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

:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --accent-color: #3b82f6;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --background: #ffffff;
    --background-light: #f8fafc;
    --background-dark: #1f2937;
    --border-color: #e5e7eb;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

body {
    font-family: 'Noto Sans SC', sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    scroll-behavior: smooth;
}

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

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    transition: all 0.3s ease;
    border-bottom: 1px solid var(--border-color);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--shadow);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo {
    display: flex;
    align-items: center;
    font-weight: 700;
    font-size: 1.5rem;
}

.logo-number {
    color: var(--primary-color);
    margin-right: 5px;
}

.logo-text {
    color: var(--text-primary);
}

.nav-menu {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-item {
    margin-left: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width 0.3s ease;
}

.nav-link:hover::after {
    width: 100%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    margin: 3px 0;
    transition: 0.3s;
}

/* 主页部分 */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.3);
    z-index: 1;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    position: relative;
    z-index: 2;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.1;
}

.highlight {
    color: #fbbf24;
}

.hero-subtitle {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    opacity: 0.9;
}

.hero-description {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.8;
    line-height: 1.6;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    cursor: pointer;
    display: inline-block;
}

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

.btn-primary:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

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

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

.hero-visual {
    position: relative;
    height: 400px;
}

.floating-elements {
    position: relative;
    width: 100%;
    height: 100%;
}

.floating-box {
    position: absolute;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 12px;
    padding: 20px;
    font-weight: 600;
    font-size: 1.2rem;
    backdrop-filter: blur(10px);
    animation: float 6s ease-in-out infinite;
}

.floating-box:nth-child(1) {
    top: 20%;
    left: 10%;
    animation-delay: 0s;
}

.floating-box:nth-child(2) {
    top: 60%;
    right: 20%;
    animation-delay: 1s;
}

.floating-box:nth-child(3) {
    top: 10%;
    right: 10%;
    animation-delay: 2s;
}

.floating-box:nth-child(4) {
    bottom: 20%;
    left: 20%;
    animation-delay: 3s;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-20px);
    }
}

/* 通用部分样式 */
.section {
    padding: 80px 0;
}

.section-dark {
    background: var(--background-dark);
    color: white;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 1rem;
}

.section-subtitle {
    text-align: center;
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
}

.section-dark .section-subtitle {
    color: rgba(255, 255, 255, 0.8);
}

/* 关于我们 */
.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    margin-top: 3rem;
}

.about-text h3 {
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
}

.about-text p {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 2rem;
    color: var(--text-secondary);
}

.features {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: var(--background-light);
    border-radius: 8px;
    transition: transform 0.3s ease;
}

.feature-item:hover {
    transform: translateX(10px);
}

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

.about-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.image-placeholder {
    width: 300px;
    height: 300px;
    background: var(--background-light);
    border-radius: 12px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    border: 2px dashed var(--border-color);
}

.image-placeholder i {
    font-size: 4rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.about-image img {
    max-width: 100%;
    height: auto;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    display: block;
    margin: 0 auto;
}

/* 研究方向 */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.research-card {
    background: rgba(255, 255, 255, 0.1);
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    transition: transform 0.3s ease;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.research-card:hover {
    transform: translateY(-10px);
}

.research-icon {
    width: 80px;
    height: 80px;
    background: var(--primary-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
}

.research-icon i {
    font-size: 2rem;
    color: white;
}

.research-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.research-card p {
    line-height: 1.6;
    opacity: 0.9;
}

/* 实验设施 */
.facilities-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.facility-item {
    text-align: center;
    padding: 2rem;
    background: var(--background-light);
    border-radius: 12px;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.facility-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.facility-icon {
    width: 60px;
    height: 60px;
    background: var(--primary-color);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1rem;
}

.facility-icon i {
    font-size: 1.5rem;
    color: white;
}

.facility-item h4 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.facility-item p {
    color: var(--text-secondary);
}

/* 联系我们 */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    margin-top: 3rem;
}

.contact-info h3 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
}

.contact-info p {
    margin-bottom: 2rem;
    opacity: 0.9;
    line-height: 1.6;
}

.contact-items {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.contact-item i {
    color: var(--primary-color);
    width: 20px;
}

.contact-form {
    background: rgba(255, 255, 255, 0.1);
    padding: 2rem;
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.1);
    color: white;
    font-family: inherit;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: rgba(255, 255, 255, 0.7);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* 页脚 */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 2rem 0;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-links {
    display: flex;
    gap: 2rem;
}

.footer-links a {
    color: white;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: var(--accent-color);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: white;
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: var(--shadow);
        padding: 2rem 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-item {
        margin: 1rem 0;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active .bar:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .nav-toggle.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-buttons {
        justify-content: center;
        flex-wrap: wrap;
    }

    .about-grid,
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .research-grid,
    .facilities-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }

    .footer-links {
        flex-wrap: wrap;
        justify-content: center;
    }

    .section-title {
        font-size: 2rem;
    }

    .container {
        padding: 0 15px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

    .hero-description {
        font-size: 1rem;
    }

    .section {
        padding: 60px 0;
    }

    .btn {
        padding: 10px 20px;
        font-size: 0.9rem;
    }
}

/* 导航栏激活状态 */
.nav-link.active {
    color: var(--primary-color);
}

.nav-link.active::after {
    width: 100%;
}

/* 新页面通用头部 */
.page-header {
    padding: 120px 0 60px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
}

