/* --- 主内容区域布局 (宽屏) --- */
    .main-content-wrapper {
        display: flex;
        gap: 2rem;
        max-width: 1600px;
        margin: 0 auto;
        padding: 2rem;
        flex-grow: 1;
        width: 100%;
    }

    /* 左侧书籍列表容器 - 占据剩余3/4宽度 */
    .books-section {
        flex: 3;
        width: 75%;
    }

    /* 右侧分类侧边栏 - 固定1/4宽度 */
    .category-sidebar {
        width: 25%;
        min-width: 280px;
        max-width: 400px;
        background-color: #fff;
        border-radius: 12px;
        padding: 1.5rem;
        box-shadow: 0 4px 15px rgba(0,0,0,0.05);
        align-self: flex-start;
        position: sticky;
        top: 100px;
        height: fit-content;
    }

    .category-title {
        font-size: 1.3rem;
        font-weight: 600;
        color: #2c3e50;
        margin-bottom: 1rem;
        padding-bottom: 0.5rem;
        border-bottom: 1px solid #eee;
    }

    .category-list {
        display: flex;
        flex-wrap: wrap;
        gap: 0.7rem;
    }

    /* --- 修改: 分类按钮样式为流式排列 --- */
    .category-btn {
        padding: 0.5rem 1rem;
        background-color: #ecf0f1;
        border: none;
        border-radius: 20px;
        color: #7f8c8d;
        font-size: 0.9rem;
        cursor: pointer;
        transition: all 0.2s ease;
        white-space: nowrap; /* 防止文字换行 */
        text-align: center;
    }

    .category-btn:hover,
    .category-btn.active {
        background-color: #3498db;
        color: #fff;
        transform: translateY(-2px);
    }

    /* --- 书籍列表标题样式 --- */
    .section-title {
        font-size: 1.8rem;
        font-weight: 600;
        color: #2c3e50;
        margin-bottom: 1.5rem;
        border-bottom: 2px solid #3498db;
        padding-bottom: 0.5rem;
        display: inline-block;
    }

    /* --- 新增: 顶部分类框样式 --- */
    .top-category-container {
        background-color: #fff;
        border-radius: 12px;
        padding: 1.5rem;
        box-shadow: 0 4px 15px rgba(0,0,0,0.05);
        margin-bottom: 2rem;
    }

    /* --- 多列网格布局 --- */
    .book-container {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(187px, 1fr));
        gap: 1.5rem;
        width: 100%;
    }

    .book-card {
        background-color: #fff;
        border-radius: 12px;
        overflow: hidden;
        box-shadow: 0 4px 15px rgba(0,0,0,0.05);
        transition: all 0.3s ease;
        cursor: pointer;
        position: relative;
        height: 100%;
        display: flex;
        flex-direction: column;
        border: 1px solid #eee;
    }

    .book-card:hover {
        transform: translateY(-5px);
        box-shadow: 0 8px 25px rgba(0,0,0,0.15);
        border-color: #3498db;
    }

    .book-cover {
        height: 200px;
        overflow: hidden;
        position: relative;
    }

    .book-cover img {
        width: 100%;
        height: 100%;
        object-fit: cover;
        transition: transform 0.5s ease;
    }

    .book-card:hover .book-cover img {
        transform: scale(1.08);
    }

    .book-info {
        padding: 1.2rem;
        flex-grow: 1;
        display: flex;
        flex-direction: column;
    }

    .book-title {
        font-size: 1.1rem;
        font-weight: 600;
        color: #2c3e50;
        margin-bottom: 0.5rem;
        line-height: 1.3;
        display: -webkit-box;
        -webkit-line-clamp: 2;
        -webkit-box-orient: vertical;
        overflow: hidden;
    }

    .book-author {
        color: #7f8c8d;
        font-size: 0.9rem;
        margin-bottom: 0.8rem;
    }

    .book-meta {
        display: flex;
        justify-content: space-between;
        align-items: center;
        font-size: 0.85rem;
        color: #95a5a6;
        margin-top: auto;
    }

