The primary and secondary navigation are actually pretty much identical. You can change the colors, spacing and typography of both of them identically. The only difference is the primary navigation has the sticky effects and navigation search.
So theoretically, you could style your primary navigation to look like your secondary navigation and include the navigation search. Then style your secondary navigation to look like your primary navigation.
It doesn’t work for everyone (if they need the primary nav to be sticky for example), but does do the trick for some who are trying to achieve this.
Let me know if you need more info π