/* ===============================================
   通用样式和重置
   =============================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    font-family: "Microsoft YaHei", "微软雅黑", Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: #333;
    background-color: transparent;
    background-image:
        linear-gradient(rgba(255, 255, 255, 0.7), rgba(255, 255, 255, 0.7)),
        url('../assets/images/81f0aea80070ae84852616fe29e4242568a2446d6500e29a27ad2623baa147d7.jpg');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    background-attachment: fixed;
    cursor: default;
}

/* 隐藏文本光标 */
* {
    caret-color: transparent;
}

a {
    text-decoration: none;
    color: #1a5490;
    transition: color 0.3s ease;
}

a:hover {
    color: #0d3a6f;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ===============================================
   英文模式字体
   =============================================== */
html.lang-en {
    font-family: "IBM Plex Sans", -apple-system, BlinkMacSystemFont, sans-serif;
}

html.lang-en body {
    font-family: "IBM Plex Sans", -apple-system, BlinkMacSystemFont, sans-serif;
    letter-spacing: 0.01em;
}

html.lang-en h1,
html.lang-en h2,
html.lang-en h3,
html.lang-en h4,
html.lang-en h5,
html.lang-en h6 {
    font-family: "Cormorant Garamond", Georgia, serif;
    font-weight: 600;
    letter-spacing: 0.02em;
}

html.lang-en .header h1 {
    font-family: "Cormorant Garamond", Georgia, serif;
    font-weight: 700;
    letter-spacing: 0.01em;
}

html.lang-en .header .subtitle {
    font-family: "IBM Plex Sans", sans-serif;
    font-weight: 400;
    letter-spacing: 0.03em;
}

html.lang-en .nav-menu a {
    font-family: "IBM Plex Sans", sans-serif;
    font-weight: 500;
    letter-spacing: 0.02em;
}

html.lang-en .section-header h2,
html.lang-en .overview-text h2,
html.lang-en .professor-details h2 {
    font-family: "Cormorant Garamond", Georgia, serif;
    font-weight: 600;
}

html.lang-en .news-info h3,
html.lang-en .research-card h3,
html.lang-en .paper-title {
    font-family: "Cormorant Garamond", Georgia, serif;
    font-weight: 500;
}

html.lang-en p,
html.lang-en .news-info p,
html.lang-en .professor-details .description {
    font-family: "IBM Plex Sans", sans-serif;
    line-height: 1.7;
    letter-spacing: 0.01em;
}

html.lang-en .footer {
    font-family: "IBM Plex Sans", sans-serif;
    letter-spacing: 0.02em;
}

/* ===============================================
   顶部栏样式
   =============================================== */
.top-bar {
    background-color: #f8f8f8;
    border-bottom: 1px solid #e0e0e0;
    padding: 8px 0;
    font-size: 14px;
}

.language-switch {
    text-align: right;
    color: #666;
}

.language-switch a {
    color: #666;
    margin: 0 5px;
}

.language-switch a.active {
    color: #1a5490;
    font-weight: bold;
}

.language-switch .mobile-link {
    margin-left: 15px;
}

/* ===============================================
   头部样式
   =============================================== */
.header {
    background-color: white;
    color: #333;
    padding: 30px 0;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.header-content {
    display: flex;
    align-items: center;
    gap: 20px;
}

.header-logo {
    width: 80px;
    height: 80px;
    object-fit: contain;
    flex-shrink: 0;
}

.header-text {
    flex: 1;
}

.header h1 {
    font-size: 32px;
    margin-bottom: 8px;
    font-weight: 600;
    color: #000;
}

.header .subtitle {
    font-size: 18px;
    color: #666;
}

/* 语言切换 */
.lang-switch {
    display: flex;
    gap: 4px;
    align-items: center;
}

.lang-btn {
    font-family: "Microsoft YaHei", "微软雅黑", Arial, sans-serif;
    font-size: 14px;
    font-weight: 500;
    color: #666;
    background: none;
    border: none;
    padding: 6px 12px;
    cursor: pointer;
    position: relative;
    transition: all 0.3s ease;
    letter-spacing: 0.3px;
}

.lang-btn::after {
    content: '';
    position: absolute;
    bottom: 2px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background-color: #1a5490;
    transition: width 0.3s ease;
}

