<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<style>
.box{width: 300px;height: 300px;border: 1px red solid;margin: 0 auto;display: flex;}
.box div{width: 50px;height: 50px;background-color: rgb(20, 71, 223);line-height: 50px;text-align: center;}
/* .box div:nth-child(2){order: 1;}
.box div:nth-child(3){order: -1;} */
.box div:nth-child(2){flex-grow: 1;background-color: seagreen;}
.box div:nth-child(3){flex-grow: 3;background-color: saddlebrown;}
.box2{width: 300px;height: 300px;border: 1px red solid;margin: 0 auto;display: flex;}
.box2 div{width: 50px;height: 50px;background-color: rgb(20, 71, 223);line-height: 50px;text-align: center;}
.box2 div:nth-child(2){background-color: seagreen;flex-shrink: 0;}
.box2{width: 300px;height: 300px;border: 1px red solid;margin: 0 auto;display: flex;}
.box2 div{width: 50px;height: 50px;background-color: rgb(20, 71, 223);line-height: 50px;text-align: center;}
.box2 div:nth-child(2){background-color: seagreen;
/* 100px;flex-basis: 150px; */
/* flex: 0 1 auto; */
align-self: center;
}
</style>
<body>
<!-- <div class="box">
<div>1</div>
<div>2</div>
<div>3</div>
<div>4</div>
<div>5</div>
</div> -->
<!-- <div class="box2">
<div>1</div>
<div>2</div>
<div>3</div>
<div>4</div>
<div>5</div>
<div>3</div>
<div>4</div>
<div>5</div>
</div> -->
<div class="box2">
<div>1</div>
<div>2</div>
<div>3</div>
<div>4</div>
<div>5</div>
</div>
</body>
</html>
