body {
  margin: 0;
  background-color: black;
  color: white;
  font-family: sans-serif;
  max-width: 800px;
  margin: 0 auto;
}
header {
}
h1 {
  margin: 2em;
  text-align: center;
  font-weight: inherit;
  font-size: inherit;
}
video {
  width: 100%;
  margin-bottom: 2em;
}