<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>css3 布局常用参数</title>
<style>
.box2{
width:100%;height:100vh;
display:flex;/**/
justify-content:center;/*内容居中,简单理解为水平 X */
align-items:center;/*容器居中,简单理解为水平 Y */
}
.box{
box-sizing:border-box; /*无论怎么设置,最终大小都是width的100px */
margin:10px;
width:100px;height:100px;
border: 10px solid red;
}
</style>
</head>
<body>
<div class="box2">
<div class="box">1</div>
<div class="box">2</div>
<div class="box">3</div>
</div>
</body>
</html>
效果
更多请了解:https://www.runoob.com/w3cnote/flex-grammar.html