 @import url('https://fonts.googleapis.com/css2?family=Nunito:wght@400;600;700;800&display=swap');
        
        :root {
            --primary: #FF6B98;
            --secondary: #5E17EB;
            --tertiary: #00C2FF;
            --quaternary: #FFC700;
            --success: #5DE04A;
            --background: #F5F7FF;
            --white: #FFFFFF;
            --dark: #333333;
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Nunito', sans-serif;
        }
        
        body {
            background-color: var(--background);
        }
        
        .navbar {
            background-color: var(--white);
            padding: 15px 40px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
            position: sticky;
            top: 0;
            z-index: 100;
        }
        
        .logo img {
            height: 80px;
        }
        
        .nav-links {
            display: flex;
            gap: 30px;
        }
        
        .nav-links a {
            text-decoration: none;
            color: var(--dark);
            font-weight: 600;
            font-size: 16px;
            transition: all 0.3s ease;
        }
        
        .nav-links a:hover, .nav-links a.active {
            color: var(--primary);
        }
        
        .search-container {
            position: relative;
            width: 300px;
        }
        
        .search-container input {
            width: 100%;
            padding: 10px 40px 10px 15px;
            border-radius: 25px;
            border: 1px solid #ddd;
            outline: none;
            font-size: 14px;
        }
        
        .search-container button {
            position: absolute;
            right: 15px;
            top: 50%;
            transform: translateY(-50%);
            background: none;
            border: none;
            cursor: pointer;
            color: #777;
        }
        
        .auth-buttons {
            display: flex;
            gap: 15px;
        }
        
        .btn {
            padding: 10px 25px;
            border-radius: 25px;
            font-weight: 700;
            cursor: pointer;
            transition: all 0.3s ease;
            text-decoration: none;
            font-size: 15px;
            text-align: center;
        }
        
        .btn-outline {
            border: 2px solid var(--primary);
            background: transparent;
            color: var(--primary);
        }
        
        .btn-outline:hover {
            background: var(--primary);
            color: white;
        }
        
        .btn-filled {
            background: var(--secondary);
            color: white;
            border: none;
        }
        
        .btn-filled:hover {
            background: #4a12c9;
        }
        
        /* Mobile Navigation */
        .mobile-menu-btn {
            display: none;
            background: none;
            border: none;
            font-size: 24px;
            cursor: pointer;
            color: var(--dark);
        }
        
        /* Virtual Book Styles */
        .container {
            max-width: 1200px;
            margin: 30px auto;
            padding: 0 20px;
        }
        
        .breadcrumb {
            margin-bottom: 20px;
            font-size: 14px;
        }
        
        .breadcrumb a {
            color: var(--tertiary);
            text-decoration: none;
        }
        
        .breadcrumb span {
            color: var(--dark);
        }
        
        .book-container {
            display: flex;
            flex-direction: column;
            background: var(--white);
            border-radius: 15px;
            overflow: hidden;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
        }
        
        .book-header {
            background: linear-gradient(135deg, var(--primary), var(--secondary));
            color: white;
            padding: 20px;
            display: flex;
            justify-content: space-between;
            align-items: flex-start;
            flex-wrap: wrap;
            gap: 15px;
        }
        
        .book-title {
            flex: 1;
            min-width: 250px;
        }
        
        .book-title h1 {
            font-size: 24px;
            font-weight: 800;
            margin-bottom: 10px;
        }
        
        .book-details {
            display: flex;
            flex-wrap: wrap;
            gap: 15px;
            font-size: 14px;
        }
        
        .book-details span {
            display: flex;
            align-items: center;
            gap: 5px;
        }
        
        .book-actions {
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
        }
        
        .btn-book {
            background: rgba(255, 255, 255, 0.2);
            border: none;
            color: white;
            padding: 8px 15px;
            border-radius: 20px;
            display: flex;
            align-items: center;
            gap: 5px;
            cursor: pointer;
            transition: all 0.3s ease;
            white-space: nowrap;
        }
        
