body {
  position: relative;
  margin: 0;
}
.sect {
  width: 100%;
  min-height: 500px;
   z-index: -1;
}
#sect1,


video {
  position: fixed;
  right: 0;
  bottom: 0;
  min-width: 105%;
  min-height: 100%;
  transform: translateX(calc((100% - 100vw) / 2));
  z-index: -2;
}