body {
            font-family: 'Arial', sans-serif;
            margin: 0;
            padding: 0;
            background-color: #f4f4f4;
            color: #333;
        }
        header {
            background: linear-gradient(135deg, #3498db, #2c3e50);
            color: #fff;
            padding: 20px 0;
            text-align: center;
            box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
            position: sticky;
            top: 0;
        }
        header h1 {
            margin: 0;
            font-size: 2.5rem;
            font-weight: bold;
        }
        nav {
            margin-top: 10px;
        }
        nav a {
            color: #fff;
            text-decoration: none;
            padding: 10px 20px;
            font-size: 1rem;
            background-color: #2c3e50;
            border-radius: 5px;
            transition: background-color 0.3s;
        }
        nav a:hover {
            background-color: #34495e;
        }
        main {
            max-width: 900px;
            margin: 20px auto;
            padding: 20px;
            background: #fff;
            border-radius: 10px;
            box-shadow: 0 6px 12px rgba(0, 0, 0, 0.1);
            position: relative;
        }
        .book-cover {
            width: 220px;
            height: auto;
            border-radius: 10px;
            box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
            display: block;
            margin: 20px auto;
            transition: transform 0.3s;
        }
        .book-cover:hover {
            transform: scale(1.05);
        }
        .tabs {
            display: flex;
            cursor: pointer;
            margin-top: 20px;
            border-radius: 10px;
            overflow: hidden;
            border-bottom: 3px solid #3498db;
        }
        .tab-button {
            flex: 1;
            padding: 15px;
            text-align: center;
            background: #ecf0f1;
            border: 1px solid #ddd;
            border-bottom: none;
            transition: background 0.3s, color 0.3s, transform 0.3s;
            border-radius: 10px 10px 0 0;
            font-size: 1.1rem;
            font-weight: 600;
        }
        .tab-button.active {
            background: #fff;
            color: #3498db;
            border-bottom: 3px solid #3498db;
            font-weight: bold;
            transform: scale(1.05);
        }
        .tab-content {
            max-height: 0;
            overflow: hidden;
            opacity: 0;
            transition: max-height 0.6s ease, opacity 0.6s ease;
        }
        .tab-content.active {
            max-height: fit-content; /* Adjust based on content */
            opacity: 1;
        }
        h2 {
            color: #2c3e50;
            font-size: 1.8rem;
        }
        p {
            line-height: 1.6;
            margin-bottom: 20px;
        }
        .author-info {
            display: flex;
            align-items: center;
            gap: 20px;
            background: #ecf0f1;
            padding: 20px;
            border-radius: 10px;
            box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }
        .author-info img {
            width: 180px;
            height: auto;
            border-radius: 10px;
            box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
        }
 
        .author-info:hover {
            transform: scale(1.02);
            box-shadow: 0 6px 12px rgba(0, 0, 0, 0.3);
        }
        @media (max-width: 600px) {
            .tabs {
                flex-direction: column;
            }
            .tab-button {
                margin-bottom: 1px;
            }
            .author-info {
                flex-direction: column;
                align-items: flex-start;
            }
            .author-info img {
                width: 100%;
                max-width: 300px;
            }
        }
        .button-container {
            display: flex;
            justify-content: center;
            gap: 20px;
            margin-top: 20px;
        }
        .download-btn, .buy-btn {
            padding: 15px 30px;
            color: #fff;
            text-decoration: none;
            border-radius: 5px;
            font-size: 1rem;
            font-weight: bold;
            transition: background-color 0.3s, transform 0.3s;
            cursor: pointer;
        }
        .download-btn {
            background-color: #3498db;
        }
        .download-btn:hover {
            background-color: #2980b9;
            transform: scale(1.05);
        }
        .buy-btn {
            background-color: #e74c3c;
        }
        .buy-btn:hover {
            background-color: #c0392b;
            transform: scale(1.05);
        }
		
		/*Pop Up*/
		 /* Popup container - can be anything you want */
        .popup {
            display: none; /* Hidden by default */
            position: fixed; /* Stay in place */
            z-index: 1; /* Sit on top */
            left: 0;
            top: 0;
            width: 100%;
            height: 100%;
            overflow: auto; /* Enable scroll if needed */
            background-color: rgba(0,0,0,0.4); /* Black w/ opacity */
        }

        /* Popup content */
        .popup-content {
            background-color: #fefefe;
            margin: 15% auto; /* 15% from the top and centered */
            padding: 20px;
            border: 1px solid #888;
            width: 80%; /* Could be more or less, depending on screen size */
            max-width: 400px;
            border-radius: 10px;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
            animation: fadeIn 0.5s; /* Fade in animation */
        }

        /* Close button */
        .close-btn {
            color: #3498db;
            float: right;
            font-size: 28px;
            font-weight: bold;
            cursor: pointer;
        }

        .close-btn:hover,
        .close-btn:focus {
            color: black;
            text-decoration: none;
            cursor: pointer;
        }

        /* Input field */
        .popup-content input[type="password"] {
            width: 100%;
            padding: 10px;
            margin: 10px 0;
            display: inline-block;
            border: 1px solid #ccc;
            border-radius: 4px;
            box-sizing: border-box;
            font-size: 16px;
        }

        /* Submit button */
        .popup-content button {
            background-color: #3498db;
            color: white;
            padding: 10px 20px;
            margin: 10px 0;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            width: 100%;
            font-size: 16px;
        }

        .popup-content button:hover {
            background-color: #2980b9;
        }

        /* Fade in animation */
        @keyframes fadeIn {
            from {opacity: 0;}
            to {opacity: 1;}
        }