:root {
            --background: #0a0a0a;
            --card-bg: #2c2c2c;
            --text: #e0e0e0;
            --secondary-text: #bdc1c6;
            --primary: #1a73e8;
            --highlight: #00ffcc;
            --shadow: rgba(0, 0, 0, 0.2);
            --spacing-unit: 1rem;
            --transition-speed: 0.3s;
        }
        [data-theme="light"] {
            --background: #f0f0f0;
            --card-bg: #ffffff;
            --text: #333333;
            --secondary-text: #666666;
            --primary: #1a73e8;
            --highlight: #00cc99;
            --shadow: rgba(0, 0, 0, 0.1);
             }
        [data-theme="pure"] {
            --background: #fff6e6;
            --card-bg: #fff0cc;
            --text: #4d1a00;
            --secondary-text: #994d00;
            --primary: #cc3300;
            --highlight: #ff9900;
            --shadow: rgba(204, 102, 0, 0.3);}
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Roboto', sans-serif;
        }
        body {
            background-color: var(--background);
            color: var(--text);
            line-height: 1.6;
            overflow-x: hidden;
            transition: background-color var(--transition-speed) ease, color var(--transition-speed) ease;
            -webkit-user-select: none;
            -moz-user-select: none;
            -ms-user-select: none;
            user-select: none;
        }
        body::-webkit-scrollbar {
            width: 8px;
        }
        body::-webkit-scrollbar-thumb {
            background-color: var(--primary);
            border-radius: 4px;
        }
        body::-webkit-scrollbar-track {
            background-color: var(--card-bg);
        }
        .header {
            padding: calc(var(--spacing-unit) * 1.5) calc(var(--spacing-unit) * 2);
            display: flex;
            align-items: center;
            justify-content: space-between;
            background: var(--card-bg);
            box-shadow: 0 4px 10px var(--shadow);
            position: sticky;
            top: 0;
            z-index: 1000;
            flex-wrap: nowrap;
            gap: var(--spacing-unit);
        }
        .header-logo {
            font-size: 2rem;
            font-weight: 700;
            color: var(--primary);
            display: flex;
            align-items: center;
            gap: 0.5rem;
            flex-shrink: 0;
        }
        .search-bar {
            flex: 1;
            max-width: 50%;
            position: relative;
            min-width: 150px;
        }
        .search-bar input {
            width: 100%;
            padding: 0.75rem 1rem;
            border: 1px solid var(--primary);
            border-radius: 24px;
            background-color: var(--background);
            color: var(--text);
            font-size: 1rem;
            outline: none;
            transition: all var(--transition-speed) ease;
        }
        .search-bar input:focus {
            border-color: var(--highlight);
            box-shadow: 0 0 5px var(--highlight);
        }
        .settings-icon {
            font-size: 1.75rem;
            color: var(--primary);
            cursor: pointer;
            flex-shrink: 0;
            display: flex;
            align-items: center;
            justify-content: center;
            background: none !important;
            box-shadow: none !important;
            padding: 0;
        }
        .gear-icon {
            display: inline-block;
            transition: transform var(--transition-speed) ease;
        }
        .settings-icon:hover .gear-icon {
            transform: rotate(90deg);
        }
        .settings-icon:hover {
            background: none !important;
            box-shadow: none !important;
        }
        .tabs {
            background-color: var(--card-bg);
            padding: calc(var(--spacing-unit) * 0.75) calc(var(--spacing-unit) * 1.5);
            border-bottom: 1px solid var(--shadow);
            overflow-x: auto;
            white-space: nowrap;
        }
        .tab-list {
            display: inline-flex;
            gap: calc(var(--spacing-unit) * 2);
            align-items: center;
        }
        .tab {
            padding: 0.75rem 1rem;
            font-size: 1rem;
            font-weight: 500;
            color: var(--secondary-text);
            cursor: pointer;
            transition: all var(--transition-speed) ease;
            position: relative;
            border-radius: 8px;
        }
        .tab.active {
            color: var(--highlight);
            background-color: full-screen;
        }
        .tab.hidden {
            display: none;
        }
        .content {
            padding: calc(var(--spacing-unit) * 2);
            max-width: 1400px;
            margin: 0 auto;
            width: 100%;
        }
        .section {
            display: none;
            opacity: 0;
            transition: opacity var(--transition-speed) ease;
        }
        .section.active {
            display: block;
            opacity: 1;
        }
        .section-title {
            font-size: 1.75rem;
            font-weight: 500;
            margin-bottom: calc(var(--spacing-unit) * 1.5);
            color: var(--text);
        }
        .card-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
            gap: calc(var(--spacing-unit) * 1.5);
            width: 100%;
        }
        .featured-section {
            display: none;
        }
        .section#all.active ~ .featured-section {
            display: block;
