/* Global Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* 清华紫色系 - 优化的学术色彩方案 */
    --primary-color: #6B3AA0;
    --primary-dark: #5A2E8A;
    --primary-light: #7D4BB2;
    --secondary-color: #8B5BB1;
    --accent-color: #9B7BC1;
    --light-purple: #F3EDFA;
    --lighter-purple: #FAF7FD;
    --dark-purple: #4A2370;
    
    /* 学术中性色彩 */
    --dark-color: #1A1A1A;
    --text-primary: #212529;
    --text-secondary: #495057;
    --text-muted: #6C757D;
    --light-color: #FAFBFC;
    --white: #FFFFFF;
    --gray-100: #F8F9FA;
    --gray-200: #E9ECEF;
    --gray-300: #DEE2E6;
    --gray-400: #CED4DA;
    --gray-500: #ADB5BD;
    --gray-600: #6C757D;
    --gray-700: #495057;
    --gray-800: #343A40;
    --gray-900: #212529;
    --border-color: #E1E5E9;
    
    /* 功能色彩 */
    --success-color: #16a34a;
    --success-light: #dcfce7;
    --warning-color: #d97706;
    --warning-light: #fef3c7;
    --danger-color: #E74C3C;
    --info-color: #3498DB;
    
    /* 阴影系统 */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
    --shadow-xl: 0 12px 48px rgba(0,0,0,0.15);
    --shadow-purple: 0 8px 24px rgba(107, 58, 160, 0.15);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', 'Microsoft YaHei', Arial, sans-serif;
    color: var(--text-primary);
    line-height: 1.5;
    background-color: var(--gray-100);
    overflow-x: hidden;
    font-size: 15px;
    letter-spacing: 0.01em;
}

/* Typography System */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

/* Utility Classes */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

.clearfix::after {
    content: "";
    display: table;
    clear: both;
}

.more {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.875rem;
    transition: all 0.2s ease;
    position: relative;
    display: inline-flex;
    align-items: center;
}

.more::after {
    content: '→';
    margin-left: 4px;
    transition: transform 0.2s ease;
}

.more:hover {
    color: var(--primary-dark);
}

.more:hover::after {
    transform: translateX(3px);
}

/* Header Styles - 更紧凑和专业 */
.header {
    background-color: var(--white);
    box-shadow: 0 1px 0 var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(10px);
    background-color: rgba(255, 255, 255, 0.98);
    transition: all 0.3s ease;
}

.header.scrolled {
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.1);
    background-color: rgba(255, 255, 255, 0.95);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    min-height: 64px;
    position: relative;
}

.logo {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: var(--text-primary);
}

.logo-img {
    height: 60px;
    width: auto;
    max-width: 420px;
}

.logo-text h3 {
    color: var(--primary-color);
    font-size: 1.375rem;
    margin-bottom: 0;
    font-weight: 700;
    letter-spacing: -0.03em;
}

.logo-text p {
    color: var(--text-secondary);
    font-size: 0.75rem;
    margin: 0;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 500;
}

.navbar-toggle {
    display: none;
    background: transparent;
    border: none;
    cursor: pointer;
    flex-direction: column;
    gap: 4px;
    padding: 10px;
}

.icon-bar {
    width: 25px;
    height: 3px;
    background-color: var(--text-color);
    border-radius: 2px;
    transition: all 0.3s ease;
}

.search {
    display: flex;
    align-items: center;
    gap: 16px;
}

.search-container {
    display: flex;
    background: var(--gray-100);
    border-radius: 20px;
    padding: 2px;
    border: 1px solid var(--gray-300);
    transition: all 0.2s ease;
}

.search-container:focus-within {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(107, 58, 160, 0.1);
}

.search-input {
    background: transparent;
    border: none;
    color: var(--text-primary);
    padding: 6px 12px;
    outline: none;
    width: 180px;
    font-size: 0.875rem;
}

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

.search-button {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 6px 10px;
    border-radius: 50%;
    transition: all 0.2s ease;
}

.search-button:hover {
    background: var(--primary-color);
    color: var(--white);
}

.language-switcher {
    margin-left: 8px;
    display: flex;
    background: var(--gray-100);
    border-radius: 20px;
    padding: 2px;
    border: 1px solid var(--gray-300);
}

.lang-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 6px 12px;
    border-radius: 18px;
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 0.8125rem;
    font-weight: 500;
    white-space: nowrap;
}

.lang-btn:hover {
    color: var(--text-primary);
}

.lang-btn.active {
    background: var(--primary-color);
    color: var(--white);
    box-shadow: 0 2px 4px rgba(107, 58, 160, 0.2);
}

.lang-btn.active:hover {
    background: var(--primary-dark);
}

/* Navigation Menu - 更紧凑和专业 */
.nav {
    background-color: var(--white);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 64px; /* header的高度 */
    z-index: 999;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
    background-color: rgba(255, 255, 255, 0.98);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.nav.scrolled {
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.12);
    background-color: rgba(255, 255, 255, 0.95);
}

.daohang {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
    justify-content: center;
    align-items: center;
}

.daohang > li {
    position: relative;
}

.daohang > li > a {
    display: block;
    padding: 12px 20px;
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9375rem;
    transition: all 0.2s ease;
    position: relative;
}

.daohang > li > a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width 0.2s ease;
}

.daohang > li:hover > a {
    color: var(--primary-color);
}

.daohang > li:hover > a::after {
    width: 60%;
}

.nav .daohang .nav_item {
    position: absolute !important;
    top: 100% !important;
    left: 50% !important;
    transform: translateX(-50%) translateY(-10px) !important;
    background: var(--white) !important;
    box-shadow: var(--shadow-lg) !important;
    min-width: 180px !important;
    list-style: none !important;
    opacity: 0 !important;
    visibility: hidden !important;
    transition: all 0.2s ease !important;
    border-radius: 8px !important;
    overflow: hidden !important;
    border: 1px solid var(--border-color) !important;
    margin-top: 8px !important;
    z-index: 1000 !important;
    padding: 0 !important;
    margin: 8px 0 0 0 !important;
}

.nav .daohang > li:hover .nav_item {
    opacity: 1 !important;
    visibility: visible !important;
    transform: translateX(-50%) translateY(0) !important;
    display: block !important;
}

.nav .daohang .nav_item li a {
    display: block;
    padding: 10px 16px;
    color: var(--text-primary);
    text-decoration: none;
    font-size: 0.875rem;
    transition: all 0.2s ease;
}

.nav .daohang .nav_item li a:hover {
    background-color: var(--light-purple);
    color: var(--primary-color);
    padding-left: 20px;
}

