<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>第七章浮动</title>
<style type="text/css">
.a_1{
border-style: inset;
border-width: 10px 20px 30px 40px;
border-color: brown;
width:1000px;
height: 500px;
font-size: 80px;
margin: 0px auto;
background-color: aqua;
display: flex;
}
.a_2{
width: 100px;
height: 100px;
background-color: black;
margin: 15px;
}
</style>
</head>
<body>
<div class="a_1">
<div class="a_2"></div>
<div class="a_2"></div>
<div class="a_2"></div>
<div class="a_2"></div>
<div class="a_2"></div>
<div class="a_2"></div>
<div class="a_2"></div>
<div class="a_2"></div>
</div>
</body>
</html>