Targeting the last external link in navigation?

I've finally figured out how to make external links in my navigation become italic. But now I'd like to figure out how to only target the last external link (maybe using "child"? new to css haha) 

Here is the code I have working now:

.header-nav-item--external a {
    font-style: italic;
  }

Any ideas on what to add to make it so only the word "STUDIO" is italic in my nav?
Site is forhomeandharvest.com

Thanks for any help!!!

On 1/18/2023 at 2:35 AM, Ziggy said:

This would work, but be wary of adding or removing navigation items.

.header-nav-item:nth-child(4) {
  font-style:italic;
  font-weight:900;
}
  

Hope that helps!

THANK YOU! This is perfect.