/*样式设置*/
.box {
position: relative;
}
.box-main {
width: 400px;
height: 400px;
background: #f40;
position: absolute;
left: 20%;
top: 20%;
}
.box-size {
width: 20px;
/*line-height: 20px;*/
color: pink;
text-align: center;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}
</style>
<div class="box">
<div class="box-main">
<div class="box-size">文字居中了吗 ？居中了</div>
</div>
</div>