<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">

    <title>Document Infinite Scroll</title>
    <style>
      body {
        box-sizing: border-box;

        margin: 0;
        padding: 20px;

        background: #444;
        color: #fff;
      }

      .block {
        box-sizing: border-box;

        margin-bottom: 50px;
        border: 4px solid #fff;
        padding: 20px;

        width: 100%;
        height