body {
      font-family: Arial, sans-serif;
      background: #f5f7fa;
      margin: 0;
      padding: 20px;
    }

    .container {
      max-width: 600px;
      margin: auto;
      background: #ffffff;
      padding: 20px;
      border-radius: 8px;
      box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    }

    h1 {
      text-align: center;
      color: #c62828;
    }

    label {
      display: block;
      margin-top: 12px;
      font-weight: bold;
    }

    input, select {
      width: 100%;
      padding: 10px;
      margin-top: 5px;
      font-size: 16px;
    }

    .result {
      margin-top: 20px;
      background: #fff3e0;
      padding: 15px;
      border-radius: 6px;
      font-weight: bold;
    }

    .warning {
      margin-top: 15px;
      color: #b71c1c;
      font-size: 14px;
    }