:root {
            --primary: #3498db;
            --primary-dark: #2980b9;
            --secondary: #2ecc71;
            --accent: #9b59b6;
            --warning: #f39c12;
            --danger: #e74c3c;
            --dark: #2c3e50;
            --light: #ecf0f1;
            --gray: #7f8c8d;
            --light-gray: #bdc3c7;
            --border-radius: 16px;
            --shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
            --gradient: linear-gradient(135deg, #3498db, #9b59b6);
            --premium-gradient: linear-gradient(135deg, #f39c12, #e74c3c);
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', 'Roboto', sans-serif;
            max-width: 100%;
        }
        
        html, body {
            overflow-x: hidden;
            min-height: 100vh;
            background: linear-gradient(135deg, #f5f7fa 0%, #e4e7ec 100%);
            color: var(--dark);
        }
        
        .container {
            max-width: 1400px;
            margin: 0 auto;
            padding: 0 20px;
        }
        
        /* Premium Header */
        .premium-header {
            background: linear-gradient(135deg, #2c3e50 0%, #1a2530 100%);
            color: white;
            padding: 30px 40px;
            border-radius: var(--border-radius);
            margin: 30px auto;
            box-shadow: var(--shadow);
            position: relative;
            overflow: hidden;
            border: 1px solid rgba(255, 255, 255, 0.1);
        }
        
        .premium-header::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 5px;
            background: var(--premium-gradient);
        }
        
        .header-content {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 20px;
        }
        
        .logo-section {
            display: flex;
            align-items: center;
            gap: 20px;
        }
        
        .logo-icon {
            width: 60px;
            height: 60px;
            background: var(--gradient);
            border-radius: 15px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 28px;
            box-shadow: 0 6px 20px rgba(52, 152, 219, 0.3);
        }
        
        .logo-text h1 {
            font-size: 2.5rem;
            font-weight: 800;
            background: var(--gradient);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            line-height: 1.2;
        }
        
        .premium-tag {
            background: var(--premium-gradient);
            padding: 8px 20px;
            border-radius: 25px;
            font-size: 0.9rem;
            font-weight: 700;
            display: inline-block;
            margin-top: 8px;
            box-shadow: 0 4px 15px rgba(243, 156, 18, 0.3);
        }
        
        .header-stats {
            display: flex;
            gap: 25px;
            align-items: center;
            flex-wrap: wrap;
        }
        
        .stat-badge {
            text-align: center;
        }
        
        .stat-value {
            font-size: 2rem;
            font-weight: 800;
            color: var(--secondary);
        }
        
        .stat-label {
            font-size: 0.9rem;
            opacity: 0.9;
        }
        
        /* Main Layout */
        .main-layout {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 30px;
            margin: 40px 0;
        }
        
        /* Premium Cards */
        .premium-card {
            background: white;
            border-radius: var(--border-radius);
            box-shadow: var(--shadow);
            padding: 35px;
            border: 1px solid rgba(0, 0, 0, 0.05);
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }
        
        .premium-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
        }
        
        .card-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 30px;
            padding-bottom: 20px;
            border-bottom: 2px solid var(--light);
        }
        
        .card-title {
            display: flex;
            align-items: center;
            gap: 15px;
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--dark);
        }
        
        .card-title i {
            color: var(--primary);
            background: rgba(52, 152, 219, 0.1);
            width: 40px;
            height: 40px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        /* Upload Area */
        .upload-area {
            border: 3px dashed var(--light-gray);
            border-radius: var(--border-radius);
            padding: 60px 30px;
            text-align: center;
            cursor: pointer;
            transition: all 0.3s ease;
            margin-bottom: 30px;
            position: relative;
            background: white;
        }
        
        .upload-area:hover {
            border-color: var(--primary);
            background: rgba(52, 152, 219, 0.02);
        }
        
        .upload-area.dragover {
            border-color: var(--primary);
            background: rgba(52, 152, 219, 0.05);
            transform: scale(1.01);
        }
        
        .upload-icon {
            font-size: 3.5rem;
            color: var(--primary);
            margin-bottom: 25px;
            opacity: 0.8;
        }
        
        /* Conversion Settings */
        .settings-grid {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 25px;
            margin-bottom: 30px;
        }
        
        .setting-item {
            margin-bottom: 20px;
        }
        
        .setting-label {
            display: flex;
            align-items: center;
            gap: 10px;
            margin-bottom: 12px;
            font-weight: 600;
            color: var(--dark);
            font-size: 1.1rem;
        }
        
        .setting-label i {
            color: var(--primary);
        }
        
        /* Range Sliders */
        .range-slider-container {
            position: relative;
            padding-top: 10px;
        }
        
