public/404.html

<!DOCTYPE html>
<html lang="en">
<head>
  <title>SUI2</title>
  <meta charset="utf-8">
  <meta name="description" content="a startpage for your server and / or new tab page">
  <meta content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no" name="viewport" />
  <link rel="shortcut icon" href="/icon-512.png" type="image/png">
  <style>
    .container {
      display: flex;
      flex-direction: column;
      font-family: -apple-system, BlinkMacSystemFont, Helvetica Neue, Roboto, sans-serif;
      margin-top: 20vh;
    }
    .container * {
      align-self: center;
    }
  </style>
</head>
<body>
  <div class="container">
    <h2>404 Not Found</h2>
    <p>
      You are coming to the wrong place.
    </p>
  </div>

</body>
</html>