.xmas {
  height: 100%;
  width: 100%;
  position: relative;
  background: url("https://images.unsplash.com/photo-1513195301785-4b50e6b11a43") no-repeat 0 0/cover;
}

.xmas .xmas-message {
  position: absolute;
  left: 50%;
  top: 50%;
  z-index: 2;
  -webkit-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
  width: calc(90% - 6rem);
  height: calc(100% - 12rem);
  margin: 0 auto;
  background: url(../img/overlay.png) no-repeat 50% 50%/contain;
}

.xmas #xmas {
  width: 100%;
  height: 100%;
  position: relative;
  z-index: 2;
}