:root {
            --primary-color: #2d3436;
            --secondary-color: #0984e3;
            --background-color: #f5f6fa;
            --text-color: #2d3436;
        }

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

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.6;
            color: var(--text-color);
            background-color: var(--background-color);
        }

        .container {
            max-width: 800px;
            margin: 0 auto;
            padding: 2rem;
        }

        header {
            text-align: center;
            padding: 2rem 0;
            background-color: white;
            box-shadow: 0 2px 4px rgba(0,0,0,0.1);
            margin-bottom: 2rem;
        }

        h1 {
            font-size: 2.5rem;
            margin-bottom: 1rem;
            color: var(--primary-color);
        }

        .book-list {
            background: white;
            padding: 2rem;
            border-radius: 10px;
            box-shadow: 0 2px 4px rgba(0,0,0,0.1);
        }

        .book-category {
            margin-top: 2rem;
            border-bottom: 2px solid var(--primary-color);
            padding-bottom: 0.5rem;
            margin-bottom: 1.5rem;
            font-size: 1.8rem;
            color: var(--primary-color);
        }

        .book-category:first-child {
            margin-top: 0;
        }

        .book-item {
            display: flex;
            align-items: flex-start;
            gap: 1.5rem;
            margin-bottom: 1.5rem;
            padding-bottom: 1.5rem;
            border-bottom: 1px solid #eee;
        }

        .book-item img {
            width: 100px;
            height: auto;
            flex-shrink: 0;
            border-radius: 4px;
            box-shadow: 0 2px 4px rgba(0,0,0,0.1);
        }

        .book-item .book-details {
            flex: 1;
        }

        .book-item:last-child {
            border-bottom: none;
            margin-bottom: 0;
            padding-bottom: 0;
        }

        .book-title {
            font-size: 1.2rem;
            color: var(--secondary-color);
            text-decoration: none;
            font-weight: bold;
        }

        .book-title:hover {
            text-decoration: underline;
        }

        .back-link {
            display: inline-block;
            margin-top: 2rem;
            color: var(--secondary-color);
            text-decoration: none;
        }

        .back-link:hover {
            text-decoration: underline;
        }