如何用html来创建一个三角图标_html li标签前面加三角形

1.废话不多说直接上代码，事实说话

<div class="list">列表
   <i class="list-shadow1"></i>
   <ul class="top-nav">
        <li><a href="javascript:void(0)">列表1</a></li>
        <li><a href="javascript:void(0)">列表2</a></li>
        <li><a href="javascript:void(0)">列表3</a></li>
        <li><a href="javascript:void(0)">列表4</a></li>
  </ul>
/div>

.list{
    position: relative;
    width: 70px;
    height: 35px;
    line-height: 35px;
    margin-left: 10px;
    background-color: #000000;
    color: #f1f1f1;
    text-align: center;
}
.top-nav{
    position: absolute;
    top: 35px;
    width: 90px;
    display: none;
    padding-top: 10px;
    border: 1px solid 	#999999;
}
.top-nav>li{
    height: 30px;
    line-height: 30px;
    font-size: 14px;
    background-color: #FAFAFA;
}
.top-nav>li>a{
    display:inline-block;
    width: 90px;
    text-align: center;
    color: 	#696969;
}
.list:hover{
    cursor: pointer;
}
.top-nav>li:hover{
    background-color: #ccccCC;
}
.list:hover .top-nav{
    display: block;
}
.list-shadow1{
    position: absolute;
    top: 17px;
    margin-left: 5px;
    border-color: #DDD transparent transparent transparent;
    border-style: solid dashed dashed dashed;
    border-width:5px;
 
}
.list:hover .list-shadow1{
    position: absolute;
    margin-top: -5px;
    border-color: transparent transparent #E64E3E transparent;
    border-style: dashed dashed solid dashed;
}

2.效果查看演示