给子元素设置flex属性，其高度属性会失效吗？
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>flex占比</title>
<style type="text/css">
.box {
height: 300px;
background: blue;
display: flex;
}
.box div {
width: 200px;
height: 200px;
}
.box1 {
flex: 1;
background: red;
width:50px;
height:100px;
}
.box2 {
flex: 3;
background: orange;
}
.box3 {
flex: 2;
background: green;
}
</style>
</head>
<body>
<div class="box">
<div class="box1">flex:1</div>
<div class="box2">flex:3</div>
<div class="box3">flex:2</div>
</div>
</body>
</html>