        }
        .featured-section .card-grid {
            display: flex;
            overflow-x: auto;
            white-space: nowrap;
            gap: calc(var(--spacing-unit) * 1.5);
            padding-bottom: var(--spacing-unit);
        }
        .featured-section .card-grid::-webkit-scrollbar {
            height: 8px;
        }
        .featured-section .card-grid::-webkit-scrollbar-thumb {
            background-color: var(--primary);
            border-radius: 4px;
        }
        .featured-section .card-grid::-webkit-scrollbar-track {
            background-color: var(--card-bg);
        }
        .featured-section .card {
            flex: 0 0 auto;
            width: 200px;
            min-width: 200px;
        }
        .card {
            background: var(--card-bg);
            border-radius: 16px;
            padding: calc(var(--spacing-unit) * 1.5);
            text-align: center;
            box-shadow: 0 4px 12px var(--shadow);
            transition: transform var(--transition-speed) ease, box-shadow var(--transition-speed) ease;
            cursor: pointer;
            overflow: hidden;
            display: flex;
            flex-direction: column;
            justify-content: space-between;
        }
        .card:hover {
            transform: translateY(-10px);
            box-shadow: 0 8px 20px var(--shadow);
        }
        .card-logo {
            width: 5rem;
            height: 5rem;
            border-radius: 20px;
            object-fit: cover;
            margin: 0 auto calc(var(--spacing-unit) * 1);
        }
        .card-title {
            font-size: 1.25rem;
            font-weight: 600;
            margin-bottom: 0.5rem;
            color: var(--text);
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: normal;
            overflow-wrap: break-word;
            max-height: 3.75rem;
        }
        .card-type {
            font-size: 0.875rem;
            color: var(--secondary-text);
            margin-bottom: calc(var(--spacing-unit) * 1);
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: nowrap;
        }
        .card-download {
            padding: 0.625rem 1.5rem;
            background: linear-gradient(135deg, var(--primary), var(--highlight));
            color: #fff;
            border: none;
            border-radius: 24px;
            font-size: 0.875rem;
            font-weight: 500;
            cursor: pointer;
            transition: transform var(--transition-speed) ease;
            margin-top: auto;
        }
        .card-download:hover {
            transform: scale(1.05);
        }
        .no-results {
            text-align: center;
            color: var(--secondary-text);
            font-size: 1rem;
            margin-top: calc(var(--spacing-unit) * 2);
            display: none;
        }
        .detail-view {
            position: fixed;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            width: 90vw;
            max-width: 800px;
            max-height: 85vh;
            overflow-y: auto;
            background: var(--background);
            padding: calc(var(--spacing-unit) * 2);
            border-radius: 16px;
            box-shadow: 0 8px 24px var(--shadow);
            opacity: 0;
            transition: opacity var(--transition-speed) ease, transform var(--transition-speed) ease;
            display: none;
            z-index: 1001;
        }
        .detail-view.active {
            display: block;
            opacity: 1;
            transform: translate(-50%, -50%) scale(1);
        }
        .close-btn {
            position: absolute;
            top: var(--spacing-unit);
            right: var(--spacing-unit);
            background: var(--primary);
            color: #fff;
            border: none;
            font-size: 1.5rem;
            width: 2.5rem;
            height: 2.5rem;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            transition: background var(--transition-speed) ease;
        }
        .close-btn:hover {
            background: var(--highlight);
        }
        .detail-header {
            display: flex;
            gap: calc(var(--spacing-unit) * 2);
            align-items: flex-start;
            margin-bottom: calc(var(--spacing-unit) * 2);
            flex-wrap: wrap;
        }
        .detail-logo {
            width: 6rem;
            height: 6rem;
            border-radius: 24px;
            object-fit: cover;
            box-shadow: 0 4px 12px var(--shadow);
            flex-shrink: 0;
        }
        .detail-info {
            flex: 1;
            min-width: 200px;
        }
        .detail-title {
            font-size: 2rem;
            font-weight: 600;
            color: var(--text);
        }
        .detail-type {
            font-size: 1rem;
            color: var(--secondary-text);
            margin-bottom: 0.5rem;
        }
        .detail-verified {
            font-size: 1rem;
            color: var(--highlight);
            margin-bottom: calc(var(--spacing-unit) * 1.5);
        }
        .detail-download {
            padding: 0.75rem 2rem;
            background: linear-gradient(45deg, var(--primary), var(--highlight));
            color: #fff;
            border: none;
            border-radius: 25px;
            font-size: 1rem;
            font-weight: 500;
            cursor: pointer;
            transition: transform var(--transition-speed) ease;
        }
        .detail-download:hover {
            transform: scale(1.05);
        }
        .detail-short-desc {
