body {
  font-family: Arial, sans-serif;
  padding: 20px;
  max-width: 800px;
}

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

#lessonArea {
  margin-top: 20px;
  padding: 15px;
  border: 1px solid #ddd;
  border-radius: 10px;
}