/* ========================================
   学术风格个人主页 v2.0
   现代简洁设计
   ======================================== */

/* CSS Variables */
:root {
  --primary-color: #1a1a2e;
  --secondary-color: #4a6cf7;
  --accent-color: #6366f1;
  --text-color: #1f2937;
  --text-light: #6b7280;
  --text-lighter: #9ca3af;
  --bg-color: #ffffff;
  --bg-light: #f9fafb;
  --bg-alt: #f3f4f6;
  --border-color: #e5e7eb;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-serif: 'Noto Serif SC', 'Source Han Serif SC', Georgia, serif;
  --container-max: 900px;
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
}

/* Reset & Base */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-serif);
  color: var(--text-color);
  background-color: var(--bg-color);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* Container */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--spacing-xl);
}

/* Typography */
h1, h2, h3, h4 {
  font-family: var(--font-sans);
  font-weight: 600;
  line-height: 1.3;
  color: var(--primary-color);
}

h2 {
  font-size: 1.5rem;
  margin-bottom: var(--spacing-lg);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

h2::before {
  content: '';
  width: 4px;
  height: 1.5rem;
  background: var(--secondary-color);
  border-radius: 2px;
}

h3 {
  font-size: 1.1rem;
  margin-bottom: var(--spacing-xs);
}

p {
  margin-bottom: var(--spacing-sm);
}

a {
  color: var(--secondary-color);
  text-decoration: none;
  transition: color 0.2s;
}

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

/* ========================================
   Header & Navigation
   ======================================== */
.site-header {
  background-color: rgba(255,255,255,0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md) 0;
}

.site-title {
  font-family: var(--font-sans);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--primary-color);
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: var(--spacing-xl);
}

.nav-links a {
  color: var(--text-light);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 500;
  padding: var(--spacing-xs) 0;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--secondary-color);
  transition: width 0.2s;
}

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

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-xs);
}

.hamburger {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--primary-color);
  position: relative;
  border-radius: 2px;
}

.hamburger::before,
.hamburger::after {
  content: '';
  position: absolute;
  width: 22px;
  height: 2px;
  background-color: var(--primary-color);
  border-radius: 2px;
}

.hamburger::before { top: -7px; }
.hamburger::after { top: 7px; }

/* ========================================
   Hero Section
   ======================================== */
.hero-section {
  padding: var(--spacing-2xl) 0;
  background: linear-gradient(135deg, var(--bg-color) 0%, var(--bg-light) 100%);
}

.hero-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-2xl);
}

.hero-text {
  flex: 1;
}

.hero-name {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: var(--spacing-xs);
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--accent-color) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-title {
  font-family: var(--font-sans);
  font-size: 1.2rem;
  color: var(--secondary-color);
  font-weight: 500;
  margin-bottom: var(--spacing-xs);
}

.hero-affiliation {
  font-family: var(--font-sans);
  color: var(--text-light);
  font-size: 0.95rem;
  margin-bottom: var(--spacing-md);
}

.hero-bio {
  font-size: 1rem;
  color: var(--text-light);
  max-width: 480px;
  line-height: 1.8;
  margin-bottom: var(--spacing-lg);
}

.hero-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.link-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-color);
  transition: all 0.2s;
}

.link-btn:hover {
  border-color: var(--secondary-color);
  color: var(--secondary-color);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.link-btn svg {
  flex-shrink: 0;
}

.hero-photo {
  flex-shrink: 0;
}

.photo-frame {
  width: 200px;
  height: 200px;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--bg-alt);
  box-shadow: var(--shadow-lg);
  border: 4px solid var(--bg-color);
}

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

.photo-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-sans);
  font-size: 4rem;
  font-weight: 700;
  color: var(--secondary-color);
  background: linear-gradient(135deg, var(--bg-alt) 0%, var(--border-color) 100%);
}

/* ========================================
   Sections
   ======================================== */
.section {
  padding: var(--spacing-2xl) 0;
}

.alt-bg {
  background-color: var(--bg-light);
}

.section-title {
  margin-bottom: var(--spacing-xl);
}

/* ========================================
   Interests Section
   ======================================== */
.interests-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--spacing-lg);
}

.interest-card {
  padding: var(--spacing-lg);
  background: var(--bg-color);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  transition: all 0.3s;
}

