/* ========================================
   GitHub Pages 个人主页样式
   简洁大方，移动端适配
   ======================================== */

/* CSS Variables */
:root {
  --primary-color: #2c3e50;
  --secondary-color: #3498db;
  --accent-color: #e74c3c;
  --text-color: #333;
  --text-light: #666;
  --text-lighter: #999;
  --bg-color: #fff;
  --bg-light: #f8f9fa;
  --border-color: #e0e0e0;
  --shadow: 0 2px 8px rgba(0,0,0,0.1);
  --shadow-hover: 0 4px 12px rgba(0,0,0,0.15);
  --transition: all 0.3s ease;
  --font-sans: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-serif: 'Noto Serif SC', Georgia, serif;
  --container-max: 1200px;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
}

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

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

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

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: var(--spacing-sm);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

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

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

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

/* ========================================
   Header & Navigation
   ======================================== */
.site-header {
  background-color: var(--bg-color);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: var(--shadow);
}

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

.site-title {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
}

.site-title:hover {
  color: var(--secondary-color);
}

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

.nav-links a {
  color: var(--text-color);
  font-weight: 500;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: 4px;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--secondary-color);
  background-color: var(--bg-light);
}

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

.hamburger {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--primary-color);
  position: relative;
  transition: var(--transition);
}

.hamburger::before,
.hamburger::after {
  content: '';
  position: absolute;
  width: 24px;
  height: 2px;
  background-color: var(--primary-color);
  transition: var(--transition);
}

.hamburger::before { top: -8px; }
.hamburger::after { top: 8px; }

/* ========================================
   Main Content
   ======================================== */
.main-content {
  min-height: calc(100vh - 200px);
}

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

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

.section-title {
  font-size: 2rem;
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-sm);
  border-bottom: 3px solid var(--secondary-color);
  display: inline-block;
}

/* ========================================
   Profile Section
   ======================================== */
.about-section {
  background: linear-gradient(135deg, var(--bg-light) 0%, var(--bg-color) 100%);
}

.profile {
  display: grid;
  grid-template-columns: 250px 1fr;
  gap: var(--spacing-lg);
  align-items: start;
}

.profile-image {
  width: 100%;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow);
}

.profile-image img {
  width: 100%;
  height: auto;
  display: block;
}

.profile-info {
  padding: var(--spacing-sm) 0;
}

.profile-name {
  font-size: 2.5rem;
  margin-bottom: var(--spacing-xs);
  color: var(--primary-color);
}

.profile-title {
  font-size: 1.25rem;
  color: var(--text-light);
  margin-bottom: var(--spacing-md);
}

.profile-bio {
  font-size: 1.1rem;
  line-height: 1.8;
  margin-bottom: var(--spacing-md);
}

.profile-contact {
  margin-bottom: var(--spacing-md);
}

.contact-link {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-xs) var(--spacing-sm);
  background-color: var(--bg-light);
  border-radius: 4px;
  font-size: 0.95rem;
}

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

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

.social-links a {
  color: var(--text-light);
  transition: var(--transition);
}

.social-links a:hover {
  color: var(--secondary-color);
  transform: translateY(-2px);
}

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

.publication-item {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: var(--spacing-md);
  padding: var(--spacing-md);
  background-color: var(--bg-color);
  border-radius: 8px;
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.publication-item:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}

.pub-year {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--secondary-color);
  text-align: center;
  padding-top: var(--spacing-xs);
}

.pub-content {
  flex: 1;
}

.pub-title {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-xs);
  color: var(--primary-color);
}

.pub-authors {
  color: var(--text-light);
  font-size: 0.95rem;
  margin-bottom: var(--spacing-xs);
}

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

.pub-doi a {
  font-size: 0.85rem;
  color: var(--secondary-color);
}

.pub-tags {
  margin-top: var(--spacing-sm);
}

/* ========================================
   Timeline (Education & Work)
   ======================================== */
.timeline {
  position: relative;
  padding-left: var(--spacing-lg);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 8px;
  top: 0;
  bottom: 0;
  width: 2px;
  background-color: var(--border-color);
}

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

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

.timeline-marker {
  position: absolute;
  left: calc(-1 * var(--spacing-lg) + 4px);
  top: 4px;
  width: 12px;
  height: 12px;
  background-color: var(--secondary-color);
  border-radius: 50%;
  border: 3px solid var(--bg-color);
  box-shadow: 0 0 0 3px var(--secondary-color);
}

.timeline-content {
  background-color: var(--bg-color);
  padding: var(--spacing-md);
  border-radius: 8px;
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.timeline-content:hover {
  box-shadow: var(--shadow-hover);
}

.timeline-header {
  display: flex;
  justify-content: space-between;
  align-items: start;
  margin-bottom: var(--spacing-sm);
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

.timeline-title {
  font-size: 1.25rem;
  color: var(--primary-color);
  margin-bottom: 0;
}

.timeline-period {
  color: var(--secondary-color);
  font-weight: 500;
  font-size: 0.9rem;
  white-space: nowrap;
}

.timeline-institution {
  font-size: 1.05rem;
  margin-bottom: var(--spacing-xs);
}

.timeline-description {
  color: var(--text-light);
  margin-bottom: 0;
}

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

/* ========================================
   Contact Section
   ======================================== */
.contact-content {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

