Nav bar not hidden on mobile

I can’t get my nav bar hidden on mobile, the hamburger menu button won’t appear either, I’ve followed the lessons of the courses and I even compared side to side the portfolio they built vs mine and can’t understand where’s the issue.

PS: I’d appreciate if you have any more resources to share I could learn from.

Here is my site Read-Only: LINK
(how to share your site Read-Only link)