18.多重圆圈

<span class="delete">
.delete{
    display: inline-block;
    width: 28px;
    height: 25px;
    border-radius: 14px;
    border: 6px double #FFF;
    background: #CCC;
    line-height: 14px;
    text-align: center;
    color: #FFF;
    font-weight: bold;
    font-size: 14px;
    cursor: pointer;
    margin-top: 3px;
}