.nav {
    font-size: 12px;
}

.nav li {
    float: left;
    list-style: none;
    position: relative;
}

.nav a {
    display: block;
    height: 32px;
    width: 80px;
    line-height: 32px;
    background: #f7f7f7;
    color: #000;
    text-decoration: none;
    text-align: center;
    overflow: hidden;
}
.nav a:hover {
    background: #eaeaea;
    color: #ff4901;
}

.nav ul ul {
    visibility: hidden;
    position: absolute;
    left: 0px;
    top: 32px;
}
.nav ul ul a{
    background: #f7f7f7;
    border: 1px solid #b3d0e4;
    margin-top: -1px;
    width: 100px;
}

.nav ul li:hover ul.second, /*非IE6*/
.nav ul a:hover ul.second {
    /*IE6*/
    visibility: visible;
}

.nav ul ul li {
    clear: both; /*垂直显示*/
    text-align: left;
}

.nav .third, .nav .fourth, .nav .fifth, .nav .sixth {
    top: 0;
    left: 100px;
}

.nav ul ul li:hover ul.third,
.nav ul ul a:hover ul.third {
    visibility: visible;
}

.nav ul ul ul li:hover ul.fourth,
.nav ul ul ul a:hover ul.fourth {
    visibility: visible;
}

/*指定是显示五级子菜单*/
.nav ul ul ul ul li:hover ul.fifth,
.nav ul ul ul ul a:hover ul.fifth {
    visibility: visible;
}

/*指定是显示六级子菜单*/
.nav ul ul ul ul ul li:hover ul.sixth,
.nav ul ul ul ul ul a:hover ul.sixth {
    visibility: visible;
}

/*重设子菜单在鼠标滑过时的样式，有多少个ul就表明当前是多少级子菜单*/
/*二级子菜单*/
.nav ul ul a:hover {
}

/*三级子菜单*/
.nav ul ul ul a:hover {
    background: #B45B3E;
    color: #369;
}

.nav ul ul ul ul a:hover {
    background: #FFE8AA;
    color: #68DFFB;
}

.nav ul ul ul ul ul a:hover {
    background: #8080C0;
    color: #F8F8F8;
}

.nav ul ul ul ul ul ul a:hover {
    background: #f00;
    color: #000;
}

.nav table {
    border-collapse: collapse;
}

.icon-arrow-down {
    display: inline-block;
    width: 20px;
    height: 20px;
    background-image: url("http://g1.dfcfw.com/g1/201306/20130621150230.png");
    background-repeat: no-repeat;
    background-position: right -355px;
}