/* 变量定义 */
        :root {
            --primary-color: #4a6bff;
            --secondary-color: #f8f9fa;
            --dark-color: #212529;
            --light-color: #ffffff;
            --hover-color: #e9ecef;
            --shadow-color: rgba(0, 0, 0, 0.1);
            --gradient-start: #4a6bff;
            --gradient-end: #6e8fff;
            --font-primary: 'Poppins', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
            --font-size-base: 1rem;
            --font-size-sm: 0.875rem;
            --font-size-lg: 1.125rem;
            --font-size-xl: 1.25rem;
            --font-weight-normal: 400;
            --font-weight-medium: 500;
            --font-weight-semibold: 600;
            --font-weight-bold: 700;
        }

        /* 基础样式 */
        body {
            padding-top: 56px;
            background-color: #f5f7fa;
            font-family: var(--font-primary);
            font-size: var(--font-size-base);
            font-weight: var(--font-weight-normal);
            line-height: 1.6;
        }

        /* 导航栏样式 */
        .navbar {
            height: 56px;
            background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end)) !important;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
        }

        /* 导航栏按钮样式 */
        .navbar .btn-outline-light {
            padding-left: 1.25rem;
            padding-right: 1.25rem;
            min-width: 64px;
            display: flex;
            align-items: center;
            justify-content: center;
            white-space: nowrap;
            height: 38px;
            border-radius: 5px;
            transition: all 0.3s ease;
            background-color: rgba(255, 255, 255, 0.2);
            border: none;
        }

        .navbar .btn-outline-light:hover {
            background-color: rgba(255, 255, 255, 0.3);
            transform: translateY(-2px);
            box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
        }

        .navbar .d-flex {
            align-items: center;
        }

        /* 搜索框样式 */
        .search-container {
            position: relative;
            flex-grow: 1;
            margin-right: 0.5rem;
        }

        .search-container .form-control {
            padding-left: 90px;
            height: 38px;
            border-radius: 5px;
            border: none;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
            transition: all 0.3s ease;
        }

        .search-container .form-control:focus {
            box-shadow: 0 4px 10px rgba(0, 0, 0, 0.15);
            transform: translateY(-1px);
        }

        .search-container .form-select {
            position: absolute;
            left: 1px;
            top: 1px;
            bottom: 1px;
            width: 80px;
            padding: 2px 2px 2px 12px;
            border: none;
            background-color: rgba(255, 255, 255, .8);
            color: var(--dark-color);
            z-index: 5;
            font-size: 0.875rem;
            border-right: 1px solid rgba(0, 0, 0, .1);
            border-radius: 20px 0 0 20px;
            height: 36px;
            background-position: right 5px center;
            transition: all 0.3s ease;
        }

        .search-container .form-select:focus {
            outline: none;
            box-shadow: none;
        }

        .search-container .form-select option {
            background-color: var(--light-color);
            color: var(--dark-color);
            padding: 8px 12px;
        }

        /* 侧边栏样式 */
        .sidebar {
            width: 250px;
            position: fixed;
            top: 56px;
            left: 0;
            height: calc(100vh - 56px);
            background-color: var(--light-color);
            padding: 10px 0;
            overflow-y: auto;
            z-index: 100;
            scrollbar-gutter: stable;
            box-shadow: 2px 0 10px var(--shadow-color);
            transition: all 0.3s ease;
            padding-right: 5px;
        }

        /* 分类项样式 - 增加字体层次感 */
        .category-item {
            cursor: pointer;
            padding: 10px 15px;
            border-bottom: 1px solid #e9ecef;
            display: flex;
            justify-content: space-between;
            align-items: center;
            transition: all 0.3s ease;
            width: calc(100% - 5px);
            border-radius: 4px;
            margin: 2px 0;
            font-size: var(--font-size-lg);
            font-weight: var(--font-weight-medium);
            letter-spacing: 0.3px;
        }

        .category-item:hover {
            background-color: rgba(74, 107, 255, 0.1);
            color: var(--primary-color);
            transform: translateX(5px);
        }

        .category-item-link {
            text-decoration: none;
            color: var(--dark-color);
            display: block;
            width: 100%;
            transition: color 0.3s;
            font-size: var(--font-size-lg);
            font-weight: var(--font-weight-medium);
        }

        .category-item-link:hover {
            color: var(--primary-color);
        }

        /* 分类切换图标样式 */
        .category-toggle {
            margin-left: 8px;
            cursor: pointer;
            font-size: 14px;
            color: #6c757d;
            width: 16px;
            height: 16px;
            display: flex;
            justify-content: center;
            align-items: center;
            transition: all 0.3s ease;
            background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 16 16'%3E%3Cpath fill='%236c757d' d='M4.646 1.646a.5.5 0 0 1 .708 0l6 6a.5.5 0 0 1 0 .708l-6 6a.5.5 0 0 1-.708-.708L10.293 8 4.646 2.354a.5.5 0 0 1 0-.708z'/%3E%3C/svg%3E");
            background-repeat: no-repeat;
            background-position: center;
            background-size: contain;
        }

