Why is all the HTML on my react app so zoomed in?

I created a new react app using create-react-app and copied in a few lines of basic HTML from another project I built. It’s just a couple divs with H1s, buttons and p tags, so nothing crazy. The code and styling is identical, as I copied and pasted it (I did adjust the syntax to fit react). The issue is, on the react app everything is zoomed in SIGNIFICANTLY. I’ll include images though I doubt it’ll be clear in a screenshot aside from the massive text going off screen on react. No errors in the console, and the inspector confirms all styles are the same, but everything is noticeably bigger on the react version. Is this just how react behaves?
Opening the regular HTML file with code in browser

When opening same code with React