CSS------添加注释框

<div><a href="#" class="tip">你好<span><k>哈哈哈哈</k></span></a></div>

.tip {
    color:#1a772d;
    text-decoration:none;
}
.tip:hover {
    color:#000;
}
.tip span {
    display:none;
}

.tip:hover span{
    display: block;
    background-color:#fff;
    border: 1px solid #aa9;
    position: absolute;
    text-align:left;
    height: 25px;
    width:  76px;
    top:40px;
    left:20px;
    padding-top:5px;
    padding-right:1px;
    padding-bottom:0px;
    padding-left:0px;
}

.tip:hover span k {
    color: #aaa;
    padding:5px;
    background-color: #fff;
    text-align: center;
    border:1px solid #aaa;
    
}