body {
  background-image: url(back.png);
  background-position: center center;
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-color:#fff;
  background-size: cover !important;
}

@media only screen and (max-width: 767px) {
  body {
    background-image: url(back.png);
  }
	}

a {
    display: block;
    height: 100%;
    width: 100%;
    position: fixed;
}