css 菱形写法
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style type="text/css">
.one {
border: 20px solid transparent;
width: 0;
border-bottom: 20px solid black;
}
.two {
border: 20px solid transparent;
width: 0;
border-top: 20px solid black;
}
</style>
</head>
<body>
<div class="one"></div>
<div class="two"> </div>
</body>
</html>
