CSS "background-position: bottom" Imperfect on Mobile Browsers

body
{
  background-color: #000000;
  background-image: url('http://ift.tt/15VJ8lx');
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-position: center bottom;
  background-size: cover;
}

a
{
  color: #ffffff;
}

<a>Hello, world!</a>

A site I'm developing has a background-image that fills the viewport and is anchored to the bottom. It works perfectly on PC, but mobile browsers on Android anchor the background-image to the bottom of the last element if the content doesn't fill the screen, leaving a blank space below it. How can I fix this to make the background-image correctly fill the screen on Android?