All 5 Responsive Web Design Projects Finished

Would love to hear any feedback on my 5 projects, my main goal was to make all of them fully responsive and you can tell I got gradually better at making them fully responsive and then much better with the last 2 projects being built mobile first (which was so much nicer to work with). Any criticism/advice appreciated.

All 5 Projects:
https://codepen.io/FreemanW/pen/zYxZZBW Tribute
https://codepen.io/FreemanW/pen/MWWxOyL Survery
https://codepen.io/FreemanW/pen/JjoEzNO Product Landing
https://codepen.io/FreemanW/pen/LYErMVd Tech Documentation
https://codepen.io/FreemanW/pen/NWPBgZV PORTFOLIO

you can use gradient background on first one instead of creating so many divs