> For the complete documentation index, see [llms.txt](https://reactbkk.gitbook.io/react-in-patterns-th/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://reactbkk.gitbook.io/react-in-patterns-th/good-to-know/styling/the-good-old-css-class.md).

# The good old CSS class