Technical Documentation Page - Finished and in need of feedback

Hi. I just finished my Technical Documentation Page Project. I took the content from the example I was given, but did the design on my own. I made it as responsive as I could, but if there are any problems, feel free to point it out.

Feedback is much appreciated.

Thanks in advance.

Project: https://codepen.io/Anhatel/full/zLKNLV/

Overall it’s very nice look and code. You’ve done good job.
However the main section could use more contrast (accessibility issue) and the scrolling in contents when viewport is small looks rather weird and is uncomfortable to use on mobile (UX issue).
Keep it up!