一点
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>flex-direction</title>
<style>
body, html {
width: 100%;
height: 100%;
padding: 0;
margin: 0;
}
.demo{
margin-left: 200px;
margin-top: 200px;
width: 200px;
height: 200px;
background: #fff;
border: 1px solid #111;
border-radius: 10px;
display: flex;
justify-content: center;
align-items: center;
}
.item {
overflow: hidden;
width: 40px;
height: 40px;
background: #111111;
color: #fff;
border-radius: 10px;
line-height: 40px;
text-align: center;
border: 1px solid #333;
}
</style>
</head>
<body>
<div class="demo">
<div class="item">1</div>
</div>
</body>
</html>