body{background: #F4F4F4;}
.list{width: 100%;text-align: center;}
.list-content{width: 1280px;margin: 0 auto;display:flex;justify-content: space-between;flex-wrap: wrap;}
.list-nav{float: left;width: 100%;height: 50px;line-height: 50px;}
.list-nav a{float: left;height: 50px;line-height: 50px;}
.list-nav span{float: left;height: 50px;line-height: 50px;margin: 0 2px;}