:root {
    --bili-pink: #FB7299;
    --bili-blue: #00A1D6;
    --light-bg: #F5F7FA;
    --white: #FFFFFF;
    --card-bg: #FFFFFF;
    --dark-text: #18191C;
    --medium-text: #61666D;
    --light-text: #9499A0;
    --border-color: #E5E9EF;
    --hover-bg: #F8F9FA;
    --filter-bg: #f0f2f5;
    --filter-active: #e6f7ff;
    --book-theme: #3a7bd5;
    --book-secondary: #00d2ff;
    --banner-gradient: linear-gradient(135deg, #3a7bd5, #00d2ff);
    --card-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    --card-hover-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
    --nav-height: 64px;
    --section-padding: 24px;
    --douyin-color: #ff0050;
    --xiaohongshu-color: #ff2442;
    --wechat-color: #07c160;
    --bilibili-color: #fb7299;
    --main-gradient: linear-gradient(135deg, #3a7bd5, #00d2ff);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Noto Sans SC', 'Microsoft YaHei', sans-serif;
}

html {
    font-size: 16px;
    -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}

body {
    font-size: 16px;
    background-color: var(--light-bg);
    color: var(--dark-text);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    overflow-x: hidden;
}

a:hover, a:focus {
    color: #262a3b;
    text-decoration: none;
}

/* 导航栏样式 - Bilibili风格 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--nav-height);
    background-color: var(--white);
    display: flex;
    align-items: center;
    padding: 0 5%;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

.navbar.scrolled {
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
}

.logo {
    display: flex;
    align-items: center;
    margin-right: 30px;
    height: var(--nav-height); /* 确保高度与导航栏一致 */
}

.logo-img {
    height: 40px; /* 设置适当的高度 */
    width: auto; /* 保持宽高比 */
    max-height: 80%; /* 确保不超过导航栏高度 */
    transition: transform 0.3s ease;
    cursor: pointer;
}

.logo-img:hover {
    transform: scale(1.05); /* 添加悬停效果 */
}

/* 移除不再需要的样式 */
.logo-icon, .logo-text {
    display: none;
}

.logo-icon {
    color: var(--bili-pink);
    font-size: 28px;
    margin-right: 8px;
}

.logo-text {
    font-size: 22px;
    font-weight: bold;
    background: linear-gradient(90deg, var(--book-theme), var(--book-secondary));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.nav-links {
    display: flex;
    gap: 20px;
}

.nav-link {
    display: flex;
    color: var(--medium-text);
    text-decoration: none;
    font-size: 14px;
    padding: 8px 12px;
    border-radius: 4px;
    transition: all 0.3s ease;
    position: relative;
    font-weight: 500;
}

.nav-link:hover {
    color: var(--book-theme);
}

.nav-link.active {
    color: var(--book-theme);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 3px;
    background: var(--book-theme);
    border-radius: 2px;
}

/* 新增：导航下拉菜单 */
.nav-dropdown {
    position: relative;
}

.dropdown-toggle {
    display: flex;
    align-items: center;
    cursor: pointer;
    color: var(--book-theme);
    font-weight: 500;
}

.dropdown-toggle::after {
    content: '\f078';
    font-family: 'Font Awesome 5 Free';
    font-weight: 900;
    font-size: 10px;
    transition: transform 0.3s;
}

.nav-dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background-color: var(--white);
    min-width: 180px;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
    border-radius: 6px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all 0.3s ease;
    z-index: 1001;
    border: 1px solid var(--border-color);
}

.nav-dropdown:hover .nav-dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.nav-dropdown-menu .nav-link {
    display: block;
    padding: 10px 20px;
    border-radius: 0;
    color: var(--dark-text);
}

.nav-dropdown-menu .nav-link:hover {
    background-color: var(--hover-bg);
    color: var(--book-theme);
}

.nav-dropdown-menu .nav-link::after {
    display: none;
}

.search-form {
    margin-left: auto;
    display: flex;
}

.search-box {
    display: flex;
    width: 300px;
    background-color: var(--hover-bg);
    border-radius: 4px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.search-box.focused {
    border-color: var(--book-theme);
    box-shadow: 0 0 0 3px rgba(58, 123, 213, 0.15);
}

.search-input {
    width: 100px;
    flex: 1;
    border: none;
    background: transparent;
    padding: 8px 16px;
    color: var(--dark-text);
    outline: none;
    font-size: 14px;
}

