Jekyl on the GitHub Page produces a different output than you have.

The reason why two articles are displayed on the front page may be because the layout on the page is post.In the theme minima, home seems to be the layout for index.html.

The reason why the formula is not displayed in this article is because MathJax is trying to load via HTTP, so it was judged to be a mixed content and failed to load.In addition, cdn.mathjax.org is It has already been deprecated, so you need to switch to another one.

Also, ./_site is currently git-pushed, but the contents of ./site are automatically generated by Jekyl and are usually .gitignore.It will also make it difficult to see the diff of the commit, so it's good to ignore it.