Personal Portfolio - feedback and having trouble with code pen


I just created my personal portfolio and posted it to codepen. I developed it first locally and thought it looked okay, even when I adjusted the screen size. I then copied everything to codepen. When viewed on codepen in full page view it looks fine, I think. However, when in editor view, all of my elements are showing as on top of each other. I"m not sure why this is happening in codepen as when I minimize my browser on my local version of the portfolio, all of the elements stay in place ( ie not overlapping).

I would appreciate 1) any feedback on the design and 2) any help with the codepen problem. Here is the link to my portfolio.

I think I just fixed part of the codepen issue by using an overflow: hidden on one of my second divs. My design relies on three divs that are each set to 100% height.

Any ways to make this code better would definitely be appreciated. Also, please do send any feedback on the design. I’m definitely not a designer and even something as simple as creating this page resulted in so much struggle to just come up with with a design that I thought was okay. Even now though, looking at it makes me want to scrap the whole thing and start over.