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

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            padding: 20px;
            color: #212529;
        }

        .container {
            max-width: 600px;
            margin: 0 auto;
            background: white;
            border-radius: 20px;
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
            overflow: hidden;
        }

        .header {
            background: linear-gradient(135deg, #2563eb 0%, #1d4ed8 100%);
            padding: 30px 20px;
            text-align: center;
            color: white;
        }

        .header h1 {
            font-size: 2rem;
            font-weight: 600;
            margin-bottom: 10px;
        }

        .header p {
            opacity: 0.9;
            font-size: 1.1rem;
        }

        .privacy-note {
            font-size: 0.9rem !important;
            opacity: 0.95 !important;
            margin-top: 10px;
        }

        .content {
            padding: 30px 20px;
        }

        .input-section {
            margin-bottom: 30px;
        }

        .input-label {
            display: block;
            font-weight: 600;
            color: #2c3e50;
            margin-bottom: 10px;
            font-size: 1.1rem;
        }

        .input-field {
            width: 100%;
            padding: 15px;
            border: 2px solid #e1e5e9;
            border-radius: 10px;
            font-size: 16px;
            transition: all 0.3s ease;
            background: #f8f9fa;
        }

        .input-field:focus {
            outline: none;
            border-color: #4facfe;
            background: white;
            box-shadow: 0 0 0 3px rgba(79, 172, 254, 0.1);
        }

        .button-group {
            display: flex;
            gap: 10px;
            flex-wrap: wrap;
            margin-bottom: 30px;
        }

        .btn {
            flex: 1;
            min-width: 140px;
            padding: 15px 20px;
            border: none;
            border-radius: 10px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            text-align: center;
        }

        .btn-primary {
            background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
            color: white;
        }

        .btn-secondary {
            background: linear-gradient(135deg, #10b981 0%, #059669 100%);
            color: white;
        }

        .btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
        }

        .btn:active {
            transform: translateY(0);
        }

        .btn:disabled {
            opacity: 0.6;
            cursor: not-allowed;
            transform: none;
            box-shadow: none;
        }

        .qr-display {
            text-align: center;
            padding: 20px;
            background: #f8f9fa;
            border-radius: 15px;
            border: 2px dashed #e1e5e9;
            min-height: 200px;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .qr-display img {
            max-width: 100%;
            height: auto;
            border-radius: 10px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
        }

        .placeholder {
            color: #6c757d;
            font-style: italic;
            font-size: 1.1rem;
        }

        .error-message {
            background: #f8d7da;
            color: #721c24;
            padding: 15px;
            border-radius: 10px;
            margin-bottom: 20px;
            border-left: 4px solid #dc3545;
            display: none;
        }

        .success-message {
            background: #d1e7dd;
            color: #0f5132;
            padding: 15px;
            border-radius: 10px;
            margin-bottom: 20px;
            border-left: 4px solid #198754;
            display: none;
        }

        /* Mobile optimizations */
        @media (max-width: 480px) {
            body {
                padding: 10px;
            }

            .header {
                padding: 20px 15px;
            }

            .header h1 {
                font-size: 1.5rem;
            }

            .content {
                padding: 20px 15px;
            }

            .button-group {
                flex-direction: column;
            }

            .btn {
                min-width: auto;
                width: 100%;
            }

            .input-field {
                font-size: 16px; /* Prevents zoom on iOS */
            }
        }

        /* Responsive typography */
        @media (max-width: 360px) {
            .header h1 {
                font-size: 1.3rem;
            }

            .header p {
                font-size: 1rem;
            }

            .btn {
                padding: 12px 16px;
                font-size: 14px;
            }
        }

        /* Loading animation */
        .loading {
            display: inline-block;
            width: 20px;
            height: 20px;
            border: 3px solid #f3f3f3;
            border-top: 3px solid #4facfe;
            border-radius: 50%;
            animation: spin 1s linear infinite;
            margin-right: 10px;
        }

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

        /* GitHub Corner */
        .github-corner {
            position: fixed;
            top: 0;
            right: 0;
            z-index: 1000;
        }

        .github-corner:hover .octo-arm {
            animation: octocat-wave 560ms ease-in-out;
        }

        @keyframes octocat-wave {
            0%, 100% { transform: rotate(0); }
            20%, 60% { transform: rotate(-25deg); }
            40%, 80% { transform: rotate(10deg); }
        }

        @media (max-width: 500px) {
            .github-corner:hover .octo-arm {
                animation: none;
            }
            .github-corner .octo-arm {
                animation: octocat-wave 560ms ease-in-out;
            }
        }