.modal-content {
  position: fixed ;
  display: none ;
  z-index: 2 ;
}
#modal-overlay {
  z-index: 1 ;
  display: none ;
  position: fixed ;
  top: 0 ;
  left: 0 ;
  width: 100% ;
  height: 120% ;
  background-color: rgba( 0,0,0, 0.75 ) ;
}