body {
  font-family: sans-serif;
  background: #222;
  color: white;
  text-align: center;
  margin: 0;
  padding: 1em;
}
video {
  width: 100%;
  max-width: 500px;
  border: 2px solid #444;
  border-radius: 10px;
}
#result {
  margin-top: 1em;
  font-size: 1.2em;
}
button {
  margin-top: 1em;
  padding: 0.5em 1em;
  font-size: 1em;
}