:root {
            --primary-color: #00d1b2;
            --secondary-color: #667eea;
            --accent-color: #764ba2;
            --dark-bg: #0a0a0a;
            --card-bg: #1a1a1a;
            --text-primary: #ffffff;
            --text-secondary: #a8a8a8;
            --gradient-primary: linear-gradient(135deg, #00d1b2 0%, #667eea 50%, #764ba2 100%);
            --gradient-card: linear-gradient(145deg, #1a1a1a 0%, #2a2a2a 100%);
        }

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

        body {
            font-family: 'Inter', sans-serif;
            background-color: var(--dark-bg);
            color: var(--text-primary);
            overflow-x: hidden;
            line-height: 1.6;
        }

        /* Custom Navbar Styling */
        .custom-navbar {
              top: 0;            /* sticks to the very top */
  left: 0;
            background: rgba(10, 10, 10, 0.95);
            backdrop-filter: blur(20px);
            padding: 1rem 0;
            border-bottom: 1px solid rgba(0, 209, 178, 0.2);
            position: fixed;
            width: 100%;
            z-index: 1000;
            transition: all 0.3s ease;
        }

        .custom-navbar.scrolled {
            background: rgba(10, 10, 10, 0.98);
            box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
        }

        .navbar-brand {
            font-family: 'Space Grotesk', sans-serif;
            font-size: 1.8rem;
            font-weight: 700;
            color: var(--text-primary) !important;
            text-decoration: none;
            transition: all 0.3s ease;
        }

        .navbar-brand:hover {
            transform: scale(1.05);
        }

        .navbar-brand span {
            background: var(--gradient-primary);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }

        .navbar-nav .nav-link {
            color: var(--text-primary) !important;
            margin: 0 1rem;
            font-weight: 500;
            position: relative;
            transition: all 0.3s ease;
        }

        .navbar-nav .nav-link::after {
            content: '';
            position: absolute;
            bottom: -5px;
            left: 50%;
            width: 0;
            height: 2px;
            background: var(--gradient-primary);
            transition: all 0.3s ease;
            transform: translateX(-50%);
        }

        .navbar-nav .nav-link:hover::after,
        .navbar-nav .nav-link.active::after {
            width: 100%;
        }

        .navbar-nav .nav-link:hover {
            color: var(--primary-color) !important;
            transform: translateY(-2px);
        }

        /* Hero Section */
        .hero {
            position: relative;
            height: 50vh; /* Adjusted for library page */
            display: flex;
            align-items: center;
            justify-content: center;
            background: url('hero_background.png') center/cover no-repeat;
            overflow: hidden;
            margin-top: 70px; /* To account for fixed navbar */
        }

        .hero::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(10, 10, 10, 0.4);
            z-index: 1;
        }

        .hero-content {
            position: relative;
            z-index: 2;
            text-align: center;
            max-width: 800px;
            padding: 0 2rem;
            animation: fadeInUp 1s ease-out;
        }

        .hero-title {
            font-family: 'Space Grotesk', sans-serif;
            font-size: clamp(2.5rem, 5vw, 4rem);
            font-weight: 700;
            margin-bottom: 1.5rem;
            background: var(--gradient-primary);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            line-height: 1.2;
        }

        .hero-subtitle {
            font-size: clamp(1.1rem, 2vw, 1.3rem);
            color: var(--text-secondary);
            margin-bottom: 2rem;
            font-weight: 400;
        }

        /* Books container */
        .books-container {
            max-width: 1200px;
            margin: 4rem auto;
            padding: 0 2rem;
        }

        .book-item {
            display: flex;
            align-items: center;
            margin-bottom: 4rem;
            padding: 2rem;
            background: var(--card-bg);
            border-radius: 20px;
            border: 1px solid rgba(255, 255, 255, 0.1);
            transition: all 0.3s ease;
            position: relative;
            overflow: hidden;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
        }

        .book-item::before {
            content: '';
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(90deg, transparent, rgba(0, 209, 178, 0.1), transparent);
            transition: all 0.5s ease;
        }

        .book-item:hover {
            transform: translateY(-10px);
            box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
            border-color: var(--primary-color);
        }

        .book-item:hover::before {
            left: 100%;
        }

        .book-item:nth-child(even) {
            flex-direction: row-reverse;
        }

        /* 3D Book Styles */
        .book3d {
            margin: 0 2rem;
            transition: all 0.3s ease;
            filter: drop-shadow(0 10px 20px rgba(0, 0, 0, 0.3));
        }

        .book3d:hover {
            transform: scale(1.05);
        }

        .book3d img {
            max-width: 100%;
            border: 2px solid var(--primary-color);
            border-radius: 8px;
            transition: all 0.3s ease;
        }

        .csstransforms3d .books {
            -moz-perspective: 100px;
            -moz-transform-style: preserve-3d;
            -webkit-transform-style: preserve-3d;
        }

