/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #3498db;
    --secondary-color: #2c3e50;
    --accent-color: #e74c3c;
    --text-color: #333;
    --light-gray: #f5f6fa;
    --white: #fff;
}

body {
    font-family: 'Microsoft YaHei', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
}

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

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 12px 24px;
    background-color: var(--primary-color);
    color: var(--white);
    text-decoration: none;
    border-radius: 30px;
    transition: all 0.3s ease;
}

.btn:hover {
    background-color: var(--secondary-color);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

.btn i {
    margin-right: 8px;
}

/* 导航栏 */
.navbar {
    background-color: var(--white);
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
    background-color: rgba(255, 255, 255, 0.95);
}

.navbar.scrolled {
    background-color: rgba(255, 255, 255, 0.98);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--secondary-color);
}

.nav-links {
    display: flex;
    list-style: none;
}

.nav-links li a {
    color: var(--secondary-color);
    text-decoration: none;
    padding: 10px 15px;
    transition: color 0.3s;
}

.nav-links li a:hover {
    color: var(--primary-color);
}

/* 主页横幅 */
.hero {
    background: linear-gradient(rgba(44, 62, 80, 0.7), rgba(44, 62, 80, 0.7)),
                url('../images/hero-bg.jpg') center/cover;
    height: 100vh;
    display: flex;
    align-items: center;
    text-align: center;
    color: var(--white);
    padding-top: 70px;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
}

.hero-icon {
    font-size: 4rem;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 30px;
}

.hero-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
}

/* 章节通用样式 */
.section {
    padding: 80px 0;
    background-color: var(--white);
}

.section:nth-child(even) {
    background-color: var(--light-gray);
}

.section-header {
    text-align: center;
    margin-bottom: 50px;
}

.section-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.section h2 {
    font-size: 2.5rem;
    color: var(--secondary-color);
    margin-bottom: 15px;
}

.section-subtitle {
    color: #666;
    font-size: 1.1rem;
}

/* 研究方向 */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.research-item {
    background: var(--white);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.research-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.research-item i {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.research-item h3 {
    color: var(--secondary-color);
    margin-bottom: 0.5rem;
    font-size: 1.5rem;
}

.research-item p {
    color: var(--text-color);
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

.research-details {
    list-style: none;
    padding: 0;
    margin: 1rem 0;
}

.research-details li {
    display: flex;
    align-items: center;
    margin-bottom: 0.5rem;
    color: var(--text-color);
    font-size: 0.9rem;
}

.research-details li i {
    font-size: 1rem;
    margin-right: 0.5rem;
    color: var(--accent-color);
}

.section-header {
    text-align: center;
    margin-bottom: 3rem;
}

.section-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.section-subtitle {
    color: var(--text-color);
    font-size: 1.1rem;
    opacity: 0.8;
    margin-top: 0.5rem;
}

/* 团队成员 */
.team-category {
    margin-bottom: 4rem;
}

.category-title {
    display: flex;
    align-items: center;
    font-size: 1.8rem;
    color: var(--secondary-color);
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--primary-color);
}

.category-title i {
    margin-right: 1rem;
    color: var(--primary-color);
}

.team-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.faculty-grid {
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.masters-grid {
    grid-template-columns: repeat(4, 1fr);
}

.team-member {
    background: var(--white);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.team-member:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.member-photo {
    width: 100%;
    height: 250px;
    overflow: hidden;
}

.member-photo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.team-member:hover .member-photo img {
    transform: scale(1.05);
}

.member-info {
    padding: 1.5rem;
}

.member-info h4 {
    color: var(--secondary-color);
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

.member-title {
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.member-year {
    color: var(--text-color);
    opacity: 0.8;
    margin-bottom: 0.5rem;
}

.member-research {
    color: var(--text-color);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.member-contact {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.member-contact a {
    color: var(--secondary-color);
    transition: color 0.3s ease;
    width: 35px;
    height: 35px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background-color: var(--light-gray);
}

.member-contact a:hover {
    color: var(--white);
    background-color: var(--primary-color);
}

.member-contact i {
    font-size: 1.1rem;
}

.student-group {
    margin-bottom: 3rem;
}

.group-title {
    color: var(--secondary-color);
    font-size: 1.4rem;
    margin-bottom: 1.5rem;
    padding-left: 1rem;
    border-left: 4px solid var(--primary-color);
    display: flex;
    align-items: center;
}

.group-title i {
    margin-right: 0.8rem;
    color: var(--primary-color);
    font-size: 1.2rem;
}

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

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

.faculty-card {
    background: var(--white);
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.08);
    overflow: hidden;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    padding-top: 2rem;
}

.faculty-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
}

.faculty-card .faculty-photo {
    width: 150px;
    height: 150px;
    margin: 0 auto 1.5rem;
    border-radius: 50%;
    overflow: hidden;
    background-color: var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    border: 4px solid rgba(var(--primary-color-rgb), 0.1);
}

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

@media (max-width: 768px) {
    .faculty-card .faculty-photo {
        width: 120px;
        height: 120px;
    }
}

.faculty-info {
    padding: 1.5rem;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.faculty-info h3 {
    color: var(--secondary-color);
    font-size: 1.4rem;
    margin-bottom: 0.5rem;
}

.faculty-info p {
    color: var(--text-color);
    margin-bottom: 0.5rem;
    line-height: 1.5;
}

.research-areas {
    font-size: 0.95rem;
    color: var(--text-color);
    opacity: 0.85;
    margin: 0.5rem 0;
}

.view-details-btn {
    display: inline-block;
    margin-top: auto;
    padding: 0.8rem 1.5rem;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: var(--white);
    text-decoration: none;
    border-radius: 25px;
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.view-details-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(var(--primary-color-rgb), 0.3);
}

/* 响应式调整 */
@media (max-width: 1200px) {
    .masters-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 900px) {
    .masters-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 600px) {
    .masters-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .section {
        padding: 40px 0;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 100%;
        max-width: 300px;
        margin: 10px 0;
    }
}

@media (max-width: 768px) {
    .undergrad-grid {
        grid-template-columns: 1fr;
    }
    
    .group-title {
        font-size: 1.2rem;
    }
    
    .group-title i {
        font-size: 1rem;
    }
}

/* 联系我们 */
.contact-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.contact-item {
    text-align: center;
    padding: 30px;
    background: var(--white);
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

.contact-item:hover {
    transform: translateY(-5px);
}

.contact-item i {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.contact-item h3 {
    margin-bottom: 10px;
    color: var(--secondary-color);
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-top: 30px;
}

.social-link {
    width: 50px;
    height: 50px;
    background: var(--primary-color);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    transition: all 0.3s;
}

.social-link:hover {
    background: var(--secondary-color);
    transform: translateY(-5px);
}

/* 页脚 */
.footer {
    background: var(--secondary-color);
    color: var(--white);
    text-align: center;
    padding: 20px 0;
}