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('//demosthenes.info/assets/images/polina.jpg') no-repeat;
  background-size: cover;
  transition: 1s opacity;
}
.stopfade { 
   opacity: .5;
}
#video_fusion_button { 
  display: block;
  width: 80%;
  padding: .4rem;
  border: none; 
  margin: 1rem auto; 
  font-size: 1.3rem;
  background: rgba(255,255,255,0.23);
  color: #fff;
  border-radius: 3px; 
  cursor: pointer;
  transition: .3s background;
}
#video_fusion_button:hover { 
   background: rgba(0,0,0,0.5);
}

/*@media screen and (max-width: 500px) { 
  div{width:70%;} 
}
@media screen and (max-device-width: 800px) {
  html { background: url(//demosthenes.info/assets/images/polina.jpg) #000 no-repeat center center fixed; }
  #bgvid { display: none; }
}
*/