.search-btn {
    background-color: var(--hover-bg);
    border: none;
    color: var(--medium-text);
    padding: 0 15px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.search-btn:hover {
    background-color: var(--book-theme);
    color: white;
}

.user-actions {
    display: flex;
    align-items: center;
    margin-left: 30px;
    gap: 15px;
}

.upload-btn {
    background: linear-gradient(to right, var(--book-theme), var(--book-secondary));
    color: white;
    border: none;
    padding: 6px 16px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    display: flex;
    align-items: center;
    gap: 5px;
    transition: all 0.3s ease;
}

.upload-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(58, 123, 213, 0.3);
}

.auth-buttons {
    display: flex;
    gap: 10px;
}

.auth-btn {
    padding: 8px 8px;
    border-radius: 4px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 14px;
    border: none;
    text-decoration: none;
}

.login-btn {
    background-color: var(--white);
    color: var(--book-theme);
    border: 1px solid var(--book-theme);
}

.login-btn:hover {
    background-color: rgba(58, 123, 213, 0.1);
}

.register-btn {
    background: linear-gradient(to right, var(--book-theme), var(--book-secondary));
    color: white;
}

.register-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(58, 123, 213, 0.3);
}

.user-avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: linear-gradient(45deg, var(--book-theme), var(--book-secondary));
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    color: white;
    position: relative;
    overflow: hidden;
}

.user-avatar::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.2);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.user-avatar:hover::after {
    opacity: 1;
}

/* 用户下拉菜单 - 美化样式 */
.user-dropdown {
    position: relative;
}

.user-dropdown-menu {
    position: absolute;
    top: calc(100% + 10px);
    right: 0;
    background-color: var(--white);
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
    width: 240px;
    z-index: 1001;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
    overflow: hidden;
}

.user-dropdown:hover .user-dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-header {
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 15px;
    background: linear-gradient(135deg, #f8faff, #eef5ff);
}

.dropdown-header .avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: linear-gradient(45deg, var(--book-theme), var(--book-secondary));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
    font-size: 20px;
    flex-shrink: 0;
}

.dropdown-header .user-info {
    flex: 1;
    min-width: 0;
}

.dropdown-header .username {
    font-weight: 600;
    margin-bottom: 5px;
    font-size: 16px;
    color: var(--dark-text);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.dropdown-header .email {
    font-size: 13px;
    color: var(--medium-text);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.dropdown-items {
    list-style: none;
    padding: 10px 0;
}

.dropdown-item {
    padding: 14px 20px;
    color: var(--dark-text);
    font-size: 15px;
    display: flex;
    align-items: center;
    gap: 15px;
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
}

.dropdown-item:hover {
    background: linear-gradient(90deg, rgba(58, 123, 213, 0.1), transparent);
    color: var(--book-theme);
    padding-left: 25px;
}

.dropdown-item:hover i {
    transform: scale(1.1);
}

.dropdown-item i {
    width: 24px;
    text-align: center;
    font-size: 18px;
    transition: all 0.3s ease;
    color: var(--book-theme);
}

.dropdown-divider {
    height: 1px;
    background-color: var(--border-color);
    margin: 5px 0;
}

.dropdown-item.logout {
    color: #e74c3c;
}

.dropdown-item.logout:hover {
    background: linear-gradient(90deg, rgba(231, 76, 60, 0.1), transparent);
}

.dropdown-item.logout i {
    color: #e74c3c;
}

/* 修改：用户下拉菜单链接样式 */
.dropdown-item a {
    text-decoration: none; /* 去掉下划线 */
    color: inherit; /* 继承父元素颜色 */
    display: block;
    width: 100%;
    height: 100%;
}

.dropdown-item a:visited {
    color: inherit; /* 访问后颜色不变 */
}

.dropdown-item.logout a {
    color: #e74c3c;
}

.dropdown-item.logout a:visited {
    color: #e74c3c;
}

/* 主体内容布局 */
.main-container {
    display: flex;
    max-width: 1920px;
    margin: calc(var(--nav-height) + 20px) auto 0;
    padding: 20px;
    flex: 1;
    width: 100%;
    gap: 20px;
}

/* 侧边栏样式 */
.sidebar-wrapper {
    width: 220px;
    position: relative;
    flex-shrink: 0;
}

.sidebar {
    width: 220px;
    position: sticky;
    top: calc(var(--nav-height) + 20px);
    height: calc(100vh - var(--nav-height) - 40px);
    overflow-y: auto;
    padding: 15px 0;
    z-index: 900;
    background-color: var(--white);
    border-radius: 8px;
    box-shadow: var(--card-shadow);
    transition: all 0.3s ease;
}

