I only added some functions to my hamburger menu in JavaScript because I actually don't know if I can do it using only CSS (if you actually want to contribute, please write me a msg and I'll be glad to learn!)
This project took me maybe more than a week (just because I wanted to learn some cool transforms in CSS and see if I could make the hamburger icon without using an svg)
You can see it right here if you want to: https://itscrisu.github.io/Portfolio/