/* Banner/Slider Styles - 更紧凑和学术化 */
.banner {
    position: relative;
    height: 420px;
    overflow: hidden;
    background: var(--gray-900);
}

.sliderContainer {
    position: relative;
    width: 100%;
    height: 100%;
}

.heroSlider {
    position: relative;
    width: 100%;
    height: 100%;
}

.slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    transition: opacity 1s ease-in-out;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--gray-900);
}

.slide.active {
    opacity: 1;
}

.slide-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    filter: brightness(0.7);
}

.slide-caption {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    text-align: center;
    z-index: 10;
    padding: 48px 20px 32px;
    background: linear-gradient(
        to top,
        rgba(0, 0, 0, 0.9) 0%,
        rgba(0, 0, 0, 0.7) 40%,
        rgba(0, 0, 0, 0.4) 70%,
        transparent 100%
    );
}

.slide-caption h3 {
    font-size: 2.25rem;
    margin-bottom: 0.75rem;
    color: var(--white);
    font-weight: 700;
    text-shadow: 0 2px 12px rgba(0, 0, 0, 0.7);
    letter-spacing: -0.03em;
    line-height: 1.1;
}

.slide-caption p {
    font-size: 1.125rem;
    color: rgba(255, 255, 255, 0.9);
    margin: 0;
    max-width: 700px;
    margin: 0 auto;
    line-height: 1.4;
    text-shadow: 0 1px 6px rgba(0, 0, 0, 0.7);
    font-weight: 400;
}

.banner-shaw {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.1);
    pointer-events: none;
}

/* 轮播图导航 - 更精致 */
.slider-dots {
    position: absolute;
    bottom: 16px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 8px;
    z-index: 15;
}

.slider-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.4);
    cursor: pointer;
    transition: all 0.2s ease;
    border: 1px solid rgba(255, 255, 255, 0.5);
}

.slider-dot:hover {
    background: rgba(255, 255, 255, 0.6);
}

.slider-dot.active {
    width: 24px;
    border-radius: 4px;
    background: var(--white);
    border-color: var(--white);
}

/* 轮播图左右切换按钮 */
.slider-nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    cursor: pointer;
    z-index: 12;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    color: var(--white);
    transition: all 0.2s ease;
}

.slider-nav:hover {
    background: rgba(255, 255, 255, 0.2);
    border-color: rgba(255, 255, 255, 0.3);
}

.slider-nav.prev {
    left: 24px;
}

.slider-nav.next {
    right: 24px;
}

/* 添加暂停/播放指示器 */
.slider-play-pause {
    position: absolute;
    top: 16px;
    right: 16px;
    background: rgba(0, 0, 0, 0.6);
    color: var(--white);
    border: none;
    padding: 8px;
    border-radius: 50%;
    cursor: pointer;
    z-index: 12;
    font-size: 14px;
    transition: all 0.2s ease;
    backdrop-filter: blur(10px);
    opacity: 0.7;
}

.slider-play-pause:hover {
    opacity: 1;
}

/* Content Sections - 更紧凑的间距 */
.write-content, .research-content {
    padding: 48px 0;
    background-color: var(--white);
}

.index-content {
    background-color: var(--gray-100);
}

.research-content {
    background-color: var(--white);
}

.index-title {
    margin-bottom: 32px;
    position: relative;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.index-title h3 {
    font-size: 1.75rem;
    color: var(--text-primary);
    margin: 0;
    position: relative;
    font-weight: 700;
}

.index-title h3 span {
    color: var(--primary-color);
    position: relative;
}

.index-title h3 span::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--primary-light));
    border-radius: 2px;
}

/* Introduction Section - 更紧凑和学术化 */
.intro-section {
    margin-bottom: 56px;
}

.intro-content {
    display: grid;
    grid-template-columns: 3fr 1fr;
    gap: 48px;
    align-items: center;
    margin-top: 32px;
    background: var(--white);
    padding: 32px;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
}

.intro-text h4 {
    color: var(--primary-color);
    font-size: 1.375rem;
    margin-bottom: 16px;
    font-weight: 600;
}

.intro-text p {
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: 24px;
    text-align: justify;
}

.intro-stats {
    display: flex;
    gap: 32px;
    margin-top: 24px;
}

.stat-item {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 4px;
}

.stat-label {
    color: var(--text-muted);
    font-size: 0.875rem;
    font-weight: 500;
}

.intro-image {
    text-align: center;
}

.intro-image img {
    width: 100%;
    max-width: 240px;
    border-radius: 12px;
    box-shadow: var(--shadow-purple);
    border: 3px solid var(--white);
}

.intro-title {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-bottom: 16px;
    margin-top: -8px;
}

.intro-contact {
    margin: 16px 0;
}

.intro-contact p {
    margin-bottom: 8px;
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

.intro-contact i {
    color: var(--primary-color);
    margin-right: 8px;
    width: 16px;
}

.intro-recruitment {
    background: var(--light-purple);
    padding: 16px;
    border-radius: 8px;
    margin: 20px 0;
}

.recruitment-note {
    margin: 0 !important;
    color: var(--text-primary);
    font-size: 0.9375rem;
}

/* Group Introduction Styles - 团队化的课题组介绍 */
.group-intro-content {
    margin-top: 32px;
    background: var(--white);
    border-radius: 16px;
    padding: 40px;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

.group-description h4 {
    color: var(--primary-color);
    font-size: 1.75rem;
    margin-bottom: 20px;
    text-align: center;
    font-weight: 700;
}

.group-description > p {
    font-size: 1.0625rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 32px;
    text-align: justify;
}

.research-overview {
    margin: 32px 0;
}

.research-overview-image {
    text-align: center;
    background: var(--gray-100);
    padding: 24px;
    border-radius: 12px;
    border: 2px solid var(--light-purple);
}

.research-diagram {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
}

.image-caption {
    margin-top: 16px;
    font-size: 0.9375rem;
    color: var(--text-muted);
    font-style: italic;
    margin-bottom: 0;
}

.group-highlights {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin: 32px 0;
}

.highlight-item {
    text-align: center;
    padding: 24px 16px;
    background: var(--lighter-purple);
    border-radius: 12px;
    transition: all 0.2s ease;
    border: 1px solid var(--light-purple);
}

.highlight-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.highlight-item i {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 16px;
    display: block;
}

.highlight-item h5 {
    color: var(--text-primary);
    font-size: 1.125rem;
    margin-bottom: 12px;
    font-weight: 600;
}

.highlight-item p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.5;
    margin: 0;
}



