/* ============================================
   THAO P. LE - ACADEMIC WEBSITE
   Warm Academic Theme: Navy, Burgundy, Cream
   ============================================ */

/* ---------- CSS Variables ---------- */
:root {
  /* Primary Palette */
  --navy-deep: #1a2744;
  --navy: #2c3e5a;
  --navy-light: #3d5278;
  --burgundy: #8b3a4c;
  --burgundy-dark: #6d2c3b;
  --burgundy-light: #a84d61;
  
  /* Neutrals */
  --cream: #faf8f5;
  --cream-dark: #f0ebe3;
  --warm-white: #fffefa;
  --warm-gray: #6b6560;
  --warm-gray-light: #9a948d;
  --charcoal: #2d2a26;
  
  /* Accents */
  --gold: #c9a227;
  --gold-light: #e8c84a;
  
  /* Typography */
  --font-display: 'Playfair Display', Georgia, serif;
  --font-body: 'Source Sans 3', 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  
  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 2rem;
  --space-xl: 4rem;
  --space-2xl: 6rem;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;
  
  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(26, 39, 68, 0.08);
  --shadow-md: 0 4px 12px rgba(26, 39, 68, 0.1);
  --shadow-lg: 0 8px 30px rgba(26, 39, 68, 0.12);
}

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

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

body {
  font-family: var(--font-body);
  font-size: 1.0625rem;
  line-height: 1.7;
  color: var(--charcoal);
  background-color: var(--cream);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ---------- Typography ---------- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.3;
  color: var(--navy-deep);
  margin-bottom: var(--space-md);
}

h1 {
  font-size: 2.75rem;
  letter-spacing: -0.02em;
}

h2 {
  font-size: 2rem;
  letter-spacing: -0.01em;
}

h3 {
  font-size: 1.5rem;
}

h4 {
  font-size: 1.25rem;
  font-family: var(--font-body);
  font-weight: 600;
}

p {
  margin-bottom: var(--space-md);
}

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

a:hover {
  color: var(--burgundy-dark);
  text-decoration: underline;
  text-underline-offset: 3px;
}

strong {
  font-weight: 600;
}

/* ---------- Layout ---------- */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.page-content {
  min-height: calc(100vh - 200px);
  padding: var(--space-xl) 0 var(--space-2xl);
}

/* ---------- Header & Navigation ---------- */
.site-header {
  background: linear-gradient(135deg, var(--navy-deep) 0%, var(--navy) 100%);
  padding: var(--space-md) 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-md);
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.site-title {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--cream);
  text-decoration: none;
  letter-spacing: 0.01em;
}

.site-title:hover {
  color: var(--gold-light);
  text-decoration: none;
}

.site-nav {
  display: flex;
  gap: var(--space-lg);
}

.site-nav a {
  color: var(--cream-dark);
  font-size: 0.95rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: var(--space-sm) 0;
  position: relative;
}

.site-nav a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gold);
  transition: width var(--transition-base);
}

.site-nav a:hover,
.site-nav a.active {
  color: var(--cream);
  text-decoration: none;
}

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

/* Mobile Navigation */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--cream);
  margin: 5px 0;
  transition: var(--transition-fast);
}

@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }
  
  .site-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--navy-deep);
    flex-direction: column;
    padding: var(--space-md) var(--space-lg);
    gap: var(--space-md);
  }
  
  .site-nav.active {
    display: flex;
  }
}

/* ---------- About Page ---------- */
.about-hero {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: var(--space-xl);
  align-items: start;
  margin-bottom: var(--space-2xl);
}

@media (max-width: 768px) {
  .about-hero {
    grid-template-columns: 1fr;
    text-align: center;
  }
}

.profile-photo-wrapper {
  position: relative;
}

.profile-photo {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
  border-radius: 8px;
  box-shadow: var(--shadow-lg);
  border: 4px solid var(--warm-white);
}

.profile-photo-wrapper::before {
  content: '';
  position: absolute;
  top: 12px;
  left: 12px;
  right: -12px;
  bottom: -12px;
  background: var(--burgundy);
  opacity: 0.15;
  border-radius: 8px;
  z-index: -1;
}

