Nested lists have a strange syntax.
there are 4 items in the list.
item 3 has a sub list which needs a ul or ol.
The sub list is placed before the closing list tag for item 3.
Now you’re going to use lists far more often than you might think at first glance. They’re great for organizing things like menus, form elements, product information, really any content that needs to be grouped together in a related manner fits within a list. lynda.com