.interest-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--secondary-color);
}

.interest-icon {
  font-size: 2rem;
  margin-bottom: var(--spacing-sm);
}

.interest-card h3 {
  font-size: 1rem;
  margin-bottom: var(--spacing-xs);
}

.interest-card p {
  font-size: 0.9rem;
  color: var(--text-light);
  margin: 0;
}

/* ========================================
   Timeline
   ======================================== */
.timeline {
  position: relative;
  padding-left: var(--spacing-xl);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: var(--border-color);
  border-radius: 1px;
}

.timeline-item {
  position: relative;
  padding-bottom: var(--spacing-xl);
}

.timeline-item:last-child {
  padding-bottom: 0;
}

.timeline-marker {
  position: absolute;
  left: calc(-1 * var(--spacing-xl) + 2px);
  top: 6px;
  width: 12px;
  height: 12px;
  background: var(--secondary-color);
  border-radius: 50%;
  border: 3px solid var(--bg-color);
  box-shadow: 0 0 0 3px var(--bg-light);
}

.alt-bg .timeline-marker {
  box-shadow: 0 0 0 3px var(--bg-alt);
}

.timeline-date {
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--secondary-color);
  display: inline-block;
  margin-bottom: var(--spacing-xs);
}

.timeline-location {
  color: var(--text-light);
  font-size: 0.95rem;
  margin: 0;
}

.timeline-desc {
  color: var(--text-lighter);
  font-size: 0.9rem;
  margin-top: var(--spacing-xs);
  margin-bottom: 0;
}

/* ========================================
   Publications
   ======================================== */
.publications-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.pub-list-card {
  background: var(--bg-color);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  padding: var(--spacing-lg);
}

.pub-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.pub-item {
  display: flex;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) 0;
  border-bottom: 1px solid var(--border-light);
}

.pub-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.pub-item:first-child {
  padding-top: 0;
}

.pub-item .pub-number {
  font-family: var(--font-sans);
  font-weight: 600;
  color: var(--text-light);
  flex-shrink: 0;
  min-width: 24px;
}

.pub-item .pub-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.pub-item .pub-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--primary-color);
  line-height: 1.4;
}

.pub-item .pub-authors {
  font-size: 0.85rem;
  color: var(--text-color);
}

.pub-item .pub-venue {
  font-size: 0.8rem;
  color: var(--text-light);
}

.pub-item .pub-venue em {
  font-style: italic;
}

.pub-card {
  display: flex;
  gap: var(--spacing-md);
  padding: var(--spacing-lg);
  background: var(--bg-color);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  transition: all 0.2s;
}

.pub-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--secondary-color);
}

.pub-number {
  font-family: var(--font-sans);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--border-color);
  flex-shrink: 0;
  width: 40px;
}

.pub-content {
  flex: 1;
}

.pub-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--primary-color);
  margin-bottom: var(--spacing-xs);
  line-height: 1.4;
}

.pub-authors {
  font-size: 0.9rem;
  color: var(--text-color);
  margin-bottom: var(--spacing-xs);
}

.pub-venue {
  font-size: 0.85rem;
  color: var(--text-light);
  margin: 0;
}

.pub-venue em {
  font-style: italic;
  color: var(--secondary-color);
}

.pub-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  margin-top: var(--spacing-sm);
}

.pub-tag {
  padding: 2px 8px;
  background: var(--bg-light);
  color: var(--text-light);
  font-family: var(--font-sans);
  font-size: 0.75rem;
  border-radius: var(--radius-sm);
}

.more-link {
  text-align: center;
  margin-top: var(--spacing-xl);
  font-family: var(--font-sans);
}

.more-link a {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-lg);
  background: var(--secondary-color);
  color: white;
  border-radius: var(--radius-md);
  font-weight: 500;
}

.more-link a:hover {
  background: var(--accent-color);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* ========================================
   Awards
   ======================================== */
.awards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-md);
}

.award-card {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-md);
  padding: var(--spacing-lg);
  background: var(--bg-color);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.award-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
}

.award-content h3 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
}

.award-content p {
  font-size: 0.85rem;
  color: var(--text-light);
  margin: 0;
}

