body {
  margin: 0;
  padding: 0;
}
.bg-video-wrap {
  position: relative;
  overflow: hidden;
  width: 100%;
  height: 100vh;
}
video {
  min-width: 100%;
  min-height: 100vh;
  z-index: 1;
}
.overlay {
  width: 100%;
  height: 100vh;
  position: absolute;
  top: 0;
  left: 0;
  background-image: linear-gradient(45deg, rgba(0,0,0,.3) 50%, rgba(0,0,0,.7) 50%);
  background-size: 3px 3px;
  z-index: 2;
}
h1 {
    text-align: center;
    color: #fff;
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    margin: auto;
    z-index: 3;
    height: 50px;
    font-size: 64px;
}
@media only screen and (max-width: 600px) {
  h1  {
     font-size: 48px;
  }
}