        .category-item:hover .category-toggle {
            filter: invert(32%) sepia(98%) saturate(1332%) hue-rotate(213deg) brightness(97%) contrast(101%);
        }

        [data-bs-toggle="collapse"][aria-expanded="true"] .category-toggle {
            transform: rotate(90deg);
        }


        /* 子分类样式 */
        .subcategory {
            padding-left: 20px;
            background-color: rgba(74, 107, 255, 0.03);
            border-radius: 0 0 4px 4px;
            transition: all 0.3s ease;
        }

        .subcategory-item {
            padding: 8px 15px;
            transition: all 0.3s ease;
            border-radius: 4px;
            margin: 2px 0;
            cursor: pointer;
            font-size: var(--font-size-base);
            font-weight: var(--font-weight-normal);
            color: var(--text-secondary, #6c757d);
        }

        .subcategory-item:hover {
            background-color: rgba(74, 107, 255, 0.1);
            color: var(--primary-color);
            transform: translateX(5px);
            font-weight: var(--font-weight-medium);
        }

        .subcategory-item-link {
            display: block;
            text-decoration: none;
            color: var(--text-secondary, #6c757d);
        }

        /* 内容区域样式 */
        .content {
            margin-left: 250px;
            padding: 20px;
            background-color: #f5f7fa;
            min-height: calc(100vh - 56px);
            display: flex;
            flex-direction: column;
        }

        /* 内容区域标题样式 - 增强标题字体 */
        .content h2 {
            position: relative;
            display: inline-block;
            margin-bottom: 1.5rem;
            color: var(--dark-color);
            font-weight: var(--font-weight-bold);
            padding-bottom: 0.5rem;
            font-size: var(--font-size-xl);
            letter-spacing: 0.5px;
        }

        .content h2::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 50px;
            height: 3px;
            background: linear-gradient(90deg, var(--gradient-start), var(--gradient-end));
            border-radius: 3px;
            transition: width 0.3s ease;
        }

        .content h2:hover::after {
            width: 100%;
        }

        /* 卡片容器样式 */
        .card-container {
            flex: 1;
        }

        /* 卡片样式 */
        .card {
            margin-bottom: 20px;
            transition: all 0.3s ease;
            cursor: pointer;
            position: relative;
            border: none;
            border-radius: 10px;
            overflow: hidden;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
            background-color: var(--light-color);
        }

        .card:hover {
            transform: translateY(-8px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
        }

        .card-body {
            padding: 1.5rem;
        }

        .card-title {
            color: var(--primary-color);
            font-weight: var(--font-weight-semibold);
            margin-bottom: 0.75rem;
            font-size: var(--font-size-lg);
            letter-spacing: 0.2px;
        }

        .card-text {
            color: #6c757d;
            font-size: var(--font-size-sm);
            line-height: 1.5;
        }

        .card-link {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            z-index: 10;
        }

        /* 页脚样式 */
        footer {
            background-color: var(--light-color);
            box-shadow: 0 -5px 15px rgba(0, 0, 0, 0.05);
            border-radius: 10px;
            margin-top: 2rem;
            padding: 1.5rem 0;
            position: relative;
            clear: both;
            width: 100%;
        }

        footer h5 {
            color: var(--primary-color);
            font-weight: 600;
            margin-bottom: 1rem;
        }

        footer a {
            color: #6c757d;
            transition: color 0.3s;
        }

        footer a:hover {
            color: var(--primary-color);
        }

        /* 自定义滚动条 */
        ::-webkit-scrollbar {
            width: 8px;
        }

        ::-webkit-scrollbar-track {
            background: #f1f1f1;
            border-radius: 10px;
        }

        ::-webkit-scrollbar-thumb {
            background: #c1c1c1;
            border-radius: 10px;
        }

        ::-webkit-scrollbar-thumb:hover {
            background: #a8a8a8;
        }

        /* 响应式布局调整 */
        @media (max-width: 991.98px) {
            .navbar-collapse {
                position: absolute;
                top: 56px;
                left: 0;
                right: 0;
                background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
                max-height: none;
                z-index: 1030;
                padding: 1rem;
                border-radius: 0 0 10px 10px;
                box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
            }

            .content {
                margin-left: 0;
                transition: margin-left 0.3s ease;
            }

            .sidebar {
                transform: translateX(-100%);
            }

            .sidebar.show {
                transform: translateX(0);
            }
        }

        /* 回到顶部按钮样式 */
        .back-to-top {
            position: fixed;
            bottom: 30px;
            right: 30px;
            width: 50px;
            height: 50px;
            border-radius: 50%;
            background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
            color: white;
            border: none;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            opacity: 0;
            visibility: hidden;
            transition: all 0.3s ease;
            z-index: 9999;
            /* 增加z-index值确保按钮显示在最上层 */
        }

        .back-to-top.show {
            opacity: 1;
            visibility: visible;
        }

        .back-to-top:hover {
            transform: translateY(-5px);
            box-shadow: 0 6px 15px rgba(0, 0, 0, 0.2);
        }

        .back-to-top i {
            font-size: 20px;
        }