console 命令行工具 X clear

console

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<style>
.son {
   background-color: red;
   padding-top: 56.25%;
}
</style>	
<body>
<div class="son">
</div>

</body>
</html>