/* Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=Lora:ital,wght@0,400..700;1,400..700&family=Plus+Jakarta+Sans:ital,wght@0,300..800;1,300..800&display=swap');

/* CSS Variables & Theme Setup */
:root {
  /* Colors - Light Theme (Academic & Clean) */
  --bg-primary: #fdfdfc;
  --bg-secondary: #f6f6f3;
  --bg-tertiary: #eeeeea;
  --text-primary: #1c1f26;
  --text-secondary: #586174;
  --accent: #2c5282;          /* Academic Navy */
  --accent-light: #ebf8ff;
  --accent-muted: #4a5568;
  --border: #e2e8f0;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.05), 0 1px 2px rgba(0,0,0,0.1);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.05), 0 2px 4px -1px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  
  /* Fonts */
  --font-serif: 'Lora', Georgia, serif;
  --font-sans: 'Plus Jakarta Sans', system-ui, -apple-system, sans-serif;
  
  /* Layout */
  --container-width: 1040px;
}

[data-theme="dark"] {
  /* Colors - Dark Theme (Sleek Slate) */
  --bg-primary: #0b0f19;
  --bg-secondary: #151c2c;
  --bg-tertiary: #1f293d;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --accent: #60a5fa;          /* Electric Academic Blue */
  --accent-light: rgba(96, 165, 250, 0.1);
  --accent-muted: #cbd5e1;
  --border: #1e293b;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.2);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.4);
}

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

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Typography */
h1, h2, h3, h4 {
  font-family: var(--font-serif);
  color: var(--text-primary);
  font-weight: 700;
  line-height: 1.25;
}

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

h2 {
  font-size: 2rem;
  position: relative;
  padding-bottom: 0.5rem;
  margin-bottom: 2rem;
}

h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 45px;
  height: 3px;
  background-color: var(--accent);
  border-radius: 2px;
  transition: var(--transition);
}

h3 {
  font-size: 1.35rem;
  margin-bottom: 0.5rem;
}

p {
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
  font-size: 1.05rem;
}

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

a:hover {
  opacity: 0.85;
}

/* Navigation Bar */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(253, 253, 252, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: var(--transition);
}

[data-theme="dark"] header {
  background-color: rgba(11, 15, 25, 0.8);
}

.nav-container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 1.25rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.35rem;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo span {
  color: var(--accent);
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 2rem;
  align-items: center;
}

.nav-links a {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.25rem 0;
  position: relative;
}

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

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--accent);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.3s ease;
}

.nav-links a:hover::after,
.nav-links a.active::after {
  transform: scaleX(1);
  transform-origin: left;
}

/* Theme Toggle Button */
.theme-toggle-btn {
  background: none;
  border: 1px solid var(--border);
  color: var(--text-primary);
  cursor: pointer;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

.theme-toggle-btn:hover {
  background-color: var(--bg-secondary);
  transform: scale(1.05);
}

.theme-toggle-btn svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

/* Mobile Nav Toggle */
.mobile-nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

/* Container */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 2rem;
}

/* Section styling */
section {
  padding: 5.5rem 0;
}

/* Hero Section */
.hero {
  display: flex;
  align-items: center;
  gap: 4rem;
  padding-top: 7rem;
  padding-bottom: 5.5rem;
}

.hero-content {
  flex: 1.2;
}

.hero-tag {
  display: inline-block;
  background-color: var(--accent-light);
  color: var(--accent);
  padding: 0.35rem 1rem;
  border-radius: 100px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.hero-content h1 {
  margin-bottom: 1.5rem;
}

.hero-content p.subtitle {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-style: italic;
  color: var(--text-primary);
  margin-bottom: 2rem;
}

.hero-image-container {
  flex: 0.8;
  display: flex;
  justify-content: center;
  position: relative;
}

.hero-image-wrapper {
  position: relative;
  width: 320px;
  height: 320px;
  border-radius: 30% 70% 70% 30% / 30% 30% 70% 70%;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  border: 4px solid var(--bg-primary);
  animation: morphing 15s ease-in-out infinite;
  transition: var(--transition);
}

.hero-image-wrapper::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, transparent 50%, rgba(0,0,0,0.15));
}

@keyframes morphing {
  0% { border-radius: 30% 70% 70% 30% / 30% 30% 70% 70%; }
  25% { border-radius: 58% 42% 75% 25% / 76% 46% 54% 24%; }
  50% { border-radius: 50% 50% 33% 67% / 55% 27% 73% 45%; }
  75% { border-radius: 33% 67% 58% 42% / 63% 68% 32% 37%; }
  100% { border-radius: 30% 70% 70% 30% / 30% 30% 70% 70%; }
}

.hero-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition);
}

.social-links {
  display: flex;
  gap: 1.25rem;
  margin-top: 2rem;
}

.social-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  font-size: 1.2rem;
  transition: var(--transition);
}

.social-btn:hover {
  background-color: var(--accent);
  color: var(--bg-primary);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

/* About / Biography section details */
.bio-details {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: 3.5rem;
}

.bio-card {
  background-color: var(--bg-secondary);
  padding: 2.5rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}

.bio-card h3 {
  font-family: var(--font-sans);
  font-weight: 700;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
}

.interest-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.interest-item {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
}

.interest-item svg {
  width: 20px;
  height: 20px;
  color: var(--accent);
  margin-top: 0.15rem;
  flex-shrink: 0;
}

/* Publications Grid & Interactive Filters */
.filter-container {
  display: flex;
  gap: 1rem;
  margin-bottom: 2.5rem;
  flex-wrap: wrap;
}