        .btn-book:hover {
            background: rgba(255, 255, 255, 0.3);
        }
        
        .book-viewer {
            display: flex;
            height: 600px;
            max-height: 70vh;
        }
        
        .book-content {
            flex: 1;
            position: relative;
            overflow: hidden;
        }
        
        .page {
            width: 100%;
            height: 100%;
            position: absolute;
            display: flex;
            justify-content: center;
            align-items: center;
            transition: transform 0.5s ease;
        }
        
        .page img {
            max-width: 100%;
            max-height: 100%;
            object-fit: contain;
        }
        
        .audio-zones {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            pointer-events: none;
        }
        
        .audio-zone {
            position: absolute;
            background: rgba(255, 255, 255, 0.1);
            border: 2px dashed rgba(255, 255, 255, 0.3);
            border-radius: 10px;
            cursor: pointer;
            pointer-events: auto;
            transition: all 0.3s ease;
        }
        
        .audio-zone:hover {
            background: rgba(0, 194, 255, 0.2);
            border-color: var(--tertiary);
        }
        
        .controls {
            display: flex;
            justify-content: space-between;
            padding: 15px 20px;
            background: #f7f7f7;
            border-top: 1px solid #eee;
            flex-wrap: wrap;
            gap: 10px;
        }
        
        .control-left, .control-right {
            display: flex;
            gap: 10px;
        }
        
        .control-center {
            display: flex;
            align-items: center;
            gap: 10px;
        }
        
        .btn-control {
            background: white;
            border: 1px solid #ddd;
            width: 40px;
            height: 40px;
            border-radius: 50%;
            display: flex;
            justify-content: center;
            align-items: center;
            cursor: pointer;
            transition: all 0.3s ease;
        }
        
        .btn-control:hover {
            background: #f0f0f0;
        }
        
        .btn-control.primary {
            background: var(--primary);
            color: white;
            border: none;
        }
        
        .btn-control.primary:hover {
            background: #ff5288;
        }
        
        .page-count {
            font-size: 14px;
            font-weight: 600;
            color: #777;
            white-space: nowrap;
        }
        
        /* Animation for page turn */
        @keyframes pageInLeft {
            from { transform: translateX(-100%); }
            to { transform: translateX(0); }
        }
        
        @keyframes pageOutRight {
            from { transform: translateX(0); }
            to { transform: translateX(100%); }
        }
        
        @keyframes pageInRight {
            from { transform: translateX(100%); }
            to { transform: translateX(0); }
        }
        
        @keyframes pageOutLeft {
            from { transform: translateX(0); }
            to { transform: translateX(-100%); }
        }
        
        /* Task section */
        .task-section {
            margin-top: 30px;
            background: white;
            border-radius: 15px;
            padding: 20px;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
        }
        
        .task-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 15px;
            flex-wrap: wrap;
            gap: 15px;
        }
        
        .task-header h2 {
            font-size: 20px;
            font-weight: 700;
            color: var(--dark);
            display: flex;
            align-items: center;
            gap: 10px;
        }
        
        .task-header h2 i {
            color: var(--secondary);
        }
        
        .task-list {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            gap: 20px;
        }
        
        .task-card {
            background: #f9f9f9;
            border-radius: 10px;
            padding: 20px;
            border-left: 5px solid var(--tertiary);
            transition: all 0.3s ease;
        }
        
        .task-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 20px rgba(0, 0, 0, 0.05);
        }
        
        .task-title {
            font-size: 18px;
            font-weight: 700;
            color: var(--tertiary);
            margin-bottom: 10px;
        }
        
        .task-meta {
            display: flex;
            justify-content: space-between;
            margin-bottom: 15px;
            font-size: 14px;
            color: #777;
            flex-wrap: wrap;
            gap: 10px;
        }
        
        .task-meta span {
            display: flex;
            align-items: center;
            gap: 5px;
        }
        
        .task-description {
            margin-bottom: 15px;
            font-size: 14px;
            line-height: 1.6;
        }
        
        .task-button {
            width: 100%;
            padding: 10px;
            border: none;
            background: var(--success);
            color: white;
            border-radius: 5px;
            font-weight: 700;
            cursor: pointer;
            transition: all 0.3s ease;
        }
        
