body {
  font-family: Arial;
  text-align: center;
  padding: 20px;
  background: #f4f4f4;
}

h2 {
  color: #333;
}

#waveform {
  margin-top: 30px;
  height: 150px;
}

.controls {
  margin-top: 20px;
}

button {
  padding: 10px 15px;
  margin: 5px;
  cursor: pointer;
}

select {
  padding: 5px;
}