        .csstransforms3d .book3d {
            position: relative;
            -moz-perspective: 100px;
            -moz-transform: rotateY(-3deg);
            -webkit-transform: perspective(100) rotateY(-3deg);
            outline: 1px solid transparent;
            box-shadow: none;
            margin: 0;
        }

        .csstransforms3d .book3d img {
            position: relative;
            max-width: 100%;
        }

        .csstransforms3d .book3d:before,
        .csstransforms3d .book3d:after {
            position: absolute;
            top: 2%;
            height: 96%;
            content: ' ';
            z-index: -1;
        }

        .csstransforms3d .book3d:before {
            width: 100%;
            left: 7.5%;
            background-color: #5a2d18;
            box-shadow: 5px 5px 20px rgba(0, 0, 0, 0.6);
            border-radius: 0 8px 8px 0;
        }

        .csstransforms3d .book3d:after {
            width: 5%;
            left: 100%;
            background-color: #EFEFEF;
            box-shadow: inset 0px 0px 5px #aaa;
            -moz-transform: rotateY(20deg);
            -webkit-transform: perspective(100) rotateY(20deg);
            border-radius: 0 4px 4px 0;
        }

        /* Book spine colors - adjust to match new theme */
        .csstransforms3d #book1:before { background-color: #8B4513; }
        .csstransforms3d #book2:before { background-color: #333; }
        .csstransforms3d #book3:before { background-color: #254053; }
        .csstransforms3d #book4:before { background-color: #1d1a30; }
        .csstransforms3d #book5:before { background-color: #000000; }
        .csstransforms3d #book6:before { background-color: #2c5530; }

        /* Book content */
        .book-content {
            flex: 1;
            padding: 0 2rem;
        }

        .book-title {
            font-family: 'Space Grotesk', sans-serif;
            font-size: 2rem;
            font-weight: 600;
            margin-bottom: 0.5rem;
            color: var(--text-primary);
            line-height: 1.2;
        }

        .book-author {
            font-size: 1.1rem;
            color: var(--primary-color);
            margin-bottom: 1rem;
            font-weight: 500;
        }

        .book-description {
            font-size: 1rem;
            color: var(--text-secondary);
            line-height: 1.6;
            margin-bottom: 1.5rem;
        }

        /* Download button */
        .download-btn {
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
            padding: 12px 24px;
            background: var(--gradient-primary);
            color: white;
            text-decoration: none;
            border-radius: 50px;
            font-size: 1rem;
            font-weight: 600;
            transition: all 0.3s ease;
            box-shadow: 0 4px 15px rgba(0, 209, 178, 0.3);
            position: relative;
            overflow: hidden;
        }

        .download-btn::before {
            content: '';
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
            transition: left 0.5s;
        }

        .download-btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 8px 25px rgba(0, 209, 178, 0.4);
            color: white;
        }

        .download-btn:hover::before {
            left: 100%;
        }

        /* Loader styles */
        .loader-container {
            position: fixed;
            top: 0;
            left: 0;
            width: 100vw;
            height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            background: var(--dark-bg);
            z-index: 9999;
            transition: opacity 0.5s ease;
        }

        .loader {
            width: 60px;
            height: 60px;
            border: 3px solid rgba(0, 209, 178, 0.3);
            border-top: 3px solid var(--primary-color);
            border-radius: 50%;
            animation: spin 1s linear infinite;
        }

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

        /* Footer */
        footer {
            background: #000000;
            padding: 3rem 0 1rem;
            border-top: 1px solid rgba(0, 209, 178, 0.2);
        }

        .footer-section {
            margin-bottom: 2rem;
        }

        .footer-section h3 {
            font-family: 'Space Grotesk', sans-serif;
            font-size: 1.3rem;
            margin-bottom: 1rem;
            color: var(--text-primary);
        }

        .footer-section p,
        .footer-section a {
            color: var(--text-secondary);
            text-decoration: none;
            transition: color 0.3s ease;
        }

        .footer-section a:hover {
            color: var(--primary-color);
        }

        .footer-section ul {
            list-style: none;
            padding: 0;
        }

        .footer-section ul li {
            margin-bottom: 0.5rem;
        }

        .footer-bottom {
            text-align: center;
            padding-top: 2rem;
            border-top: 1px solid rgba(255, 255, 255, 0.1);
            margin-top: 2rem;
            color: var(--text-secondary);
        }

        /* Responsive Design */
        @media (max-width: 768px) {
            .book-item {
                flex-direction: column !important;
                text-align: center;
            }
            .book3d {
                margin: 0 0 1.5rem 0;
            }
            .book-content {
                padding: 0;
            }
        }

        /* Animations */
        @keyframes fadeInUp {
            from {
                opacity: 0;
                transform: translateY(30px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .fade-in {
            opacity: 0;
            transform: translateY(30px);
            transition: opacity 0.6s ease-out, transform 0.6s ease-out;
        }

        .fade-in.visible {
            opacity: 1;
            transform: translateY(0);
        }