Dropdown menu not working or responding - html

Question

I'm new here & am working on my first mobile web project. Am having a problem with my dropdown menu. It drops down when hovered. However, it only display the first sub-menu. The rest of the menu is frozen. Nothing happens even when I click on any of the other parts of the menu. Appreciate any help coming this way. Many thanks in advanced.
This is my menu...
<nav>
<div id="nav"><!-- #Begin navigation -->
<div class="dropdown">
<button class="dropbtn">Menu</button>
<div class="dropdown-content">
<ul>
<ul>
<li>HOME</li>
</ul>
<ul>
<li>Sauces
<ul>
<li>French</li>
<li>Italian</li>
<li>Indian</li>
<li>Mexican</li>
<li>Chinese</li>
</ul>
</li>
</ul>
<ul>
<li>Cheese
<ul>
<li>Swiss</li>
<li>Danish</li>
<li>Dutch</li>
<li>French</li>
<li>Italian</li>
<li>American</li>
<li>Australian</li>
<li>German</li>
</ul>
</li>
</ul>
<ul>
<li>Wine
<ul>
<li>California</li>
<li>Chile</li>
<li>Argentina</li>
<li>France</li>
<li>Germany</li>
<li>Spain</li>
<li>Italy</li>
<li>Portugal</li>
<li>Australia</li>
<li>New Zealand</li>
</ul>
</li>
</ul>
<ul>
<li>Crusine
<ul>
<li>American</li>
<li>French</li>
<li>Chinese</li>
<li>Japanese</li>
<li>Korean</li>
<li>Indian</li>
<li>Indonesian</li>
<li>Thai</li>
</ul>
</li>
</ul>
<ul>
<li>Bread
<ul>
<li>American</li>
<li>French</li>
<li>British</li>
<li>Italian</li>
<li>Mexican</li>
<li>Indian</li>
</ul>
</li>
</ul>
</ul>
</div>
</div>
</div><!-- #End navigation -->
</nav>
...and this is my CSS...
/* 360 Resolution */
#media (max-width: 360px) {
/* Dropdown Button */
.dropbtn {
background-color: blue;
color: white;
margin-top: 25px;
padding: 16px;
font-size: 16px;
font-weight: bold;
text-align: center;
border: none;
cursor: pointer;
}
/* The container <div> - needed to position the dropdown content */
.dropdown {
position: relative;
display: inline-block;
}
/* Dropdown Content (Hidden by Default) */
.dropdown-content {
display: none;
position: absolute;
background-color: #f9f9f9;
min-width: 160px;
box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
}
/* Links inside the dropdown */
.dropdown-content a {
color: black;
padding: 8px 8px;
text-decoration: none;
display: block;
}
/* Change color of dropdown links on hover */
.dropdown-content a:hover {
background-color: orange;
}
.dropdown-content ul li:hover > ul {
display: block;
padding-left: 100px;
left: auto;
}
.dropdown-content li li li {
margin-left: 1em;
}
/* Show the dropdown menu on hover */
.dropdown:hover .dropdown-content {
display: block;
}
/* Change the background color of the dropdown button when the dropdown content is shown */
.dropdown:hover .dropbtn {
background-color: #3e8e41;
}
}