/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #fff;
}

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

/* 导航栏 */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    transition: all 0.3s ease;
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

.header.scrolled {
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
}

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

.nav-logo {
    font-size: 1.5rem;
    font-weight: 600;
    color: #2563eb;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: #333;
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-link:hover {
    color: #2563eb;
}

/* 语言切换按钮 */
.language-switch {
    margin-left: 1rem;
}

.lang-btn {
    background: transparent;
    border: 2px solid #2563eb;
    color: #2563eb;
    padding: 8px 16px;
    border-radius: 8px;
    cursor: pointer;
    font-family: inherit;
    font-size: 0.9rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.3s ease;
    outline: none;
}

.lang-btn:hover {
    background: #2563eb;
    color: white;
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(37, 99, 235, 0.3);
}

.lang-btn:active {
    transform: translateY(0);
}

.lang-text {
    font-weight: 600;
}

/* 语言切换样式 - 移除错误的display:none规则 */
/* 这些规则被移除因为它们会隐藏所有文本 */

/* 主要内容 */
.main {
    margin-top: 70px;
}

.section {
    padding: 80px 0;
}

.section-alt {
    background-color: #f8fafc;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: #1e293b;
}

/* 英雄区域 */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    min-height: 90vh;
    display: flex;
    align-items: center;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 400;
    margin-bottom: 1.5rem;
    opacity: 0.9;
}

.hero-description {
    font-size: 1.1rem;
    line-height: 1.7;
    margin-bottom: 2rem;
    opacity: 0.9;
}

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

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 12px 24px;
    text-decoration: none;
    border-radius: 8px;
    font-weight: 500;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.btn-primary {
    background: white;
    color: #2563eb;
}

.btn-primary:hover {
    background: #f1f5f9;
    transform: translateY(-2px);
}

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

.btn-secondary:hover {
    background: white;
    color: #2563eb;
    transform: translateY(-2px);
}

/* 照片区域 */
.hero-image {
    display: flex;
    justify-content: center;
}

.profile-image {
    width: 300px;
    height: 300px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid rgba(255, 255, 255, 0.3);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.profile-image:hover {
    transform: scale(1.05);
    border-color: rgba(255, 255, 255, 0.5);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.15);
}

.image-placeholder {
    width: 300px;
    height: 300px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    border: 3px dashed rgba(255, 255, 255, 0.3);
    color: rgba(255, 255, 255, 0.8);
    transition: all 0.3s ease;
}

.image-placeholder:hover {
    background: rgba(255, 255, 255, 0.2);
    border-color: rgba(255, 255, 255, 0.5);
}

.image-placeholder i {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.image-placeholder p {
    font-size: 1.1rem;
    font-weight: 500;
}

/* 时间线 */
.timeline {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 2px;
    height: 100%;
    background: #e2e8f0;
}

.timeline-item {
    position: relative;
    margin-bottom: 3rem;
    display: flex;
    align-items: center;
}

.timeline-item:nth-child(odd) {
    flex-direction: row;
}

.timeline-item:nth-child(even) {
    flex-direction: row-reverse;
}

.timeline-marker {
    width: 16px;
    height: 16px;
    background: #2563eb;
    border-radius: 50%;
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    z-index: 1;
    border: 4px solid white;
    box-shadow: 0 0 0 4px #e2e8f0;
}

.timeline-content {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.07);
    width: calc(50% - 2rem);
    position: relative;
}

.timeline-item:nth-child(odd) .timeline-content {
    margin-right: auto;
}

.timeline-item:nth-child(even) .timeline-content {
    margin-left: auto;
}

.timeline-title {
    font-size: 1.3rem;
    font-weight: 600;
    color: #1e293b;
    margin-bottom: 0.5rem;
}

.timeline-subtitle {
    font-size: 1.1rem;
    color: #2563eb;
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.timeline-date {
    font-size: 0.9rem;
    color: #64748b;
    margin-bottom: 1rem;
    font-weight: 500;
}