/* News Section - 学术期刊风格 */
.news {
    margin-bottom: 56px;
}

.news-rec {
    margin-bottom: 32px;
}

.news-featured {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 24px;
    background: var(--white);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    text-decoration: none;
    color: inherit;
    transition: all 0.2s ease;
    border: 1px solid var(--border-color);
}

.news-featured:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.news-img {
    position: relative;
    overflow: hidden;
    background: var(--gray-200);
}

.news-img img {
    width: 100%;
    height: 240px;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.news-featured:hover .news-img img {
    transform: scale(1.05);
}

.date-boxs {
    position: absolute;
    top: 16px;
    right: 16px;
}

.date-box {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 8px;
    padding: 8px 12px;
    text-align: center;
    box-shadow: var(--shadow-sm);
}

.date-text p {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
    margin: 0;
    line-height: 1;
}

.date-text h6 {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin: 0;
    margin-top: 2px;
    font-weight: 600;
}

.news-text {
    padding: 24px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.news-text h3 {
    color: var(--text-primary);
    font-size: 1.25rem;
    margin-bottom: 12px;
    font-weight: 600;
    line-height: 1.3;
}

.news-text p {
    color: var(--text-secondary);
    line-height: 1.6;
    font-size: 0.9375rem;
}

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

.news-list li {
    background: var(--white);
    margin-bottom: 12px;
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
    transition: all 0.2s ease;
    border: 1px solid var(--border-color);
}

.news-list li:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-light);
}

.news-list a {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    text-decoration: none;
    color: inherit;
}

.news-list .text h4 {
    color: var(--text-primary);
    font-size: 1rem;
    margin-bottom: 6px;
    font-weight: 600;
    line-height: 1.3;
}

.news-list .text p {
    color: var(--text-muted);
    font-size: 0.875rem;
    line-height: 1.4;
}

.news-list .time {
    color: var(--primary-color);
    font-weight: 600;
    white-space: nowrap;
    font-size: 0.875rem;
}

/* Research Results Section - 学术论文风格 */
.research-rec ul {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 24px;
    margin-bottom: 32px;
}

.research-rec li {
    background: var(--white);
    border-radius: 10px;
    box-shadow: var(--shadow-sm);
    transition: all 0.2s ease;
    border: 1px solid var(--border-color);
}

.research-rec li:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-light);
}

.research-rec a {
    display: block;
    padding: 24px;
    text-decoration: none;
    color: inherit;
    height: 100%;
}

.research-rec h3 {
    color: var(--primary-color);
    font-size: 1.125rem;
    margin-bottom: 12px;
    font-weight: 600;
    line-height: 1.3;
}

.research-rec p {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 16px;
    font-size: 0.9375rem;
    text-align: justify;
}

.research-rec .date {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text-muted);
    font-size: 0.875rem;
    padding-top: 12px;
    border-top: 1px solid var(--gray-200);
    font-weight: 500;
}

.research-icon {
    width: 16px;
    height: 16px;
    background: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="%236B3AA0"><path d="M9 2L7.17 4H4c-1.1 0-2 .9-2 2v12c0 1.1.9 2 2 2h16c1.1 0 2-.9 2-2V6c0-1.1-.9-2-2-2h-3.17L15 2H9zm3 15c-2.76 0-5-2.24-5-5s2.24-5 5-5 5 2.24 5 5-2.24 5-5 5z"/></svg>') no-repeat center;
    background-size: contain;
}

.research-list {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
}

.research-list li {
    background: var(--white);
    border-radius: 6px;
    box-shadow: var(--shadow-sm);
    transition: all 0.2s ease;
    border: 1px solid var(--border-color);
}

.research-list li:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.research-list a {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 16px;
    text-decoration: none;
    color: inherit;
}

.research-list p {
    color: var(--text-primary);
    font-size: 0.875rem;
    margin: 0;
    font-weight: 500;
    line-height: 1.4;
}

.research-list span {
    color: var(--primary-color);
    font-size: 0.8125rem;
    white-space: nowrap;
    font-weight: 600;
}

/* Group Activities Section - 更紧凑 */
.group {
    margin-bottom: 56px;
}

.group-rec {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
    margin-bottom: 32px;
}

.group-recimg a {
    display: block;
    text-decoration: none;
    color: inherit;
}

.rec-img {
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: 16px;
    position: relative;
}

.rec-img img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.group-recimg:hover .rec-img img {
    transform: scale(1.05);
}

.rec-text h3 {
    color: var(--text-primary);
    font-size: 1.125rem;
    margin-bottom: 8px;
    font-weight: 600;
}

.rec-text .date {
    color: var(--primary-color);
    font-size: 0.875rem;
    font-weight: 600;
}

.group-reclist {
    list-style: none;
}

.group-reclist li {
    background: var(--white);
    margin-bottom: 12px;
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
    transition: all 0.2s ease;
    border: 1px solid var(--border-color);
}

.group-reclist li:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
}

.group-reclist a {
    display: block;
    padding: 16px;
    text-decoration: none;
    color: inherit;
    position: relative;
}

.group-reclist .text h4 {
    color: var(--text-primary);
    margin-bottom: 8px;
    font-size: 1rem;
    font-weight: 600;
}

.group-reclist .text p {
    color: var(--text-muted);
    font-size: 0.875rem;
    line-height: 1.5;
}

.group-reclist .time {
    position: absolute;
    top: 16px;
    right: 16px;
    color: var(--primary-color);
    font-size: 0.8125rem;
    font-weight: 600;
}

.group-icon {
    position: absolute;
    bottom: 16px;
    right: 16px;
    width: 16px;
    height: 16px;
    background: var(--primary-color);
    border-radius: 50%;
    opacity: 0.3;
}

.group-list {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
}

.group-list li {
    background: var(--white);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: all 0.2s ease;
    border: 1px solid var(--border-color);
}

.group-list li:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.group-list a {
    display: block;
    text-decoration: none;
    color: inherit;
}

.group-list .rec-img {
    margin-bottom: 0;
}

.group-list .rec-img img {
    height: 160px;
}

.group-list .text {
    padding: 16px;
}

.group-list .text h4 {
    color: var(--text-primary);
    margin-bottom: 8px;
    font-size: 1rem;
    font-weight: 600;
    line-height: 1.3;
}

.group-list .time {
    color: var(--primary-color);
    font-size: 0.8125rem;
    position: static;
    font-weight: 600;
}

/* Research Directions - 学术机构风格 */
.research-directions {
    padding: 48px 0;
    background: linear-gradient(135deg, var(--lighter-purple) 0%, var(--gray-100) 100%);
}

.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
    margin-top: 32px;
}

.research-item {
    background: var(--white);
    padding: 32px 24px;
    border-radius: 12px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: all 0.2s ease;
    position: relative;
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.research-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--primary-light));
}

