/* ==========================================
   CSS Variables
   ========================================== */
:root {
    --primary: #1e3a5f;
    --primary-light: #2d5a87;
    --secondary: #0ea5e9;
    --accent: #f43f5e;
    --text: #1e293b;
    --text-light: #64748b;
    --text-muted: #94a3b8;
    --bg: #ffffff;
    --bg-alt: #f8fafc;
    --bg-sidebar: #1e293b;
    --border: #e2e8f0;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow: 0 4px 6px rgba(0,0,0,0.07);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.1);
    --transition: all 0.25s ease;
    --sidebar-width: 280px;
    --radius: 10px;
}

/* Reset */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    font-family: 'Source Sans Pro', -apple-system, sans-serif;
    font-size: 15px;
    line-height: 1.7;
    color: var(--text);
    background: var(--bg);
}

a { color: var(--secondary); text-decoration: none; transition: var(--transition); }
a:hover { color: var(--primary); }
h1, h2, h3, h4 { font-weight: 700; color: var(--primary); line-height: 1.3; }
p { margin-bottom: 0.8rem; }
ul { list-style: none; }
img, video { max-width: 100%; height: auto; }
u { text-decoration: none; font-weight: 600; color: var(--primary); }
sup { font-size: 0.65em; color: var(--secondary); }

/* ==========================================
   Layout - 左侧固定 + 右侧滚动
   ========================================== */
.layout-wrapper {
    display: flex;
    min-height: 100vh;
}

/* ==========================================
   左侧边栏 - 固定
   ========================================== */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    bottom: 0;
    width: var(--sidebar-width);
    background: var(--bg-sidebar);
    color: #e2e8f0;
    overflow-y: auto;
    z-index: 100;
}

.sidebar-content {
    padding: 30px 24px;
    display: flex;
    flex-direction: column;
    min-height: 100%;
}

.profile-card {
    text-align: center;
    margin-bottom: 24px;
}

.profile-photo {
    width: 140px;
    height: 140px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid rgba(255,255,255,0.1);
    margin-bottom: 16px;
}

.profile-name {
    font-size: 1.4rem;
    color: #fff;
    margin-bottom: 2px;
}

.profile-name-cn {
    font-size: 1rem;
    color: #94a3b8;
    margin-bottom: 8px;
}

.profile-title {
    font-size: 0.9rem;
    color: var(--secondary);
    font-weight: 600;
    margin-bottom: 4px;
}

.profile-affiliation {
    font-size: 0.85rem;
    color: #94a3b8;
}

.profile-affiliation a {
    color: #94a3b8;
}

.profile-affiliation a:hover {
    color: var(--secondary);
}

.sidebar-section {
    padding: 16px 0;
    border-top: 1px solid rgba(255,255,255,0.08);
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.85rem;
    color: #cbd5e1;
    margin-bottom: 8px;
}

.contact-item i {
    width: 16px;
    color: var(--secondary);
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 10px;
    flex-wrap: wrap;
}

.social-links a {
    width: 38px;
    height: 38px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255,255,255,0.08);
    border-radius: 10px;
    color: #cbd5e1;
    font-size: 1.1rem;
    transition: var(--transition);
}

.social-links a:hover {
    background: var(--secondary);
    color: white;
    transform: translateY(-2px);
}

.btn-cv {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    width: 100%;
    padding: 12px;
    background: var(--secondary);
    color: white;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.9rem;
    transition: var(--transition);
}

.btn-cv:hover {
    background: #0284c7;
    color: white;
}

.sidebar-nav {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid rgba(255,255,255,0.08);
}

.sidebar-nav a {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    color: #cbd5e1;
    font-size: 0.9rem;
    border-radius: 8px;
    transition: var(--transition);
    margin-bottom: 4px;
}

.sidebar-nav a:hover,
.sidebar-nav a.active {
    background: rgba(255,255,255,0.08);
    color: white;
}

.sidebar-nav a.active {
    background: rgba(14, 165, 233, 0.2);
    color: var(--secondary);
}

.sidebar-nav a i {
    width: 18px;
    font-size: 0.9rem;
}

.sidebar-footer {
    margin-top: auto;
    padding-top: 20px;
}

.lang-switch {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px;
    background: rgba(255,255,255,0.08);
    color: #cbd5e1;
    border-radius: 8px;
    font-size: 0.9rem;
    transition: var(--transition);
}

.lang-switch:hover {
    background: rgba(255,255,255,0.15);
    color: white;
}

/* ==========================================
   右侧主内容区
   ========================================== */
.main-content {
    margin-left: var(--sidebar-width);
    flex: 1;
    background: var(--bg);
    min-height: 100vh;
}

