console 命令行工具 X clear

console

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <title>Document</title>
</head>
<body>
    <div class="box">
      <div class="txt"></div>
    </div>
</body>
</html>

.box{
  width: 100px;
  margin:0 auto;
}
.txt{
  width:150px;
  height: 200px;
  border:1px solid #000;
}