/*二重線*/
.box2 {
	margin: 2em auto;
	padding:2em;/*内側余白*/
	border:double 5px #CCCFD6;/*線の種類・太さ・色*/
}.container {
      max-width: 600px;
      margin: 0 auto;
      padding: 20px;
      border: 3px double #3498db;
      border-radius: 10px;
      background-color: #f9f9f9;
    }
    h1 {
      text-align: center;
    }
    p {
      text-align: justify;
      margin-bottom: 10px;.link-btn {
      display: inline-block;
      width: 200px;
      margin: 20px auto;
      padding: 10px;
      text-align: center;
      color: #fff;
      background-color: #3498db;
      border-radius: 5px;
      text-decoration: none;
    }
    .link-btn:hover {
      background-color: #2980b9;
    }