This podcast episode explores the creation and evolution of Tailwind CSS, a highly customizable CSS framework developed by Adam Wathan. Tailwind CSS provides a unique approach by offering granular classes that allow developers to specify individual CSS properties, enabling the building of highly customized designs quickly and efficiently. The episode also discusses the major changes in Tailwind 4, including the codebase rewrite, the move to a CSS-only configuration system, and the adoption of modern CSS features. Furthermore, the episode explores Tailwind's decision to use JavaScript as its core language, the use of Lightning CSS and CSS nesting, as well as the sustainable business model that combines open source and commercial components. The episode also addresses the pros and cons of Tailwind CSS and potential limitations and challenges.