.sidebar-scroll {
    padding: 10px 0;
}

.sidebar-item {
    display: flex;
    align-items: center;
    padding: 12px 20px;
    border-radius: 4px;
    margin: 0 10px 5px;
    cursor: pointer;
    transition: all 0.3s ease;
    color: var(--medium-text);
    font-size: 14px;
    position: relative;
}

.sidebar-item:hover {
    background-color: var(--hover-bg);
    color: var(--book-theme);
}

.sidebar-item.active {
    background-color: rgba(58, 123, 213, 0.1);
    color: var(--book-theme);
}

.sidebar-item.active::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 4px;
    background: var(--book-theme);
    border-radius: 0 4px 4px 0;
}

.sidebar-icon {
    margin-right: 12px;
    font-size: 18px;
    width: 24px;
    text-align: center;
}

/* 新增：侧边栏详情按钮 */
.detail-btn {
    margin-left: auto;
    color: var(--light-text);
    font-size: 12px;
    padding: 4px;
    border-radius: 4px;
    transition: all 0.3s ease;
    opacity: 0.6;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    background: transparent;
    border: none;
    cursor: pointer;
}

.detail-btn:hover {
    color: var(--book-theme);
    background-color: rgba(58, 123, 213, 0.1);
    opacity: 1;
    transform: scale(1.1);
}

.sidebar-item:hover .detail-btn {
    opacity: 0.8;
}

.sidebar-item.active .detail-btn {
    color: var(--book-theme);
    opacity: 0.8;
}

/* 内容区域 */
.content {
    flex: 1;
    padding: 0 0 40px;
}

/* 书籍介绍板块 - Bilibili风格横幅 */
.book-intro {
    background: var(--banner-gradient);
    border-radius: 12px;
    padding: 30px;
    margin-bottom: 30px;
    color: white;
    box-shadow: 0 10px 30px rgba(58, 123, 213, 0.3);
    position: relative;
    overflow: hidden;
}

.book-intro::before {
    content: '';
    position: absolute;
    top: -50px;
    right: -30px;
    width: 200px;
    height: 200px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
}

.book-intro::after {
    content: '';
    position: absolute;
    bottom: -80px;
    right: 50px;
    width: 150px;
    height: 150px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
}

.book-header {
    display: flex;
    align-items: center;
    margin-bottom: 20px;
    position: relative;
    z-index: 1;
}

.book-icon {
    font-size: 36px;
    margin-right: 15px;
    background: rgba(255, 255, 255, 0.2);
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.book-title {
    font-size: 28px;
    font-weight: bold;
}

.book-subtitle {
    font-size: 18px;
    opacity: 0.9;
    margin-top: 5px;
}

.book-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 30px;
    position: relative;
    z-index: 1;
    align-items: flex-start;
}

.book-description {
    line-height: 1.8;
}

.book-description p {
    margin-bottom: 15px;
}

.book-features {
    background: rgba(255, 255, 255, 0.15);
    border-radius: 10px;
    padding: 20px;
    backdrop-filter: blur(5px);
}

.book-features h3 {
    margin-bottom: 15px;
    font-size: 18px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.3);
    padding-bottom: 10px;
}

.features-list {
    list-style: none;
}

.features-list li {
    padding: 8px 0;
    display: flex;
    align-items: center;
}

.features-list li i {
    margin-right: 10px;
    color: #ffd700;
}

.book-cta {
    display: flex;
    gap: 15px;
    margin-top: 20px;
}

.btn {
    padding: 10px 20px;
    border-radius: 30px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    position: relative;
    overflow: hidden;
}

.btn::after {
    content: '';
    position: absolute;
    top: -50%;
    left: -60%;
    width: 20px;
    height: 200%;
    background: rgba(255, 255, 255, 0.3);
    transform: rotate(25deg);
    transition: all 0.5s ease;
}

.btn:hover::after {
    left: 120%;
}

.btn-primary {
    background: white;
    color: var(--book-theme);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

/* 新增：书籍缩略图预览区 */
.book-preview {
    margin: 20px 0;
    position: relative;
}

.preview-title {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.preview-title i {
    color: #ffd700;
}

.thumbnails-container {
    position: relative;
    overflow: hidden;
    padding: 5px 0;
}

.thumbnails-wrapper {
    display: flex;
    gap: 10px;
    transition: transform 0.3s ease;
}