.lang-btn:hover {
    color: #1a5490;
}

.lang-btn:hover::after {
    width: 80%;
}

.lang-btn.active {
    color: #1a5490;
    font-weight: 600;
}

.lang-btn.active::after {
    width: 80%;
}

/* 按钮之间的分隔符 */
.lang-btn:not(:last-child)::before {
    content: '';
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 1px;
    height: 12px;
    background-color: #e0e0e0;
}

/* ===============================================
   导航栏样式
   =============================================== */
.navbar {
    background-color: #fff;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-menu {
    list-style: none;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    padding: 0;
}

.nav-menu li {
    margin: 0;
}

.nav-menu a {
    display: block;
    padding: 15px 20px;
    color: #333;
    font-weight: 500;
    transition: all 0.3s ease;
}

.nav-menu a:hover,
.nav-menu a.active {
    background-color: #1a5490;
    color: white;
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    padding: 10px;
}

/* ===============================================
   主内容区样式
   =============================================== */
.main-content {
    flex: 1 0 auto;
    padding: 30px 0;
    min-height: calc(100vh - 300px);
}

.page-header {
    background-color: white;
    padding: 25px;
    margin-bottom: 25px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

.page-header h1 {
    color: #1a5490;
    font-size: 28px;
    border-left: 4px solid #1a5490;
    padding-left: 15px;
}

.content-page {
    background-color: white;
    padding: 30px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

.intro-text {
    margin-bottom: 30px;
    padding: 20px;
    background-color: #f9f9f9;
    border-left: 4px solid #2980b9;
    border-radius: 3px;
}

.intro-text p {
    line-height: 1.8;
    color: #555;
}

/* ===============================================
   教授介绍卡片
   =============================================== */
.professor-card {
    background-color: white;
    padding: 30px;
    margin-bottom: 25px;
    border-radius: 5px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.professor-info {
    display: flex;
    gap: 30px;
    align-items: flex-start;
}

.professor-photo {
    flex-shrink: 0;
}

.photo-placeholder {
    width: 200px;
    height: 250px;
    background-color: #e8e8e8;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 5px;
    overflow: hidden;
}

.photo-placeholder img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.no-image {
    color: #999;
    font-size: 14px;
}

.professor-details h2 {
    color: #1a5490;
    font-size: 26px;
    margin-bottom: 10px;
}

.professor-details .title {
    color: #666;
    font-size: 16px;
    margin-bottom: 8px;
}

.professor-details .lab {
    color: #2980b9;
    font-size: 16px;
    margin-bottom: 20px;
    font-weight: 500;
}

.professor-details .description {
    line-height: 1.8;
    color: #555;
    text-align: justify;
}

/* ===============================================
   区块样式（研究方向、新闻等）
   =============================================== */
.section-block {
    background-color: white;
    padding: 25px;
    margin-bottom: 25px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 2px solid #1a5490;
}

.section-header h2 {
    color: #1a5490;
    font-size: 22px;
}

.more-link {
    color: #2980b9;
    font-size: 14px;
    font-weight: 500;
}

.more-link:hover {
    color: #1a5490;
}

.section-content {
    padding: 15px 0;
}

.section-content p {
    line-height: 1.8;
    color: #555;
    text-align: justify;
}

