Highlight one menu item on navigation

Site URL: https://www.infinix.com/

Hello,

How do I highlight and or make a square around one menu item to stand out?  On our navigation menu we have the word "Shop".  I would like that to be bold and have a square line around it. 

How can that be accomplished?

Thank you,

Stephanie

Add to Design > Custom CSS

.horizontal-navigation-bar nav.main-nav .folder:nth-child(8)>a {
    border: 1px solid black;
}