console 命令行工具 X clear

console

<body>
  <main>
    <h1>Am I centered yet?</h1>
    <p>Center me, please!</p>
  </main>
</body>

body{
  background:#E7E5D5;
  border:2px dashed;
  padding:0;
  margin:0;
}
main{
  border:1px solid red;
  text-align:center;
  background:gray;
  font-size:.5em;
  width:20em;
  margin:0 auto;
}