纯css二级导航下拉菜单*{margin: 0;padding: 0;} #bg{background: red;width: 100%;height: 35px;} nav{height: 35px;width: 1000px;margin: 0 auto;} nav ul li{list-style-type:none;float: left} nav ul li a{ text-decoration: none;display: block;width: 130px;line-height: 35px; text-align: center;color:white;font-fimily:微软雅黑;} nav ul li ul li{float: none} nav ul li ul li a{color:black} nav ul li ul{display: none;} nav ul li:hover ul{display: block;}