. The idea is to let them write content in a simple, minimal syntax like Pug or Markdown and then style everything with standard CSS. This would be a much friendlier alternative to something like LaTeX.

The key feature is that it should be interactive. When you run the tool, it should generate the PDF and then watch the project's folder. Any time a file is saved, it should automatically and quickly regenerate the PDF, so the user can see their changes almost instantly. It should be flexible enough to create complex layouts for things like resumes, books, reports, or even business cards. It should also have built-in support for rendering things like math equations and diagrams to make it really useful for technical documents. The final tool should be a JavaScript project installable via NPM.