* {
    padding:0px;
    margin:0px;
}
#previousNav{
    width:1200px;
    height:40px;
    margin:0px auto;
    padding-top:15px;
    border-bottom:1px dashed #ccc; 
    font-family:"微软雅黑";
    font-size:16px;
}
#previousNav>span{
    float:left;
    font-family:"微软雅黑";
    font-size:16px;
    color:#6c6c6c;
}
#previousNav>span:last-of-type{
    float:right;
    color:#9bcac9;
}