带三角形下标的提示框（按钮button）

HTML:
<div class="leaflet-popup-content-wrapper">
    <div class="leaflet-popup-content" >按钮</div>
</div>
<div class="leaflet-popup-tip-container">
    <div class="leaflet-popup-tip"></div>
</div>

css:
<style>
    .leaflet-popup-content-wrapper,.leaflet-popup-tip{
        background:white;
        box-shadow:0 1px 14px rgba(0,0,0,0.4)
    }
    .leaflet-popup-content-wrapper{
        zoom:1;
        border:1px solid #999;
        padding:1px;
        border-radius:12px;
        text-align:center !important;
    }
    .leaflet-popup-tip-container{
        margin:-1px auto;
        width:40px;
        height:20px;
        position:relative;
        overflow:hidden;
    }
    .leaflet-popup-tip{
        width:17px;
        height:17px;
        padding:1px;
        margin:-10px auto 0;
        -webkit-transform:rotate(45deg);
        -moz-transform:rotate(45deg);
        -ms-transform:rotate(45deg);
        -o-transform:rotate(45deg);
        transform:rotate(45deg);
    }
    .leaflet-popup-content{
        width: 51px;
        margin:0 !important;
        overflow: hidden;
        padding: 10px;
        line-height: 1.4
    }
</style>