.research-item:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-purple);
}

.research-item i {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.research-item h3 {
    color: var(--text-primary);
    font-size: 1.25rem;
    margin-bottom: 12px;
    font-weight: 600;
}

.research-item p {
    color: var(--text-secondary);
    line-height: 1.5;
    font-size: 0.9375rem;
}

/* Team Overview - 数据展示风格 */
.team-overview {
    padding: 48px 0;
    background-color: var(--white);
}

.team-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
    margin-top: 32px;
}

.stat-card {
    background: var(--white);
    color: var(--text-primary);
    padding: 28px 20px;
    border-radius: 10px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: all 0.2s ease;
    border: 2px solid var(--light-purple);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.stat-card .stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 8px;
    display: block;
    color: var(--primary-color);
    letter-spacing: -0.03em;
}

.stat-card .stat-label {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 500;
}

/* Footer - 清华学术风格 */
.footer {
    background-color: var(--dark-color);
    color: var(--white);
    padding: 40px 0 24px;
}

.footer-link ul {
    list-style: none;
    display: flex;
    justify-content: center;
    gap: 32px;
    margin-bottom: 32px;
    flex-wrap: wrap;
}

.footer-link a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.2s ease;
    font-size: 0.9375rem;
}

.footer-link a:hover {
    color: var(--white);
}

.footer-copyright {
    text-align: center;
    padding-top: 24px;
    border-top: 1px solid rgba(255,255,255,0.1);
}

.footer-copyright p {
    margin-bottom: 4px;
    opacity: 0.7;
    font-size: 0.875rem;
}

/* ICP备案号样式 */
.icp-beian {
    margin-top: 16px !important;
    padding-top: 16px;
    border-top: 1px solid rgba(255,255,255,0.1);
    text-align: center;
}

.icp-beian a {
    color: rgba(255,255,255,0.7);
    text-decoration: none;
    font-size: 0.8rem;
    transition: color 0.2s ease;
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

.icp-beian a:hover {
    color: var(--white);
    opacity: 1;
}

.icp-beian a::before {
    content: "🔗";
    font-size: 0.7rem;
}

/* Image Modal */
.image-modal {
    display: none;
    position: fixed;
    z-index: 9999;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.9);
}

.image-modal-close {
    position: absolute;
    top: 15px;
    right: 35px;
    color: #f1f1f1;
    font-size: 40px;
    font-weight: bold;
    cursor: pointer;
    transition: 0.3s;
}

.image-modal-close:hover {
    color: #bbb;
}

.modal-image {
    margin: auto;
    display: block;
    max-width: 90%;
    max-height: 90%;
    width: auto;
    height: auto;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    border-radius: 10px;
    object-fit: contain;
}

.image-modal-caption {
    margin: auto;
    display: block;
    width: 80%;
    max-width: 700px;
    text-align: center;
    color: #ccc;
    padding: 10px 0;
    position: absolute;
    bottom: 10%;
    left: 50%;
    transform: translateX(-50%);
}

/* 图片模态框响应式设计 */
@media screen and (max-width: 768px) {
    .modal-image {
        max-width: 95%;
        max-height: 80%;
    }
    
    .image-modal-close {
        top: 10px;
        right: 20px;
        font-size: 30px;
    }
    
    .image-modal-caption {
        width: 90%;
        bottom: 5%;
        font-size: 14px;
    }
}

/* Responsive Design - 更紧凑和专业的响应式布局 */
@media screen and (max-width: 1024px) {
    .container {
        padding: 0 20px;
    }
    
    .logo-img {
        height: 56px;
        max-width: 400px;
    }
    
    .intro-content {
        grid-template-columns: 1fr;
        gap: 32px;
        text-align: center;
        padding: 24px;
    }
    
    .group-highlights {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    
    .group-intro-content {
        padding: 32px 24px;
    }
    
    .intro-stats {
        justify-content: center;
    }
    
    .news-featured {
        grid-template-columns: 1fr;
    }
    
    .news-img img {
        height: 200px;
    }
    
    .group-rec {
        grid-template-columns: 1fr;
        gap: 24px;
    }
    
    .research-list {
        grid-template-columns: 1fr;
    }
    
    .team-stats {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media screen and (max-width: 768px) {
    body {
        font-size: 14px;
    }
    
    .container {
        padding: 0 16px;
    }
    
    .header .container {
        flex-wrap: wrap;
        min-height: 56px;
    }
    
    .navbar-toggle {
        display: flex;
    }
    
    .search {
        order: 3;
        width: 100%;
        margin-top: 12px;
        justify-content: space-between;
    }
    
    .search-container {
        flex: 1;
        margin-right: 12px;
    }
    
    .search-input {
        width: 100%;
    }
    
    .language-switcher {
        margin-left: 8px;
        min-width: auto;
    }
    
    .lang-btn {
        padding: 5px 10px;
        font-size: 0.75rem;
    }
    
    .daohang {
        flex-direction: column;
        position: fixed;
        top: 0;
        left: -100%;
        width: 280px;
        height: 100vh;
        background: var(--white);
        box-shadow: var(--shadow-xl);
        transition: left 0.3s ease;
        z-index: 1001;
        overflow-y: auto;
        padding-top: 60px;
    }
    
    .daohang.active {
        left: 0;
    }
    
    .daohang > li {
        width: 100%;
    }
    
    .daohang > li > a {
        padding: 12px 20px;
        border-bottom: 1px solid var(--gray-200);
    }
    
    .daohang > li > a::after {
        display: none;
    }
    
    .nav .daohang .nav_item {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        background: var(--gray-100);
        margin-top: 0;
        margin-bottom: 0;
        width: 100%;
        border-radius: 0;
    }
    
    .nav .daohang .nav_item li a {
        padding-left: 40px;
        font-size: 0.8125rem;
    }
    
    /* 移动端遮罩层 */
    .mobile-overlay {
        display: none;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background: rgba(0, 0, 0, 0.5);
        z-index: 1000;
    }
    
    .mobile-overlay.active {
        display: block;
    }
    
    .banner {
        height: 350px;
    }
    
    .slide-caption {
        padding: 32px 16px 24px;
    }
    
    .slide-caption h3 {
        font-size: 1.75rem;
        margin-bottom: 0.5rem;
    }
    
    .slide-caption p {
        font-size: 1rem;
        max-width: 90%;
    }
    
    .slider-nav {
        width: 36px;
        height: 36px;
        font-size: 14px;
    }
    
    .slider-nav.prev {
        left: 12px;
    }
    
    .slider-nav.next {
        right: 12px;
    }
    
    .write-content, .research-content {
        padding: 32px 0;
    }
    
    .index-title {
        flex-direction: column;
        gap: 12px;
        text-align: center;
        margin-bottom: 24px;
    }
    
