这是使用弹性包装所需的行为：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
.css-flex {
border: 1px solid;
display: flex;
flex-wrap: wrap;
gap: 5px;
padding: 5px;
}
.css-flex>.css-item {
border: 1px solid;
min-width: 250px;
height: 200px;
flex: 1;
}
</style>
</head>
<body>
<section class="css-flex">
<div class="css-item"></div>
<div class="css-item"></div>
<div class="css-item"></div>
<div class="css-item"></div>
<div class="css-item"></div>
<div class="css-item"></div>
</section>
</body>
</html>