/* ===============================================
   研究方向页面
   =============================================== */
.research-page { max-width: 1160px; }
.research-intro-block { padding: 24px 0 48px; }
.eyebrow { display:block; color:#6d8799; font:600 11px/1.4 "IBM Plex Sans",sans-serif; letter-spacing:.18em; text-transform:uppercase; margin-bottom:12px; }
.research-hero h2 { color:#173b57; font:500 clamp(28px,4vw,44px)/1.2 "Noto Serif SC",serif; margin:0 0 20px; }
.research-hero-copy p { color:#566674; font-size:16px; line-height:2.05; margin:0; text-align:justify; }
.research-areas { display:flex; flex-direction:column; margin-top:8px; }
.research-section { display:grid; grid-template-columns:minmax(0,1.15fr) minmax(280px,.85fr); gap:56px; align-items:center; padding:54px 0; border-bottom:1px solid #dbe5e8; }
.research-section-copy { min-width:0; }.research-card-top { display:flex; align-items:center; gap:12px; margin-bottom:18px; }.research-number { color:#6d8799; font:600 13px "IBM Plex Sans",sans-serif; letter-spacing:.1em; }.research-rule { height:1px; flex:1; background:#dbe5e8; }
.research-section h3 { color:#173b57; font:500 25px/1.45 "Noto Serif SC",serif; margin:0 0 20px; }.research-section p { color:#566674; font-size:15px; line-height:2.05; margin:0; text-align:justify; }
.research-section-media { min-height:270px; border-radius:16px; background:linear-gradient(135deg,#edf3f5,#f5f1ea); overflow:hidden; box-shadow:0 12px 32px rgba(23,59,87,.1); }.research-section-media img,.research-section-media video { width:100%; height:100%; min-height:270px; display:block; object-fit:cover; }.media-placeholder { min-height:270px; height:100%; display:flex; flex-direction:column; align-items:center; justify-content:center; text-align:center; color:#617987; }.media-placeholder span { font-size:42px; color:#9ab8bd; margin-bottom:10px; }.media-placeholder strong { font:500 18px "Noto Serif SC",serif; }.media-placeholder small { margin-top:8px; color:#82939d; }
@media (max-width: 800px) { .research-section { grid-template-columns:1fr; gap:24px; padding:38px 0; }.research-section-media { order:2; min-height:210px; }.research-section-media img,.research-section-media video,.media-placeholder { min-height:210px; } }

/* ===============================================
   新闻列表
   =============================================== */
.news-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.news-item {
    background-color: #f9f9f9;
    padding: 20px;
    border-radius: 5px;
    border-left: 4px solid #2980b9;
    transition: all 0.3s ease;
}

.news-item:hover {
    box-shadow: 0 3px 10px rgba(0,0,0,0.08);
}

.news-date {
    color: #999;
    font-size: 14px;
    margin-bottom: 8px;
}

.news-item h3 {
    color: #1a5490;
    font-size: 18px;
    margin-bottom: 10px;
}

.news-item p {
    color: #666;
    line-height: 1.7;
}

/* 分页控件 */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid #e0e0e0;
}

.pagination-btn {
    padding: 8px 15px;
    border: 1px solid #ddd;
    border-radius: 4px;
    background-color: white;
    color: #333;
    font-size: 14px;
    transition: all 0.3s ease;
    cursor: pointer;
    text-decoration: none;
}

.pagination-btn:hover {
    background-color: #1a5490;
    color: white;
    border-color: #1a5490;
}

.pagination-btn.active {
    background-color: #1a5490;
    color: white;
    border-color: #1a5490;
    font-weight: 600;
    cursor: default;
}

.pagination-btn.disabled {
    background-color: #f5f5f5;
    color: #999;
    border-color: #ddd;
    cursor: not-allowed;
}

.pagination-btn.disabled:hover {
    background-color: #f5f5f5;
    color: #999;
    border-color: #ddd;
}

/* ===============================================
   论文列表
   =============================================== */
/* 论文页面布局 */
.publications-page-layout {
    display: flex;
    gap: 30px;
    align-items: flex-start;
}

/* 侧边栏 */
.publications-sidebar {
    flex: 0 0 200px;
    position: sticky;
    top: 80px; /* 导航栏高度 + 间距 */
    max-height: calc(100vh - 100px);
    overflow-y: auto;
}

.sidebar-sticky {
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.sidebar-sticky h3 {
    color: #1a5490;
    font-size: 18px;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid #2980b9;
}

/* 目录样式 */
.publications-toc {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.toc-item {
    display: block;
    padding: 8px 12px;
    color: #666;
    font-size: 14px;
    border-radius: 4px;
    transition: all 0.3s ease;
    border-left: 3px solid transparent;
}

.toc-item:hover {
    background-color: #f0f7ff;
    color: #1a5490;
    border-left-color: #2980b9;
}

.toc-item.active {
    background-color: #e6f2ff;
    color: #1a5490;
    font-weight: 600;
    border-left-color: #1a5490;
}

/* 主内容区 */
.publications-main-content {
    flex: 1;
    min-width: 0;
}

/* 标签页导航 */
.publications-tabs {
    display: flex;
    gap: 0;
    margin-bottom: 30px;
    border-bottom: 2px solid #e0e0e0;
    background-color: rgba(255, 255, 255, 0.95);
    border-radius: 8px 8px 0 0;
    overflow: hidden;
}

.pub-tab-btn {
    flex: 1;
    padding: 16px 24px;
    background: transparent;
    border: none;
    color: #666;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    font-family: inherit;
}

