How to host your Tailwind CSS and Jekyll personal blog on GitHub Pages

This is not a plea for feedback on whether or not Jekyll or Tailwind CSS are good or bad tools to build websites with.

Love them? Good! Hate them? Also fine! But if you have such a website and want to host it on GitHub Pages for free, it's not going to work out of box (unless you are using Tailwind CSS over CDN, or their "Play" version via JS). And here's what to do instead.