body {
  font-family: sans-serif;
  padding: 20px;
  background: #f9f9f9;
}

h1 {
  font-size: 18px;
}

video {
  width: 100%;
  max-width: 600px;
  border: 2px solid #333;
}
#feedback {
  margin-top: 10px;
  font-size: 1.2em;
  color: green;
}
#controls {
  margin-top: 10px;
}
button {
  padding: 15px;
  margin-right: 10px;
  font-size: 18px;
}
#history {
  margin-top: 20px;
  font-family: monospace;
}