        .task-button:hover {
            background: #4bc439;
        }
        
        /* Audio player */
        .audio-player {
            position: fixed;
            bottom: 20px;
            right: 20px;
            background: white;
            border-radius: 10px;
            padding: 15px;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
            display: flex;
            align-items: center;
            gap: 15px;
            opacity: 0;
            transform: translateY(20px);
            transition: all 0.3s ease;
            z-index: 1000;
            max-width: calc(100% - 40px);
        }
        
        .audio-player.active {
            opacity: 1;
            transform: translateY(0);
        }
        
        .audio-play {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            background: var(--quaternary);
            color: white;
            display: flex;
            justify-content: center;
            align-items: center;
            cursor: pointer;
            flex-shrink: 0;
        }
        
        .audio-info {
            flex: 1;
            min-width: 0;
            overflow: hidden;
        }
        
        .audio-title {
            font-weight: 600;
            font-size: 14px;
            margin-bottom: 5px;
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
        }
        
        .audio-progress {
            width: 100%;
            height: 5px;
            background: #eee;
            border-radius: 5px;
            overflow: hidden;
        }
        
        .audio-progress-bar {
            height: 100%;
            background: var(--quaternary);
            width: 0%;
            transition: width 0.1s linear;
        }
        
        .audio-close {
            color: #777;
            cursor: pointer;
            transition: all 0.3s ease;
            flex-shrink: 0;
        }
        
        .audio-close:hover {
            color: var(--dark);
        }
        
        /* Guide overlay */
        .guide-overlay {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.7);
            display: flex;
            justify-content: center;
            align-items: center;
            z-index: 2000;
            opacity: 0;
            visibility: hidden;
            transition: all 0.3s ease;
            padding: 15px;
        }
        
        .guide-overlay.active {
            opacity: 1;
            visibility: visible;
        }
        
        .guide-content {
            background: white;
            border-radius: 15px;
            width: 500px;
            max-width: 100%;
            padding: 25px;
            position: relative;
        }
        
        .guide-close {
            position: absolute;
            top: 15px;
            right: 15px;
            color: #777;
            cursor: pointer;
            transition: all 0.3s ease;
        }
        
        .guide-close:hover {
            color: var(--dark);
        }
        
        .guide-title {
            font-size: 22px;
            font-weight: 800;
            color: var(--primary);
            margin-bottom: 15px;
            display: flex;
            align-items: center;
            gap: 10px;
        }
        
        .guide-steps {
            list-style: none;
        }
        
        .guide-step {
            display: flex;
            margin-bottom: 15px;
        }
        
        .step-number {
            width: 30px;
            height: 30px;
            background: var(--secondary);
            color: white;
            border-radius: 50%;
            display: flex;
            justify-content: center;
            align-items: center;
            font-weight: 700;
            margin-right: 15px;
            flex-shrink: 0;
        }
        
        .step-text {
            flex: 1;
            padding-top: 5px;
        }
        
        .guide-footer {
            margin-top: 20px;
            text-align: center;
        }
        
        .btn-start {
            background: var(--quaternary);
            color: white;
            border: none;
            padding: 10px 25px;
            border-radius: 25px;
            font-weight: 700;
            cursor: pointer;
            transition: all 0.3s ease;
        }
        
        .btn-start:hover {
            background: #e0b000;
        }
        
        /* Loading animation */
        .loading {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: white;
            display: flex;
            justify-content: center;
            align-items: center;
            z-index: 3000;
            transition: opacity 0.5s ease;
        }
        
        .loading.hidden {
            opacity: 0;
            pointer-events: none;
        }
        
        .loading-animation {
            display: flex;
            align-items: center;
            justify-content: center;
            flex-direction: column;
        }
        
        .loading-circles {
            display: flex;
            gap: 10px;
            margin-bottom: 20px;
        }
        
        .loading-circle {
            width: 20px;
            height: 20px;
            border-radius: 50%;
            animation: bounce 1.4s infinite ease-in-out both;
        }
        
