Hi! It seems I may have had a similar problem with my RWD projects when I tested them locally. That is, every time I saved the projects as files on my hard drive and then ran them in my browser, some of the tests failed - as opposed to when the same project was on CodePen.
I don’t know what’s the reason behind it. However, when I uploaded the files online, the problem disappeared. So perhaps you can try putting your project live somewhere, like GitHub Pages or any other hosting you may have access to, and see if the problem’s still there.
Here’s a guide for setting up GitHub pages:
Let me know how it goes
Thank you let me try that out …