边框的使用，border-radius，box-shadow，border-image
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style type="text/css">
*{
margin: auto;
padding: 0;
}
#a1{
width: 100px;
height: 100px;
border: 1px solid red;
margin-top: 30px;
border-radius: 15px 20%;
box-shadow: 5px 10px;
}
</style>
</head>
<body>
<div id="a1">
</div>
</body>
</html>