.timeline-description {
    color: #475569;
    line-height: 1.6;
}

/* 研究领域卡片 */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 2rem;
    max-width: 1000px;
    margin: 0 auto;
}

.research-card {
    background: white;
    padding: 2.5rem;
    border-radius: 16px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.07);
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.research-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 25px rgba(0, 0, 0, 0.1);
}

.research-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    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-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: #1e293b;
    margin-bottom: 1rem;
}

.research-description {
    color: #475569;
    line-height: 1.7;
    font-size: 1rem;
}

/* 论文列表 */
.publications-list {
    max-width: 900px;
    margin: 0 auto;
}

.publication-item {
    background: white;
    padding: 2.5rem;
    border-radius: 16px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.07);
    margin-bottom: 2rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.publication-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 25px rgba(0, 0, 0, 0.1);
}

.publication-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
    gap: 1rem;
}

.publication-title {
    font-size: 1.3rem;
    font-weight: 600;
    color: #1e293b;
    line-height: 1.4;
    flex: 1;
}

.publication-year {
    background: #2563eb;
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
    white-space: nowrap;
}

.publication-authors {
    font-size: 1rem;
    color: #475569;
    margin-bottom: 0.8rem;
    line-height: 1.5;
}

.publication-authors strong {
    color: #2563eb;
    font-weight: 600;
}

.publication-venue,
.publication-date {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.95rem;
    color: #64748b;
    margin-bottom: 0.5rem;
}

.publication-venue i,
.publication-date i {
    color: #94a3b8;
}

.publication-abstract {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid #e2e8f0;
}

.publication-abstract p {
    color: #475569;
    line-height: 1.7;
    font-size: 0.95rem;
}

/* 联系方式 */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    max-width: 1000px;
    margin: 0 auto;
}

.contact-card {
    background: white;
    padding: 2.5rem;
    border-radius: 16px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.07);
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.contact-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 25px rgba(0, 0, 0, 0.1);
}

.contact-icon {
    width: 70px;
    height: 70px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
}

.contact-icon i {
    font-size: 1.8rem;
    color: white;
}

.contact-title {
    font-size: 1.3rem;
    font-weight: 600;
    color: #1e293b;
    margin-bottom: 1rem;
}

.contact-info {
    color: #475569;
    line-height: 1.6;
}

.contact-info a {
    color: #2563eb;
    text-decoration: none;
    transition: color 0.3s ease;
}

.contact-info a:hover {
    color: #1d4ed8;
    text-decoration: underline;
}

/* 页脚 */
.footer {
    background: #1e293b;
    color: white;
    padding: 2rem 0;
    text-align: center;
}

.footer-content p {
    margin-bottom: 0.5rem;
    opacity: 0.8;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-menu { gap: 1rem; }
    .nav-link { font-size: 0.9rem; }
    .hero-content { grid-template-columns: 1fr; text-align: center; gap: 2rem; }
    .hero-title { font-size: 2.5rem; }
    .section-title { font-size: 2rem; }
    .hero-buttons { justify-content: center; flex-wrap: wrap; }
    .image-placeholder { width: 250px; height: 250px; }
    .profile-image { width: 250px; height: 250px; }
    .timeline::before { left: 20px; }
    .timeline-item { flex-direction: row !important; padding-left: 60px; }
    .timeline-marker { left: 20px; transform: none; }
    .timeline-content { width: 100%; margin: 0 !important; }
    .research-grid { grid-template-columns: 1fr; }
    .contact-grid { grid-template-columns: 1fr; }
    .publication-header { flex-direction: column; align-items: flex-start; }
    .publication-year { align-self: flex-start; }
}

@media (max-width: 480px) {
    .nav-container { padding: 0 15px; }
    .nav-menu { gap: 0.5rem; }
    .nav-link { font-size: 0.8rem; }
    .container { padding: 0 15px; }
    .section { padding: 60px 0; }
    .hero-title { font-size: 2rem; }
    .section-title { font-size: 1.8rem; }
    .btn { padding: 10px 20px; font-size: 0.9rem; }
}