vertical-align和text-align属性实现垂直水平居中

<div class="box">
    <div class="content">
        <span class="span1"></span>
        <span class="span2">一段文字呢一段文字呢一段文字呢</span>
    </div>
</div>

.box{
    display: table;
    width: 45%;
}
.content{
    display: table-cell; 
    height: 180px;
    vertical-align: middle; 
    background-color: aquamarine;
    text-align: center;
}
.content span{
    display: inline-block;
}
.content .span1{
    vertical-align: middle;
    width: 100px;
    height: 60px;
    background-color: cornflowerblue;
}