.thumbnail {
    padding: 0;
    position: relative;
    height: 140px;
    background: linear-gradient(45deg, var(--book-theme), var(--book-secondary));
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 40px;
    transition: all 0.3s ease;
}

.thumbnail:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    border-color: white;
}

.thumbnail-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.4);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.thumbnail-overlay:hover {
    opacity: 1;
}

.thumbnail-overlay i {
    font-size: 24px;
    color: white;
}

.thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.scroll-arrow {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 30px;
    height: 30px;
    background: rgba(255, 255, 255, 0.7);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 10;
    opacity: 0.7;
    transition: all 0.3s ease;
}

.scroll-arrow:hover {
    opacity: 1;
    background: white;
}

.scroll-arrow.left {
    left: -15px;
}

.scroll-arrow.right {
    right: -15px;
}

.scroll-arrow i {
    font-size: 16px;
    color: var(--book-theme);
}

.section-title {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 20px;
}

.section-title h2 {
    font-size: 20px;
    position: relative;
    padding-left: 12px;
    color: var(--dark-text);
    font-weight: 700;
}

.section-title h2::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 18px;
    background-color: var(--book-theme);
    border-radius: 2px;
}

/* 图片模态框 */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    padding-top: 60px;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.9);
    overflow: auto;
}

.modal-content {
    margin: auto;
    display: block;
    max-width: 80%;
    max-height: 80vh;
    animation: zoom 0.3s;
}

@keyframes zoom {
    from {transform: scale(0.8);}
    to {transform: scale(1);}
}

.close {
    position: absolute;
    top: 20px;
    right: 35px;
    color: #f1f1f1;
    font-size: 40px;
    font-weight: bold;
    transition: 0.3s;
    cursor: pointer;
}

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

/* 筛选工具栏 - 取消固定定位 */
.filter-bar {
    background-color: var(--white);
    border-radius: 8px;
    padding: 15px 20px;
    box-shadow: var(--card-shadow);
    border: 1px solid var(--border-color);
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    z-index: 800;
    transition: all 0.3s ease;
}

.filter-group {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
}

.filter-label {
    font-weight: bold;
    margin-right: 15px;
    min-width: 40px;
    color: var(--dark-text);
    white-space: nowrap;
    font-size: 14px;
}

.filter-options {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.filter-option {
    padding: 6px 15px;
    background-color: var(--filter-bg);
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 14px;
    display: flex;
    align-items: center;
    gap: 5px;
    user-select: none;
}

.filter-option:hover {
    background-color: var(--filter-active);
    color: var(--book-theme);
}

.filter-option.active {
    background-color: var(--filter-active);
    color: var(--book-theme);
    border: 1px solid var(--book-theme);
}

.filter-option input[type="checkbox"] {
    display: none;
}

.filter-option .checkmark {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 1px solid var(--border-color);
    border-radius: 3px;
    position: relative;
    background-color: var(--white);
}

.filter-option.active .checkmark::after {
    content: "";
    position: absolute;
    top: 1px;
    left: 5px;
    width: 5px;
    height: 10px;
    border: solid var(--book-theme);
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

/* 新增的放大动画 */
@keyframes pulse {
    0% {
        transform: scale(1);
        background-color: var(--filter-active);
    }
    50% {
        transform: scale(1.15);
        background-color: #d1e7ff;
        box-shadow: 0 0 10px rgba(58, 123, 213, 0.3);
    }
    100% {
        transform: scale(1);
        background-color: var(--filter-active);
    }
}

.pulse-animation {
    animation: pulse 0.4s ease-out;
}

.more-link {
    color: var(--book-theme);
    text-decoration: none;
    font-size: 14px;
    display: flex;
    align-items: center;
    gap: 5px;
    transition: all 0.3s ease;
}

.more-link:hover {
    color: #1a5fc1;
    text-decoration: underline;
}

/* 视频卡片网格 - 5列布局 */
.video-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 20px;
}

.video-card {
    background-color: var(--card-bg);
    border-radius: 6px;
    overflow: hidden;
    transition: all 0.3s ease;
    cursor: pointer;
    box-shadow: var(--card-shadow);
    border: 1px solid var(--border-color);
    position: relative;
    transform: translateY(0);
    will-change: transform;
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--card-hover-shadow);
    border-color: var(--book-theme);
}

.video-card-thumb {
    padding: 0;
    position: relative;
    height: 140px;
    background: linear-gradient(45deg, var(--book-theme), var(--book-secondary));
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 26px;
    transition: all 0.3s ease;
}