.filter-btn {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 0.5rem 1.25rem;
  border-radius: 100px;
  font-weight: 500;
  font-size: 0.9rem;
  cursor: pointer;
  transition: var(--transition);
}

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

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

.publication-item {
  background-color: var(--bg-primary);
  border: 1px solid var(--border);
  padding: 2rem;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

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

.pub-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 0.75rem;
  flex-wrap: wrap;
}

.pub-tag {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.25rem 0.75rem;
  border-radius: 4px;
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
}

.pub-tag.journal {
  background-color: #ebf8ff;
  color: #2b6cb0;
}

[data-theme="dark"] .pub-tag.journal {
  background-color: rgba(96, 165, 250, 0.15);
  color: #93c5fd;
}

.pub-tag.conference {
  background-color: #f0fff4;
  color: #2f855a;
}

[data-theme="dark"] .pub-tag.conference {
  background-color: rgba(74, 222, 128, 0.15);
  color: #86efac;
}

.pub-year {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-weight: 600;
}

.pub-title {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.pub-authors {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.pub-authors strong {
  color: var(--text-primary);
}

.pub-venue {
  font-style: italic;
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
}

.pub-links {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.pub-link-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  border-radius: var(--radius-sm);
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  transition: var(--transition);
}

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

.pub-link-btn.primary-btn {
  background-color: var(--accent);
  color: var(--bg-primary);
  border-color: var(--accent);
}

.pub-link-btn.primary-btn:hover {
  opacity: 0.9;
}

.abstract-toggle {
  background: none;
  border: none;
  color: var(--accent);
  font-weight: 600;
  font-size: 0.85rem;
  cursor: pointer;
  padding: 0.4rem 0;
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.abstract-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  background-color: var(--bg-secondary);
  border-radius: var(--radius-sm);
  margin-top: 1rem;
  font-size: 0.95rem;
}

.abstract-content.open {
  max-height: 300px;
  padding: 1.25rem;
  border: 1px solid var(--border);
}

/* Teaching and Research Experience Timeline */
.timeline {
  position: relative;
  max-width: 800px;
  margin: 0 auto;
}

.timeline::after {
  content: '';
  position: absolute;
  width: 2px;
  background-color: var(--border);
  top: 0;
  bottom: 0;
  left: 50%;
  margin-left: -1px;
}

.timeline-item {
  padding: 10px 40px;
  position: relative;
  background-color: inherit;
  width: 50%;
}

.timeline-item::after {
  content: '';
  position: absolute;
  width: 16px;
  height: 16px;
  right: -8px;
  background-color: var(--bg-primary);
  border: 4px solid var(--accent);
  top: 15px;
  border-radius: 50%;
  z-index: 1;
  transition: var(--transition);
}

.timeline-item:hover::after {
  background-color: var(--accent);
  transform: scale(1.2);
}

.left {
  left: 0;
}

.right {
  left: 50%;
}

.right::after {
  left: -8px;
}

.timeline-content {
  padding: 1.75rem;
  background-color: var(--bg-secondary);
  position: relative;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}

.timeline-date {
  font-weight: 700;
  color: var(--accent);
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
}

.timeline-content h3 {
  font-family: var(--font-sans);
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.timeline-institution {
  font-style: italic;
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

/* News Section */
.news-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 2rem;
}

.news-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 2rem;
  transition: var(--transition);
}

.news-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--accent);
}

.news-date {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 0.75rem;
  display: block;
}

.news-card h3 {
  font-family: var(--font-serif);
  margin-bottom: 1rem;
}

/* Contact Details */
.contact-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.contact-method {
  display: flex;
  align-items: flex-start;
  gap: 1.25rem;
}

.contact-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-sm);
  background-color: var(--accent-light);
  color: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.contact-text h4 {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 1.1rem;
  margin-bottom: 0.25rem;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  background-color: var(--bg-secondary);
  padding: 2.5rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.form-group label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.form-control {
  padding: 0.75rem 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  transition: var(--transition);
}

.form-control:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-light);
}

.submit-btn {
  background-color: var(--accent);
  color: var(--bg-primary);
  border: none;
  padding: 0.85rem 1.5rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  display: inline-flex;
  justify-content: center;
  align-items: center;
}

.submit-btn:hover {
  opacity: 0.95;
  transform: translateY(-1px);
}

/* Footer styling */
footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: 3rem 0;
  margin-top: 4rem;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.footer-copy {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* Responsive Styles */
@media (max-width: 900px) {
  h1 {
    font-size: 2.25rem;
  }
  .hero {
    flex-direction: column-reverse;
    text-align: center;
    gap: 2.5rem;
    padding-top: 4rem;
  }
  .hero-content {
    display: flex;
    flex-direction: column;
    align-items: center;
  }
  .social-links {
    justify-content: center;
  }
  .bio-details,
  .contact-container {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }
  /* Timeline shift to left */
  .timeline::after {
    left: 31px;
  }
  .timeline-item {
    width: 100%;
    padding-left: 70px;
    padding-right: 25px;
  }
  .timeline-item.right {
    left: 0%;
  }
  .timeline-item::after {
    left: 23px;
  }
}

@media (max-width: 600px) {
  .nav-container {
    padding: 1rem 1.5rem;
  }
  .nav-links {
    display: none; /* Can add a mobile hamburger menu via JS if desired */
  }
  .mobile-nav-toggle {
    display: block;
  }
  .hero-image-wrapper {
    width: 250px;
    height: 250px;
  }
  section {
    padding: 3.5rem 0;
  }
  .publication-item {
    padding: 1.5rem;
  }
  .pub-title {
    font-size: 1.15rem;
  }
}