/* ============================================
   ACADEMIC WEBSITE - MODERN PROFESSIONAL THEME
   ============================================ */

/* CSS Custom Properties */
:root {
  /* Light theme colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --text-primary: #1e293b;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --accent-primary: #1e40af;
  --accent-secondary: #3b82f6;
  --accent-light: rgba(59, 130, 246, 0.1);
  --accent-hover: #1d4ed8;
  --border-color: #e2e8f0;
  --border-light: #f1f5f9;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-serif: 'Merriweather', Georgia, 'Times New Roman', serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing */
  --nav-height: 64px;
  --section-spacing: 5rem;
  --container-max: 900px;
  --container-padding: 1.5rem;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;

  /* Border radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;
}

/* Dark theme */
[data-theme="dark"] {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --accent-primary: #60a5fa;
  --accent-secondary: #3b82f6;
  --accent-light: rgba(59, 130, 246, 0.15);
  --accent-hover: #93c5fd;
  --border-color: #334155;
  --border-light: #1e293b;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 10px 10px -5px rgba(0, 0, 0, 0.4);
}

/* ============================================
   BASE STYLES
   ============================================ */

*, *::before, *::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 2rem);
}

body {
  font-family: var(--font-serif);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  margin: 0;
  padding: 0;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--transition-base), color var(--transition-base);
}

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

/* ============================================
   NAVIGATION
   ============================================ */

.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
  transition: all var(--transition-base);
}

.navbar.scrolled {
  box-shadow: var(--shadow-md);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-brand {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 1.125rem;
  color: var(--text-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.nav-brand:hover {
  color: var(--accent-primary);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

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

.nav-controls {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* Theme toggle */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  color: var(--text-secondary);
}

.theme-toggle:hover {
  background: var(--accent-light);
  color: var(--accent-primary);
  border-color: var(--accent-primary);
}

.theme-toggle .icon-sun,
.theme-toggle .icon-moon {
  width: 20px;
  height: 20px;
}

[data-theme="dark"] .theme-toggle .icon-sun {
  display: block;
}

[data-theme="dark"] .theme-toggle .icon-moon {
  display: none;
}

[data-theme="light"] .theme-toggle .icon-sun,
:root:not([data-theme]) .theme-toggle .icon-sun {
  display: none;
}

[data-theme="light"] .theme-toggle .icon-moon,
:root:not([data-theme]) .theme-toggle .icon-moon {
  display: block;
}

/* Mobile menu toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  margin: 3px 0;
  transition: all var(--transition-fast);
  border-radius: 2px;
}

.nav-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ============================================
   MAIN CONTENT
   ============================================ */

main {
  padding-top: calc(var(--nav-height) + 2rem);
  padding-bottom: 4rem;
}

/* Sections */
section {
  padding: var(--section-spacing) 0;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

section.visible {
  opacity: 1;
  transform: translateY(0);
}

section:first-child {
  padding-top: 2rem;
}

/* Section headers */
.section-header {
  margin-bottom: 2rem;
}

.section-title {
  font-family: var(--font-sans);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 0 0 0.5rem 0;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.section-title::before {
  content: '';
  display: inline-block;
  width: 4px;
  height: 1.5rem;
  background: var(--accent-primary);
  border-radius: 2px;
}

.section-subtitle {
  font-size: 1rem;
  color: var(--text-muted);
  margin: 0;
}

/* Divider */
.section-divider {
  height: 1px;
  background: linear-gradient(to right, var(--border-color), transparent);
  margin: 3rem 0;
}

/* ============================================
   HEADER / HERO SECTION
   ============================================ */

.hero {
  padding: 3rem 0 4rem;
}

.hero-content {
  display: grid;
  grid-template-columns: 1fr 200px;
  gap: 3rem;
  align-items: center;
}

.hero-text h1 {
  font-family: var(--font-sans);
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 0 0 0.5rem 0;
  letter-spacing: -0.02em;
}

.hero-subtitle {
  font-family: var(--font-sans);
  font-size: 1.125rem;
  color: var(--accent-primary);
  font-weight: 500;
  margin: 0 0 1.5rem 0;
}

.hero-bio {
  font-size: 1.0625rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 1.5rem;
}

.hero-bio p {
  margin: 0 0 1rem 0;
}

.hero-bio p:last-child {
  margin-bottom: 0;
}

.hero-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.hero-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  padding: 0.625rem 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.hero-link:hover {
  color: var(--accent-primary);
  background: var(--accent-light);
  border-color: var(--accent-primary);
  transform: translateY(-2px);
}

