body { font-family: 'Segoe UI', sans-serif; background-color: #f0f2f5; margin: 0; padding: 20px; }
        
        /* Main Button */
        .start-btn {
            background: linear-gradient(135deg, #004aad, #002b64);
            color: white;
            font-size: 20px;
            padding: 15px 40px;
            border: none;
            border-radius: 50px;
            cursor: pointer;
            box-shadow: 0 5px 15px rgba(0, 74, 173, 0.4);
            display: block; margin: 100px auto; width: 90%; max-width: 350px; font-weight: bold;
        }

        /* Modal Overlay */
        .modal-overlay {
            display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%;
            background: rgba(0, 0, 0, 0.9); z-index: 999; align-items: center; justify-content: center;
        }
        .modal-box {
            background: white; width: 90%; max-width: 400px; border-radius: 15px;
            overflow: hidden; padding: 20px; animation: slideUp 0.4s ease;
        }
        @keyframes slideUp { from {transform: translateY(100px); opacity: 0;} to {transform: translateY(0); opacity: 1;} }
        
        .step-section { display: none; text-align: center; }
        .step-section.active { display: block; }

        /* Form Inputs */
        .form-input {
            width: 100%; padding: 12px; margin-bottom: 12px; border: 1px solid #ccc;
            border-radius: 5px; box-sizing: border-box; font-size: 14px;
        }
        .submit-btn {
            background: #ff9900; color: white; width: 100%; padding: 12px;
            border: none; border-radius: 5px; font-size: 18px; font-weight: bold; cursor: pointer;
        }
        
        /* UPI Button */
        .upi-btn {
            display: block; background: #25d366; color: white; text-decoration: none;
            padding: 12px; border-radius: 8px; margin-top: 15px; font-weight: bold;
        }