.about-intro h1 {
  margin-bottom: var(--space-sm);
}

.about-intro .subtitle {
  font-size: 1.25rem;
  color: var(--warm-gray);
  margin-bottom: var(--space-lg);
  font-style: italic;
}

.about-intro .bio {
  font-size: 1.1rem;
  margin-bottom: var(--space-lg);
}

/* Contact Links */
.contact-links {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
  margin-top: var(--space-lg);
}

@media (max-width: 768px) {
  .contact-links {
    justify-content: center;
  }
}

.contact-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background: var(--navy);
  color: var(--cream) !important;
  border-radius: 6px;
  font-size: 0.9rem;
  font-weight: 500;
  transition: all var(--transition-fast);
}

.contact-link:hover {
  background: var(--burgundy);
  text-decoration: none;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.contact-link svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

/* News Section */
.news-section {
  margin-top: var(--space-2xl);
  padding-top: var(--space-xl);
  border-top: 1px solid var(--cream-dark);
}

.section-header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.section-header h2 {
  margin-bottom: 0;
}

.section-header::after {
  content: '';
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, var(--cream-dark), transparent);
}

.news-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.news-item {
  display: grid;
  grid-template-columns: 100px 1fr;
  gap: var(--space-md);
  padding: var(--space-md);
  background: var(--warm-white);
  border-radius: 6px;
  border-left: 3px solid var(--burgundy);
  transition: all var(--transition-fast);
}

.news-item:hover {
  box-shadow: var(--shadow-sm);
  transform: translateX(4px);
}

.news-date {
  font-size: 0.85rem;
  color: var(--warm-gray);
  font-weight: 500;
}

.news-content {
  font-size: 0.95rem;
}

.news-tag {
  display: inline-block;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 2px 8px;
  border-radius: 3px;
  margin-right: var(--space-sm);
  font-weight: 600;
}

.news-tag.publication {
  background: var(--burgundy);
  color: var(--cream);
}

.news-tag.talk {
  background: var(--navy);
  color: var(--cream);
}

.news-tag.award {
  background: var(--gold);
  color: var(--charcoal);
}

.news-tag.general {
  background: var(--warm-gray-light);
  color: var(--charcoal);
}

/* ---------- Publications Page ---------- */
.publications-header {
  margin-bottom: var(--space-xl);
}

.search-filter-bar {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
  margin-bottom: var(--space-lg);
}

.search-box {
  flex: 1;
  min-width: 250px;
  position: relative;
}

.search-box input {
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  padding-left: 40px;
  border: 2px solid var(--cream-dark);
  border-radius: 6px;
  font-size: 1rem;
  font-family: var(--font-body);
  transition: border-color var(--transition-fast);
}

.search-box input:focus {
  outline: none;
  border-color: var(--burgundy);
}

.search-box svg {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 18px;
  height: 18px;
  fill: var(--warm-gray-light);
}

.filter-dropdown {
  padding: var(--space-sm) var(--space-md);
  border: 2px solid var(--cream-dark);
  border-radius: 6px;
  font-size: 0.95rem;
  font-family: var(--font-body);
  background: var(--warm-white);
  cursor: pointer;
}

.filter-dropdown:focus {
  outline: none;
  border-color: var(--burgundy);
}

/* Publication Cards */
.publications-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.pub-year-group {
  margin-bottom: var(--space-lg);
}

.pub-year {
  font-family: var(--font-display);
  font-size: 1.75rem;
  color: var(--navy);
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 2px solid var(--cream-dark);
}

.publication-card {
  padding: var(--space-lg);
  background: var(--warm-white);
  border-radius: 8px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
  margin-bottom: var(--space-md);
}

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

.pub-type {
  display: inline-block;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 3px 10px;
  border-radius: 3px;
  background: var(--navy);
  color: var(--cream);
  margin-bottom: var(--space-sm);
  font-weight: 600;
}

.pub-type.journal {
  background: var(--burgundy);
}

.pub-type.conference {
  background: var(--navy);
}

.pub-type.preprint {
  background: var(--warm-gray);
}

.pub-type.working-paper {
  background: var(--gold);
  color: var(--charcoal);
}

.pub-title {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--navy-deep);
  margin-bottom: var(--space-sm);
  line-height: 1.4;
}