/* ========================================
   Footer
   ======================================== */
.site-footer {
  background-color: var(--primary-color);
  color: rgba(255,255,255,0.7);
  padding: var(--spacing-xl) 0;
  font-size: 0.85rem;
  font-family: var(--font-sans);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
}

.footer-section h3,
.footer-section h4 {
  margin-bottom: var(--spacing-sm);
  color: rgba(255,255,255,0.9);
}

.footer-section h4 {
  font-size: 0.9rem;
}

.footer-section ul {
  list-style: none;
}

.footer-section li {
  margin-bottom: var(--spacing-xs);
}

.footer-section a {
  color: rgba(255,255,255,0.7);
}

.footer-section a:hover {
  color: white;
}

.footer-bottom {
  text-align: center;
  padding-top: var(--spacing-md);
  border-top: 1px solid rgba(255,255,255,0.1);
  color: rgba(255,255,255,0.5);
}

.footer-bottom a {
  color: rgba(255,255,255,0.7);
}

/* ========================================
   Blog Section (for blog pages)
   ======================================== */
.blog-section {
  min-height: 60vh;
}

.blog-nav {
  margin-bottom: var(--spacing-lg);
}

.blog-categories ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.blog-categories a {
  padding: var(--spacing-xs) var(--spacing-sm);
  background-color: var(--bg-light);
  font-size: 0.9rem;
  border-radius: var(--radius-sm);
}

.posts-list {
  display: grid;
  gap: var(--spacing-md);
}

.post-card {
  padding: var(--spacing-md);
  border-bottom: 1px solid var(--border-color);
}

.post-card-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-xs);
  flex-wrap: wrap;
}

.post-date {
  color: var(--text-lighter);
  font-size: 0.85rem;
  font-family: var(--font-sans);
}

.post-categories {
  display: flex;
  gap: var(--spacing-xs);
}

.category {
  padding: 2px 8px;
  background-color: var(--secondary-color);
  color: white !important;
  font-size: 0.75rem;
  font-family: var(--font-sans);
  border-radius: var(--radius-sm);
}

.post-card-title {
  font-size: 1.1rem;
  margin-bottom: var(--spacing-xs);
}

.post-card-title a {
  color: var(--primary-color);
}

.post-card-title a:hover {
  color: var(--secondary-color);
}

.post-excerpt {
  color: var(--text-light);
  font-size: 0.9rem;
  line-height: 1.6;
  margin-bottom: var(--spacing-sm);
}

.post-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

.tag {
  padding: 2px 8px;
  background-color: var(--bg-light);
  color: var(--text-light) !important;
  font-size: 0.8rem;
  font-family: var(--font-sans);
  border-radius: var(--radius-sm);
}

.tag:hover {
  background-color: var(--secondary-color);
  color: white !important;
}

.no-posts {
  text-align: center;
  padding: var(--spacing-xl);
  color: var(--text-light);
}

.back-link {
  display: inline-flex;
  align-items: center;
  color: var(--secondary-color);
  font-size: 0.9rem;
  font-family: var(--font-sans);
}

/* ========================================
   Single Post
   ======================================== */
.post-header {
  background-color: var(--bg-light);
  padding: var(--spacing-lg) 0;
  margin-bottom: var(--spacing-lg);
}

.post-title {
  font-size: 1.75rem;
  margin-bottom: var(--spacing-sm);
}

.post-meta {
  color: var(--text-light);
  font-size: 0.9rem;
  font-family: var(--font-sans);
  display: flex;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-sm);
}

.post-content {
  line-height: 1.8;
}

.post-content h2 {
  margin-top: var(--spacing-lg);
}

.post-content h2::before {
  display: none;
}

.post-content h3 {
  margin-top: var(--spacing-md);
}

.post-content ul,
.post-content ol {
  margin-left: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
}

.post-content li {
  margin-bottom: var(--spacing-xs);
}

.post-content code {
  background-color: var(--bg-light);
  padding: 2px 6px;
  font-family: 'SF Mono', 'Fira Code', monospace;
  font-size: 0.9em;
  border-radius: var(--radius-sm);
}

.post-content pre {
  background-color: #1e1e2e;
  color: #cdd6f4;
  padding: var(--spacing-md);
  overflow-x: auto;
  margin-bottom: var(--spacing-md);
  border-radius: var(--radius-md);
}