        .range-slider {
            width: 100%;
            height: 10px;
            -webkit-appearance: none;
            background: linear-gradient(to right, var(--light-gray), var(--primary));
            border-radius: 5px;
            outline: none;
        }
        
        .range-slider::-webkit-slider-thumb {
            -webkit-appearance: none;
            width: 24px;
            height: 24px;
            background: white;
            border-radius: 50%;
            cursor: pointer;
            border: 3px solid var(--primary);
            box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
            transition: all 0.3s ease;
        }
        
        .range-slider::-webkit-slider-thumb:hover {
            transform: scale(1.2);
            box-shadow: 0 6px 15px rgba(0, 0, 0, 0.3);
        }
        
        .slider-labels {
            display: flex;
            justify-content: space-between;
            margin-top: 8px;
            font-size: 0.9rem;
            color: var(--gray);
        }
        
        .slider-value {
            position: absolute;
            top: -5px;
            right: 0;
            background: var(--primary);
            color: white;
            padding: 4px 12px;
            border-radius: 15px;
            font-weight: 600;
            font-size: 0.9rem;
        }
        
        /* Buttons */
        .premium-btn {
            background: var(--gradient);
            color: white;
            border: none;
            padding: 18px 32px;
            border-radius: var(--border-radius);
            font-size: 1.1rem;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 12px;
            box-shadow: 0 6px 20px rgba(52, 152, 219, 0.3);
        }
        
        .premium-btn:hover:not(:disabled) {
            transform: translateY(-3px);
            box-shadow: 0 10px 25px rgba(52, 152, 219, 0.4);
        }
        
        .premium-btn:active:not(:disabled) {
            transform: translateY(-1px);
        }
        
        .premium-btn:disabled {
            opacity: 0.6;
            cursor: not-allowed;
            transform: none !important;
        }
        
        .btn-success {
            background: linear-gradient(135deg, var(--secondary), #27ae60);
        }
        
        .btn-danger {
            background: linear-gradient(135deg, var(--danger), #c0392b);
        }
        
        .btn-warning {
            background: linear-gradient(135deg, var(--warning), #d35400);
        }
        
        .btn-accent {
            background: var(--premium-gradient);
        }
        
        /* Stats */
        .stats-grid {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 15px;
            margin: 25px 0;
        }
        
        .stat-card {
            background: linear-gradient(135deg, #f8fafc, #f1f5f9);
            padding: 20px;
            border-radius: 12px;
            border-left: 4px solid var(--primary);
            transition: all 0.3s ease;
            text-align: center;
        }
        
        .stat-card:hover {
            transform: translateY(-3px);
            box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
        }
        
        .stat-value-large {
            font-size: 1.8rem;
            font-weight: 800;
            color: var(--primary);
            margin-bottom: 5px;
        }
        
        /* Progress Bar */
        .progress-container {
            margin: 25px 0;
        }
        
        .progress-label {
            display: flex;
            justify-content: space-between;
            margin-bottom: 10px;
            font-weight: 600;
            color: var(--dark);
        }
        
        .progress-bar {
            height: 12px;
            background: var(--light);
            border-radius: 6px;
            overflow: hidden;
            position: relative;
        }
        
        .progress-fill {
            height: 100%;
            background: var(--gradient);
            border-radius: 6px;
            transition: width 0.4s ease;
            width: 0%;
        }
        
        /* Image Preview */
        .preview-container {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 25px;
            margin: 30px 0;
        }
        
        .preview-box {
            border: 2px solid var(--light);
            border-radius: var(--border-radius);
            padding: 25px;
            text-align: center;
            background: white;
            transition: all 0.3s ease;
        }
        
        .preview-box:hover {
            border-color: var(--primary);
            box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
        }
        
        .preview-title {
            font-weight: 600;
            margin-bottom: 20px;
            color: var(--dark);
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 10px;
            padding-bottom: 15px;
            border-bottom: 1px solid var(--light);
        }
        
        .image-preview {
            max-width: 100%;
            max-height: 250px;
            border-radius: 10px;
            margin-bottom: 20px;
            object-fit: contain;
            box-shadow: 0 6px 20px rgba(0, 0, 0, 0.1);
            border: 1px solid var(--light-gray);
        }
        
        /* Files List */
        .files-container {
            max-height: 400px;
            overflow-y: auto;
            border: 1px solid var(--light);
            border-radius: var(--border-radius);
            margin-top: 25px;
            background: white;
        }
        
        .file-item {
            padding: 20px;
            border-bottom: 1px solid var(--light);
            display: flex;
            align-items: center;
            gap: 20px;
            transition: all 0.3s ease;
            cursor: pointer;
            position: relative;
        }
        
