:root {
            --brand-green: #5B705B; /* 枯叶绿 */
            --brand-light: #E8EDE8;
            --page-bg: #F9F6F1;    /* 奶茶纸色 */
            --text-main: #3E3A39;
            --text-muted: #8E8782;
            --card-bg: #FFFFFF;
        }

        body {
            margin: 0;
            background-color: var(--page-bg);
            font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
            color: var(--text-main);
        }

        .app-container {
            max-width: 500px;
            margin: 0 auto;
            min-height: 100vh;
            padding-bottom: 30px;
            background-color: var(--page-bg);
        }

        /* 顶部大标题 */
        .header-title {
            padding: 30px 20px 10px;
            font-size: 26px;
            font-weight: 800;
            color: var(--brand-green);
            letter-spacing: 1px;
        }

        /* 搜索框 */
        .search-container {
            padding: 10px 20px;
        }
        .search-bar {
            display: flex;
            background: var(--card-bg);
            padding: 4px;
            border-radius: 25px;
            box-shadow: 0 2px 8px rgba(0,0,0,0.03);
        }
        .search-bar input {
            flex: 1;
            border: none;
            padding: 10px 15px;
            outline: none;
            font-size: 14px;
            background: transparent;
        }
        .search-bar button {
            background: var(--brand-green);
            color: white;
            border: none;
            padding: 0 22px;
            border-radius: 20px;
            font-size: 13px;
        }

        /* 导航栏包含全部分类 */
        .nav-wrapper {
            position: relative;
            display: flex;
            align-items: center;
            margin: 15px 0;
            padding: 0 0 0 20px;
        }
        .nav-scroller {
            flex: 1;
            overflow-x: auto;
            white-space: nowrap;
            -webkit-overflow-scrolling: touch;
        }
        .nav-scroller::-webkit-scrollbar { display: none; }

        .nav-link {
            display: inline-block;
            margin-right: 25px;
            font-size: 15px;
            color: var(--text-muted);
            text-decoration: none;
            padding-bottom: 5px;
        }
        .nav-link.active {
            color: var(--brand-green);
            font-weight: bold;
            border-bottom: 3px solid var(--brand-green);
        }

        .all-cat-trigger {
            padding: 5px 15px;
            background: var(--page-bg);
            color: var(--brand-green);
            font-size: 14px;
            font-weight: bold;
            border-left: 1px solid #E4E0D9;
            cursor: pointer;
            box-shadow: -10px 0 10px -5px var(--page-bg); /* 渐变遮挡效果 */
        }

        /* 内容板块 */
        .section {
            margin: 20px 15px;
        }
        .section-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 12px;
        }
        .section-header h2 {
            font-size: 17px;
            margin: 0;
            color: var(--text-main);
        }

        /* 列表卡片 */
        .book-card-list {
            background: var(--card-bg);
            border-radius: 12px;
            overflow: hidden;
            box-shadow: 0 2px 10px rgba(0,0,0,0.02);
        }
        .book-item {
            padding: 18px 15px;
            border-bottom: 1px solid #F9F6F1;
            display: block;
            text-decoration: none;
            color: inherit;
        }
        .book-item:last-child { border-bottom: none; }
        .book-name {
            font-size: 16px;
            font-weight: bold;
            color: #333;
            margin-bottom: 6px;
        }
        .book-desc {
            font-size: 13px;
            color: var(--text-muted);
            line-height: 1.6;
            display: -webkit-box;
            -webkit-line-clamp: 2;
            -webkit-box-orient: vertical;
            overflow: hidden;
        }

        /* 侧边分类栏 */
        .side-mask {
            position: fixed; top: 0; left: 0; right: 0; bottom: 0;
            background: rgba(0,0,0,0.5); display: none; z-index: 1000;
        }
        .side-panel {
            position: fixed; top: 0; right: -80%; width: 80%; height: 100%;
            background: var(--page-bg); z-index: 1001; transition: 0.3s;
            padding: 20px; box-sizing: border-box;
        }
        .side-panel.active { right: 0; }
        .side-mask.active { display: block; }

        .side-title {
            font-size: 18px; font-weight: bold; margin-bottom: 20px;
            color: var(--brand-green); border-bottom: 1px solid #E4E0D9;
            padding-bottom: 10px;
        }
        .cat-grid {
            display: grid; grid-template-columns: 1fr 1fr; gap: 10px;
        }
        .cat-box {
            background: var(--card-bg); padding: 15px; border-radius: 8px;
            text-align: center; text-decoration: none; color: var(--text-main);
            font-size: 14px; border: 1px solid #E4E0D9;
        }