        .loading-circle:nth-child(1) {
            background-color: var(--primary);
            animation-delay: -0.32s;
        }
        
        .loading-circle:nth-child(2) {
            background-color: var(--secondary);
            animation-delay: -0.16s;
        }
        
        .loading-circle:nth-child(3) {
            background-color: var(--tertiary);
        }
        
        .loading-circle:nth-child(4) {
            background-color: var(--quaternary);
            animation-delay: 0.16s;
        }
        
        .loading-text {
            font-size: 18px;
            font-weight: 700;
            color: var(--dark);
            text-align: center;
            padding: 0 10px;
        }
        
        @keyframes bounce {
            0%, 80%, 100% {
                transform: scale(0);
            }
            40% {
                transform: scale(1);
            }
        }
        
        /* Responsive Styles */
        @media (max-width: 1024px) {
            .book-viewer {
                height: 500px;
            }
        }
        
        @media (max-width: 768px) {
            .navbar {
                padding: 12px 15px;
            }
            
            .logo img {
                height: 32px;
            }
            
            .nav-links, .search-container {
                display: none;
            }
            
            .mobile-menu-btn {
                display: block;
            }
            
            .auth-buttons {
                gap: 8px;
            }
            
            .btn {
                padding: 8px 15px;
                font-size: 14px;
            }
            
            .book-header {
                padding: 15px;
            }
            
            .book-title h1 {
                font-size: 20px;
                line-height: 1.3;
            }
            
            .book-viewer {
                height: 400px;
            }
            
            .book-actions {
                width: 100%;
                justify-content: center;
            }
            
            .controls {
                justify-content: center;
            }
            
            .control-center {
                order: -1;
                width: 100%;
                justify-content: center;
                margin-bottom: 10px;
            }
        }
        
        @media (max-width: 480px) {
            .container {
                padding: 0 12px;
                margin: 15px auto;
            }
            
            .book-title h1 {
                font-size: 18px;
            }
            
            .book-details {
                gap: 8px;
            }
            
            .book-details span {
                font-size: 12px;
            }
            
            .btn-book {
                padding: 6px 12px;
                font-size: 13px;
            }
            
            .book-viewer {
                height: 300px;
            }
            
            .btn-control {
                width: 36px;
                height: 36px;
            }
            
            .task-header h2 {
                font-size: 18px;
            }
            
            .task-list {
                grid-template-columns: 1fr;
            }
            
            .task-title {
                font-size: 16px;
            }
            
            .guide-content {
                padding: 20px 15px;
            }
            
            .guide-title {
                font-size: 18px;
            }
            
            .step-text {
                font-size: 14px;
            }
        }
        
        /* Mobile Navigation Menu */
        .mobile-nav {
            position: fixed;
            top: 0;
            left: -100%;
            width: 80%;
            max-width: 300px;
            height: 100%;
            background: var(--white);
            z-index: 1000;
            transition: left 0.3s ease;
            box-shadow: 0 0 20px rgba(0, 0, 0, 0.2);
            overflow-y: auto;
        }
        
        .mobile-nav.active {
            left: 0;
        }
        
        .mobile-nav-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 15px;
            border-bottom: 1px solid #eee;
        }
        
        .mobile-nav-close {
            font-size: 24px;
            color: #777;
            background: none;
            border: none;
            cursor: pointer;
        }
        
        .mobile-nav-links {
            padding: 20px 15px;
        }
        
        .mobile-nav-links a {
            display: block;
            padding: 12px 0;
            text-decoration: none;
            color: var(--dark);
            font-weight: 600;
            border-bottom: 1px solid #eee;
        }
        
        .mobile-nav-links a.active {
            color: var(--primary);
        }
        
        .mobile-nav-search {
            padding: 0 15px 15px;
        }
        
        .mobile-nav-search input {
            width: 100%;
            padding: 10px 15px;
            border-radius: 25px;
            border: 1px solid #ddd;
            outline: none;
            font-size: 14px;
        }
        
        .overlay {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.5);
            z-index: 999;
            display: none;
        }
        
        .overlay.active {
            display: block;
        }