.fullscreen-bg {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    overflow: hidden;
    z-index: -100;
}

.fullscreen-bg__video {
    position: absolute;
    top: 0;
    left: 0;
   width: 100vh; min-width: 100%;   
  background-size: cover;
  -webkit-transition: 1s opacity;
  transition: 1s opacity;
}
.mask{
  position: fixed;
  top: 50%;
  left: 50%;
  min-width: 100%;
  min-height: 100%;
  width: auto;
  height: auto;
  z-index: -50;
  -webkit-transform: translateX(-50%) translateY(-50%);
  transform: translateX(-50%) translateY(-50%);
  background-size: cover;
  background: #000;
  opacity: 0.7;
}