CSS ' nav ul li ul ' and ' Nav>ul>li ' are the differences between the two ways

> refers to a generation only, such as: Nav>ul>li>ul>li, must be the following

            <nav>                <ul>                    <li>                        <ul>                            <li></li> </ul> </li> </ul> </nav>

Then the Nav UL Li ul only requires that the following elements are in the order of the Nav label, which is insensitive to the interval of several layers , such as:

  <nav> <div> <ul> & lt;div> <a> <li> <div> <ul> <li> </li> </ul> </div> Span class= "hljs-section" ></li> </a> </div > </ul> </div>  </nav>                    
 
 
 
 
 
 

<Nav><UlId="A" ><Li></Li><Li></Li><Li></Li><Li></Li><Li><UlId="B" ><Li></Li><Li></li> </ul> </li> < li> <ul id=  "C" > <li> </li>< Li></li> </ ul> </li> </ul></ Nav>               

nav>ulSelect only the UL elements in the lower level of NAV, such as UL with ID A in the DOM structure above.
nav ulSelect all UL elements contained within NAV, such as all UL IDs A, B, and C in the DOM structure above.

nav>ulnav ulmore stringent than the qualification, the element must be behind only one level lower than the previous.

CSS ' nav ul li ul ' and ' Nav>ul>li ' are the differences between the two ways