Better fixed background image

better-background.css

html,body {
  height: 100%;
  margin: 0
}

.hero {
  min-height: 100%;
  position: relative;
  overflow: hidden;

  &::before {
    background-image: url('http://bit.ly/1KnDNGG');
    background-repeat: no-repeat;
    background-position: center top;
    background-size: cover;
    content: '';
    height: 100%;
    left: 0;
    position: fixed;
    top: 0;
    width: 100%;
    will-change: transform;
    z-index: -1;
  }
}