    .index-title h3 {
        font-size: 1.5rem;
    }
    
    .intro-section {
        margin-bottom: 40px;
    }
    
    .group-intro-content {
        padding: 24px 20px;
    }
    
    .group-description h4 {
        font-size: 1.5rem;
    }
    
    .group-description > p {
        font-size: 1rem;
    }
    
    .research-overview-image {
        padding: 20px;
    }
    
    .intro-stats {
        gap: 24px;
    }
    
    .stat-number {
        font-size: 1.75rem;
    }
    
    .news {
        margin-bottom: 40px;
    }
    
    .news-text {
        padding: 20px;
    }
    
    .news-text h3 {
        font-size: 1.125rem;
    }
    
    .research-rec ul {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    
    .research-rec a {
        padding: 20px;
    }
    
    .research-list {
        gap: 10px;
    }
    
    .research-list a {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
    }
    
    .group {
        margin-bottom: 40px;
    }
    
    .group-reclist .time {
        position: static;
        margin-top: 8px;
        display: inline-block;
    }
    
    .group-reclist .text {
        padding-right: 0;
    }
    
    .group-icon {
        display: none;
    }
    
    .group-list {
        grid-template-columns: 1fr;
    }
    
    .research-directions {
        padding: 32px 0;
    }
    
    .research-grid {
        gap: 16px;
        margin-top: 24px;
    }
    
    .research-item {
        padding: 24px 20px;
    }
    
    .research-item i {
        font-size: 2rem;
        margin-bottom: 16px;
    }
    
    .research-item h3 {
        font-size: 1.125rem;
    }
    
    .team-overview {
        padding: 32px 0;
    }
    
    .team-stats {
        gap: 12px;
        margin-top: 24px;
    }
    
    .stat-card {
        padding: 20px 16px;
    }
    
    .stat-card .stat-number {
        font-size: 2rem;
    }
    
    .stat-card .stat-label {
        font-size: 0.875rem;
    }
    
    .footer {
        padding: 32px 0 20px;
    }
    
    .footer-link ul {
        flex-direction: column;
        gap: 12px;
        text-align: center;
        margin-bottom: 24px;
    }
}

@media screen and (max-width: 480px) {
    .logo-img {
        height: 44px;
        max-width: 340px;
    }
    
    .banner {
        height: 280px;
    }
    
    .slide-caption {
        padding: 24px 12px 20px;
    }
    
    .slide-caption h3 {
        font-size: 1.5rem;
        line-height: 1.2;
    }
    
    .slide-caption p {
        font-size: 0.875rem;
        line-height: 1.3;
    }
    
    .slider-nav {
        width: 32px;
        height: 32px;
        font-size: 12px;
    }
    
    .slider-nav.prev {
        left: 8px;
    }
    
    .slider-nav.next {
        right: 8px;
    }
    
    .slider-play-pause {
        top: 8px;
        right: 8px;
        padding: 6px;
        font-size: 12px;
    }
    
    .slider-dots {
        bottom: 12px;
        gap: 6px;
    }
    
    .slider-dot {
        width: 6px;
        height: 6px;
    }
    
    .slider-dot.active {
        width: 18px;
    }
    
    .write-content, .research-content {
        padding: 24px 0;
    }
    
    .index-title h3 {
        font-size: 1.25rem;
    }
    
    .intro-content {
        padding: 20px 16px;
    }
    
    .intro-image img {
        max-width: 180px;
    }
    
    .news-list a {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
        padding: 14px 16px;
    }
    
    .news-list .time {
        align-self: flex-end;
        font-size: 0.75rem;
    }
    
    .research-rec h3 {
        font-size: 1rem;
    }
    
    .research-rec p {
        font-size: 0.875rem;
    }
    
    .research-list p {
        font-size: 0.8125rem;
    }
    
    .research-list span {
        font-size: 0.75rem;
    }
    
    .stat-item {
        margin-bottom: 16px;
    }
    
    .modal-image {
        width: 95%;
        max-height: 85%;
    }
}

/* 打印样式 */
@media print {
    body {
        font-size: 12pt;
        line-height: 1.5;
    }
    
    .header, .nav, .footer, .search, .language-switcher, .navbar-toggle, .slider-nav, .slider-play-pause, .slider-dots, .more {
        display: none !important;
    }
    
    .banner {
        height: auto;
        page-break-inside: avoid;
    }
    
    .slide-image {
        max-height: 300px;
    }
    
    .container {
        max-width: 100%;
        padding: 0;
    }
    
    a {
        text-decoration: none;
        color: inherit;
    }
    
    .intro-content, .news-featured, .research-rec li, .group-list li {
        page-break-inside: avoid;
    }
}

/* 添加过渡动画 */
.fade-in {
    animation: fadeIn 0.5s ease-in;
}

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

/* 添加骨架屏加载效果 */
.skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
}

@keyframes loading {
    0% {
        background-position: 200% 0;
    }
    100% {
        background-position: -200% 0;
    }
}

/* 优化滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--gray-100);
}

::-webkit-scrollbar-thumb {
    background: var(--gray-400);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--gray-500);
}

/* 新闻条目可点击样式 */
.news-item-clickable {
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.news-item-clickable:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
}

/* 添加焦点样式改善可访问性 */
a:focus,
button:focus,
input:focus,
textarea:focus,
select:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* 优化选中文本样式 */
::selection {
    background: var(--primary-light);
    color: var(--white);
}

::-moz-selection {
    background: var(--primary-light);
    color: var(--white);
}

/* Research Page Specific Styles */
.page-banner {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 50%, var(--secondary-color) 100%);
    padding: 100px 0 80px;
    position: relative;
    overflow: hidden;
    margin-top: 0;
    width: 100%;
}

.page-banner::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml;base64,PHN2ZyB3aWR0aD0iNDAiIGhlaWdodD0iNDAiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PGRlZnM+PHBhdHRlcm4gaWQ9ImdyaWQiIHdpZHRoPSI0MCIgaGVpZ2h0PSI0MCIgcGF0dGVyblVuaXRzPSJ1c2VyU3BhY2VPblVzZSI+PHBhdGggZD0iTSA0MCAwIEwgMCAwIDAgNDAiIGZpbGw9Im5vbmUiIHN0cm9rZT0icmdiYSgyNTUsMjU1LDI1NSwwLjA4KSIgc3Ryb2tlLXdpZHRoPSIxIi8+PC9wYXR0ZXJuPjwvZGVmcz48cmVjdCB3aWR0aD0iMTAwJSIgaGVpZ2h0PSIxMDAlIiBmaWxsPSJ1cmwoI2dyaWQpIiAvPjwvc3ZnPg==');
    opacity: 0.4;
    animation: patternMove 20s linear infinite;
}

