:root {
    --primary-color: #4CAF50;
    --secondary-color: #45a049;
    --accent-color: #8BC34A;
    --text-color: #333;
    --background-color: #f5f5f5;
}

body {
    font-family: 'Segoe UI', '微软雅黑', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
    margin: 0;
    padding: 0;
}

header {
    background-color: var(--primary-color);
    padding: 1.5rem 2rem;
    text-align: center;
    color: white;
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
}

.logo {
    max-width: 120px;
    height: auto;
    margin: 0 1.5rem 0 0;
    image-rendering: optimizeQuality;
    display: block;
    align-self: center;
}

nav {
    background-color: var(--primary-color);
    padding: 0.8rem 1rem;
    position: fixed;
    top: 10rem;  /* 增加顶部间距 */
    width: 100%;
    z-index: 999;
    margin-top: 0;
}

nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    justify-content: center;
    gap: 2rem;
}

nav a {
    color: #f0f9f1;
    text-decoration: none;
    padding: 1.2rem 1.5rem;
    border-radius: 4px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    font-weight: 600;
    font-size: 1.1rem;
    text-shadow: 0 1px 2px rgba(0,0,0,0.15);
    line-height: 1.5;
    position: relative;
    overflow: hidden;
}


@media (max-width: 768px) {
    nav a {
        padding: 1rem 1.2rem;  /* 移动端保持比例 */
        font-size: 1.05rem;    /* 字号微调 */
    }
}

nav a:hover, 
nav a.active, 
nav a:active,
nav a.current {
  color: #f0f9f1 !important;
  background-color: rgba(255,255,255,0.1) !important;
  text-decoration: none !important;
  box-shadow: 0 2px 4px rgba(0,0,0,0.15) !important;
  transform: scale(0.95) translateY(-2px) !important;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1) !important;
  animation: navHighlight 0.3s forwards !important;
}

@keyframes navHighlight {
  0% {
    opacity: 0.8;
    transform: scale(0.98) translateY(0);
  }
  50% {
    opacity: 0.95;
    transform: scale(0.96) translateY(-1px);
  }
  100% {
    opacity: 1;
    transform: scale(0.95) translateY(-2px);
  }
}

main {
    max-width: 1200px;
    margin: 14rem auto 2rem; /* header(8rem) + nav(6rem) */
    padding: 0 1rem;
}

.intro {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.research-areas {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2.5rem;
    padding: 2rem;
    background: rgba(255,255,255,0.95);
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.08);
    margin: 3rem 0;
}

.section-title {
    margin: 2.2rem 0;
    padding: 1rem 1.5rem;
    background: linear-gradient(95deg, var(--primary-color) 30%, rgba(255,255,255,0) 90%);
    border-radius: 5px;
    position: relative;
    transition: all 0.3s ease;
}

.section-title h2 {
    margin: 0;
    font-size: 1.5rem;
    color: #fff;
    text-shadow: 1px 1px 3px rgba(0,0,0,0.2);
    position: relative;
    z-index: 1;
    line-height: 1.4;
    padding: 0.4rem 0;
}

@media (max-width: 768px) {
    .section-title {
        margin: 1.8rem 0;
        padding: 0.9rem 1.2rem;
    }
    .section-title h2 {
        font-size: 1.3rem;
    }
}

.section-title:hover, .section-title:active {
    background: linear-gradient(95deg, var(--primary-color) 45%, rgba(255,255,255,0) 90%);
    transform: scale(0.98);
    transition: all 0.2s ease-out;
}

.title-line {
    width: 100%;
    height: 2px;
    background: rgba(255,255,255,0.3);
    margin: 0.8rem 0;
    position: relative;
    overflow: hidden;
}

.title-line::after {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 40%;
    height: 100%;
    background: var(--accent-color);
    animation: lineFlow 2s ease-in-out infinite;
}

@keyframes lineFlow {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(250%); }
}

.research-areas li {
    background: white;
    padding: 2rem;
    border: 1px solid rgba(0,0,0,0.1);
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.research-areas li:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0,0,0,0.1);
}

