.backstretch {
  position: fixed;
  width: 100vw;
  height: 100vh;
  top: 0;
  left: 0;
  overflow: hidden;
  z-index: -1;
}

.backstretch img {
  width: 100vw;
  height: 100vh;
  object-fit: cover;
  position: absolute;
  top: 0;
  left: 0;
}