.page-title {
    font-size: 2.8rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.page-description {
    font-size: 1.2rem;
    max-width: 700px;
    margin: 0 auto;
    opacity: 0.9;
}

/* 科研成果页面样式 */
.achievement-section {
    margin-bottom: 4rem;
}

/* 论文卡片 */
.papers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.paper-card {
    background: var(--background-light);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    position: relative;
    overflow: hidden;
}

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

.paper-year {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: var(--primary-color);
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
}

.paper-title {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    line-height: 1.4;
    padding-right: 60px;
}

.paper-authors {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.paper-journal {
    font-size: 0.95rem;
    font-style: italic;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.paper-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.tag {
    background: rgba(59, 130, 246, 0.1);
    color: var(--primary-color);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

.paper-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: color 0.3s ease;
}

.paper-link:hover {
    color: var(--secondary-color);
}

/* 项目样式 */
.projects-wrapper {
    margin-top: 2rem;
}

.project-item {
    padding: 2rem;
    background: var(--background-light);
    border-radius: 12px;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease;
}

.project-item:hover {
    transform: translateX(5px);
}

.project-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.project-title {
    font-size: 1.5rem;
    margin: 0;
}

.project-period {
    background: rgba(59, 130, 246, 0.1);
    color: var(--primary-color);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
}

.project-desc {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 1.5rem;
}

.project-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.project-type {
    font-weight: 500;
    color: var(--text-primary);
}

.project-status {
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.9rem;
}

.project-status.ongoing {
    background: rgba(16, 185, 129, 0.1);
    color: #10b981;
}

.project-status.completed {
    background: rgba(99, 102, 241, 0.1);
    color: #6366f1;
}

/* 专利列表 */
.patents-wrapper {
    margin-top: 2rem;
}

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

.patent-item {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    padding: 1.5rem;
    margin-bottom: 1rem;
    background: var(--background-light);
    border-radius: 8px;
    transition: transform 0.3s ease;
}

.patent-item:hover {
    transform: translateX(5px);
}

.patent-title {
    flex-basis: 60%;
    font-weight: 500;
    color: var(--text-primary);
}

.patent-number {
    flex-basis: 25%;
    color: var(--text-secondary);
}

.patent-year {
    flex-basis: 15%;
    text-align: right;
    color: var(--primary-color);
    font-weight: 500;
}

/* 团队成员页面样式 */
.team-section {
    margin-bottom: 4rem;
}

/* 教授卡片 */
.professors-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
    margin-top: 2rem;
}

.professor-card {
    display: flex;
    background: var(--background-light);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow);
}

.professor-avatar {
    flex: 0 0 200px;
    background: rgba(59, 130, 246, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
}

.avatar-placeholder {
    width: 120px;
    height: 120px;
    background: var(--primary-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 3rem;
}

.professor-info {
    flex: 1;
    padding: 2rem;
}

.professor-name {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
}

.professor-title {
    font-size: 1.1rem;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.professor-research {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.professor-desc {
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.professor-contact {
    display: flex;
    gap: 1.5rem;
}

.contact-link {
    color: var(--primary-color);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: color 0.3s ease;
}

.contact-link:hover {
    color: var(--secondary-color);
}

/* 学生卡片 */
.students-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.student-card {
    background: var(--background-light);
    border-radius: 12px;
    padding: 2rem;
    text-align: center;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease;
}

.student-card:hover {
    transform: translateY(-5px);
}

.student-avatar {
    margin-bottom: 1.5rem;
}

.student-avatar .avatar-placeholder {
    margin: 0 auto;
    width: 100px;
    height: 100px;
    font-size: 2.5rem;
}

.student-name {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
}

.student-year {
    color: var(--primary-color);
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.student-research {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* 校友部分 */
.alumni-wrapper {
    margin-top: 2rem;
    text-align: center;
}

.alumni-intro {
    max-width: 800px;
    margin: 0 auto 3rem;
    color: var(--text-secondary);
    line-height: 1.8;
    font-size: 1.1rem;
}

.alumni-stats {
    display: flex;
    justify-content: center;
    gap: 4rem;
}

.alumni-stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.alumni-number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.alumni-desc {
    color: var(--text-secondary);
}

/* 加入我们部分 */
.join-section {
    text-align: center;
}

.join-desc {
    max-width: 800px;
    margin: 0 auto 3rem;
    opacity: 0.9;
    line-height: 1.8;
    font-size: 1.1rem;
}

.join-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.join-step {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    padding: 2rem;
    text-align: left;
    border: 1px solid rgba(255, 255, 255, 0.1);
    position: relative;
}

.step-number {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.step-title {
    font-size: 1.3rem;
    margin-bottom: 1rem;
}

.step-desc {
    opacity: 0.9;
    line-height: 1.6;
}

.join-cta {
    margin-top: 2rem;
}

/* 媒体查询 - 适配移动设备 */
@media (max-width: 768px) {
    .page-title {
        font-size: 2rem;
    }
    
    .page-description {
        font-size: 1rem;
    }
    
    .papers-grid {
        grid-template-columns: 1fr;
    }
    
    .professor-card {
        flex-direction: column;
    }
    
    .professor-avatar {
        flex: 0 0 auto;
        padding: 2rem 0;
    }
    
    .alumni-stats {
        flex-direction: column;
        gap: 2rem;
    }
    
    .project-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .project-period {
        margin-top: 0.5rem;
    }
    
    .project-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
    
    .patent-item {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .patent-title, .patent-number, .patent-year {
        flex-basis: 100%;
        text-align: left;
    }
}