body {
  font-family: Arial, sans-serif;
  background-color: #f5f5f5;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}
.quiz-container {
  background: #fff;
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
  width: 400px;
}
button {
  margin: 1rem 0.5rem 0 0;
  padding: 0.5rem 1rem;
  cursor: pointer;
}
button:disabled {
  background-color: #ccc;
  cursor: not-allowed;
}