.nav {
    padding: 0 20px;
    margin: 0 auto 0px;
    width: 780px;
    font-size: 88%;
    background: #555;
}
.nav li {
    list-style: none;
    float: left;
}
.nav li a {
    text-decoration: none;
    color: #fff;
    padding: 7px 10px;
    display: block;
}
.nav li a:hover {
    background: #777;
}
.fixed {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
}