            font-size: 1.125rem;
            color: var(--text);
            margin-bottom: calc(var(--spacing-unit) * 1.5);
        }
        .detail-long-desc {
            font-size: 1rem;
            color: var(--secondary-text);
            line-height: 1.8;
        }
        .detail-images {
            display: flex;
            flex-wrap: nowrap;
            overflow-x: auto;
            gap: calc(var(--spacing-unit) * 1.5);
            padding: calc(var(--spacing-unit) * 1.5) 0;
            background: var(--card-bg);
            border-radius: 12px;
            box-shadow: 0 4px 12px var(--shadow);
            scroll-snap-type: x mandatory;
        }
        .detail-images::-webkit-scrollbar {
            height: 8px;
        }
        .detail-images::-webkit-scrollbar-thumb {
            background-color: var(--primary);
            border-radius: 4px;
        }
        .detail-images::-webkit-scrollbar-track {
            background-color: var(--card-bg);
        }
        .detail-images img {
            width: 250px;
            height: 150px;
            border-radius: 12px;
            object-fit: cover;
            transition: transform var(--transition-speed) ease;
            flex-shrink: 0;
            cursor: pointer;
            scroll-snap-align: start;
        }
        .detail-images img:hover {
            transform: scale(1.05);
        }
        .settings-window {
            position: fixed;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            background: var(--card-bg);
            padding: calc(var(--spacing-unit) * 2);
            border-radius: 12px;
            box-shadow: 0 8px 16px var(--shadow);
            z-index: 1002;
            width: 90vw;
            max-width: 450px;
            opacity: 0;
            transition: opacity var(--transition-speed) ease, transform var(--transition-speed) ease;
            display: none;
        }
        .settings-window.active {
            display: block;
            opacity: 1;
            transform: translate(-50%, -50%) scale(1);
        }
        .settings-window h2 {
            font-size: 1.75rem;
            font-weight: 500;
            margin-bottom: calc(var(--spacing-unit) * 1.5);
            color: var(--text);
        }
        .settings-option {
            margin-bottom: calc(var(--spacing-unit) * 1.5);
        }
        .settings-window label {
            display: block;
            font-size: 1rem;
            color: var(--secondary-text);
            margin-bottom: 0.5rem;
        }
        .settings-window select,
        .settings-window input[type="checkbox"] {
            width: 100%;
            padding: 0.75rem;
            border: 1px solid var(--primary);
            border-radius: 8px;
            font-size: 1rem;
            background: var(--background);
            color: var(--text);
            outline: none;
        }
        .settings-window input[type="checkbox"] {
            width: auto;
            margin-right: 0.5rem;
        }
        .settings-window button {
            padding: 0.75rem 1.5rem;
            background: linear-gradient(45deg, var(--primary), var(--highlight));
            color: #fff;
            border: none;
            border-radius: 8px;
            font-size: 1rem;
            font-weight: 500;
            cursor: pointer;
            transition: transform var(--transition-speed) ease;
            width: 100%;
        }
        .settings-window button:hover {
            transform: scale(1.05);
        }
        .overlay {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0,0,0,0.7);
            z-index: 1000;
            opacity: 0;
            transition: opacity var(--transition-speed) ease;
            display: none;
        }
        .overlay.active {
            display: block;
            opacity: 1;
        }
        footer {
            background: var(--card-bg);
            padding: var(--spacing-unit);
            text-align: center;
            color: var(--secondary-text);
            font-size: 0.875rem;
            margin-top: calc(var(--spacing-unit) * 2);
        }
        footer nav {
            margin-top: 0.5rem;
            display: flex;
            justify-content: center;
            gap: 1rem;
            flex-wrap: wrap;
        }
        footer a {
            color: var(--primary);
            text-decoration: none;
            transition: color var(--transition-speed) ease;
        }
        footer a:hover {
            color: var(--highlight);
        }
        .books-filter-bar {
            display: flex;
            align-items: center;
            gap: 1rem;
            margin-bottom: 1.5rem;
            flex-wrap: wrap;
            background: rgba(255, 255, 255, 0.05);
            padding: 0.75rem 1rem;
            border-radius: 12px;
            box-shadow: 0 2px 12px rgba(0, 0, 0, 0.15);
        }
        .filter-label {
            font-weight: 600;
            font-size: 1rem;
            color: var(--text);
        }
        .custom-select-wrapper {
            position: relative;
            width: 250px;
            max-width: 100%;
        }
        .custom-select-wrapper select {
            width: 100%;
            padding: 0.6rem 2.5rem 0.6rem 1rem;
            font-size: 0.95rem;
            font-weight: 500;
            border-radius: 8px;
            background-color: var(--card-bg);
            color: var(--text);
            border: 1px solid rgba(255, 255, 255, 0.2);
            appearance: none;
