body {
  background-color: #212121;
  color: #fff;
  font-family: Arial, sans-serif;
  text-align: center;
}

nav {
  margin: 20px 0;
}

a {
  color: #ff9800;
  text-decoration: none;
  font-size: 18px;
  margin: 0 10px;
}

button {
  padding: 10px 20px;
  font-size: 18px;
  font-weight: bold;
  border: none;
  cursor: pointer;
  margin: 10px;
  border-radius: 5px;
  transition: background-color 0.3s;
}

#start {
  background-color: #4caf50;
  color: white;
}

#start:hover {
  background-color: #45a049;
}

#stop {
  background-color: #f44336;
  color: white;
}

#stop:hover {
  background-color: #d32f2f;
}