<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <div class="container">
    <div class="box1">
    </div>
  </div>
  <div class="box2"></div>

</body>

</html>
.container {
  overflow: auto;
}
.box1 {
  height: 100px;
  margin-bottom: 40px;
  background-color: red;
}
.box2 {
  height: 100px;
  margin-top: 20px;
  background-color: black;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.