.video-card-thumb:hover {
    transform: translateY(-3px);
    transform: scale(1.05);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    border-color: white;
}

.video-card-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.video-card-thumb .play-icon {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    opacity: 0;
    transition: all 0.3s ease;
    background: rgba(0, 0, 0, 0.5);
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.video-card:hover .play-icon {
    opacity: 1;
}

.video-card-thumb .model-icon {
    margin-right: 12px;
    font-size: 26px;
    width: 28px;
    text-align: center;
}

.video-card-thumb dd {
    margin-right: 12px;
    font-size: 20px;
    text-align: center;
}

.video-card-thumb dd .model-icon {
    margin-right: 12px;
    font-size: 20px;
    width: 28px;
    text-align: center;
}

.grade-tag {
    position: absolute;
    top: 10px;
    left: 10px;
    background-color: var(--book-theme);
    color: white;
    padding: 4px 10px;
    border-radius: 4px;
    font-size: 12px;
    z-index: 2;
    font-weight: 500;
}

.book-tag {
    position: absolute;
    top: 10px;
    right: 10px;
    background-color: var(--book-secondary);
    color: white;
    padding: 4px 10px;
    border-radius: 4px;
    font-size: 12px;
    z-index: 2;
    font-weight: 500;
}

.duration {
    position: absolute;
    bottom: 8px;
    right: 8px;
    background-color: rgba(0, 0, 0, 0.7);
    color: white;
    padding: 3px 8px;
    border-radius: 4px;
    font-size: 12px;
    z-index: 1;
}

.video-info {
    padding: 12px;
}

.video-title {
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 8px;
    height: 42px;
    overflow: hidden;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    color: var(--dark-text);
    line-height: 1.5;
}

.video-stats {
    display: flex;
    justify-content: space-between;
    color: var(--light-text);
    font-size: 12px;
}

.video-stats span {
    display: flex;
    align-items: center;
    gap: 4px;
}

/* 页脚样式 */
footer {
    background-color: var(--white);
    padding: 20px 0; /* 减少上下内边距 */
    margin-top: 40px;
    border-top: 1px solid var(--border-color);
}

.copyright {
    text-align: center;
    padding: 15px 0; /* 调整内边距 */
    color: var(--light-text);
    font-size: 12px;
    border-top: none; /* 移除上边框 */
    margin-top: 0; /* 移除上外边距 */
}

/* 移动端菜单按钮 */
.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    color: var(--medium-text);
    cursor: pointer;
    margin-right: 15px;
}

/* 移动端菜单容器 */
.mobile-menu-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.9);
    z-index: 2000;
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 0;
    visibility: hidden;
    transition: all 0.4s ease;
}

.mobile-menu-container.open {
    opacity: 1;
    visibility: visible;
}

.mobile-menu {
    width: 90%;
    max-width: 400px;
    max-height: 90vh;
    background: var(--white);
    border-radius: 12px;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    transform: translateY(20px);
    transition: transform 0.4s ease;
}

.mobile-menu-container.open .mobile-menu {
    transform: translateY(0);
}

.mobile-menu-header {
    background: linear-gradient(135deg, var(--book-theme), var(--book-secondary));
    padding: 15px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: white;
}

.mobile-menu-title {
    font-size: 18px;
    font-weight: bold;
}

.mobile-menu-close {
    background: none;
    border: none;
    color: white;
    font-size: 24px;
    cursor: pointer;
}

.mobile-menu-content {
    overflow-y: auto;
    padding: 20px;
}

.mobile-nav-links {
    margin-bottom: 30px;
}

.mobile-nav-link {
    display: block;
    padding: 12px 15px;
    text-decoration: none;
    color: var(--dark-text);
    font-size: 16px;
    border-radius: 6px;
    transition: all 0.3s ease;
    margin-bottom: 5px;
}

.mobile-nav-link:hover, 
.mobile-nav-link.active {
    background-color: rgba(58, 123, 213, 0.1);
    color: var(--book-theme);
}

.mobile-sidebar {
    border-top: 1px solid var(--border-color);
    padding-top: 20px;
}

.mobile-sidebar-title {
    font-size: 16px;
    font-weight: bold;
    margin-bottom: 15px;
    color: var(--book-theme);
    display: flex;
    align-items: center;
    gap: 10px;
}

.mobile-sidebar-title i {
    font-size: 18px;
}

.mobile-sidebar-item {
    display: flex;
    align-items: center;
    padding: 12px 15px;
    border-radius: 6px;
    transition: all 0.3s ease;
    color: var(--dark-text);
    margin-bottom: 5px;
}