.research-areas li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 4px;
    height: 100%;
    background: var(--accent-color);
}

@media (max-width: 768px) {
    .research-areas li {
        padding: 1.5rem;
        margin: 0 1rem;
    }
}

/* 新增时间线样式 */
.timeline-item {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

/* 科研成果优化 */
.pub-category {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    margin-bottom: 2.5rem;
}

.pub-item {
    padding: 1.5rem;
    margin: 1.5rem 0;
    border-left: 4px solid var(--accent-color);
    background: #f8f8f8;
    border-radius: 4px;
    transition: all 0.3s ease;
}

.pub-item:hover {
    transform: translateX(10px);
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.pub-item h4 {
    color: var(--primary-color);
    margin: 0 0 0.8rem;
    font-size: 1.1rem;
    line-height: 1.4;
}

.pub-info {
    color: #444;
    font-size: 0.9em;
    padding-left: 1.2rem;
    border-left: 2px solid #ddd;
    margin: 0.8rem 0;
}

.pub-info span {
    display: block;
    margin: 0.3rem 0;
}

.year-group {
    margin: 2rem 0;
    padding: 1rem;
    background: #f5f5f5;
    border-radius: 6px;
}

/* 团队成员优化 */
.member-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    padding: 2rem 0;
}

.member-card {
    background: white;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    text-align: left;
    transition: all 0.3s ease;
}

.member-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.member-avatar {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    background: #eee;
    margin: 0 auto 1rem;
    overflow: hidden;
}

.member-info h3 {
    color: var(--primary-color);
    margin: 0.5rem 0 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--accent-color);
    text-align: left;
    width: 100%;
}

.member-role {
    color: #666;
    font-size: 0.9em;
    margin-bottom: 1rem;
}

.member-bio {
    font-size: 0.9em;
    color: #444;
    text-align: left;
    line-height: 1.6;
}

@media (max-width: 768px) {
    .member-grid {
        grid-template-columns: 1fr;
        padding: 1rem;
    }
    
    .member-card {
        margin: 0.5rem;
    }
}

@media (max-width: 768px) {
    .member-info {
        padding: 1rem;
        gap: 1rem;
    }
    
    .member-info > div {
        padding: 0.8rem;
    }
}

.member-info p {
    margin: 1rem 0;
}

.degree {
    margin-top: 1.5rem;
    padding-left: 2rem;
    color: #444;
    margin-bottom: 0.8rem;
}

.affiliation {
    margin-top: 1.2rem;
    padding-left: 2.5rem;
    color: #666;
    border-left: 3px solid var(--primary-color);
    margin-bottom: 1rem;
}

.awards-grid,
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2.5rem;
    margin: 2.5rem 0;
    padding: 2rem;
    background: white;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.08);
}

.awards-grid h3,
.projects-grid h3 {
    color: var(--primary-color);
    font-size: 1.4rem;
    margin: 0 0 1.5rem;
    padding-bottom: 0.8rem;
    border-bottom: 2px solid var(--accent-color);
}

.award-category,
.project-type {
    padding: 1.5rem;
    background: #f8f8f8;
    border-radius: 8px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.award-category::before,
.project-type::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 4px;
    height: 100%;
    background: var(--accent-color);
}

.award-category h6,
.project-type h6 {
    color: var(--primary-color);
    font-size: 1.2rem;
    margin: 0 0 1rem;
    padding-left: 1.8rem;
    position: relative;
}

.award-category h6::before,
.project-type h6::before {
    content: '▹';
    position: absolute;
    left: 0;
    color: var(--accent-color);
    font-size: 1.1em;
}

.award-category ul,
.project-type ul {
    padding-left: 1.8rem;
    margin: 0.8rem 0;
}

.award-category li,
.project-type li {
    margin-bottom: 0.8rem;
    line-height: 1.6;
    position: relative;
    padding-left: 1.2rem;
}

.award-category li::before,
.project-type li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--accent-color);
}

.award-category:hover,
.project-type:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 12px rgba(0,0,0,0.1);
}