.pub-title a {
  color: inherit;
}

.pub-title a:hover {
  color: var(--burgundy);
}

.pub-authors {
  font-size: 0.95rem;
  color: var(--warm-gray);
  margin-bottom: var(--space-sm);
}

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

.pub-venue {
  font-size: 0.9rem;
  font-style: italic;
  color: var(--warm-gray);
  margin-bottom: var(--space-sm);
}

.pub-links {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
  margin-top: var(--space-md);
}

.pub-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.8rem;
  padding: 4px 10px;
  border: 1px solid var(--cream-dark);
  border-radius: 4px;
  color: var(--navy);
  transition: all var(--transition-fast);
}

.pub-link:hover {
  background: var(--navy);
  color: var(--cream);
  border-color: var(--navy);
  text-decoration: none;
}

/* No results */
.no-results {
  text-align: center;
  padding: var(--space-xl);
  color: var(--warm-gray);
}

/* ---------- CV Page ---------- */
.cv-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: var(--space-xl);
  flex-wrap: wrap;
  gap: var(--space-md);
}

.cv-download {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  background: var(--burgundy);
  color: var(--cream) !important;
  border-radius: 6px;
  font-weight: 500;
  transition: all var(--transition-fast);
}

.cv-download:hover {
  background: var(--burgundy-dark);
  text-decoration: none;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.cv-embed {
  margin-top: var(--space-lg);
}

.cv-embed iframe {
  background: var(--warm-white);
}

.cv-section {
  margin-bottom: var(--space-xl);
}

.cv-section-title {
  font-family: var(--font-display);
  font-size: 1.5rem;
  color: var(--navy);
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-sm);
  border-bottom: 2px solid var(--burgundy);
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.cv-section-title svg {
  width: 24px;
  height: 24px;
  fill: var(--burgundy);
}

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

.cv-timeline::before {
  content: '';
  position: absolute;
  left: 8px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, var(--burgundy), var(--cream-dark));
}

.cv-entry {
  position: relative;
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-lg);
}

.cv-entry:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
}

.cv-entry::before {
  content: '';
  position: absolute;
  left: calc(-1 * var(--space-xl) + 4px);
  top: 6px;
  width: 10px;
  height: 10px;
  background: var(--burgundy);
  border-radius: 50%;
  border: 2px solid var(--cream);
}

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

.cv-entry-title {
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--navy-deep);
}

.cv-entry-date {
  font-size: 0.9rem;
  color: var(--warm-gray);
  font-style: italic;
}

.cv-entry-org {
  font-size: 1rem;
  color: var(--burgundy);
  margin-bottom: var(--space-sm);
}

.cv-entry-details {
  font-size: 0.95rem;
  color: var(--warm-gray);
}

.cv-entry-details ul {
  margin-top: var(--space-sm);
  padding-left: var(--space-lg);
}

.cv-entry-details li {
  margin-bottom: var(--space-xs);
}

/* Skills */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-lg);
}

.skill-category h4 {
  color: var(--navy);
  margin-bottom: var(--space-sm);
  font-size: 1rem;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.skill-tag {
  display: inline-block;
  padding: 4px 12px;
  background: var(--cream-dark);
  color: var(--charcoal);
  border-radius: 20px;
  font-size: 0.85rem;
  transition: all var(--transition-fast);
}

.skill-tag:hover {
  background: var(--navy);
  color: var(--cream);
}

/* ---------- Footer ---------- */
.site-footer {
  background: var(--navy-deep);
  color: var(--cream-dark);
  padding: var(--space-lg) 0;
  margin-top: var(--space-2xl);
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.footer-text {
  font-size: 0.9rem;
  opacity: 0.8;
}

.footer-links {
  display: flex;
  gap: var(--space-lg);
}

.footer-links a {
  color: var(--cream-dark);
  font-size: 0.9rem;
  opacity: 0.8;
  transition: opacity var(--transition-fast);
}

.footer-links a:hover {
  opacity: 1;
  text-decoration: none;
}

/* ---------- Utilities ---------- */
.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;
}