        .file-item:hover {
            background: #f8fafc;
        }
        
        .file-item.selected {
            background: rgba(52, 152, 219, 0.05);
            border-left: 4px solid var(--primary);
        }
        
        .file-icon {
            width: 50px;
            height: 50px;
            background: rgba(52, 152, 219, 0.1);
            border-radius: 12px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
            color: var(--primary);
        }
        
        .file-info {
            flex: 1;
            min-width: 0;
        }
        
        .file-name {
            font-weight: 600;
            margin-bottom: 8px;
            color: var(--dark);
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
        }
        
        .file-details {
            display: flex;
            gap: 20px;
            font-size: 0.9rem;
            color: var(--gray);
            flex-wrap: wrap;
        }
        
        .file-status {
            padding: 6px 15px;
            border-radius: 20px;
            font-size: 0.85rem;
            font-weight: 600;
            min-width: 100px;
            text-align: center;
        }
        
        .status-converted {
            background: rgba(46, 204, 113, 0.1);
            color: var(--secondary);
        }
        
        .status-pending {
            background: rgba(243, 156, 18, 0.1);
            color: var(--warning);
        }
        
        /* Download Section */
        .download-section {
            background: linear-gradient(135deg, #f8fafc, #e8edf5);
            padding: 30px;
            border-radius: var(--border-radius);
            margin-top: 30px;
            text-align: center;
            border: 2px dashed var(--light);
        }
        
        /* Premium Features */
        .premium-features {
            background: linear-gradient(135deg, #2c3e50 0%, #1a2530 100%);
            color: white;
            padding: 50px 40px;
            border-radius: var(--border-radius);
            margin: 50px 0;
            box-shadow: var(--shadow);
            position: relative;
            overflow: hidden;
        }
        
        .features-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 30px;
            margin-top: 40px;
        }
        
        .feature-card {
            background: rgba(255, 255, 255, 0.05);
            padding: 30px;
            border-radius: var(--border-radius);
            border: 1px solid rgba(255, 255, 255, 0.1);
            transition: all 0.3s ease;
            position: relative;
            overflow: hidden;
        }
        
        .feature-card::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 3px;
            background: var(--premium-gradient);
        }
        
        .feature-card:hover {
            transform: translateY(-8px);
            background: rgba(255, 255, 255, 0.1);
            box-shadow: 0 15px 35px rgba(0, 0, 0, 0.2);
        }
        
        .feature-icon {
            width: 60px;
            height: 60px;
            background: var(--premium-gradient);
            border-radius: 15px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.8rem;
            margin-bottom: 25px;
        }
        
        .feature-title {
            font-size: 1.4rem;
            margin-bottom: 15px;
            color: white;
        }
        
        /* Notification */
        .notification {
            position: fixed;
            bottom: 30px;
            right: 30px;
            padding: 20px 30px;
            background: var(--dark);
            color: white;
            border-radius: var(--border-radius);
            box-shadow: var(--shadow);
            display: none;
            z-index: 1000;
            animation: slideIn 0.3s ease;
            max-width: 400px;
            border-left: 5px solid var(--primary);
        }
        
        @keyframes slideIn {
            from {
                opacity: 0;
                transform: translateX(100px);
            }
            to {
                opacity: 1;
                transform: translateX(0);
            }
        }
        
        .notification.show {
            display: block;
        }
        
        /* Loader */
        .loader {
            display: inline-block;
            width: 24px;
            height: 24px;
            border: 3px solid rgba(255, 255, 255, 0.3);
            border-radius: 50%;
            border-top-color: white;
            animation: spin 1s linear infinite;
        }
        
        @keyframes spin {
            to { transform: rotate(360deg); }
        }
        
        /* Tool Options */
        .tool-options {
            display: flex;
            gap: 15px;
            margin: 25px 0;
            flex-wrap: wrap;
        }
        
        .tool-option {
            padding: 12px 25px;
            background: var(--light);
            border: 2px solid transparent;
            border-radius: var(--border-radius);
            cursor: pointer;
            font-weight: 500;
            transition: all 0.3s ease;
            display: flex;
            align-items: center;
            gap: 10px;
        }
        
        .tool-option.active {
            background: var(--primary);
            color: white;
            border-color: var(--primary);
        }
        
        .tool-option:hover:not(.active) {
            background: #e0e6ed;
        }
        
        /* AI Features */
        .ai-features {
            background: linear-gradient(135deg, rgba(52, 152, 219, 0.05), rgba(155, 89, 182, 0.05));
            padding: 25px;
            border-radius: var(--border-radius);
            margin: 25px 0;
            border: 1px solid rgba(52, 152, 219, 0.1);
        }
        