.page-banner::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 30% 20%, rgba(255,255,255,0.1) 0%, transparent 50%),
                radial-gradient(circle at 70% 80%, rgba(255,255,255,0.05) 0%, transparent 50%);
    pointer-events: none;
}

@keyframes patternMove {
    0% { transform: translateX(0) translateY(0); }
    100% { transform: translateX(-40px) translateY(-40px); }
}

.page-banner .banner-content {
    position: relative;
    z-index: 2;
    text-align: center;
    color: var(--white);
    max-width: 800px;
    margin: 0 auto;
}

.page-banner h1 {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--white);
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
    line-height: 1.1;
    letter-spacing: -0.02em;
}

.page-banner p {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.95);
    line-height: 1.6;
    font-weight: 400;
    max-width: 600px;
    margin: 0 auto;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .page-banner {
        padding: 80px 0 60px;
    }
    
    .page-banner h1 {
        font-size: 2.5rem;
        margin-bottom: 1rem;
    }
    
    .page-banner p {
        font-size: 1.1rem;
    }
}

@media (max-width: 480px) {
    .page-banner {
        padding: 60px 0 40px;
    }
    
    .page-banner h1 {
        font-size: 2rem;
    }
    
    .page-banner p {
        font-size: 1rem;
    }
}

.main-content {
    padding: 60px 0;
    background-color: var(--light-color);
}

.section {
    margin-bottom: 60px;
}

.section-header {
    text-align: center;
    margin-bottom: 48px;
}

.section-header h2 {
    font-size: 2.25rem;
    color: var(--primary-color);
    margin-bottom: 16px;
    font-weight: 700;
}

.section-line {
    width: 60px;
    height: 4px;
    background: var(--primary-color);
    margin: 0 auto;
    border-radius: 2px;
}

.research-overview-section {
    margin-bottom: 48px;
}

.research-item-detailed {
    background: var(--white);
    border-radius: 16px;
    padding: 32px;
    margin-bottom: 32px;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.research-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-bottom: 32px;
}

.research-item-compact {
    background: var(--white);
    border-radius: 16px;
    padding: 24px;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
    text-align: center;
}

.research-item-compact:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.research-item-compact .research-icon {
    width: 60px;
    height: 60px;
    background: var(--light-purple);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
}

.research-item-compact .research-icon i {
    font-size: 1.8rem;
    color: var(--primary-color);
}

.research-item-compact h3 {
    color: var(--primary-color);
    font-size: 1.25rem;
    margin-bottom: 12px;
    font-weight: 600;
}

.research-item-compact p {
    color: var(--text-secondary);
    line-height: 1.5;
    font-size: 0.875rem;
}

.research-item-detailed:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.research-item-detailed .research-icon {
    width: 80px;
    height: 80px;
    background: var(--light-purple);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 24px;
}

.research-item-detailed .research-icon i {
    font-size: 2.5rem;
    color: var(--primary-color);
}

.research-item-detailed h3 {
    color: var(--primary-color);
    font-size: 1.5rem;
    margin-bottom: 16px;
    text-align: center;
    font-weight: 600;
}

.research-item-detailed p {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 20px;
    text-align: center;
}

.research-details {
    list-style: none;
    padding: 0;
}

.research-details li {
    padding: 8px 0;
    padding-left: 24px;
    position: relative;
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

.research-details li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

.equipment-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.equipment-item {
    background: var(--white);
    border-radius: 12px;
    padding: 24px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.equipment-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.equipment-image {
    width: 60px;
    height: 60px;
    background: var(--light-purple);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
}

.equipment-image i {
    font-size: 1.75rem;
    color: var(--primary-color);
}

.equipment-item h4 {
    color: var(--text-primary);
    font-size: 1.125rem;
    margin-bottom: 12px;
    font-weight: 600;
}

.equipment-item p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.5;
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 32px;
}

.tool-category {
    background: var(--white);
    border-radius: 12px;
    padding: 24px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.tool-category h3 {
    color: var(--primary-color);
    font-size: 1.25rem;
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--light-purple);
    font-weight: 600;
}

.tools-list {
    list-style: none;
    padding: 0;
}

.tools-list li {
    padding: 12px 0;
    border-bottom: 1px solid var(--gray-200);
    font-size: 0.9375rem;
    line-height: 1.5;
}

.tools-list li:last-child {
    border-bottom: none;
}

.tools-list strong {
    color: var(--text-primary);
    font-weight: 600;
}

.tools-list span {
    color: var(--text-secondary);
}

.achievement-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.achievement-item {
    background: var(--white);
    border-radius: 12px;
    padding: 24px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.achievement-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.achievement-icon {
    width: 60px;
    height: 60px;
    background: var(--light-purple);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
}

.achievement-icon i {
    font-size: 1.75rem;
    color: var(--primary-color);
}

.achievement-item h4 {
    color: var(--text-primary);
    font-size: 1.125rem;
    margin-bottom: 12px;
    font-weight: 600;
}

.achievement-item p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.5;
}

/* Activities Page Specific Styles */
.featured-activity {
    margin-bottom: 60px;
}

.activity-hero {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    background: var(--white);
    border-radius: 16px;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
}

.activity-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.activity-content {
    padding: 40px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.activity-content h2 {
    color: var(--primary-color);
    font-size: 2rem;
    margin-bottom: 12px;
    font-weight: 700;
}

.activity-date {
    color: var(--text-muted);
    font-size: 1rem;
    margin-bottom: 20px;
    font-weight: 500;
}

.activity-content p {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 24px;
}

.activity-highlights {
    display: flex;
    gap: 24px;
    flex-wrap: wrap;
}

.highlight {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-primary);
    font-weight: 500;
    font-size: 0.9375rem;
}

.highlight i {
    color: var(--primary-color);
    font-size: 1.125rem;
}

.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 24px;
}

.category-card {
    background: var(--white);
    border-radius: 12px;
    padding: 24px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
    position: relative;
}

.category-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.category-icon {
    width: 60px;
    height: 60px;
    background: var(--light-purple);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
}

.category-icon i {
    font-size: 1.75rem;
    color: var(--primary-color);
}

.category-card h3 {
    color: var(--text-primary);
    font-size: 1.125rem;
    margin-bottom: 12px;
    font-weight: 600;
}

.category-card p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.5;
    margin-bottom: 16px;
}

