Codepen provides the boilerplate for you. It only expects the code you’d put within the body element in the HTML editor. (No need to include the body tags). For anything you want to add to the <head> element click on the ‘Settings’ button, then HTML and add it into the ‘Stuff for <head>’ box.
For instance, links to fonts go in the box labeled ‘Stuff for <head>’
There are HTML syntax/coding errors you should be aware of and address.
Since copy/paste from codepen you can ignore the first warning and first two errors.
Codepen provides validators for HTML, CSS and JS. Click on the chevron in the upper right of each section and then click on the respective ‘Analyze’ link.
The one for CSS is good. Use it and address the issue(s).
(The one for HTML misses things which is why I recommend W3C)
Do not use the <br> element to force line breaks or spacing. That’s what CSS is for.
The link to the survey form gives uses a 404 error
overflow-x: hidden; will completely hide anything that extends outside its container element horizontally. It’s recommended to not do this, and refactor your CSS to be more responsive - otherwise it is possible for your site to appear to be missing content.