.mobile-sidebar-item:hover {
    background-color: rgba(58, 123, 213, 0.1);
    color: var(--book-theme);
}

.mobile-sidebar-item.active {
    background-color: rgba(58, 123, 213, 0.1);
    color: var(--book-theme);
    font-weight: 500;
}

.mobile-sidebar-icon {
    margin-right: 12px;
    font-size: 18px;
    width: 24px;
    text-align: center;
}

/* 新增移动端下拉菜单样式 */
.mobile-nav-dropdown {
    width: 100%;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.mobile-nav-dropdown-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.mobile-nav-dropdown-header:hover {
    background-color: rgba(255, 255, 255, 0.05);
}

.mobile-nav-dropdown-title {
    font-size: 18px;
    font-weight: 500;
    color: rgb(0, 0, 0);
}

.mobile-nav-dropdown-icon {
    transition: transform 0.3s ease;
    color: rgb(0, 0, 0);
}

.mobile-nav-dropdown.active .mobile-nav-dropdown-icon {
    transform: rotate(180deg);
}

.mobile-nav-submenu {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease;
    background-color: rgba(0, 0, 0, 0.15);
}

.mobile-nav-dropdown.active .mobile-nav-submenu {
    max-height: 500px; /* 足够容纳子菜单 */
}

.mobile-nav-submenu a {
    display: block;
    padding: 12px 30px;
    color: rgba(34, 34, 34, 0.8);
    text-decoration: none;
    font-size: 16px;
    transition: all 0.3s;
    position: relative;
}

.mobile-nav-submenu a:before {
    content: "•";
    position: absolute;
    left: 15px;
    opacity: 0.5;
}

.mobile-nav-submenu a:hover {
    background-color: rgba(255, 255, 255, 0.1);
    color: rgb(97, 97, 97);
    padding-left: 35px;
}

/* 调整移动端菜单内容布局 */
.mobile-menu-content {
    display: flex;
    flex-direction: column;
    height: calc(100vh - 60px);
}

/* 响应式调整 */
@media (max-width: 480px) {
    .mobile-nav-dropdown-header {
        padding: 12px 15px;
    }
    
    .mobile-nav-submenu a {
        padding: 10px 25px;
    }
}

/* 响应式设计 */
@media (max-width: 1600px) {
    .video-grid {
        grid-template-columns: repeat(5, 1fr);
    }
}

@media (max-width: 1400px) {
    .video-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

@media (max-width: 1200px) {
    .sidebar-wrapper {
        width: 200px;
    }
    
    .sidebar {
        width: 200px;
    }
    
    .video-grid {
        grid-template-columns: repeat(4, 1fr);
    }
    
    .book-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 1100px) {
    .video-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .search-box {
        width: 200px;
    }
}

@media (max-width: 992px) {
    .sidebar-wrapper {
        width: 180px;
    }
    
    .sidebar {
        width: 180px;
    }
    
    .video-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 900px) {
    .video-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 768px) {
    .navbar {
        padding: 0 15px;
    }
    
    .nav-links {
        display: none;
    }
    
    .sidebar-wrapper {
        display: none;
    }
    
    .video-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .filter-group {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .filter-label {
        margin-bottom: 10px;
    }
    
    .mobile-menu-btn {
        display: block;
    }
    
    .nav-dropdown-menu {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        border: none;
    }
    
    .nav-dropdown-menu .nav-link {
        padding: 8px 12px;
    }
    
    .dynamic-bg-element {
        display: none;
    }
}

@media (max-width: 576px) {
    .search-box {
        display: none;
    }
    
    .logo-text {
        display: none;
    }
    
    .upload-btn span {
        display: none;
    }
    
    .video-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .book-cta {
        flex-direction: column;
    }
    
    .book-preview .scroll-arrow {
        display: none;
    }
    
    .thumbnails-wrapper {
        overflow-x: auto;
        scrollbar-width: none;
    }
    
    .thumbnails-wrapper::-webkit-scrollbar {
        display: none;
    }
    
    .pagination {
        flex-wrap: wrap;
        gap: 6px;
    }
    
    .page-btn {
        width: 32px;
        height: 32px;
        font-size: 13px;
    }
}

@media (max-width: 480px) {
    .video-grid {
        grid-template-columns: 1fr;
    }
    
    .pagination {
        gap: 4px;
    }
    
    .page-btn {
        width: 28px;
        height: 28px;
        font-size: 12px;
    }
}