.category-count {
    position: absolute;
    top: 16px;
    right: 16px;
    width: 32px;
    height: 32px;
    background: var(--primary-color);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.875rem;
    font-weight: 600;
}

.activities-timeline {
    position: relative;
    padding-left: 40px;
}

.activities-timeline::before {
    content: '';
    position: absolute;
    left: 20px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--light-purple);
}

.timeline-item {
    position: relative;
    margin-bottom: 40px;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -29px;
    top: 20px;
    width: 16px;
    height: 16px;
    background: var(--primary-color);
    border-radius: 50%;
    border: 3px solid var(--white);
    box-shadow: 0 0 0 3px var(--light-purple);
}

.timeline-date {
    position: absolute;
    left: -120px;
    top: 0;
    width: 80px;
    text-align: center;
    background: var(--white);
    border: 2px solid var(--light-purple);
    border-radius: 8px;
    padding: 8px 4px;
}

.date-month {
    color: var(--primary-color);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
}

.date-day {
    color: var(--text-primary);
    font-size: 1.5rem;
    font-weight: 700;
    line-height: 1;
    margin: 2px 0;
}

.date-year {
    color: var(--text-muted);
    font-size: 0.75rem;
}

.activity-card {
    background: var(--white);
    border-radius: 12px;
    padding: 20px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    display: flex;
    gap: 16px;
    transition: all 0.3s ease;
}

.activity-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.activity-image-small {
    width: 80px;
    height: 80px;
    border-radius: 8px;
    overflow: hidden;
    flex-shrink: 0;
}

.activity-image-small img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.activity-info h4 {
    color: var(--text-primary);
    font-size: 1.125rem;
    margin-bottom: 8px;
    font-weight: 600;
}

.activity-info p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.5;
    margin-bottom: 12px;
}

.activity-tags {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.tag {
    background: var(--light-purple);
    color: var(--primary-color);
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 500;
}

.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.gallery-item {
    position: relative;
    border-radius: 12px;
    overflow: hidden;
    aspect-ratio: 4/3;
    cursor: pointer;
    transition: all 0.3s ease;
}

.gallery-item:hover {
    transform: scale(1.05);
}

.gallery-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.gallery-overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(transparent, rgba(0,0,0,0.8));
    color: var(--white);
    padding: 20px 16px 16px;
    transform: translateY(100%);
    transition: all 0.3s ease;
}

.gallery-item:hover .gallery-overlay {
    transform: translateY(0);
}

.gallery-overlay h4 {
    font-size: 1rem;
    font-weight: 600;
    margin: 0;
}

/* Recruitment Page Specific Styles */
.welcome-section {
    margin-bottom: 60px;
}

.welcome-content {
    background: var(--white);
    border-radius: 16px;
    padding: 40px;
    text-align: center;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

.welcome-content h2 {
    color: var(--primary-color);
    font-size: 2.25rem;
    margin-bottom: 24px;
    font-weight: 700;
}

.welcome-content p {
    color: var(--text-secondary);
    font-size: 1.125rem;
    line-height: 1.6;
    margin-bottom: 32px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.welcome-highlights {
    display: flex;
    justify-content: center;
    gap: 40px;
    flex-wrap: wrap;
}

.welcome-highlights .highlight-item {
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--text-primary);
    font-weight: 600;
    font-size: 1rem;
}

.welcome-highlights .highlight-item i {
    color: var(--primary-color);
    font-size: 1.5rem;
}

.position-cards {
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.position-card {
    background: var(--white);
    border-radius: 16px;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    overflow: hidden;
    transition: all 0.3s ease;
}

.position-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.position-header {
    background: var(--light-purple);
    padding: 24px 32px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--border-color);
}

.position-header .position-icon {
    width: 60px;
    height: 60px;
    background: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: 20px;
}

.position-header .position-icon i {
    font-size: 1.75rem;
    color: var(--primary-color);
}

.position-title {
    flex: 1;
}

.position-title h3 {
    color: var(--primary-color);
    font-size: 1.5rem;
    margin-bottom: 4px;
    font-weight: 700;
}

.position-title p {
    color: var(--text-muted);
    font-size: 1rem;
    margin: 0;
    font-style: italic;
}

.position-status {
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 600;
}

.position-status.open {
    background: var(--success-light);
    color: var(--success-color);
}

.position-status.limited {
    background: var(--warning-light);
    color: var(--warning-color);
}

.position-content {
    padding: 32px;
}

.position-details h4 {
    color: var(--text-primary);
    font-size: 1.25rem;
    margin-bottom: 16px;
    margin-top: 24px;
    font-weight: 600;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--light-purple);
}

.position-details h4:first-child {
    margin-top: 0;
}

.requirements-list, .benefits-list {
    list-style: none;
    padding: 0;
}

.requirements-list li, .benefits-list li {
    padding: 8px 0;
    padding-left: 24px;
    position: relative;
    color: var(--text-secondary);
    line-height: 1.5;
}

.requirements-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

.benefits-list li::before {
    content: '★';
    position: absolute;
    left: 0;
    color: var(--secondary-color);
    font-weight: bold;
}

.research-areas-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.research-area {
    background: var(--white);
    border-radius: 12px;
    padding: 24px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.research-area:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.area-icon {
    width: 60px;
    height: 60px;
    background: var(--light-purple);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
}

.area-icon i {
    font-size: 1.75rem;
    color: var(--primary-color);
}

.research-area h4 {
    color: var(--text-primary);
    font-size: 1.125rem;
    margin-bottom: 12px;
    font-weight: 600;
}

.research-area p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.5;
}

.application-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 24px;
}

.step {
    background: var(--white);
    border-radius: 12px;
    padding: 24px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
    position: relative;
}

.step:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.step-number {
    width: 50px;
    height: 50px;
    background: var(--primary-color);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    font-weight: 700;
    margin: 0 auto 16px;
}

.step-content h4 {
    color: var(--text-primary);
    font-size: 1.125rem;
    margin-bottom: 12px;
    font-weight: 600;
}

.step-content p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.5;
}

.contact-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 24px;
    margin-bottom: 32px;
}

.contact-card {
    background: var(--white);
    border-radius: 12px;
    padding: 24px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.contact-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.contact-icon {
    width: 50px;
    height: 50px;
    background: var(--light-purple);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
}

.contact-icon i {
    font-size: 1.25rem;
    color: var(--primary-color);
}

.contact-card h4 {
    color: var(--text-primary);
    font-size: 1rem;
    margin-bottom: 8px;
    font-weight: 600;
}

.contact-card p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.4;
}

.application-note {
    background: var(--lighter-purple);
    border: 1px solid var(--light-purple);
    border-radius: 12px;
    padding: 24px;
    text-align: center;
}