/* Print styles */
@media print {
  .site-header,
  .site-footer,
  .cv-download {
    display: none;
  }
  
  body {
    font-size: 11pt;
    line-height: 1.4;
  }
  
  .container {
    max-width: none;
    padding: 0;
  }
}

/* ---------- Teaching Page ---------- */
.teaching-header {
  margin-bottom: var(--space-xl);
}

.teaching-header h1 {
  margin-bottom: var(--space-sm);
}

.teaching-header p {
  font-size: 1.1rem;
  color: var(--warm-gray);
}

.teaching-section {
  margin-bottom: var(--space-xl);
}

.section-title {
  font-family: var(--font-display);
  font-size: 1.5rem;
  color: var(--navy);
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-sm);
  border-bottom: 2px solid var(--burgundy);
}

.course-card {
  background: var(--warm-white);
  border-radius: 8px;
  padding: var(--space-lg);
  margin-bottom: var(--space-lg);
  box-shadow: var(--shadow-sm);
  border-left: 4px solid var(--burgundy);
  transition: all var(--transition-base);
}

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

.course-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
}

.course-header h3 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  color: var(--navy-deep);
  margin-bottom: 0;
}

.course-level {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 4px 12px;
  background: var(--navy);
  color: var(--cream);
  border-radius: 20px;
  font-weight: 500;
}

.course-meta {
  display: flex;
  gap: var(--space-lg);
  margin-bottom: var(--space-sm);
  flex-wrap: wrap;
}

.course-role {
  font-weight: 600;
  color: var(--burgundy);
}

.course-period {
  color: var(--warm-gray);
  font-style: italic;
}

.course-institution {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--warm-gray);
  font-size: 0.95rem;
  margin-bottom: var(--space-md);
}

.course-institution svg {
  color: var(--burgundy);
}

.course-description {
  color: var(--charcoal);
  font-size: 0.95rem;
}

.course-description p {
  margin-bottom: 0;
}

.course-award {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-top: var(--space-md);
  padding-top: var(--space-md);
  border-top: 1px solid var(--cream-dark);
  color: var(--gold);
  font-size: 0.9rem;
}

.course-award svg {
  fill: var(--gold);
}

.teaching-philosophy {
  background: linear-gradient(135deg, var(--navy-deep) 0%, var(--navy) 100%);
  color: var(--cream);
  padding: var(--space-lg);
  border-radius: 8px;
  font-size: 1.05rem;
  line-height: 1.8;
}

.teaching-philosophy p {
  margin-bottom: 0;
}

/* ---------- Personal Page ---------- */
.personal-header {
  margin-bottom: var(--space-xl);
}

.personal-header h1 {
  margin-bottom: var(--space-sm);
}

.personal-header p {
  font-size: 1.1rem;
  color: var(--warm-gray);
  font-style: italic;
}

.personal-section {
  margin-bottom: var(--space-xl);
}

.personal-intro {
  font-size: 1.05rem;
  line-height: 1.8;
  max-width: 800px;
}

.photo-gallery-section {
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-xl);
  border-bottom: 1px solid var(--cream-dark);
}

.photo-gallery-section:last-of-type {
  border-bottom: none;
}

.gallery-title {
  font-family: var(--font-display);
  font-size: 1.5rem;
  color: var(--navy);
  margin-bottom: var(--space-xs);
}

.gallery-description {
  color: var(--warm-gray);
  font-style: italic;
  margin-bottom: var(--space-lg);
}

.photo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-md);
}

.photo-item {
  aspect-ratio: 3/2;
  overflow: hidden;
  border-radius: 6px;
  box-shadow: var(--shadow-sm);
}

.photo-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

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

.photo-placeholder {
  aspect-ratio: 3/2;
  background: linear-gradient(135deg, var(--cream-dark) 0%, var(--warm-gray-light) 100%);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--warm-gray);
  font-size: 0.9rem;
  border: 2px dashed var(--warm-gray-light);
}

/* Lightbox effect for photos (optional enhancement) */
.photo-item {
  cursor: pointer;
}

@media (max-width: 768px) {
  .photo-grid {
    grid-template-columns: 1fr;
  }
  
  .course-header {
    flex-direction: column;
    align-items: flex-start;
  }
}