Menu Style with Elements

Hello guys,

Yesterday I found this great CSS code on the support forum:

.main-navigation .main-nav ul li a {
background-color: rgba(0,0,0,0.52);
border-radius: 10px;
margin: 2px;
}

I did a little tweaking. Now I a really sattisfied with the result. https://prntscr.com/wcgyxd

But as always, each sollution creates a new problem :(

I have soms none pages , like category/archives that now look like Sh**.. Because I use a different header type. These archives are excludes from the Headers i created in elements. https://prntscr.com/wcgy8b

My question is: Can I separatly edit the menu on these archive pages with elements, and is so what code can i try?