css居中对齐问题

在父容器加上这个

  			display: flex;
            align-content:center;
            line-height: 20px;
            justify-content: space-around;

参考的地址
https://www.runoob.com/cssref/css3-pr-justify-content.html
https://www.runoob.com/cssref/css3-pr-align-content.html