/* 侧边栏滚动条样式 */
.sidebar::-webkit-scrollbar {
    width: 6px;
}

.sidebar::-webkit-scrollbar-track {
    background: var(--hover-bg);
    border-radius: 10px;
}

.sidebar::-webkit-scrollbar-thumb {
    background: var(--book-theme);
    border-radius: 10px;
}

.sidebar::-webkit-scrollbar-thumb:hover {
    background: var(--book-secondary);
}

/* 页脚保护区域 */
.footer-protector {
    height: 40px;
}

/* 动画效果 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-card {
    animation: fadeIn 0.6s ease forwards;
    opacity: 0;
}

/* 动态背景元素 */
.dynamic-bg-element {
    position: absolute;
    border-radius: 50%;
    opacity: 0.1;
    z-index: -1;
}

/* 新增：分页组件 */
.pagination-container {
    margin-top: 30px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.pagination {
    gap: 8px;
    align-items: center;
    background-color: var(--white);
    padding: 8px 16px;
    border-radius: 30px;
    box-shadow: var(--card-shadow);
    border: 1px solid var(--border-color);
}

.page-btn {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--white);
    color: var(--medium-text);
    border: 1px solid var(--border-color);
    font-size: 14px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.page-btn:hover:not(.disabled):not(.active) {
    background-color: var(--hover-bg);
    color: var(--book-theme);
    border-color: var(--book-theme);
}

.page-btn.active {
    background: linear-gradient(135deg, var(--book-theme), var(--book-secondary));
    color: white;
    border-color: var(--book-theme);
    transform: scale(1.1);
}

.page-btn.disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.page-btn i {
    font-size: 12px;
}

.page-info {
    font-size: 14px;
    color: var(--medium-text);
    margin: 0 12px;
}

.pagination-divider {
    height: 20px;
    width: 1px;
    background-color: var(--border-color);
    margin: 0 10px;
}

.page-input {
    width: 50px;
    height: 36px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    text-align: center;
    font-size: 14px;
    margin: 0 5px;
}

.go-btn {
    background: linear-gradient(to right, var(--book-theme), var(--book-secondary));
    color: white;
    border: none;
    padding: 8px 15px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s ease;
}

.go-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 10px rgba(58, 123, 213, 0.3);
}

/* 新增：购买选项模态框 */
.purchase-modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    overflow: auto;
    animation: fadeIn 0.3s ease;
}

.purchase-modal-content {
    position: relative;
    background-color: var(--white);
    margin: 5% auto;
    padding: 30px;
    border-radius: 12px;
    width: 80%;
    max-width: 800px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.purchase-modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border-color);
}

.purchase-modal-title {
    font-size: 24px;
    font-weight: 700;
    color: var(--book-theme);
    display: flex;
    align-items: center;
    gap: 10px;
}

.purchase-modal-close {
    color: var(--medium-text);
    font-size: 28px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.purchase-modal-close:hover {
    color: var(--dark-text);
    transform: scale(1.1);
}

.purchase-options {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    justify-content: center;
}

.purchase-option {
    flex: 1;
    min-width: 220px;
    max-width: 250px;
    background: var(--light-bg);
    border-radius: 10px;
    padding: 20px;
    transition: all 0.3s ease;
    text-align: center;
    border: 2px solid transparent;
}

.purchase-option:hover {
    transform: translateY(-5px);
    box-shadow: var(--card-hover-shadow);
}

.purchase-option.douyin:hover {
    border-color: var(--douyin-color);
}

.purchase-option.xiaohongshu:hover {
    border-color: var(--xiaohongshu-color);
}

.purchase-option.wechat:hover {
    border-color: var(--wechat-color);
}

.purchase-icon {
    font-size: 48px;
    margin-bottom: 15px;
}

.purchase-option.douyin .purchase-icon {
    color: var(--douyin-color);
}

.purchase-option.xiaohongshu .purchase-icon {
    color: var(--xiaohongshu-color);
}

.purchase-option.wechat .purchase-icon {
    color: var(--wechat-color);
}

.purchase-option-title {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 15px;
}

.purchase-option-description {
    color: var(--medium-text);
    font-size: 14px;
    margin-bottom: 15px;
    min-height: 60px;
}

.qr-code {
    width: 120px;
    height: 120px;
    margin: 0 auto 15px;
    background: white;
    padding: 8px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border-color);
}