.application-note p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.6;
    margin: 0;
}

.application-note strong {
    color: var(--primary-color);
}

/* Responsive Styles for New Pages */
@media screen and (max-width: 768px) {
    /* Research Page Mobile */
    .research-item-detailed .research-icon {
        width: 60px;
        height: 60px;
        margin-bottom: 16px;
    }
    
    .research-item-detailed .research-icon i {
        font-size: 2rem;
    }
    
    .research-item-detailed h3 {
        font-size: 1.25rem;
    }
    
    .equipment-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .tools-grid {
        grid-template-columns: 1fr;
        gap: 24px;
    }
    
    /* Activities Page Mobile */
    .activity-hero {
        grid-template-columns: 1fr;
        gap: 0;
    }
    
    .activity-content {
        padding: 24px;
    }
    
    .activity-content h2 {
        font-size: 1.5rem;
    }
    
    .activity-highlights {
        flex-direction: column;
        gap: 16px;
    }
    
    .category-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .timeline-date {
        position: static;
        width: auto;
        margin-bottom: 12px;
        display: inline-block;
    }
    
    .activities-timeline {
        padding-left: 20px;
    }
    
    .activities-timeline::before {
        left: 10px;
    }
    
    .timeline-item::before {
        left: 1px;
    }
    
    .activity-card {
        flex-direction: column;
        text-align: center;
    }
    
    .activity-image-small {
        width: 100%;
        height: 120px;
        margin-bottom: 16px;
    }
    
    .gallery-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 16px;
    }
    
    /* Recruitment Page Mobile */
    .welcome-content {
        padding: 24px;
    }
    
    .welcome-content h2 {
        font-size: 1.75rem;
    }
    
    .welcome-content p {
        font-size: 1rem;
    }
    
    .welcome-highlights {
        flex-direction: column;
        gap: 20px;
    }
    
    .position-header {
        flex-direction: column;
        text-align: center;
        gap: 16px;
    }
    
    .position-header .position-icon {
        margin-right: 0;
    }
    
    .position-content {
        padding: 24px;
    }
    
    .research-areas-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .application-steps {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .contact-info {
        grid-template-columns: repeat(2, 1fr);
        gap: 16px;
    }
}

@media screen and (max-width: 480px) {
    .section-header h2 {
        font-size: 1.75rem;
    }
    
    .main-content {
        padding: 40px 0;
    }
    
    .section {
        margin-bottom: 40px;
    }
    
    /* Research Page Extra Small */
    .research-item-detailed {
        padding: 20px;
        margin-bottom: 20px;
    }
    
    /* Activities Page Extra Small */
    .activity-content {
        padding: 20px;
    }
    
    .gallery-grid {
        grid-template-columns: 1fr;
    }
    
    /* Recruitment Page Extra Small */
    .welcome-content {
        padding: 20px;
    }
    
    .position-header {
        padding: 20px;
    }
    
    .position-content {
        padding: 20px;
    }
    
    .contact-info {
        grid-template-columns: 1fr;
    }
}

/* Academic Exchange Section Styles */
.academic-exchange-section {
    margin-bottom: 80px;
}

/* 学术交流板块使用与小组活动相同的时间轴样式 */
.academic-exchange-section .activities-timeline {
    /* 继承小组活动的所有样式 */
}

/* Group Activities Section Styles */
.group-activities-section {
    margin-bottom: 80px;
}

.group-activities-section .section-header p {
    color: var(--text-secondary);
    font-size: 1.125rem;
    max-width: 600px;
    margin: 0 auto;
    line-height: 1.6;
}

/* Responsive Design for Exchange Timeline */
@media (max-width: 768px) {
    .exchange-timeline::before {
        left: 80px;
    }
    
    .exchange-date {
        width: 80px;
        padding: 12px 6px;
    }
    
    .date-day {
        font-size: 1.25rem;
    }
    
    .exchange-content {
        margin-left: 20px;
    }
    
    .exchange-info {
        padding: 20px;
    }
    
    .exchange-highlights {
        flex-direction: column;
        gap: 12px;
    }
}

@media (max-width: 480px) {
    .exchange-item {
        flex-direction: column;
    }
    
    .exchange-timeline::before {
        display: none;
    }
    
    .exchange-date {
        width: auto;
        margin-bottom: 16px;
        align-self: center;
    }
    
    .exchange-content {
        margin-left: 0;
    }
    
    .exchange-image {
        height: 160px;
    }
}

/* 锚点跳转视觉反馈样式 */
@keyframes anchor-highlight {
    0% {
        background-color: rgba(107, 58, 160, 0.1);
        transform: scale(1);
    }
    50% {
        background-color: rgba(107, 58, 160, 0.2);
        transform: scale(1.02);
    }
    100% {
        background-color: transparent;
        transform: scale(1);
    }
}

/* 锚点跳转后的高亮效果 */
.timeline-item:target {
    animation: anchor-highlight 2s ease-out;
}

/* 确保锚点跳转后内容不被导航栏遮挡 */
.timeline-item:target {
    scroll-margin-top: 120px;
}

/* 为新闻卡片添加悬停效果增强 */
.news-item-clickable:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

/* 新闻时间轴项目的焦点状态 */
.timeline-item:focus-within {
    outline: 2px solid var(--primary-color);
    outline-offset: 4px;
    border-radius: 8px;
}

/* 移动端隐藏子菜单 */
@media screen and (max-width: 768px) {
    .nav .daohang .nav_item {
        display: none !important;
        opacity: 0 !important;
        visibility: hidden !important;
        position: static !important;
        transform: none !important;
        box-shadow: none !important;
        background: transparent !important;
        border: none !important;
        margin: 0 !important;
        padding: 0 !important;
        min-width: auto !important;
        max-height: 0 !important;
        overflow: hidden !important;
    }
    
    .nav .daohang > li:hover .nav_item {
        display: none !important;
        opacity: 0 !important;
        visibility: hidden !important;
        transform: none !important;
    }
    
    /* 移动端一级菜单样式优化 */
    .nav .daohang > li > a {
        padding: 16px 20px !important;
        font-size: 16px !important;
        border-bottom: 1px solid var(--gray-200) !important;
        background: var(--white) !important;
        color: var(--text-primary) !important;
        transition: all 0.3s ease !important;
    }
    
    .nav .daohang > li > a:hover,
    .nav .daohang > li > a.active {
        background: var(--light-purple) !important;
        color: var(--primary-color) !important;
        padding-left: 24px !important;
    }
    
    /* 移除移动端的下拉箭头 */
    .nav .daohang > li > a.dropdown::after {
        display: none !important;
    }
}