What's wrong with the drop down list?

Question

HTML

Tell me, I created a list inside the list, drop-down, but I don’t understand why the text is invisible in it, tell me pliz what it is for, otherwise I’m not catching up with something.
Hover the mouse over the Item-menu-3 from above and there the drop-down list is invisible, please tell me why?
Here is a link to the site itself on github pages https://chekhdanil.github.io/Site-/

Answer 1

.preview-top has font-size: 0
Return children to normal values, there will be text.