console 命令行工具 X clear

console

<div class="parent">
  <div class="child"></div>
</div>

.parent {
  width: 500px;
  height: 200px;
  text-align: center;
  border:1px solid #ccc;
  background-color: #fff;
}
.child {
  display: inline-block;
  width: 300px;
  height: 100px;
  background-color: red;
}