"

From 2014.igem.org

nav {

 background-color:#2C5463;
 height:40px;

}

nav ul {

 font-family: Arial, Verdana;
 font-size: 20px;
 margin: 0;
 padding: 0;
 list-style: none;

}

nav ul li {

 display: block;
 position: relative;
 float: left;

}

nav li ul {

 display: none; 

}

nav ul li a {

 display: block;
 text-decoration: none;
 padding: 7px 15px 3px 15px;
 background: #2C5463;
 color: #ffffff;  
 margin-left: 1px;
 white-space: nowrap;
 height:30px; /* Width and height of top-level nav items */
 width:90px;
 text-align:center;

}

nav ul li a:hover {

 background: #617F8A; 

}

nav li:hover ul {

 display: block;
 position: absolute;
 height:30px;

}

nav li:hover li {

 float: none;
 font-size: 11px;

}

nav li:hover a {

 background: #3A464F; 
 height:30px; /* Height of lower-level nav items is shorter than main level */

}

nav li:hover li a:hover {

 background: #95A9B1; 

}

nav ul li ul li a {

   text-align:left; /* Top-level items are centered, but nested list items are left-aligned */

}