.thank-you-box {
      background-color: #ffffff;
      padding: 40px;
      border-radius: 12px;
      text-align: center;
    }
    .thank-you-box h1 {
      font-size: 2.5rem;
      color: #28a745;
    }
    .thank-you-box p {
      font-size: 1.2rem;
      color: #555;
    }
    .checkmark {
      font-size: 4rem;
      color: #28a745;
    }