    .book-rating {
        display: flex;
        align-items: center;
        gap: 0.3rem;
    }

    .rating-star {
        color: #f1c40f;
        font-size: 1rem;
    }

    .book-tags {
        display: flex;
        flex-wrap: wrap;
        gap: 0.4rem;
        margin-top: 0.8rem;
    }

    .book-tag {
        background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
        padding: 0.2rem 0.6rem;
        border-radius: 12px;
        font-size: 0.75rem;
        color: #fff;
        font-weight: 500;
    }

    .publish-year {
        background-color: #ecf0f1;
        padding: 0.2rem 0.6rem;
        border-radius: 10px;
        font-size: 0.8rem;
    }

    /* --- 分页控件样式 --- */
    .pagination {
        display: flex;
        justify-content: center;
        align-items: center;
        gap: 0.5rem;
        margin-top: 1rem;
        margin-bottom: 1rem;
        padding: 1rem;
        flex-wrap: wrap; /* 新增：允许分页按钮在小屏幕上换行 */
    }

    .pagination-btn {
        padding: 0.6rem 1.2rem;
        border: 1px solid #ddd;
        background-color: #fff;
        color: #333;
        border-radius: 8px;
        cursor: pointer;
        transition: all 0.2s ease;
        font-weight: 500;
    }

    .pagination-btn:hover:not(:disabled) {
        background-color: #3498db;
        color: #fff;
        border-color: #3498db;
        transform: translateY(-1px);
    }

    .pagination-btn:disabled {
        opacity: 0.5;
        cursor: not-allowed;
        transform: none;
    }

    .pagination-btn.active {
        background-color: #3498db;
        color: #fff;
        border-color: #3498db;
    }

    /* --- 页脚样式 --- */
    .main-footer {
        text-align: center;
        padding: 2rem;
        background-color: #fff;
        color: #7f8c8d;
        font-size: 0.9rem;
        border-top: 1px solid #eee;
        margin-top: auto;
    }

    .main-footer a {
        color: #3498db;
        text-decoration: none;
        font-weight: 500;
    }

    .main-footer a:hover {
        text-decoration: underline;
    }

    .more-keyword {
        font-size: 1.1rem;
        font-weight: 600;
        color: #2c3e50;
        margin-bottom: 0.5rem;
        line-height: 1.3;
        display: -webkit-box;
        -webkit-line-clamp: 2;
        -webkit-box-orient: vertical;
        overflow: hidden;
    }

    /* --- 响应式设计 --- */
    @media (max-width: 1200px) {
        .main-content-wrapper {
            gap: 1.2rem;
        }

        .category-sidebar {
            min-width: 250px;
        }
    }

    @media (max-width: 992px) {
        .main-content-wrapper {
            flex-direction: column;
        }

        .books-section {
            width: 100%;
            flex: none;
        }

        .category-sidebar {
            width: 100%;
            max-width: none;
            position: static;
            margin-top: 2rem;
        }
    }

    @media (max-width: 768px) {
        .main-header {
            padding: 1rem;
            justify-content: space-between;
        }

        .nav-links {
            display: none;
            flex-direction: column;
            position: absolute;
            top: 100%;
            left: 0;
            width: 100%;
            background-color: #fff;
            box-shadow: 0 5px 10px rgba(0,0,0,0.1);
            padding: 1rem;
            gap: 1rem;
            margin-left: 0;
            z-index: 999;
        }

        .nav-links.active {
            display: flex;
        }

        .menu-toggle {
            display: flex;
        }

        .search-container {
            order: 1;
            margin: 0;
            max-width: none;
        }

        .main-content-wrapper {
            padding: 1rem 0.5rem; /* 优化：减小手机端左右内边距 */
        }

        .book-container {
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: 1rem;
        }

        .book-cover {
            height: 180px;
        }

        .book-info {
            padding: 1rem;
        }
    }

    @media (max-width: 480px) {
        .book-container {
            grid-template-columns: 1fr;
        }

        .section-title {
            font-size: 1.5rem;
        }
    }