My CodePen looks considerably different from the version I’m viewing in my Chrome browser. The main difference appears to be the margins, which are much smaller (and the
margin-top: 2em set for the body is nonexistent).
I don’t have Bootstrap or anything linked via CodePen (only at the top of my HTML, which you can see in the CodePen). What could be causing this?
For comparison, here’s what it looks like when opening the HTML file on my browser: