title: White space at bottom on mobile, not reproducible in Chrome simulator
body: <p>I know there are various similar threads on this but none answer my question. Please look at this most simple HTML code.</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;!doctype html&gt;
  &lt;html lang="en"&gt;
   &lt;head&gt;
    &lt;meta charset="UTF-8"&gt;
    &lt;meta name="viewport" content="width=device-width, initial-scale=1"&gt;
    &lt;style&gt;
    html, body {
      margin: 0;
      height: 100%;
      background: linear-gradient(to top, blue, white);
      background-attachment: fixed;
    }
    &lt;/style&gt;
   &lt;/head&gt;
   &lt;body&gt;
   &lt;/body&gt;
  &lt;/html&gt;</code></pre>
  </div>
  </div>
  </p>
  <p>Viewed in Chrome for PC (either in normal view or in mobile simulator view) it produces a gradient background that covers the whole screen. Viewed in Firefox mobile for Android or Chrome mobile, the website has a white space at the bottom the size of the address-bar. It either appears right away or it appears when you attempt to scroll the page. Why is it there and how do I get rid of it?</p>
  <p><a href="https://i.stack.imgur.com/jqqVb.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jqqVb.png" alt="Firefox mobile" /></a></p>