CSS outline 与 border 的区别

<html>
  <head>
    <meta charset="utf-8">
    <title>outline 与 border 的区别</title>
    <style>
      .comparison {
        width: 200px;
        height: 100px;
        background-color: #f0f0f0;
        margin: 20px;
        padding: 15px;
        display: inline-block;
        vertical-align: top;
      }
      
      /* border 占用空间 */
      .with-border {
        border: 5px solid blue;
      }
      
      /* outline 不占用空间 */
      .with-outline {
        outline: 5px solid red;
      }