Feedback on Landing Page practice

I’ve been practicing making landing pages and I’d like to get some feedback on my current endeavor. I’ve written it on my CodePen and I’m including the link below. Would you mind giving me some feedback on design tips or mistakes I’m making in the code (going around my elbow to get to my thumb sorts of things)?

My Codepen

Hi there, I reviewed your page on my cellphone. I think you probably have not looked at it there? It does need a lot of work still to look good on the phone.

(Try to create a responsive design that will resize itself to the viewport width)

I also noticed that all the navbar links worked except for the contact link (which on my phone did nothing, not sure if that is a bug or not).

I did try to review in landscape mode but the result that way had problems like the text being hidden under the navbar

These are just a few comments to get you started on thinking about a more responsive design.