<b class="bottom"><i class="bottom-arrow1"></i><i class="bottom-arrow2"></i></b>

.post_list .spread .bottom{

    width:20px;

    height:20px;

    position:absolute;

    left:24px;

    top: .06rem;

    z-index:;/*兼容ie8-*/

}

.post_list .spread .bottom-arrow1,.bottom-arrow2{

    width:;

    height:;

    display:block;

    position:absolute;

    left:;

    top:;

    z-index:;/*兼容ie8-*/

    border-bottom:.13rem transparent dashed;

    border-left:.13rem transparent dashed;

    border-right:.13rem transparent dashed;

    border-top:.13rem white solid;

    overflow:hidden;

}

.post_list .spread .bottom-arrow1{

    top:1px;/*重要*/

    border-top:.13rem blue solid;

}

.post_list .spread .bottom-arrow2{

    border-top:.13rem white solid;

}

<div class="test"></div>

.test{

    display: inline-block;

    vertical-align: middle;

    margin-top: -1px;

    margin-left: 6px;

    margin-right: -14px;

    width:;

    height:;

    border-left: 4px solid transparent;

    border-right: 4px solid transparent;

    border-top: 5px solid #ccc;

}                    

div{border-bottom: 1px solid #ddd;border-image: -webkit-radial-gradient(#BFBFBF,#fff) 30 30;}

.label:after {content:"";position:absolute;left:2px;top:2px;width:9px;height:4px;border:2px solid #fff;border-top-color:transparent;border-right-color:transparent;transform:rotate(-45deg);-ms-transform:rotate(-60deg);-moz-transform:rotate(-60deg);-webkit-transform:rotate(-60deg);}