.pub-tab-btn::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    right: 0;
    height: 2px;
    background: #1a5490;
    transform: scaleX(0);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.pub-tab-btn:hover {
    background-color: rgba(26, 84, 144, 0.05);
    color: #1a5490;
}

.pub-tab-btn.active {
    color: #1a5490;
    font-weight: 600;
    background-color: rgba(26, 84, 144, 0.08);
}

.pub-tab-btn.active::after {
    transform: scaleX(1);
}

/* 标签页内容 */
.pub-tab-content {
    display: none;
    animation: fadeIn 0.4s ease-in-out;
}

.pub-tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.publications-list {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.year-group {
    background-color: #f9f9f9;
    padding: 25px;
    border-radius: 5px;
    scroll-margin-top: 20px;
}

.year-group h3 {
    color: #1a5490;
    font-size: 22px;
    margin-bottom: 20px;
    border-bottom: 2px solid #2980b9;
    padding-bottom: 10px;
}

.year-group h4 {
    color: #2980b9;
    font-size: 18px;
    margin-top: 20px;
    margin-bottom: 15px;
    padding-bottom: 8px;
    border-bottom: 1px solid #d0d0d0;
}

.paper-item {
    margin-bottom: 15px;
    padding: 15px;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    background-color: #fff;
    transition: all 0.3s ease;
}

.paper-item:last-child {
    margin-bottom: 0;
}

.paper-title {
    color: #333;
    font-size: 16px;
    font-weight: 400;
    line-height: 1.6;
    margin-bottom: 0;
}

.paper-item:has(.paper-image) .paper-title {
    margin-bottom: 10px;
}

.paper-image {
    width: 100%;
    height: 225px;
    overflow: hidden;
    border-radius: 5px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #fff;
}

.paper-image img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    display: block;
    border-radius: 5px;
}

/* 可点击论文项的样式 */
.paper-item-clickable {
    cursor: pointer;
}

.paper-item-clickable:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(26, 84, 144, 0.15);
    border-color: #2980b9;
}

.paper-item-clickable:hover .paper-title {
    color: #1a5490;
}

.paper-item-clickable:active {
    transform: translateY(-3px);
    box-shadow: 0 4px 12px rgba(26, 84, 144, 0.2);
}

/* ===============================================
   组员列表
   =============================================== */
.members-list {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.member-category {
    padding: 0;
    margin-bottom: 40px;
}

.member-category h3 {
    color: #1a5490;
    font-size: 28px;
    font-weight: 600;
    margin-bottom: 30px;
    text-align: center;
    letter-spacing: 0.5px;
    border: none;
    padding: 0;
}

.members-grid {
    display: flex;
    justify-content: center;
    gap: 30px;
    flex-wrap: wrap;
}

.member-card {
    background-color: white;
    padding: 25px 30px;
    border-radius: 5px;
    border: 1px solid #e0e0e0;
    transition: all 0.3s ease;
    width: 350px;
    max-width: 100%;
}

.member-card:hover {
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
}

.member-card-clickable {
    cursor: pointer;
}

.member-card-clickable:hover {
    box-shadow: 0 5px 15px rgba(26, 84, 144, 0.2);
    transform: translateY(-2px);
    border-color: #1a5490;
}

.member-photo {
    width: 110px;
    height: 138px;
    margin: 0 auto 12px;
    overflow: hidden;
    border-radius: 5px;
    background-color: #f0f0f0;
}

.member-photo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.member-name {
    color: #1a5490;
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 6px;
    text-align: center;
}

.member-title,
.member-year {
    color: #666;
    font-size: 13px;
    margin-bottom: 4px;
    text-align: center;
}

.member-email {
    color: #2980b9;
    font-size: 12px;
    margin-bottom: 4px;
    word-break: break-all;
    text-align: center;
}

.member-office {
    color: #666;
    font-size: 12px;
    margin-bottom: 4px;
    text-align: center;
}

.member-research {
    color: #777;
    font-size: 12px;
    margin-top: 8px;
    padding-top: 8px;
    border-top: 1px solid #f0f0f0;
}

.member-description {
    color: #555;
    font-size: 12px;
    line-height: 1.5;
    margin-top: 8px;
    padding-top: 8px;
    border-top: 1px solid #f0f0f0;
    text-align: justify;
}

