Documentation Nav Not Responsive on Mobile Only

My sample documentation project nav buttons seems to work well enough on Desktop, but when I view the codepen on my mobile device, the nav buttons are all shifted down about half a screen from where I am clicking (basically non-functional). Can anyone confirm the same issue on their device? Where would I go about fixing it? Thank you in advance!

My codepen:

In my phone the navigation is at the top of the screen nicely, just a bit wide, doesn’t fit into screen. But yes they are not clickable, and when I made my landing page I also tried to make it work, but came out that in mobile version inside page anchoring is not working.