How do I create the highlighted part over the Nav Link?

How do I make the element highlight when over it? I know how to hover and change the background color but when I change the size of the hover it changes everything. I just want it to to make a little box when hovered over and have space in-between the ages like the picture below. Exactly like that. Thanks for any help given!

Screen Shot 2020-12-29 at 3.47.41 PM

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