Full-size background image w/ effects
Stylus
div  
  &:before
    content: ''
    background: url('/img/1.jpg') 0 0 / cover fixed no-repeat
    filter: blur(2px) contrast(110%) brightness(70%)
    position: absolute
    left:0
    top:0
    right:0
    bottom:0
    z-index: -1
    pointer-events: none