<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>居中</title>
<style type="text/css">
.box{
display: flex;
width: 100%;
height: 500px;
border: 1px solid #333;
flex-direction: row; /* 子元素横向排列 */
justify-content: center; /* 相对父元素水平居中 */
align-items: center; /* 子元素相对父元素垂直居中 */
}
.cont{
width: 30%;
height: 100px;
border: 1px solid red;
flex-grow:1;/* 属性用于设置或检索弹性盒的扩展比率。 */
}
</style>
</head>
<body>
<div class="box">
<div class="cont">aaaaa</div>
<div class="cont">aaaaa</div>
</div>
</body>
</html>