Navbar's responsiveness. (is this site using flexbox?)

How do I do this kind of responsive layout? example site

I assume they used flexbox?? Could someone duplicate their navbar or explained to me how to do this kind of layout when you narrow down the viewport, all the nav bar elements (what we do, who we are, nerdfusion, etc) rearrange themselves?

you can edit this codepen I created.

It never rearrange. It uses another div that holds a new set of nav that fades in onclick.

oh… wow… all these seemed too complex for me… :joy: