* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
            background: #f5f5f5;
            padding: 20px;
            line-height: 1.6;
        }

        .form-container {
            max-width: 600px;
            margin: 0 auto;
            background: white;
            padding: 30px;
            border-radius: 8px;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
        }

        h2 {
            color: #333;
            margin-bottom: 20px;
            font-size: 24px;
            text-align: center;
        }

        .form-group {
            margin-bottom: 20px;
        }

        label {
            display: block;
            margin-bottom: 8px;
            color: #555;
            font-weight: 500;
            font-size: 14px;
        }

        .required {
            color: #e74c3c;
        }

        input[type="text"],
        input[type="email"],
        input[type="tel"],
        select {
            width: 100%;
            padding: 12px 15px;
            border: 1px solid #ddd;
            border-radius: 4px;
            font-size: 14px;
            transition: border-color 0.3s;
            font-family: inherit;
        }

        input:focus,
        select:focus {
            outline: none;
            border-color: #4CAF50;
        }

        .error-message {
            color: #e74c3c;
            font-size: 12px;
            margin-top: 5px;
            display: none;
        }

        .error-message.show {
            display: block;
        }

        input.error,
        select.error {
            border-color: #e74c3c;
        }

        button {
            width: 100%;
            padding: 14px 20px;
            background: #4CAF50;
            color: white;
            border: none;
            border-radius: 4px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: background 0.3s;
        }

        button:hover {
            background: #45a049;
        }

        button:disabled {
            background: #ccc;
            cursor: not-allowed;
        }

        .success-message {
            background: #d4edda;
            color: #155724;
            padding: 15px;
            border-radius: 4px;
            margin-bottom: 20px;
            border: 1px solid #c3e6cb;
            display: none;
        }

        .success-message.show {
            display: block;
        }

        .error-alert {
            background: #f8d7da;
            color: #721c24;
            padding: 15px;
            border-radius: 4px;
            margin-bottom: 20px;
            border: 1px solid #f5c6cb;
            display: none;
        }

        .error-alert.show {
            display: block;
        }

        .otp-section {
            display: none;
            position: fixed;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            z-index: 1000;
            width: 90%;
            max-width: 500px;
            padding: 30px;
            background: white;
            border-radius: 8px;
            border: 2px solid #4CAF50;
            box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
        }

        .otp-section.show {
            display: block;
        }

        /* Overlay backdrop */
        .otp-overlay {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.5);
            z-index: 999;
        }

        .otp-overlay.show {
            display: block;
        }

        .otp-section h3 {
            color: #4CAF50;
            margin-bottom: 10px;
            font-size: 18px;
        }

        .otp-section p {
            color: #555;
            margin-bottom: 15px;
            font-size: 14px;
        }

        /* Disable form when OTP is active */
        form.disabled {
            opacity: 0.6;
            pointer-events: none;
        }

        form.disabled input,
        form.disabled select,
        form.disabled button {
            background-color: #f5f5f5;
            cursor: not-allowed;
        }

        .otp-input {
            display: flex;
            gap: 10px;
            margin-top: 10px;
        }

        .otp-input input {
            width: 100%;
        }

        .resend-otp {
            margin-top: 10px;
            font-size: 14px;
            color: #4CAF50;
            cursor: pointer;
            text-decoration: underline;
        }

        .resend-otp.disabled {
            color: #ccc;
            cursor: not-allowed;
            text-decoration: none;
        }

        .loading {
            text-align: center;
            padding: 10px;
            display: none;
        }

        .loading.show {
            display: block;
        }

        .spinner {
            border: 3px solid #f3f3f3;
            border-top: 3px solid #4CAF50;
            border-radius: 50%;
            width: 30px;
            height: 30px;
            animation: spin 1s linear infinite;
            margin: 0 auto;
        }

        @keyframes spin {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }

        @media (max-width: 600px) {
            body {
                padding: 10px;
            }
            
            .form-container {
                padding: 20px;
            }
        }