No Horizontal Scrollbars in Mobile View for GitHub Page Link But Shows Horizontal Scrollbars for Mobile View of Same Code Pen Link

Hi, I’m having a issue with my website showing no horizontal scrollbars in the mobile view for the GitHub link, but for the CodePen link for the same website it shows horizontal scrollbars fine in mobile view

Details: CodePen link: https://codepen.io/IDCoder/full/OWbXLw/ 1
When I insert that link into the Screenfly mobile view tester at http://quirktools.com/screenfly/, I get this: http://quirktools.com/screenfly/#u=https%3A//codepen.io/IDCoder/full/OWbXLw/&w=320&h=480&a=33 (it has horizontal scrollbars)

However, when I insert my GitHub Pages link (https://mtzioncode.github.io/) into the Screenfly mobile viewer, I get this: http://quirktools.com/screenfly/#u=https%3A//mtzioncode.github.io/&w=320&h=480&a=33 (there are no horizontal scrollbars) Do you know why this is?

I think the fact that you can’t scroll is a problem on Screenfly’s end. I tried a bunch of other URLs but no scrollbars show up.

The scrollbars you see on the CodePen version are the scrollbars for the preview window, not the page itself. You can see that the CodePen controls at the top are always there.

If you want to emulate a mobile view on your browser, you can fire up Responsive Design Mode in your browser’s devtools.