.section {
    padding: 40px 50px;
}

.section:nth-child(even) {
    background: var(--bg-alt);
}

.section-title {
    font-size: 1.5rem;
    text-align: center;
    margin-bottom: 8px;
}

.section-title::after {
    content: '';
    display: block;
    width: 50px;
    height: 3px;
    background: var(--secondary);
    margin: 6px auto 0;
    border-radius: 2px;
}

.section-desc {
    text-align: center;
    color: var(--text-light);
    margin-bottom: 25px;
    font-size: 0.9rem;
}

.text-muted {
    color: var(--text-muted);
}

/* ==========================================
   About Section
   ========================================== */
.about-content {
    max-width: 800px;
    margin: 30px auto 0;
}

.about-content p {
    font-size: 0.95rem;
}

.info-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 16px;
    margin-top: 24px;
}

.info-card {
    display: flex;
    gap: 14px;
    padding: 18px;
    background: white;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
}

.info-icon {
    width: 42px;
    height: 42px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-alt);
    border-radius: 10px;
    color: var(--secondary);
    font-size: 1.1rem;
    flex-shrink: 0;
}

.info-text h4 {
    font-size: 0.95rem;
    margin-bottom: 4px;
}

.info-text p {
    font-size: 0.85rem;
    color: var(--text-light);
    margin: 0;
    line-height: 1.5;
}

/* ==========================================
   News Section
   ========================================== */
.news-list {
    max-width: 800px;
    margin: 30px auto 0;
    padding-left: 20px;
    border-left: 2px solid var(--border);
}

.news-item {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    padding: 10px 0;
    font-size: 0.92rem;
    position: relative;
}

.news-item::before {
    content: '';
    position: absolute;
    left: -25px;
    top: 16px;
    width: 8px;
    height: 8px;
    background: white;
    border: 2px solid var(--secondary);
    border-radius: 50%;
}

.news-date {
    flex-shrink: 0;
    font-weight: 700;
    color: var(--secondary);
    font-family: monospace;
    font-size: 0.85rem;
    min-width: 65px;
}

.news-badge {
    flex-shrink: 0;
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
}

.badge-oral {
    background: #fef3c7;
    color: #92400e;
}

.news-text {
    flex: 1;
}

.hidden-news {
    display: none;
}

.btn-show-more {
    display: block;
    margin: 20px auto 0;
    padding: 8px 20px;
    background: transparent;
    border: 2px solid var(--secondary);
    color: var(--secondary);
    border-radius: 20px;
    font-weight: 600;
    font-size: 0.85rem;
    cursor: pointer;
    transition: var(--transition);
}

.btn-show-more:hover {
    background: var(--secondary);
    color: white;
}

/* ==========================================
   Research Section - 大卡片布局
   ========================================== */
.research-list {
    display: flex;
    flex-direction: column;
    gap: 18px;
    max-width: 900px;
    margin: 0 auto;
}

.research-card {
    display: grid;
    grid-template-columns: 360px 1fr;
    background: white;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.research-card:hover {
    box-shadow: var(--shadow-lg);
    border-color: var(--secondary);
    transform: translateY(-2px);
}

.research-media {
    position: relative;
    background: #f1f5f9;
    display: flex;
    align-items: center;
    justify-content: center;
}

.research-media img,
.research-media video {
    width: 100%;
    height: 100%;
    object-fit: contain;
    min-height: 260px;
}

.research-tag {
    position: absolute;
    top: 12px;
    left: 12px;
    padding: 5px 12px;
    background: var(--primary);
    color: white;
    font-size: 0.75rem;
    font-weight: 700;
    border-radius: 5px;
    z-index: 10;
}

.research-tag.tag-demo { background: var(--secondary); }
.research-tag.tag-survey { background: #8b5cf6; }

.research-body {
    padding: 24px;
    display: flex;
    flex-direction: column;
}

.research-body h3 {
    font-size: 1.1rem;
    margin-bottom: 12px;
    line-height: 1.4;
}

.research-body > p {
    font-size: 0.9rem;
    color: var(--text-light);
    line-height: 1.7;
    margin-bottom: 14px;
}

.research-highlights {
    padding: 14px;
    background: var(--bg-alt);
    border-radius: 8px;
    border-left: 3px solid var(--secondary);
    margin-bottom: 16px;
}