.hero-link i {
  font-size: 1rem;
}

.hero-image {
  position: relative;
}

.hero-image img {
  width: 200px;
  height: 200px;
  object-fit: cover;
  border-radius: var(--radius-xl);
  border: 3px solid var(--border-color);
  box-shadow: var(--shadow-lg);
  transition: all var(--transition-base);
}

.hero-image::after {
  content: '';
  position: absolute;
  inset: -8px;
  border: 2px solid var(--accent-light);
  border-radius: calc(var(--radius-xl) + 8px);
  pointer-events: none;
}

.hero-image:hover img {
  transform: scale(1.02);
  box-shadow: var(--shadow-xl);
}

/* ============================================
   RESEARCH SECTION
   ============================================ */

.research-intro {
  font-size: 1.0625rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 2rem;
}

.research-themes {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.research-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all var(--transition-base);
}

.research-card:hover {
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-md);
}

.research-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1.5rem;
  cursor: pointer;
  user-select: none;
}

.research-card-title {
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.research-card-title i {
  color: var(--accent-primary);
  font-size: 1.125rem;
}

.research-card-toggle {
  color: var(--text-muted);
  transition: transform var(--transition-fast);
}

.research-card.expanded .research-card-toggle {
  transform: rotate(180deg);
}

.research-card-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-slow);
}

.research-card.expanded .research-card-content {
  max-height: 500px;
}

.research-card-body {
  padding: 0 1.5rem 1.5rem;
  border-top: 1px solid var(--border-color);
}

.research-card-body p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  margin: 1rem 0 0.75rem;
  line-height: 1.7;
}

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

.research-publications li {
  font-size: 0.875rem;
  color: var(--text-secondary);
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border-light);
}

.research-publications li:last-child {
  border-bottom: none;
}

.research-publications a {
  color: var(--accent-primary);
  text-decoration: none;
  font-weight: 500;
}

.research-publications a:hover {
  text-decoration: underline;
}

/* Earlier work subsection */
.research-subsection {
  margin-top: 2.5rem;
}

.research-subsection h3 {
  font-family: var(--font-sans);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0 0 1rem 0;
}

.research-subsection > p {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 1.5rem;
}

/* ============================================
   NEWS TIMELINE
   ============================================ */

.news-timeline {
  position: relative;
  padding-left: 2rem;
}

.news-timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--accent-primary), var(--border-color));
  border-radius: 1px;
}

.news-item {
  position: relative;
  padding-bottom: 1.5rem;
  transition: transform var(--transition-fast);
}

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

.news-item::before {
  content: '';
  position: absolute;
  left: -2rem;
  top: 0.5rem;
  width: 12px;
  height: 12px;
  background: var(--bg-primary);
  border: 3px solid var(--accent-primary);
  border-radius: 50%;
  transform: translateX(-5px);
  transition: all var(--transition-fast);
}

.news-item:hover::before {
  background: var(--accent-primary);
  box-shadow: 0 0 0 4px var(--accent-light);
}

.news-item:hover {
  transform: translateX(4px);
}

.news-date {
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--accent-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.25rem;
}

.news-content {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.news-content em {
  color: var(--text-muted);
  font-style: italic;
}

/* ============================================
   PUBLICATIONS SECTION
   ============================================ */

.publications-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 2rem;
  padding: 1rem;
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}

.publications-search {
  flex: 1;
  min-width: 200px;
  position: relative;
}

.publications-search input {
  width: 100%;
  padding: 0.75rem 1rem 0.75rem 2.75rem;
  font-family: var(--font-sans);
  font-size: 0.875rem;
  color: var(--text-primary);
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.publications-search input:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-light);
}

.publications-search input::placeholder {
  color: var(--text-muted);
}

.publications-search i {
  position: absolute;
  left: 1rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
}

.publications-filters {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.filter-btn {
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-btn:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

.filter-btn.active {
  background: var(--accent-primary);
  border-color: var(--accent-primary);
  color: white;
}

.publications-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.publication-item {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 1.5rem;
  padding: 1.5rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base);
}

.publication-item:hover {
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-md);
  transform: translateX(4px);
}

.publication-item.hidden {
  display: none;
}

.pub-thumbnail {
  width: 120px;
  height: 120px;
  border-radius: var(--radius-md);
  overflow: hidden;
  cursor: pointer;
  border: 1px solid var(--border-color);
  flex-shrink: 0;
}

.pub-thumbnail img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-base);
}

.pub-thumbnail:hover img {
  transform: scale(1.1);
}

.pub-content {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.pub-title {
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.4;
  margin: 0;
}

.pub-authors {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

.pub-authors .highlight-name {
  color: var(--accent-primary);
  font-weight: 600;
}