/* ===============================================
   Student Members Section
   =============================================== */
.students-section {
    margin-top: 60px;
    padding-top: 40px;
    border-top: 2px solid #e8e8e8;
}

.students-section-title {
    font-size: 28px;
    font-weight: 600;
    color: #1a5490;
    margin-bottom: 40px;
    text-align: center;
    letter-spacing: 0.5px;
}

.students-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 20px;
    padding: 0 10px;
}

.student-card {
    background: white;
    border-radius: 12px;
    padding: 30px 15px;
    border: 1px solid #e8e8e8;
    transition: all 0.3s ease;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.student-card:hover {
    box-shadow: 0 8px 20px rgba(26, 84, 144, 0.12);
    transform: translateY(-3px);
}

.student-avatar {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    overflow: hidden;
    margin-bottom: 20px;
    border: 3px solid #f0f0f0;
    background: linear-gradient(135deg, #f5f7fa 0%, #e8ecf1 100%);
    flex-shrink: 0;
}

.student-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.student-name {
    font-size: 18px;
    font-weight: 600;
    color: #333;
    margin-bottom: 8px;
    letter-spacing: 0.3px;
}

.student-grade {
    font-size: 15px;
    font-weight: 500;
    color: #1a5490;
    margin-bottom: 8px;
}

.student-undergraduate {
    font-size: 13px;
    color: #777;
    margin-bottom: 12px;
}

.student-research {
    font-size: 13px;
    color: #777;
    line-height: 1.6;
    margin-bottom: 12px;
    text-align: center;
    width: 100%;
}

.student-email {
    font-size: 13px;
    margin-top: auto;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
}

.student-email svg {
    width: 14px;
    height: 14px;
    flex-shrink: 0;
}

.student-email a {
    color: #2c5aa0;
    text-decoration: none;
    transition: color 0.2s ease;
}

.student-email a:hover {
    color: #1a3a6f;
    text-decoration: underline;
}

.students-empty {
    text-align: center;
    padding: 60px 20px;
    color: #999;
    font-size: 15px;
}

/* ===============================================
   活动列表
   =============================================== */
.activities-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.activity-item {
    background-color: #f9f9f9;
    padding: 25px;
    border-radius: 5px;
    border-left: 4px solid #2980b9;
}

.activity-date {
    color: #999;
    font-size: 14px;
    margin-bottom: 10px;
}

.activity-item h3 {
    color: #1a5490;
    font-size: 18px;
    margin-bottom: 12px;
}

.activity-item p {
    color: #666;
    line-height: 1.7;
}

/* ===============================================
   招聘信息
   =============================================== */
.join-requirements {
    display: flex;
    flex-direction: column;
    gap: 25px;
}

.requirement-section {
    background-color: #f9f9f9;
    padding: 25px;
    border-radius: 5px;
    border-left: 4px solid #2980b9;
}

.requirement-section h3 {
    color: #1a5490;
    font-size: 20px;
    margin-bottom: 15px;
}

.requirement-section pre {
    white-space: pre-wrap;
    font-family: "Microsoft YaHei", Arial, sans-serif;
    color: #555;
    line-height: 1.8;
}

/* ===============================================
   联系信息
   =============================================== */
.contact-info {
    background-color: #f9f9f9;
    padding: 30px;
    border-radius: 5px;
}

.contact-item {
    display: flex;
    padding: 15px 0;
    border-bottom: 1px solid #e0e0e0;
}

.contact-item:last-child {
    border-bottom: none;
}

.contact-label {
    color: #1a5490;
    font-weight: 600;
    min-width: 120px;
    font-size: 16px;
}

.contact-value {
    color: #555;
    font-size: 16px;
}

/* ===============================================
   友情链接
   =============================================== */
.links-section {
    background-color: white;
    padding: 25px;
    margin-bottom: 25px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

.links-section h3 {
    color: #1a5490;
    font-size: 18px;
    margin-bottom: 15px;
}

.links-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    align-items: center;
}

.links-grid a {
    color: #000;
    font-size: 14px;
    transition: color 0.3s ease;
    position: relative;
}

.links-grid a:hover {
    color: #1a5490;
}

.links-grid a:not(:last-child)::after {
    content: '|';
    position: absolute;
    right: -10px;
    color: #ccc;
}