.research-highlights li {
    font-size: 0.85rem;
    padding: 4px 0;
    display: flex;
    align-items: flex-start;
    gap: 8px;
}

.research-highlights li i {
    color: var(--secondary);
    margin-top: 4px;
    font-size: 0.75rem;
}

.research-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: auto;
    padding-top: 14px;
    border-top: 1px solid var(--border);
    flex-wrap: wrap;
    gap: 12px;
}

.research-meta {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.research-meta i {
    color: var(--secondary);
    margin-right: 4px;
}

.research-links {
    display: flex;
    gap: 8px;
}

.research-links a {
    padding: 6px 14px;
    background: var(--bg-alt);
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text);
    display: flex;
    align-items: center;
    gap: 5px;
    transition: var(--transition);
}

.research-links a:hover {
    background: var(--secondary);
    border-color: var(--secondary);
    color: white;
}

/* ==========================================
   Publications Section - 美化版
   ========================================== */
.pub-filter {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 10px 22px;
    background: white;
    border: 2px solid var(--border);
    border-radius: 25px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text);
    cursor: pointer;
    transition: var(--transition);
}

.filter-btn:hover {
    border-color: var(--secondary);
    color: var(--secondary);
}

.filter-btn.active {
    background: var(--secondary);
    border-color: var(--secondary);
    color: white;
}

.pub-container {
    max-width: 900px;
    margin: 0 auto;
}

.pub-year-section {
    margin-bottom: 40px;
}

.pub-year-label {
    font-size: 1.4rem;
    font-weight: 800;
    color: var(--primary);
    padding-bottom: 12px;
    margin-bottom: 20px;
    border-bottom: 3px solid var(--secondary);
    display: inline-block;
}

.pub-year-content {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.pub-card {
    display: flex;
    gap: 16px;
    padding: 20px 24px;
    background: white;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    align-items: flex-start;
}

.pub-card:hover {
    box-shadow: var(--shadow-lg);
    border-color: var(--secondary);
    transform: translateY(-2px);
}

.pub-venue {
    flex-shrink: 0;
    min-width: 100px;
    padding: 8px 14px;
    background: var(--bg-alt);
    border-radius: 8px;
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--text-light);
    text-align: center;
    line-height: 1.3;
}

.pub-venue.venue-top {
    background: linear-gradient(135deg, #dbeafe 0%, #bfdbfe 100%);
    color: #1e40af;
}

.pub-venue.venue-oral {
    background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
    color: #92400e;
}

.pub-venue.venue-conf {
    background: var(--bg-alt);
    color: var(--text-light);
}

.pub-venue.venue-journal {
    background: linear-gradient(135deg, #dcfce7 0%, #bbf7d0 100%);
    color: #166534;
}

.pub-venue.venue-top-journal {
    background: linear-gradient(135deg, #fef3c7 0%, #fed7aa 100%);
    color: #9a3412;
}

.pub-main {
    flex: 1;
    min-width: 0;
}

.pub-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 8px;
    line-height: 1.45;
}

.pub-authors {
    font-size: 0.88rem;
    color: var(--text-light);
    margin-bottom: 6px;
    line-height: 1.5;
}

.pub-authors u {
    color: var(--primary);
    font-weight: 600;
}

.pub-venue-full {
    font-size: 0.82rem;
    color: var(--text-muted);
    font-style: italic;
    margin-bottom: 10px;
}

.pub-links {
    display: flex;
    gap: 8px;
}

.pub-links a {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-alt);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text-light);
    font-size: 0.95rem;
    transition: var(--transition);
}

.pub-links a:hover {
    background: var(--secondary);
    border-color: var(--secondary);
    color: white;
    transform: scale(1.1);
}

/* Responsive */
@media (max-width: 700px) {
    .pub-card {
        flex-direction: column;
        gap: 12px;
    }
    
    .pub-venue {
        align-self: flex-start;
        min-width: auto;
    }
}

/* ==========================================
   Projects Section
   ========================================== */
.project-list {
    max-width: 800px;
    margin: 30px auto 0;
}

.project-item {
    display: flex;
    gap: 14px;
    padding: 16px 20px;
    background: white;
    border-radius: var(--radius);
    margin-bottom: 12px;
    border: 1px solid var(--border);
    border-left: 4px solid var(--secondary);
    box-shadow: var(--shadow-sm);
    align-items: flex-start;
    transition: var(--transition);
}

.project-item:hover {
    box-shadow: var(--shadow);
    transform: translateX(4px);
}

.project-role {
    flex-shrink: 0;
    padding: 5px 12px;
    border-radius: 5px;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
}

