video { 
    position: fixed;
    top: 50%;
    left: 50%;
    min-width: 100%;
    min-height: 100%;
    width: auto;
    height: auto;
    z-index: -100;
    transform: translateX(-50%) translateY(-50%);
    background: url('../img/poster.jpg') no-repeat;
    background-size: cover;
    transition: 1s opacity;
}
.stopfade { 
   opacity: .5;
}
/*
@media screen and (max-width: 500px) { 
  div{width:70%;} 
}
*/
@media only screen and (max-width: 769px) {
  html { background: url(../img/poster.jpg) no-repeat center center fixed; }
  #bgvid { display: none; }
}