/* ===============================================
   轮播图样式
   =============================================== */
.banner {
    position: relative;
    height: 430px;
    overflow: hidden;
    background-color: transparent;
}

.banner-slides {
    position: relative;
    width: 100%;
    height: 100%;
    background-color: transparent;
}

.banner-slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    transition: opacity 0.8s ease-in-out;
    background-color: transparent;
}

.banner-slide.active {
    opacity: 1;
}

.banner-slide img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    object-position: center;
}

/* 轮播图说明文字（独立定位在dots右侧） */
.banner-caption {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    margin-left: 160px;
    color: #000;
    font-size: 16px;
    font-weight: 700;
    text-shadow: -1px -1px 0 #fff, 1px -1px 0 #fff, -1px 1px 0 #fff, 1px 1px 0 #fff,
                 -2px 0 0 #fff, 2px 0 0 #fff, 0 -2px 0 #fff, 0 2px 0 #fff;
    white-space: nowrap;
    z-index: 10;
    line-height: 12px;
    display: flex;
    align-items: center;
    height: 12px;
}

.banner-dots {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 10px;
    z-index: 10;
}

.banner-dots .dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.5);
    cursor: pointer;
    transition: all 0.3s ease;
}

.banner-dots .dot.active {
    background-color: white;
    width: 30px;
    border-radius: 6px;
}

.banner-prev,
.banner-next {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background-color: rgba(0, 0, 0, 0.6);
    color: white;
    border: none;
    font-size: 40px;
    width: 50px;
    height: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    z-index: 10;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.banner-prev:hover,
.banner-next:hover {
    background-color: rgba(0, 0, 0, 0.85);
}

.banner-prev {
    left: calc((100% - 1200px) / 2 + 20px);
}

.banner-next {
    right: calc((100% - 1200px) / 2 + 20px);
}

/* 当屏幕宽度小于等于1240px时，按钮贴近边缘 */
@media (max-width: 1240px) {
    .banner-prev {
        left: 20px;
    }

    .banner-next {
        right: 20px;
    }
}

/* ===============================================
   课题组总览卡片
   =============================================== */
.overview-card {
    background-color: white;
    border-radius: 5px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    padding: 40px;
    margin-bottom: 40px;
}

.overview-content {
    display: flex;
    gap: 40px;
    align-items: center;
}

.overview-text {
    flex: 1;
}

.overview-text h2 {
    color: #1a5490;
    font-size: 26px;
    margin-bottom: 20px;
    text-align: center;
}

.overview-text p {
    color: #555;
    line-height: 1.8;
    font-size: 15px;
    text-align: justify;
    margin-bottom: 15px;
}

.overview-text p:last-child {
    margin-bottom: 0;
}

.overview-image {
    flex-shrink: 0;
    width: 400px;
}

.overview-image img {
    width: 100%;
    height: auto;
    border-radius: 0;
    box-shadow: none;
}

/* ===============================================
   左右分栏布局
   =============================================== */
.content-row {
    display: flex;
    gap: 30px;
    margin-bottom: 40px;
}

.col-left {
    flex: 2;
}

.col-right {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

/* ===============================================
   文章区块样式
   =============================================== */
.article-section {
    background-color: white;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    padding: 20px;
}

/* ===============================================
   新闻列表样式（北大风格）
   =============================================== */
/* 新闻列表容器 */
.news-list-container {
    list-style: none;
}

/* 新闻年份分组 */
.news-year-group {
    margin-bottom: 40px;
}

.news-year-group > h3 {
    color: #1a5490;
    font-size: 22px;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid #2980b9;
}

.news-year-items {
    background-color: #f9f9f9;
    padding: 20px;
    border-radius: 5px;
}

.news-list-item {
    display: flex;
    padding: 15px 0;
    border-bottom: 1px solid #eee;
    transition: background-color 0.3s ease;
}

.news-list-item:last-child {
    border-bottom: none;
}

.news-list-item:hover {
    background-color: #ffffff;
    padding: 15px;
    margin: 0 -15px;
    border-radius: 5px;
}

.date-box {
    width: 60px;
    text-align: center;
    margin-right: 20px;
    flex-shrink: 0;
}

.date-box .day {
    font-size: 24px;
    color: #1a5490;
    font-weight: bold;
    line-height: 1;
}

