:root {
            --primary-color: #3498db;
            --secondary-color: #02245B;
            --accent-color: #e74c3c;
            --light-color: #ecf0f1;
            --dark-color: #2c3e50;
            --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        
        body {
            background-color: #f5f5f5;
            color: #333;
            display: flex;
            flex-direction: column;
            min-height: 100vh;
        }
        
        header {
            background-color: var(--secondary-color);
            color: white;
            padding: 1rem 2rem;
            box-shadow: var(--shadow);
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .logo {
            font-size: 1.5rem;
            font-weight: bold;
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }
        
        .book-title {
            font-size: 1.2rem;
            text-align: center;
            flex-grow: 1;
        }
        
        .main-container {
            display: flex;
            flex-direction: column;
            align-items: center;
            padding: 2rem;
            flex-grow: 1;
        }
        
        .toolbar {
            width: 100%;
            max-width: 2000px;
            background-color: white;
            border-radius: 8px 8px 0 0;
            padding: 1rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
            box-shadow: var(--shadow);
            margin-bottom: 1px;
        }
        
        .controls {
            display: flex;
            gap: 1rem;
        }
        
        .btn {
            background-color: var(--light-color);
            color: #142c8e;
            border: none;
            padding: 0.5rem 1rem;
            border-radius: 4px;
            cursor: pointer;
            transition: all 0.3s;
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }
        
      
        .btn-icon {
            font-size: 1.2rem;
        }
        
        .zoom-controls {
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }
        
        .zoom-btn {
            background-color: var(--light-color);
            color: var(--dark-color);
            border: none;
            width: 36px;
            height: 36px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            font-weight: bold;
            transition: all 0.2s;
        }
        
        .zoom-btn:hover {
            background-color: #dde4e6;
            transform: scale(1.1);
        }
        
        .pdf-container {
            width: 100%;
            max-width: 2000px;
            background-color: white;
            border-radius: 0 0 8px 8px;
            box-shadow: var(--shadow);
            overflow: hidden;
            flex-grow: 1;
            display: flex;
            justify-content: center;
            align-items: flex-start;
            padding: 2rem;
            min-height: 70vh;
            position: relative;
        }
        
        .pdf-viewer {
            width: 100%;
            height: 100%;
            border: none;
            min-height: 600px;
            transition: all 0.3s ease;
        }
        
        .page-navigation {
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 1rem;
            margin-top: 1.5rem;
            background: white;
            padding: 0.8rem 1.5rem;
            border-radius: 50px;
            box-shadow: var(--shadow);
        }
        
        .nav-btn {
            background: var(--secondary-color);
            color: white;
            border: none;
            width: 40px;
            height: 40px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            transition: all 0.3s;
        }
        
        .nav-btn:hover {
            background: #120872;
            transform: scale(1.1);
        }
        
        .nav-btn:disabled {
            background: #bdc3c7;
            cursor: not-allowed;
            transform: scale(1);
        }
        
        .page-info {
            display: flex;
            flex-direction: column;
            align-items: center;
            min-width: 120px;
        }
        
        .page-text {
            font-size: 0.9rem;
            color: #7f8c8d;
        }
        
        .page-number {
            font-size: 1.2rem;
            font-weight: bold;
            color: var(--dark-color);
        }
        
        .loading {
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            gap: 1rem;
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(255, 255, 255, 0.9);
            z-index: 10;
        }
        
        .spinner {
            width: 50px;
            height: 50px;
            border: 5px solid #f3f3f3;
            border-top: 5px solid var( --secondary-color);
            border-radius: 50%;
            animation: spin 1s linear infinite;
        }
        
        @keyframes spin {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }
        
        footer {
            background-color: var(--secondary-color);
            color: white;
            text-align: center;
            padding: 1rem;
            margin-top: 2rem;
        }
        
        @media (max-width: 768px) {
            .toolbar {
                flex-direction: column;
                gap: 1rem;
            }
            
            .controls {
                width: 100%;
                justify-content: space-between;
            }
            
            header {
                flex-direction: column;
                gap: 0.5rem;
                text-align: center;
            }
            
            .book-title {
                margin: 0.5rem 0;
            }
            
            .page-navigation {
                padding: 0.6rem 1rem;
            }
            
            .nav-btn {
                width: 35px;
                height: 35px;
            }
        }