.contact-methods {
  margin-top: var(--spacing-lg);
}

.contact-method {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-md);
  padding: var(--spacing-md);
  background-color: var(--bg-color);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

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

.contact-info h4 {
  margin-bottom: var(--spacing-xs);
  color: var(--primary-color);
}

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

.blog-nav {
  margin-bottom: var(--spacing-lg);
  padding: var(--spacing-md);
  background-color: var(--bg-color);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.blog-categories h3,
.blog-tags h3 {
  font-size: 1.1rem;
  margin-bottom: var(--spacing-sm);
  color: var(--primary-color);
}

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

.blog-categories a {
  padding: var(--spacing-xs) var(--spacing-sm);
  background-color: var(--bg-light);
  border-radius: 4px;
  font-size: 0.9rem;
}

.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

.back-link {
  display: inline-flex;
  align-items: center;
  color: var(--secondary-color);
  font-weight: 500;
}

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

.post-card {
  background-color: var(--bg-color);
  padding: var(--spacing-md);
  border-radius: 8px;
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.post-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}

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

.post-date {
  color: var(--text-lighter);
  font-size: 0.9rem;
}

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

.category {
  padding: 2px 8px;
  background-color: var(--secondary-color);
  color: white !important;
  border-radius: 3px;
  font-size: 0.8rem;
}

.post-card-title {
  font-size: 1.3rem;
  margin-bottom: var(--spacing-sm);
}

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

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

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

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

.tag {
  padding: 3px 10px;
  background-color: var(--bg-light);
  color: var(--text-light) !important;
  border-radius: 12px;
  font-size: 0.85rem;
  transition: var(--transition);
}

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

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

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

.no-posts code {
  background-color: var(--bg-light);
  padding: 2px 8px;
  border-radius: 3px;
  font-size: 0.9rem;
}

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

.post-title {
  font-size: 2.5rem;
  margin-bottom: var(--spacing-sm);
}

.post-meta {
  color: var(--text-light);
  font-size: 0.95rem;
  display: flex;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-sm);
}

.post-content {
  max-width: 800px;
  margin: 0 auto;
  line-height: 1.8;
}

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

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

.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;
  border-radius: 3px;
  font-family: 'Courier New', monospace;
  font-size: 0.9em;
}

.post-content pre {
  background-color: #2d2d2d;
  color: #f8f8f2;
  padding: var(--spacing-md);
  border-radius: 8px;
  overflow-x: auto;
  margin-bottom: var(--spacing-md);
}

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

.post-content img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  margin: var(--spacing-md) 0;
}

.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);
}

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

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

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

.pagination a {
  padding: var(--spacing-xs) var(--spacing-sm);
  background-color: var(--secondary-color);
  color: white !important;
  border-radius: 4px;
}

.pagination a:hover {
  background-color: var(--primary-color);
}

.pagination-info {
  color: var(--text-light);
}

/* ========================================
   Footer
   ======================================== */
.site-footer {
  background-color: var(--primary-color);
  color: white;
  padding: var(--spacing-lg) 0 var(--spacing-md);
  margin-top: var(--spacing-xl);
}

.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);
}

.footer-section h4 {
  font-size: 1.1rem;
}

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

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

.footer-section a {
  color: rgba(255,255,255,0.8);
}

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

.contact-info {
  list-style: none;
}

.footer-bottom {
  text-align: center;
  padding-top: var(--spacing-md);
  border-top: 1px solid rgba(255,255,255,0.1);
  color: rgba(255,255,255,0.6);
  font-size: 0.9rem;
}

.footer-bottom a {
  color: rgba(255,255,255,0.8);
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 768px) {
  html {
    font-size: 14px;
  }
  
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--bg-color);
    flex-direction: column;
    padding: var(--spacing-md);
    box-shadow: var(--shadow);
    border-top: 1px solid var(--border-color);
  }
  
  .nav-links.active {
    display: flex;
  }
  
  .menu-toggle {
    display: block;
  }
  
  .profile {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .profile-image {
    width: 200px;
    margin: 0 auto;
  }
  
  .social-links {
    justify-content: center;
  }
  
  .publication-item {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .pub-year {
    font-size: 1.2rem;
    padding-bottom: var(--spacing-xs);
    border-bottom: 2px solid var(--secondary-color);
  }
  
  .timeline-header {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .timeline-period {
    order: -1;
    margin-bottom: var(--spacing-xs);
  }
  
  .post-title {
    font-size: 2rem;
  }
  
  .post-nav {
    flex-direction: column;
    text-align: center;
  }
  
  .footer-content {
    grid-template-columns: 1fr;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--spacing-sm);
  }
  
  .section {
    padding: var(--spacing-lg) 0;
  }
  
  .profile-name {
    font-size: 2rem;
  }
  
  h1 { font-size: 2rem; }
  h2 { font-size: 1.5rem; }
  h3 { font-size: 1.25rem; }
}

/* ========================================
   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; }

.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); }

/* ========================================
   Animations & Transitions
   ======================================== */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.fade-in {
  animation: fadeIn 0.6s ease-out;
}

/* ========================================
   Print Styles
   ======================================== */
@media print {
  .site-header,
  .site-footer,
  .menu-toggle {
    display: none;
  }
  
  body {
    font-size: 12pt;
    line-height: 1.5;
  }
  
  .section {
    page-break-inside: avoid;
  }
}