I’m having trouble getting my CSS from Codepen to apply to my Github Pages. I’m fairly new, but have looked at a TON of google searches and nothing seems to be helping.

This is what I have in my style.css

html, 
body {
  font-family: system-ui;
  font-size: 20px;
  background: #000000;
  color: red;
  text-align: center;
}
h1 {
  color: blue;
}

This is what is returned. https://nac0512.github.io/test2/
This is what it is supposed to look like on Codepen. https://codepen.io/nac0512/pen/MWKpJvb

I’ve tried it both with and without the html tag.
I have the < !DOCTYPE html > at the beginning of my index.html file.
Is there something I’m missing? Any help is appreciated. I know it works because when I right click on the link from my exported zip file from Codepen, the site has all the formatting it’s supposed to. I’m literally dragging and dropping the files directly from desktop to my repo.