body {
  margin: 0;
}
body video {
  max-width: 100%;
}
@media (max-width: 480px) {
  body video {
    display: none;
  }
}
body img {
  display: none;
  max-width: 100%;
}
@media (max-width: 480px) {
  body img {
    display: block;
  }
}