index.html

<!DOCTYPE html>
<html>
<head>
  <meta charset='utf-8'>
  <meta http-equiv='X-UA-Compatible' content='IE=edge'>
  <title>Page Title</title>
  <meta name='viewport' content='width=device-width, initial-scale=1'>
  <link rel='stylesheet' type='text/css' media='screen' href='main.css'>
</head>
<body>
  <header>DevTools</header>
  <div class="console">
    <p>Console</p>
    <div class="buttons">
      <button id="info">Log Info</button>
      <button id="warning">Log Warning</button>
      <button id="log-error">Log Error</button>
      <button id="table">Log Table</button>
      <button id="group">Log Group</button>
      <button id="custom">Log Custom</button>
      <button id="network">Cause 404</button>
      <button id="error">Cause Error</button>
    </div>
  </div>
  <script src='main.js'></script>
  <script src='examples.js'></script>
</body>
</html>