body {
  /* Location of the image */
  background-image: url(images/photo.jpg);

  /* Image is centered vertically and horizontally at all times */
  background-position: center center;

  /* Image doesn't repeat */
  background-repeat: no-repeat;

  /* Makes the image fixed in the viewport so that it doesn't move when
     the content height is greater than the image height */
  background-attachment: fixed;

  /* This is what makes the background image rescale based on its container's size */
  background-size: cover;

  /* Pick a solid background color that will be displayed while the background image is loading */
  background-color:#fff;
}