            -webkit-appearance: none;
            -moz-appearance: none;
            transition: all 0.3s ease;
            cursor: pointer;
        }
        .custom-select-wrapper select:focus {
            outline: none;
            border-color: var(--highlight);
            box-shadow: none;
        }
        .filter-dropdown-icon {
            position: absolute;
            top: 50%;
            right: 1rem;
            transform: translateY(-50%);
            pointer-events: none;
            font-size: 0.8rem;
            color: var(--text);
            transition: transform 0.3s ease;
        }
        .filter-dropdown-icon.rotate {
            transform: translateY(-50%) rotate(180deg);
        }
        #languageFilterWrapper {
            position: relative;
            width: 250px;
            max-width: 100%;
        }
        .multi-select-trigger {
            padding: 0.6rem 2.5rem 0.6rem 1rem;
            background-color: var(--card-bg);
            color: var(--text);
            border: 1px solid rgba(255, 255, 255, 0.2);
            border-radius: 8px;
            font-size: 0.95rem;
            font-weight: 500;
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        .multi-select-dropdown {
            position: absolute;
            top: 100%;
            left: 0;
            right: 0;
            background-color: var(--card-bg);
            color: var(--text);
            border: 1px solid rgba(255, 255, 255, 0.2);
            border-radius: 8px;
            padding: 0.5rem 1rem;
            margin-top: 4px;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
            z-index: 100;
            max-height: 160px;
            overflow-y: auto;
            display: none;
        }
        .multi-select-dropdown label {
            display: block;
            margin-bottom: 0.4rem;
            cursor: pointer;
        }
        .multi-select-dropdown input[type="checkbox"] {
            margin-right: 0.5rem;
        }
        .rotate-on-open.rotate {
            transform: translateY(-50%) rotate(180deg);
        }
        @keyframes rainbowGlow {
            0% { box-shadow: 0 0 10px #ff0000; }
            20% { box-shadow: 0 0 10px #ff00ff; }
            40% { box-shadow: 0 0 40px #0000ff; }
            60% { box-shadow: 0 0 60px #00ffff; }
            80% { box-shadow: 0 0 80px #00ff00; }
            100% { box-shadow: 0 0 100px #ff0000; }
        }
        .rainbow-active {
            animation: rainbowGlow 3s infinite;
        }
        /* Full-screen book modal */
        .book-modal {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: var(--background);
            z-index: 1003;
            display: none;
            opacity: 0;
            transition: opacity var(--transition-speed) ease;
        }
        .book-modal.active {
            display: flex;
            opacity: 1;
            justify-content: center;
            align-items: center;
        }
        .book-modal-content {
            width: 100%;
            height: 100%;
            position: relative;
            display: flex;
            flex-direction: column;
        }
        .book-iframe {
            width: 100%;
            height: 100%;
            border: none;
            background: var(--card-bg);
        }
        .book-modal-close {
            position: absolute;
            top: var(--spacing-unit);
            right: var(--spacing-unit);
            background: var(--primary);
            color: #fff;
            border: none;
            font-size: 1.5rem;
            width: 2.5rem;
            height: 2.5rem;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            transition: background var(--transition-speed) ease;
        }
        .book-modal-close:hover {
            background: var(--highlight);
        }
        @media (max-width: 1400px) {
            .content {
                max-width: 1200px;
            }
            .card-grid {
                grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
            }
            .featured-section .card {
                width: 180px;
                min-width: 180px;
            }
        }
        @media (max-width: 1200px) {
            .search-bar {
                max-width: 40%;
            }
            .card-grid {
                grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
            }
            .featured-section .card {
                width: 160px;
                min-width: 160px;
            }
            .detail-logo {
                width: 7rem;
                height: 7rem;
            }
        }
        @media (max-width: 900px) {
            .header {
                padding: var(--spacing-unit);
            }
            .header-logo {
                height: 1.75rem;
                font-size: 1.5rem;
            }
            .search-bar {
                max-width: 40%;
                min-width: 60px;
            }
            .card-grid {
                grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
            }
            .featured-section .card {
                width: 150px;
                min-width: 150px;
            }
            .detail-header {
                gap: var(--spacing-unit);
            }
            .detail-logo {
                width: 6rem;
                height: 6rem;
            }
            .tab-list {
                gap: var(--spacing-unit);
            }
        }
        @media (max-width: 600px) {
            .header {
                padding: calc(var(--spacing-unit) * 0.75);
