Well … dang it. I had actually made a suggestion in my first response, but I assumed it was a bad job of copy and paste.
First things first - you need to pay attention to your Javascript console - you’re getting an error on the first line of your JS. You left $ off of the first line, so you’re not making a call to jQuery, you’re getting an error.
That doesn’t solve the problem, but it’s preventing any JS from ever running because you have an error right from the get go.
But … The whole structure needs work.
My Assumptions/Observations
From what I can see, you want to set click event listeners on your nav li so that the scroll to the proper section of your page when clicked.
Right now, your nav li handler only changes classes on the list items - it doesn’t do anything else.
Then, below, you add a second handler to address clicked to list items with an active class.
In this handler, you are trying to scroll the “html, body” to the scrollTop position of a hardcoded string “.className” … which doesn’t exist anywhere in your HTML, so it will never be found.
Finally, the sections of your page (portfolio, about, etc.) have nothing to identify them. No HTML IDs or classes.
Your list item click handler has nothing to reference them by, so it can never scroll to them.
An Approach
Create a menu header with your list items. The item you bind your click handler to should have something to indicate what section it relates to below. It looks like you originally planned to do that with an anchor tag in the nav list item and wanted to read from the href attribute. That makes sense since, if Javascript is not active, the page would normally jump to that spot.
Next, your sections in the page have to be identifiable by the same data accessible to the li click handler. So a unique div ID or classname. Or that anchor tag value.
Next, on click of the li, you need to find out what identifier that li references, then find out the scroll top of that div on the page, then scroll the body.
And while you’re at it, you can toggle your active classes on the clicked li.
All of this can be done in one simple click handler function. But you need to structure your HTML to accommodate it first.
Hope that makes sense!