There is an HTML coding error 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)
Use a contrast checker. The links are very hard to see. Light text on a light background is a bad UX. (See screenshot)
Your project should be original. The sample is just one way to do the project. The instructions say yours should be functionally similar and to give it your own style. Start the project from scratch, with your own code, style and content. Don’t take code from the sample project.