                flex-direction: row;
                flex-wrap: nowrap;
                align-items: center;
                justify-content: space-between;
            }
            .header-logo {
                font-size: 1.25rem;
                flex-shrink: 1;
                max-width: 30%;
            }
            .header-logo img {
                height: 1.25rem;
            }
            .search-bar {
                max-width: 40%;
                min-width: 50px;
                flex-grow: 1;
            }
            .search-bar input {
                padding: 0.5rem;
                font-size: 0.875rem;
            }
            .settings-icon {
                font-size: 1.75rem;
                color: var(--primary);
                cursor: pointer;
                transition: transform var(--transition-speed) ease;
                flex-shrink: 0;
                display: flex;
                align-items: center;
                justify-content: center;
            }
            .gear-icon {
                display: inline-block;
                transition: transform var(--transition-speed) ease;
            }
            .settings-icon:hover .gear-icon {
                transform: rotate(90deg);
            }
            .tabs {
                padding: 0.5rem;
            }
            .tab {
                font-size: 0.875rem;
                padding: 0.5rem;
            }
            .content {
                padding: var(--spacing-unit);
            }
            .card-grid {
                grid-template-columns: repeat(2, 1fr);
                gap: var(--spacing-unit);
            }
            .featured-section .card {
                width: 140px;
                min-width: 140px;
            }
            .card {
                padding: var(--spacing-unit);
            }
            .card-logo {
                width: 3.5rem;
                height: 3.5rem;
            }
            .detail-view {
                padding: var(--spacing-unit);
                max-width: 95vw;
                width: 95vw;
            }
            .detail-header {
                flex-direction: column;
                align-items: center;
                text-align: center;
            }
            .detail-logo {
                width: 5rem;
                height: 5rem;
            }
            .detail-images {
                flex-wrap: nowrap;
                overflow-x: auto;
                scroll-snap-type: x mandatory;
            }
            .detail-images img {
                width: 200px;
                height: 120px;
                scroll-snap-align: start;
            }
            .section-title {
                font-size: 1.5rem;
            }
            .card-title {
                font-size: 1rem;
                max-height: 3rem;
            }
            .detail-title {
                font-size: 1.25rem;
            }
        }
        @media (max-width: 400px) {
            .header-logo {
                font-size: 1rem;
                max-width: 25%;
            }
            .header-logo img {
                height: 1rem;
            }
            .search-bar {
                max-width: 40%;
                min-width: 50px;
            }
            .settings-icon {
                font-size: 1rem;
            }
            .card-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            .featured-section .card {
                width: 120px;
                min-width: 120px;
            }
            .card {
                padding: calc(var(--spacing-unit) * 0.75);
            }
            .card-logo {
                width: 3rem;
                height: 3rem;
            }
            .tab {
                font-size: 0.75rem;
                padding: 0.4rem 0.6rem;
            }
            .detail-logo {
                width: 4rem;
                height: 4rem;
            }
            .settings-window {
                max-width: 90vw;
            }
            .detail-images img {
                width: 180px;
                height: 108px;
            }
        }
        @media (max-width: 320px) {
            .header {
                padding: 0.5rem;
            }
            .search-bar input {
                padding: 0.4rem;
                font-size: 0.75rem;
            }
            .card-title {
                font-size: 0.875rem;
                max-height: 2.625rem;
            }
            .card-type {
                font-size: 0.75rem;
            }
            .detail-images img {
                width: 160px;
                height: 96px;
            }
        }
        button, a, [role="button"], [role="tab"], [tabindex="0"], .card, .tab, .close-btn, .detail-download, .card-download, .settings-icon, .multi-select-trigger {
            -webkit-tap-highlight-color: transparent;
            -moz-tap-highlight-color: transparent;
        }
        button:focus, a:focus, [role="button"]:focus, [role="tab"]:focus, [tabindex="0"]:focus, .card:focus, .tab:focus, .close-btn:focus, .detail-download:focus, .card-download:focus, .settings-icon:focus, .multi-select-trigger:focus {
            outline: none;
            box-shadow: 0 0 0 2px var(--highlight);
            transition: box-shadow var(--transition-speed) ease;
        }
        .card:hover, .tab:hover, .close-btn:hover, .detail-download:hover, .card-download:hover, .settings-icon:hover, .multi-select-trigger:hover {
            box-shadow: 0 8px 20px var(--shadow);
        }