There are a lot of fonts listed some of which you never linked to or imported so there’s no reason for them to be listed.
Have one font and a fallback like sans-serif or serif
Instead of repeating yourself over and over, declare the font-family property in the body declaration. Remember DRY (Don’t Repeat Yourself)
Codepen provides validators for HTML, CSS and JS. Click on the down arrow in the upper right of each section and then click on the respective ‘Analyze’ link.
The one for HTML is not that good which is why I recommend W3C
The one for CSS is good. Use it.
You have quite a few times where you repeat a property within a declaration. Remember what the C in CSS stands for.