My Thoughts:

Tailwind has changed versions and there are several ways to install it. Check the TailwindCSS docs and this link before doing anything. Or else! Just kidding

Tailwind 4 documentation Eleventy Configuration cssnano https://tailwindcss.com/blog/tailwindcss-v4 https://www.11ty.dev/docs/config/ https://cssnano.github.io/cssnano/