.pub-venue-container {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
}

.pub-venue {
  font-size: 0.875rem;
  font-style: italic;
  color: var(--text-muted);
}

.pub-year {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent-primary);
  background: var(--accent-light);
  padding: 0.25rem 0.5rem;
  border-radius: var(--radius-sm);
}

.pub-award {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 600;
  color: white;
  background: linear-gradient(135deg, #f59e0b, #d97706);
  padding: 0.25rem 0.5rem;
  border-radius: var(--radius-sm);
}

.pub-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

.pub-link {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--accent-primary);
  text-decoration: none;
  padding: 0.375rem 0.75rem;
  background: var(--accent-light);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
}

.pub-link:hover {
  background: var(--accent-primary);
  color: white;
}

.pub-link i {
  font-size: 0.6875rem;
}

.copy-citation {
  cursor: pointer;
}

.copy-citation.copied {
  background: #10b981;
  color: white;
}

/* No results message */
.no-results {
  text-align: center;
  padding: 3rem;
  color: var(--text-muted);
  font-style: italic;
}

/* ============================================
   AWARDS SECTION
   ============================================ */

.awards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
}

.award-card {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 1.25rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base);
}

.award-card:hover {
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.award-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--accent-light), transparent);
  border: 2px solid var(--accent-primary);
  border-radius: var(--radius-md);
  color: var(--accent-primary);
  flex-shrink: 0;
}

.award-icon i {
  font-size: 1.25rem;
}

.award-info {
  flex: 1;
}

.award-year {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.25rem;
}

.award-title {
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0 0 0.25rem 0;
  line-height: 1.4;
}

.award-org {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* ============================================
   EXPERIENCE TIMELINE
   ============================================ */

.experience-timeline {
  position: relative;
  padding-left: 3rem;
}

.experience-timeline::before {
  content: '';
  position: absolute;
  left: 1rem;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--border-color);
  border-radius: 1px;
}

.experience-item {
  position: relative;
  padding-bottom: 2rem;
}

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

.experience-icon {
  position: absolute;
  left: -3rem;
  top: 0;
  width: 2rem;
  height: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-primary);
  border: 2px solid var(--accent-primary);
  border-radius: 50%;
  color: var(--accent-primary);
  font-size: 0.875rem;
  z-index: 1;
  transition: all var(--transition-fast);
}

.experience-item:hover .experience-icon {
  background: var(--accent-primary);
  color: white;
  box-shadow: 0 0 0 4px var(--accent-light);
}

.experience-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  transition: all var(--transition-base);
}

.experience-item:hover .experience-card {
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-md);
}

.experience-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.experience-title {
  font-family: var(--font-sans);
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0;
}

.experience-period {
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--accent-primary);
  background: var(--accent-light);
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-full);
}

.experience-org {
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--accent-primary);
  margin-bottom: 0.5rem;
}

.experience-desc {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin: 0;
}

/* ============================================
   SERVICES SECTION
   ============================================ */

.services-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.service-card {
  padding: 1.5rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base);
}

.service-card:hover {
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-md);
}

.service-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--accent-light);
  border-radius: var(--radius-md);
  color: var(--accent-primary);
  margin-bottom: 1rem;
}

.service-icon i {
  font-size: 1.125rem;
}

.service-title {
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0 0 0.5rem 0;
}

.service-desc {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  margin: 0;
  line-height: 1.6;
}

/* ============================================
   SKILLS SECTION
   ============================================ */

.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 1.5rem;
}

.skill-category {
  padding: 1.5rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base);
}

.skill-category:hover {
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-md);
}

.skill-category-title {
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--accent-primary);
  margin: 0 0 0.75rem 0;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.skill-category-title i {
  font-size: 1rem;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.skill-tag {
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  color: var(--text-secondary);
  background: var(--bg-primary);
  padding: 0.375rem 0.75rem;
  border-radius: var(--radius-full);
  border: 1px solid var(--border-color);
  transition: all var(--transition-fast);
}

.skill-tag:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

/* ============================================
   FOOTER
   ============================================ */

footer {
  padding: 2rem 0;
  border-top: 1px solid var(--border-color);
  text-align: center;
}

.footer-content {
  font-family: var(--font-sans);
  font-size: 0.875rem;
  color: var(--text-muted);
}

.footer-content a {
  color: var(--accent-primary);
  text-decoration: none;
}

.footer-content a:hover {
  text-decoration: underline;
}

/* ============================================
   BACK TO TOP BUTTON
   ============================================ */

.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-primary);
  color: white;
  border: none;
  border-radius: var(--radius-full);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all var(--transition-base);
  box-shadow: var(--shadow-lg);
  z-index: 999;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--accent-hover);
  transform: translateY(-4px);
}

