css常用浮出层的写法

<div class="poptip">
<span class="poptip-arrow poptip-arrow-top"><em>◆</em><i>◆</i></span>
<span class="poptip-arrow poptip-arrow-right"><em>◆</em><i>◆</i></span>
<span class="poptip-arrow poptip-arrow-bottom"><em>◆</em><i>◆</i></span>
<span class="poptip-arrow poptip-arrow-left"><em>◆</em><i>◆</i></span>
Hi，知道吗？ <br>大前端D7主题很快就疯抢了！
</div>

/* poptip */
.poptip{position: absolute;top: 20px;left:20px;padding: 6px 10px 5px;*padding: 7px 10px 4px;line-height: 16px;color: #DB7C22;font-size: 12px;background-color: #FFFCEF;border: solid 1px #FFBB76;border-radius: 2px;box-shadow: 0 0 3px #ddd;}
.poptip-arrow{position: absolute;overflow: hidden;font-style: normal;font-family: simsun;font-size: 12px;text-shadow:0 0 2px #ccc;}

.poptip-arrow em,.poptip-arrow i{position: absolute;left:0;top:0;font-style: normal;}
.poptip-arrow em{color: #FFBB76;}
.poptip-arrow i{color: #FFFCEF;text-shadow:none;}

.poptip-arrow-top,.poptip-arrow-bottom{height: 6px;width: 12px;left:12px;margin-left:-6px;}
.poptip-arrow-left,.poptip-arrow-right{height: 12px;width: 6px;top: 12px;margin-top:-6px;}

.poptip-arrow-top{top: -6px;}
.poptip-arrow-top em{top: -1px;}
.poptip-arrow-top i{top: 0px;}

.poptip-arrow-bottom{bottom: -6px;}
.poptip-arrow-bottom em{top: -8px;}
.poptip-arrow-bottom i{top: -9px;}

.poptip-arrow-left{left:-6px;}
.poptip-arrow-left em{left:1px;}
.poptip-arrow-left i{left:2px;}

.poptip-arrow-right{right:-6px;}
.poptip-arrow-right em{left:-6px;}
.poptip-arrow-right i{left:-7px;}