HTML & CSS - [CENTERED] Dropdown navigation menu

Dropdown navigation menu code from my 'HTML & CSS Creating a dropdown navigation menu' video. Centered navigation example.

HTML

<div id="nav">
    <div id="nav_wrapper">
        <ul>
            <li><a href="#">item #1</a></li><li>
            <a href="#">item #2</a></li><li>
            <a href="#">dropdown #1</a>
                <ul>
                    <li><a href="#">dropdown #1 item #1</a></li>
                    <li><a href="#">dropdown #1 item #2</a></li>
                    <li><a href="#">dropdown #1 item #3</a></li>
                </ul>
            </li><li>
            <a href="#">dropdown #2</a>
                <ul>
                    <li><a href="#">dropdown #2 item #1</a>
                    </li>
                    <li><a href="#">dropdown #2 item #2</a>
                    </li>
                    <li><a href="#">dropdown #2 item #3</a>
                    </li>
                </ul>
            </li>
            <li> <a href="#">item #3</a>
            </li>
        </ul>
    </div>
    <!-- Nav wrapper end -->
</div>
<!-- Nav end -->

CSS

#body {
    padding: 0;
    margin: 0;
    font-family: Arial;
    font-size: 17px;
}
#nav {
    background-color: #222;
}
#nav_wrapper {
    width: 960px;
    margin: 0 auto;
    text-align: center;
}
#nav ul {
    list-style-type: none;
    padding: 0;
    margin: 0;
    position: relative;
    min-width: 200px;
}
#nav ul li {
    display: inline-block;
    text-align: left;
}
#nav ul li:hover {
    background-color: #333;
}
#nav ul li a, visited {
    color: #CCC;
    display: block;
    padding: 15px;
    text-decoration: none;
}
#nav ul li:hover ul {
    display: block;
}
#nav ul ul {
    display: none;
    position: absolute;
    background-color: #333;
    border: 5px solid #222;
    border-top: 0;
    margin-left: -5px;
}
#nav ul ul li {
    display: block;
}
#nav ul ul li a:hover {
    color: #699;
}