        /* Responsive Design */
        @media (max-width: 1200px) {
            .main-layout {
                gap: 25px;
            }
            
            .premium-card {
                padding: 30px;
            }
        }
        
        @media (max-width: 992px) {
            .main-layout {
                grid-template-columns: 1fr;
                gap: 30px;
            }
            
            .stats-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            
            .preview-container {
                grid-template-columns: 1fr;
                gap: 20px;
            }
        }
        
        @media (max-width: 768px) {
            body {
                padding: 15px 10px;
            }
            
            .container {
                padding: 0 15px;
            }
            
            .premium-header {
                padding: 25px 20px;
                margin: 20px 0;
            }
            
            .header-content {
                flex-direction: column;
                text-align: center;
                gap: 25px;
            }
            
            .logo-section {
                flex-direction: column;
                text-align: center;
            }
            
            .header-stats {
                justify-content: center;
            }
            
            .premium-card {
                padding: 25px 20px;
            }
            
            .upload-area {
                padding: 40px 20px;
            }
            
            .settings-grid {
                grid-template-columns: 1fr;
                gap: 20px;
            }
            
            .stats-grid {
                grid-template-columns: repeat(2, 1fr);
                gap: 12px;
            }
            
            .card-header {
                flex-direction: column;
                align-items: flex-start;
                gap: 15px;
            }
            
            .features-grid {
                grid-template-columns: 1fr;
                gap: 25px;
            }
            
            .premium-features {
                padding: 35px 25px;
            }
            
            .feature-card {
                padding: 25px;
            }
            
            .tool-options {
                justify-content: center;
            }
            
            .premium-btn {
                padding: 16px 25px;
                width: 100%;
                justify-content: center;
            }
            
            .download-section > div {
                flex-direction: column;
                gap: 15px;
            }
            
            .notification {
                bottom: 20px;
                right: 20px;
                left: 20px;
                max-width: calc(100% - 40px);
                text-align: center;
            }
            
            .file-details {
                flex-direction: column;
                gap: 5px;
            }
        }
        
        @media (max-width: 480px) {
            .container {
                padding: 0 10px;
            }
            
            .premium-header {
                padding: 20px 15px;
            }
            
            .logo-text h1 {
                font-size: 2rem;
            }
            
            .stat-value {
                font-size: 1.7rem;
            }
            
            .stats-grid {
                grid-template-columns: 1fr;
            }
            
            .stat-card {
                padding: 15px;
            }
            
            .upload-icon {
                font-size: 3rem;
            }
            
            .premium-card {
                padding: 20px 15px;
            }
            
            .card-title {
                font-size: 1.3rem;
            }
            
            .feature-card {
                padding: 20px;
            }
            
            .feature-title {
                font-size: 1.2rem;
            }
            
            .file-item {
                padding: 15px;
                flex-direction: column;
                text-align: center;
                gap: 15px;
            }
            
            .file-info {
                width: 100%;
            }
            
            .file-status {
                margin-top: 10px;
            }
        }
        
        /* Utility Classes */
        .text-center {
            text-align: center;
        }
        
        .mt-20 {
            margin-top: 20px;
        }
        
        .mb-20 {
            margin-bottom: 20px;
        }
        
        .hidden {
            display: none !important;
        }
        
        .flex-center {
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        /* Checkbox Styles */
        .checkbox-group {
            display: flex;
            flex-direction: column;
            gap: 15px;
            margin-top: 15px;
        }
        
        .checkbox-label {
            display: flex;
            align-items: center;
            gap: 12px;
            cursor: pointer;
            user-select: none;
            padding: 10px;
            border-radius: 10px;
            transition: background 0.3s ease;
        }
        
        .checkbox-label:hover {
            background: rgba(52, 152, 219, 0.05);
        }
        
        .checkbox-label input[type="checkbox"] {
            width: 20px;
            height: 20px;
            accent-color: var(--primary);
        }
        
        .premium-badge {
            background: var(--premium-gradient);
            color: white;
            padding: 4px 12px;
            border-radius: 12px;
            font-size: 0.75rem;
            font-weight: 600;
            margin-left: auto;
        }
        
        /* Empty State */
        .empty-state {
            text-align: center;
            padding: 60px 20px;
            color: var(--gray);
        }
        
        .empty-state i {
            font-size: 4rem;
            margin-bottom: 20px;
            opacity: 0.3;
            display: block;
        }
        
        /* File Size Savings */
        .savings-badge {
            background: rgba(46, 204, 113, 0.1);
            color: var(--secondary);
            padding: 8px 15px;
            border-radius: 20px;
            font-weight: 600;
            font-size: 0.9rem;
            display: inline-flex;
            align-items: center;
            gap: 8px;
        }