video{
  width: 100%;
  border: none;
}

@media screen and (min-width: 421px) {
  video{
    width: 284px;
    height: 504px;
    border: none;
    margin-right:20px;
  }
}

@media screen and (min-width: 768px) {
  video{
    width: 284px;
    height: 504px;
    border: none;
    margin-right:20px;
  }
}