小案例！案例不限！！
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>边框</title>
<style type="text/css">
.box{width: 200px;height: 200px;border:1px dotted blue; border-radius: 11px;}
.main{background: pink; width: 90px;height: 90px;border-top: 10px solid #000;border-left: 10px dotted green;border-bottom: 10px double green;border-right: 10px dashed green;}
button{border: none;}
#shadow1{width: 80%;height: 50px; box-shadow: 0px 6px 30px #BFBFBF inset;border-radius: 20px;}
</style>
</head>
<body>
<div>
<p>你好 HTML</p>
</div>
<br/>
<div>
<p>这是一个自定义的框</p>
</div>
<br/>
<button>提交</button>
<div id="shadow1">
<p> hi，阴影</p>
</div>
</body>
</html>