Landing page using HTML, CSS and JS

Hey, nice job overall.

In terms of the nav links, I would consider using a ul for the list and then an li for each link, with an a tag inside each li - this is generally the standard way of creating a nav.

In terms of responsiveness for mobile and desktop, have a think about you could potentially use position:absolute on the nav when you're in mobile view, and how this could be combined with some simple javascript toggling of display: block/none on the click of the hamburger, as you've already demonstrated.

One general comment is that your media query breaks into mobile view a little bit too soon - I'd maybe consider lowering this to around the 700px mark.

Hope this helps!