flex上下左右居中
父元素CSS
box-sizing: border-box;
padding-left: 10px;
padding-right: 10px;
display: flex;
align-items: center;
-webkit-box-pack: justify;
justify-content: space-between;
子元素CSS
width: 100%;
word-wrap: break-word;
word-break: break-all;
margin-block-start: 1em;
margin-block-end: 1em;
margin-inline-start: 0px;
margin-inline-end: 0px;
font-size: 14px;
font-weight: bold;
color: #fff;
text-align: center;