.back-to-top i {
  font-size: 1.25rem;
}

/* ============================================
   MODAL
   ============================================ */

.modal {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.9);
  z-index: 2000;
  opacity: 0;
  transition: opacity var(--transition-base);
}

.modal.show {
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 1;
}

.modal-content {
  max-width: 90%;
  max-height: 90%;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
}

.modal-close {
  position: absolute;
  top: 1rem;
  right: 1.5rem;
  font-size: 2rem;
  color: white;
  cursor: pointer;
  opacity: 0.7;
  transition: all var(--transition-fast);
  background: none;
  border: none;
  padding: 0.5rem;
}

.modal-close:hover {
  opacity: 1;
  transform: scale(1.1);
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */

@media (max-width: 768px) {
  :root {
    --section-spacing: 3rem;
    --container-padding: 1rem;
  }

  /* Navigation */
  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem;
    gap: 0;
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
  }

  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-links a {
    display: block;
    padding: 0.75rem 1rem;
    border-radius: var(--radius-md);
  }

  .nav-toggle {
    display: flex;
  }

  /* Hero */
  .hero-content {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 2rem;
  }

  .hero-image {
    order: -1;
  }

  .hero-image img {
    width: 160px;
    height: 160px;
  }

  .hero-text h1 {
    font-size: 2rem;
  }

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

  /* Publications */
  .publication-item {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .pub-thumbnail {
    width: 100%;
    height: 180px;
  }

  .publications-controls {
    flex-direction: column;
  }

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

  /* Experience */
  .experience-timeline {
    padding-left: 2.5rem;
  }

  .experience-icon {
    left: -2.5rem;
  }

  .experience-header {
    flex-direction: column;
  }

  /* Skills */
  .skills-grid {
    grid-template-columns: 1fr;
  }

  /* Back to top */
  .back-to-top {
    bottom: 1rem;
    right: 1rem;
    width: 44px;
    height: 44px;
  }

  /* Disable hover animations on touch devices */
  .publication-item:hover,
  .award-card:hover,
  .experience-item:hover .experience-card,
  .service-card:hover,
  .skill-category:hover,
  .news-item:hover {
    transform: none;
  }
}

@media (max-width: 480px) {
  .hero-text h1 {
    font-size: 1.75rem;
  }

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

  .hero-link {
    font-size: 0.8125rem;
    padding: 0.5rem 0.75rem;
  }

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

/* ============================================
   PRINT STYLES
   ============================================ */

@media print {
  * {
    background: white !important;
    color: black !important;
    box-shadow: none !important;
    text-shadow: none !important;
  }

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

  .navbar,
  .back-to-top,
  .theme-toggle,
  .nav-toggle,
  .publications-controls,
  .modal {
    display: none !important;
  }

  main {
    padding-top: 0;
  }

  section {
    opacity: 1 !important;
    transform: none !important;
    page-break-inside: avoid;
    padding: 1rem 0;
  }

  .hero-content {
    grid-template-columns: 1fr 150px;
  }

  .hero-image img {
    width: 150px;
    height: 150px;
  }

  .hero-links {
    display: none;
  }

  a {
    text-decoration: none;
  }

  a[href]::after {
    content: none;
  }

  .publication-item,
  .award-card,
  .experience-card,
  .service-card,
  .skill-category {
    border: 1px solid #ddd !important;
    break-inside: avoid;
  }

  .pub-thumbnail {
    width: 80px;
    height: 80px;
  }

  h1 {
    font-size: 24pt;
  }

  h2 {
    font-size: 16pt;
  }

  h3 {
    font-size: 14pt;
  }
}

/* ============================================
   ACCESSIBILITY
   ============================================ */

/* Focus styles */
a:focus,
button:focus,
input:focus,
[tabindex]:focus {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
}

/* Skip link */
.skip-link {
  position: absolute;
  top: -100%;
  left: 0;
  background: var(--accent-primary);
  color: white;
  padding: 0.75rem 1.5rem;
  z-index: 10000;
  font-family: var(--font-sans);
  font-weight: 500;
  text-decoration: none;
  border-radius: 0 0 var(--radius-md) 0;
}

.skip-link:focus {
  top: 0;
  outline: none;
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  html {
    scroll-behavior: auto;
  }
}

/* High contrast mode */
@media (prefers-contrast: high) {
  :root {
    --accent-primary: #0000ff;
    --border-color: #000000;
  }

  [data-theme="dark"] {
    --accent-primary: #00ffff;
    --border-color: #ffffff;
  }
}

/* Screen reader only */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}