table {
  width: 100%;
  border-collapse: collapse;
}

th, td {
  padding: 8px;
  text-align: center;
  border-bottom: 1px solid #ddd;
}

.vowel-button {
  width: 50px;
  height: 50px;
  font-size: 24px;
}

.next-button-container {
  text-align: center;
  margin-top: 20px;
}

.next-button {
  display: inline-block;
  padding: 10px 20px;
  background-color: #4CAF50;
  color: #fff;
  text-decoration: none;
  font-weight: bold;
  border-radius: 4px;
}

.next-button:hover {
  background-color: #45a049;
}