.role-pi { background: #dbeafe; color: #1e40af; }
.role-coi { background: #f3e8ff; color: #7c3aed; }

.project-info { flex: 1; }
.project-info h4 { font-size: 0.95rem; margin-bottom: 6px; }
.project-info p { font-size: 0.85rem; color: var(--text-light); margin: 0 0 6px 0; }
.project-time { font-size: 0.8rem; color: var(--text-muted); }

/* ==========================================
   Awards Section - 时间线风格
   ========================================== */
.awards-timeline {
    max-width: 700px;
    margin: 30px auto 0;
    position: relative;
    padding-left: 30px;
}

.awards-timeline::before {
    content: '';
    position: absolute;
    left: 6px;
    top: 10px;
    bottom: 10px;
    width: 3px;
    background: linear-gradient(180deg, var(--secondary), var(--primary-light));
    border-radius: 3px;
}

.award-item {
    position: relative;
    padding: 16px 0;
}

.award-item::before {
    content: '';
    position: absolute;
    left: -30px;
    top: 24px;
    width: 12px;
    height: 12px;
    background: white;
    border: 3px solid var(--secondary);
    border-radius: 50%;
}

.award-item.award-featured::before {
    background: var(--secondary);
    box-shadow: 0 0 0 4px rgba(14, 165, 233, 0.2);
}

.award-year {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--secondary);
    font-family: monospace;
    margin-bottom: 8px;
}

.award-content {
    display: flex;
    gap: 14px;
    padding: 16px 20px;
    background: white;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.award-featured .award-content {
    background: linear-gradient(135deg, #fffbeb 0%, #fef3c7 100%);
    border-color: #fbbf24;
}

.award-item:hover .award-content {
    box-shadow: var(--shadow);
}

.award-icon {
    flex-shrink: 0;
    font-size: 1.3rem;
    color: var(--secondary);
    margin-top: 2px;
}

.award-featured .award-icon {
    color: #d97706;
}

.award-content h4 {
    font-size: 0.95rem;
    margin-bottom: 4px;
}

.award-content p {
    font-size: 0.85rem;
    color: var(--text-light);
    margin: 0;
}

/* ==========================================
   Footer
   ========================================== */
.footer {
    padding: 30px 50px;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.85rem;
    background: var(--bg-alt);
    border-top: 1px solid var(--border);
}

/* ==========================================
   Mobile Menu Button
   ========================================== */
.mobile-menu-btn {
    display: none;
    position: fixed;
    top: 16px;
    left: 16px;
    width: 44px;
    height: 44px;
    background: var(--bg-sidebar);
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 1.2rem;
    cursor: pointer;
    z-index: 200;
    box-shadow: var(--shadow);
}

/* ==========================================
   Responsive
   ========================================== */
@media (max-width: 1100px) {
    .research-card {
        grid-template-columns: 320px 1fr;
    }
    
    .section {
        padding: 50px 30px;
    }
}

@media (max-width: 900px) {
    .sidebar {
        transform: translateX(-100%);
        transition: transform 0.3s ease;
    }
    
    .sidebar.active {
        transform: translateX(0);
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .mobile-menu-btn {
        display: flex;
        align-items: center;
        justify-content: center;
    }
    
    .section {
        padding: 40px 20px;
    }
    
    .research-card {
        grid-template-columns: 1fr;
    }
    
    .research-media {
        max-height: 280px;
    }
    
    .research-media img,
    .research-media video {
        min-height: 200px;
    }
}

@media (max-width: 600px) {
    .section-title {
        font-size: 1.3rem;
    }
    
    .info-cards {
        grid-template-columns: 1fr;
    }
    
    .news-item {
        flex-wrap: wrap;
    }
    
    .pub-item {
        flex-direction: column;
        gap: 10px;
    }
    
    .pub-venue {
        align-self: flex-start;
    }
    
    .project-item {
        flex-direction: column;
        gap: 12px;
    }
    
    .award-content {
        flex-direction: column;
        gap: 10px;
        text-align: center;
    }
    
    .footer {
        padding: 24px 20px;
    }
}

/* ==========================================
   Visitor Statistics Section
   ========================================== */
.stats-container {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    gap: 60px;
    flex-wrap: wrap;
    max-width: 900px;
    margin: 30px auto 0;
}

.stats-globe {
    flex-shrink: 0;
}

.stats-counter {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.stats-counter img {
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
}

@media (max-width: 700px) {
    .stats-container {
        flex-direction: column;
        align-items: center;
        gap: 30px;
    }
}