@media (max-width: 768px) {
    .award-category,
    .project-type {
        padding: 1.2rem;
    }
    
    .award-category h6,
    .project-type h6 {
        font-size: 1.1rem;
    }
}

@media (max-width: 768px) {
    .awards-grid,
    .projects-grid {
        grid-template-columns: 1fr;
        padding: 1rem;
        gap: 1.2rem;
    }
}

.award-category h6,
.project-type h6 {
    color: var(--primary-color);
    margin: 0 0 0.8rem;
    font-size: 1.1rem;
}

.project-type ul {
    padding-left: 1.2rem;
}

.project-type li {
    margin-bottom: 0.5rem;
}

@media (max-width: 768px) {
    .awards-grid,
    .projects-grid {
        grid-template-columns: 1fr;
    }
}

/* 科研成果样式 */
.pub-category {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    margin-bottom: 2.5rem;
}

.pub-item {
    padding: 1.5rem;
    margin: 1.5rem 0;
    border-left: 4px solid var(--accent-color);
    background: #f8f8f8;
    border-radius: 4px;
    transition: all 0.3s ease;
}

.pub-item:hover {
    transform: translateX(10px);
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.pub-item h4 {
    color: var(--primary-color);
    margin: 0 0 0.8rem;
    font-size: 1.1rem;
    line-height: 1.4;
}

.pub-info {
    color: #444;
    font-size: 0.9em;
    padding-left: 1.2rem;
    border-left: 2px solid #ddd;
    margin: 0.8rem 0;
}

.pub-info span {
    display: block;
    margin: 0.3rem 0;
}

.year-group {
    margin: 2rem 0;
    padding: 1rem;
    background: #f5f5f5;
    border-radius: 6px;
}

/* 团队成员样式 */
.member-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    padding: 2rem 0;
}

.member-card {
    background: white;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    text-align: center;
    transition: all 0.3s ease;
}

.member-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.member-avatar {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    background: #eee;
    margin: 0 auto 1rem;
    overflow: hidden;
}

.member-info h3 {
    color: var(--primary-color);
    margin: 0.5rem 0;
}

.member-role {
    color: #666;
    font-size: 0.9em;
    margin-bottom: 1rem;
}

.member-bio {
    font-size: 0.9em;
    color: #444;
    text-align: left;
    line-height: 1.6;
}

@media (max-width: 768px) {
    .member-grid {
        grid-template-columns: 1fr;
        padding: 1rem;
    }
    
    .member-card {
        margin: 0.5rem;
    }
}

/* 招生模块样式 */
.admission-section {
    margin: 3rem 0;
    background: rgba(255,255,255,0.95);
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    padding: 2rem;
}

.admission-content {
    display: grid;
    gap: 2.5rem;
    margin-top: 1.5rem;
}

.phd-admission, 
.master-admission {
    padding: 1.5rem;
    border-left: 4px solid var(--accent-color);
    background: #f8f8f8;
    border-radius: 4px;
}

.admission-section h3 {
    color: var(--primary-color);
    margin-bottom: 1.2rem;
    font-size: 1.3rem;
}

.admission-section h4 {
    color: #444;
    margin: 1rem 0 0.8rem;
    font-size: 1.1rem;
}

.admission-section ul {
    padding-left: 1.8rem;
    margin: 0.8rem 0;
}

.admission-section li {
    margin-bottom: 0.6rem;
    line-height: 1.6;
}

@media (max-width: 768px) {
    .admission-content {
        grid-template-columns: 1fr;
    }
    .phd-admission, 
    .master-admission {
        padding: 1rem;
    }
}

footer {
    background-color: var(--primary-color);
    color: white;
    text-align: center;
    padding: 1rem;
    position: relative;
    bottom: 0;
    width: 100%;
}

@media (max-width: 768px) {
    nav ul {
        flex-direction: column;
        text-align: center;
        gap: 0.5rem;
    }
    
    nav {
        margin-top: 6rem; /* 移动端header高度调整 */
    }
    
    main {
        margin-top: 6rem;
    }
}