.date-box .month {
    font-size: 12px;
    color: #666;
    margin-top: 5px;
}

.news-info {
    flex: 1;
}

.news-info h3 {
    font-size: 16px;
    margin-bottom: 8px;
    color: #333;
    transition: color 0.3s ease;
}

.news-list-item:hover .news-info h3 {
    color: #1a5490;
}

.news-info p {
    font-size: 14px;
    color: #666;
    margin-bottom: 5px;
    line-height: 1.6;
}

.news-info a {
    color: inherit;
    text-decoration: none;
}

/* ===============================================
   研究方向预览
   =============================================== */
.research-preview {
    padding: 15px 0;
}

.research-preview p {
    line-height: 1.8;
    color: #555;
    text-align: justify;
    font-size: 14px;
}

/* ===============================================
   快速链接卡片
   =============================================== */
.quick-links {
    background-color: white;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    padding: 20px;
}

.quick-link-item {
    background-color: white;
    border-radius: 5px;
    padding: 20px;
    text-align: center;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
    text-decoration: none;
    display: block;
}

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

.quick-link-icon {
    font-size: 40px;
    margin-bottom: 10px;
}

.quick-link-item h3 {
    font-size: 16px;
    color: #1a5490;
    margin: 0;
}

/* ===============================================
   代表性论文预览
   =============================================== */
.publications-preview {
    list-style: none;
}

.publication-preview-item {
    padding: 12px 0;
    border-bottom: 1px solid #eee;
    transition: background-color 0.3s ease;
    cursor: pointer;
}

.publication-preview-item:last-child {
    border-bottom: none;
}

.publication-preview-item:hover {
    background-color: #f9f9f9;
}

.publication-preview-item:hover .publication-preview-title {
    color: #1a5490;
}

.publication-preview-title {
    font-size: 14px;
    color: #333;
    line-height: 1.6;
    transition: color 0.3s ease;
    text-align: left;
}

/* ===============================================
   返回顶部按钮
   =============================================== */
.go-top {
    position: fixed;
    bottom: 50px;
    right: 50px;
    width: 50px;
    height: 50px;
    background-color: #1a5490;
    color: white;
    text-align: center;
    line-height: 50px;
    border-radius: 50%;
    text-decoration: none;
    box-shadow: 0 2px 10px rgba(0,0,0,0.2);
    transition: all 0.3s ease;
    opacity: 0;
    visibility: hidden;
    z-index: 1000;
    font-size: 14px;
    font-weight: bold;
}

.go-top.show {
    opacity: 0.8;
    visibility: visible;
}

.go-top:hover {
    opacity: 1;
    transform: translateY(-5px);
    background-color: #0d3a6f;
}

/* ===============================================
   页脚样式
   =============================================== */
.footer {
    flex-shrink: 0;
    background-color: #1a5490;
    color: white;
    padding: 0 0 14px;
    margin-top: 0;
}

.footer-links {
    text-align: center;
    padding: 15px 0;
    font-size: 14px;
}

.footer-links span {
    margin-right: 10px;
    opacity: 0.9;
}

.footer-links a {
    color: white;
    text-decoration: none;
    margin: 0 10px;
    opacity: 0.9;
    transition: opacity 0.3s ease;
}

.footer-links a:hover {
    opacity: 1;
    text-decoration: underline;
}

.footer-copyright {
    text-align: center;
    padding-top: 14px;
    margin-top: 0;
    border-top: 0;
    font-size: 14px;
    opacity: 0.8;
}

.footer-copyright p {
    margin: 0;
}

/* Paired videos for the second research direction. */
.research-video-pair { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; align-items: center; padding: 12px; }
.research-section-media .research-video-pair video { width: 100%; height: auto; min-height: 0; object-fit: contain; background: #fff; }
.research-section-media:has(.research-video-pair) { min-height: 0; background: transparent; box-shadow: none; border-radius: 0; }

.research-image-stack { display:flex; flex-direction:column; gap:12px; padding:12px; }
.research-section-media .research-image-stack img { width:100%; height:auto; min-height:0; display:block; object-fit:contain; background:#fff; }
.research-section-media:has(.research-image-stack) { min-height:0; background:transparent; box-shadow:none; border-radius:0; }

/* Full-width numbered dividers above research content. */
.research-section { border-bottom: 0; row-gap: 24px; }
.research-section > .research-card-top { grid-column: 1 / -1; margin-bottom: 0; }