.post-content pre code {
  background-color: transparent;
  padding: 0;
  color: inherit;
}

.post-content img {
  max-width: 100%;
  height: auto;
  margin: var(--spacing-md) 0;
  border-radius: var(--radius-md);
}

.post-content blockquote {
  border-left: 4px solid var(--secondary-color);
  padding-left: var(--spacing-md);
  margin: var(--spacing-md) 0;
  color: var(--text-light);
  font-style: italic;
}

.post-nav {
  display: flex;
  justify-content: space-between;
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--border-color);
  gap: var(--spacing-md);
  font-size: 0.9rem;
  font-family: var(--font-sans);
}

.post-nav a {
  color: var(--text-light);
}

/* ========================================
   Pagination
   ======================================== */
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
  padding: var(--spacing-md);
  font-family: var(--font-sans);
}

.pagination a {
  padding: var(--spacing-xs) var(--spacing-sm);
  color: var(--secondary-color);
}

.pagination-info {
  color: var(--text-light);
  font-size: 0.9rem;
}

/* ========================================
   Category Navigation
   ======================================== */
.category-nav {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
  font-family: var(--font-sans);
}

.category-tab {
  padding: var(--spacing-xs) var(--spacing-md);
  color: var(--text-color);
  font-size: 0.9rem;
  border-radius: var(--radius-sm);
}

.category-tab:hover {
  background: var(--bg-light);
}

.category-tab.active {
  background: var(--secondary-color);
  color: white;
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 768px) {
  html {
    font-size: 15px;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--bg-color);
    flex-direction: column;
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--border-color);
    gap: var(--spacing-sm);
  }

  .nav-links.active {
    display: flex;
  }

  .menu-toggle {
    display: block;
  }

  .hero-content {
    flex-direction: column-reverse;
    text-align: center;
  }

  .hero-name {
    font-size: 2rem;
  }

  .hero-bio {
    max-width: 100%;
  }

  .hero-links {
    justify-content: center;
  }

  .photo-frame {
    width: 150px;
    height: 150px;
  }

  .interests-grid {
    grid-template-columns: 1fr;
  }

  .pub-card {
    flex-direction: column;
    gap: var(--spacing-sm);
  }

  .pub-number {
    width: auto;
    font-size: 1rem;
  }

  .post-title {
    font-size: 1.5rem;
  }

  .post-nav {
    flex-direction: column;
    text-align: center;
  }

  .footer-content {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .category-nav {
    flex-direction: column;
  }

  .awards-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--spacing-md);
  }

  .section {
    padding: var(--spacing-xl) 0;
  }

  h1 { font-size: 1.75rem; }
  h2 { font-size: 1.25rem; }

  .hero-section {
    padding: var(--spacing-xl) 0;
  }

  .link-btn {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: 0.8rem;
  }
}

/* ========================================
   Print Styles
   ======================================== */
@media print {
  .site-header,
  .site-footer,
  .menu-toggle {
    display: none;
  }

  body {
    font-size: 11pt;
    line-height: 1.5;
  }

  .section {
    page-break-inside: avoid;
    padding: 0.5rem 0;
  }

  a {
    color: var(--text-color);
  }

  a[href^="http"]::after {
    content: " (" attr(href) ")";
    font-size: 0.8em;
    color: var(--text-light);
  }

  .pub-card,
  .interest-card,
  .award-card {
    border: 1px solid #ddd;
    box-shadow: none;
  }
}

/* ========================================
   Utility Classes
   ======================================== */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }
.text-light { color: var(--text-light); }

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }

/* ========================================
   Language Switcher
   ======================================== */
.lang-switcher {
  display: flex;
  gap: var(--spacing-sm);
  margin-left: var(--spacing-md);
  padding-left: var(--spacing-md);
  border-left: 1px solid var(--border-color);
}

.lang-switcher a {
  color: var(--text-light);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 500;
  padding: var(--spacing-xs) 0;
  position: relative;
  transition: color 0.2s;
}

.lang-switcher a:hover,
.lang-switcher a.active {
  color: var(--primary-color);
}

@media (max-width: 768px) {
  .lang-switcher {
    margin-left: 0;
    padding-left: 0;
    border-left: none;
    justify-content: center;
    padding: var(--spacing-sm) 0;
  }
}