This repository is a companion documentation site for Zhou Zhihua's 'Machine Learning' (Watermelon Book), providing detailed step-by-step formula derivations for all chapters. It is built with VitePress, a static site generator, and deployed to GitHub Pages. The site includes 16 chapters of mathematical derivations, an errata page tracking corrections across print editions, and French translations for the first two chapters. While the content is educational and not a software application in the traditional sense, the repository functions as a VitePress project with custom theme configuration, MathJax rendering, and CI/CD deployment. It is actively maintained by the Datawhale community and serves as a learning resource for machine learning practitioners.