body {
      background: #e9f5f4;
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      padding: 20px;
    }
    .card {
      border-radius: 15px;
      box-shadow: 0 8px 20px rgb(0 0 0 / 0.1);
    }
    .info-icon {
      color: #0d6efd;
      cursor: pointer;
      margin-left: 5px;
    }
    .btn-submit {
      background-color: #0d6efd;
      color: white;
      font-weight: 600;
    }
    .btn-submit:hover {
      background-color: #084298;
    }
    .loader {
      border: 4px solid #f3f3f3;
      border-top: 4px solid #0d6efd;
      border-radius: 50%;
      width: 36px;
      height: 36px;
      animation: spin 1s linear infinite;
      margin: 20px auto;
      display: none;
    }
    @keyframes spin {
      0% { transform: rotate(0deg);}
      100% { transform: rotate(360deg);}
    }
    .result {
      margin-top: 25px;
      font-size: 18px;
      font-weight: 600;
      text-align: center;
      border-radius: 10px;
      padding: 15px;
    }
    .result.positive {
      background-color: #f8d7da;
      color: #842029;
      border: 1px solid #f5c2c7;
    }
    .result.negative {
      background-color: #d1e7dd;
      color: #0f5132;
      border: 1px solid #badbcc;
    }