Github help:
* https://docs.github.com/en/pages/setting-up-a-github-pages-site-with-jekyll/about-github-pages-and-jekyll
* https://jekyll.github.io/github-metadata/site.github/
* https://pages.github.com/themes/
  * https://github.com/pages-themes/cayman
  * https://github.com/pages-themes/midnight
  * https://github.com/jekyll/minima
  * https://github.com/pages-themes/minimal
  * https://github.com/pages-themes/slate
  * https://github.com/pages-themes/tactile
* Customize theme: https://docs.github.com/en/pages/setting-up-a-github-pages-site-with-jekyll/adding-a-theme-to-your-github-pages-site-using-jekyll


Install:
* See https://jekyllrb.com/docs/installation/ubuntu/
Test locally: see theme readme, https://github.com/pages-themes/cayman
Then run: bundle exec jekyll serve