.qr-code img {
    max-width: 100%;
    max-height: 100%;
}

.purchase-btn {
    display: block;
    width: 100%;
    padding: 10px;
    border-radius: 30px;
    background: var(--book-theme);
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    margin-top: 10px;
}

.purchase-btn:hover {
    background: var(--book-secondary);
    transform: translateY(-2px);
    box-shadow: 0 5px 10px rgba(58, 123, 213, 0.3);
}

.purchase-option.douyin .purchase-btn {
    background: var(--douyin-color);
}

.purchase-option.xiaohongshu .purchase-btn {
    background: var(--xiaohongshu-color);
}

.purchase-option.wechat .purchase-btn {
    background: var(--wechat-color);
}

.purchase-tip {
    text-align: center;
    margin-top: 25px;
    padding-top: 15px;
    border-top: 1px dashed var(--border-color);
    color: var(--medium-text);
    font-size: 14px;
}

@media (max-width: 768px) {
    .purchase-options {
        flex-direction: column;
        align-items: center;
    }
    
    .purchase-option {
        width: 100%;
        max-width: 300px;
    }
    
    .purchase-modal-content {
        width: 90%;
        margin: 10% auto;
    }
}

/* 新增：侧边栏滚动动画 */
.sidebar-scroll {
    scroll-behavior: smooth;
    transition: scroll-behavior 0.5s ease;
}

/* 新增：高亮当前激活项 */
.sidebar-item.active {
    animation: highlightPulse 1.5s ease;
    background-color: rgba(58, 123, 213, 0.15);
    box-shadow: 0 0 10px rgba(58, 123, 213, 0.2);
}

@keyframes highlightPulse {
    0% { background-color: rgba(58, 123, 213, 0.05); }
    50% { background-color: rgba(58, 123, 213, 0.25); }
    100% { background-color: rgba(58, 123, 213, 0.15); }
}

/* 新增：滚动指示器 */
.scroll-indicator {
    position: absolute;
    right: 5px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--book-theme);
    font-size: 24px;
    opacity: 0;
    transition: opacity 0.3s ease;
    animation: bounce 2s infinite;
}

@keyframes bounce {
    0%, 100% { transform: translateY(-50%) translateX(0); }
    50% { transform: translateY(-50%) translateX(5px); }
}

.sidebar-item.active .scroll-indicator {
    opacity: 1;
}

/* 社交区块 */
.social-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 10px;
}

.social-card {
    background-color: var(--light-bg);
    border-radius: 12px;
    padding: 30px;
    text-align: center;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.social-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--card-hover-shadow);
}

.social-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

.social-card.douyin .social-icon {
    color: var(--douyin-color);
}

.social-card.xiaohongshu .social-icon {
    color: var(--xiaohongshu-color);
}

.social-card.wechat .social-icon {
    color: var(--wechat-color);
}

.social-card.bilibili .social-icon {
    color: var(--bilibili-color);
}

.social-name {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 15px;
    color: var(--dark-text);
}

.social-desc {
    color: var(--medium-text);
    margin-bottom: 20px;
    min-height: 60px;
}

.social-qrcode {
    width: 150px;
    height: 150px;
    margin: 0 auto 0;
    background: white;
    padding: 10px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.social-qrcode img {
    width: 100%;
    height: 100%;
    display: block;
}

.social-link {
    display: inline-block;
    padding: 8px 20px;
    border-radius: 30px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    border: 2px solid;
}

.social-card.douyin .social-link {
    color: var(--douyin-color);
    border-color: var(--douyin-color);
}

.social-card.xiaohongshu .social-link {
    color: var(--xiaohongshu-color);
    border-color: var(--xiaohongshu-color);
}

.social-card.wechat .social-link {
    color: var(--wechat-color);
    border-color: var(--wechat-color);
}

.social-card.bilibili .social-link {
    color: var(--bilibili-color);
    border-color: var(--bilibili-color);
}

.social-link:hover {
    color: white;
}

.social-card.douyin .social-link:hover {
    background: var(--douyin-color);
    color: white;
}

.social-card.xiaohongshu .social-link:hover {
    background: var(--xiaohongshu-color);
    color: white;
}

.social-card.wechat .social-link:hover {
    background: var(--wechat-color);
    color: white;
}

.social-card.bilibili .social-link:hover {
    background: var(--bilibili-color);
    color: white;
}

.social-username {
    margin-bottom: 10px;
    background: var(--hover-bg);
    padding: 8px 15px;
    border-radius: 30px;
    font-weight: 600;
    color: var(--dark-text);
}