html,
body {
  position: absolute;
  height: 100%;
  width: 100%;
  margin: 0;
  padding: 0;
  background-color: #f0f0f0;
}

/* Main */
main {
  --main-margin: 48px;
  height: calc(100% - calc(var(--main-margin) * 2));
  width: calc(100% - calc(var(--main-margin) * 2));
  margin: var(--main-margin);
  display: flex;
  align-items: center;
  justify-content: center;
}

video {
  height: -webkit-fill-available;
  width: -webkit-fill-available;
}