Manipulating the Player Menu with Javascript

And rereading your post...its even simpler.
This will select all nth-children...
li:nth-child(n)

var targetList = "#outline-content > ul > li > ul > li:nth-child(n) > div"
switchStyle(targetList);

function switchStyle( _targetList ){
var targetNodeList = document.querySelectorAll(_targetList);
        for(var i=0; i <= targetNodeList.length;i++){
            var el = targetNodeList[i];
            //doSomething for all using a terniary operator as if/else check
            el.style.display === "none" ? (el.style.display = "flex") : (el.style.display = "none");
        }
}

So 2 methods now in this Storyline to achieve it.
And here you find some great info on selectors for nth-child...
https://css-tricks.com/useful-nth-child-recipies/


Bonus of this approach is you donot need to worry about amount of menu list items.

Kind regards,
Math