desc:after {
      content: ' \25BC';
    }

    #interactiveBookContainer {
      width: 1250px;
      height: 850px;
      margin: 0 auto;
    }

    iframe {
      width: 100%;
      height: 100%;
      border: none;
    }
  </style>
</head>

<body>
  <header>
    <div class="container">
    </div>
  </header>
  <section class="paper-list">
    <div class="container">
      <div class="container" style="display: flex; align-items: center; position: relative;">
        <a href="index.html" class="btn clr3