html, body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  background-color: #000;
  overflow: hidden;
}

.fullscreen-bg {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
}

.fullscreen-bg picture, .fullscreen-bg img {
  width: 100%;
  height: 100%;
  display: block;
}

.fullscreen-bg img {
  object-fit: contain;
  object-position: center;
}