@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@400;500;600;700;800&display=swap');

/* --- Custom Properties / Theme Tokens --- */
:root {
  /* Light Theme (Only Theme) */
  --bg-primary: #ffffff;
  --bg-secondary: #ffffff;
  --bg-glass: rgba(255, 255, 255, 0.75);
  --bg-glass-hover: rgba(255, 255, 255, 0.9);
  --border-color: rgba(15, 23, 42, 0.08);
  --border-hover: rgba(15, 23, 42, 0.15);
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --accent-color: #3b82f6;
  /* Blue */
  --accent-secondary: #0d9488;
  /* Teal */
  --accent-gradient: linear-gradient(135deg, #3b82f6 0%, #0d9488 100%);
  --accent-glow: rgba(59, 130, 246, 0.05);
  --card-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.07);
  --nav-bg: rgba(255, 255, 255, 0.85);

  --font-heading: 'Outfit', sans-serif;
  --font-body: 'Inter', sans-serif;
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --border-radius-lg: 16px;
  --border-radius-md: 12px;
  --border-radius-sm: 8px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-body);
  line-height: 1.6;
  transition: background-color 0.5s ease, color 0.5s ease;
  overflow-x: hidden;
  position: relative;
}

/* --- Container --- */
.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

/* --- Navbar / Header --- */
header.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background-color: var(--nav-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  transition: var(--transition-smooth);
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 70px;
}

.logo-link {
  display: flex;
  align-items: center;
  text-decoration: none;
  gap: 12px;
}

.logo-img {
  height: 36px;
  object-fit: contain;
  transition: var(--transition-smooth);
}

.logo-text {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.25rem;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: 0.5px;
}

.nav-menu {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 28px;
}

.nav-item a {
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  transition: var(--transition-smooth);
  position: relative;
  padding: 6px 0;
}

.nav-item a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent-gradient);
  transition: var(--transition-smooth);
}

.nav-item a:hover {
  color: var(--text-primary);
}

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

.nav-item.active a {
  color: var(--text-primary);
  font-weight: 600;
}

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

.theme-toggle:hover {
  background-color: var(--border-color);
  transform: rotate(15deg);
}

/* Mobile Menu Burger */
.burger {
  display: none;
  cursor: pointer;
  background: none;
  border: none;
  padding: 8px;
}

.burger span {
  display: block;
  width: 25px;
  height: 2px;
  background-color: var(--text-primary);
  margin: 5px 0;
  transition: var(--transition-smooth);
}

/* --- Hero Section --- */
.hero-section {
  padding-top: 140px;
  padding-bottom: 60px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 48px;
  align-items: start;
}

.profile-card {
  position: sticky;
  top: 100px;
  background: var(--bg-glass);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: 24px;
  box-shadow: var(--card-shadow);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  text-align: center;
  transition: var(--transition-smooth);
}

.profile-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-4px);
}

.profile-image-container {
  width: 180px;
  height: 180px;
  margin: 0 auto 20px;
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  border: 3px solid var(--border-color);
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
  transition: var(--transition-smooth);
}

.profile-card:hover .profile-image-container {
  border-color: var(--accent-color);
}

.profile-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top;
}

.profile-info h1 {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 6px;
  color: var(--text-primary);
}

.profile-title {
  font-size: 0.85rem;
  color: var(--accent-color);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 16px;
}

.divider {
  height: 1px;
  background-color: var(--border-color);
  margin: 16px 0;
}

.contact-list {
  list-style: none;
  text-align: left;
  font-size: 0.85rem;
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 12px;
  color: var(--text-secondary);
}

.contact-item svg {
  width: 16px;
  height: 16px;
  margin-top: 3px;
  color: var(--accent-color);
  flex-shrink: 0;
}

.contact-item a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: var(--transition-smooth);
}

.contact-item a:hover {
  color: var(--text-primary);
}

/* Hero Content Area */
.hero-content {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

/* Sections & Typography */
h2.section-title {
  font-family: var(--font-heading);
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 20px;
  position: relative;
  display: inline-block;
}

h2.section-title::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -4px;
  width: 40px;
  height: 3px;
  background: var(--accent-gradient);
  border-radius: 2px;
}

.bio-card,
.news-card {
  background: var(--bg-glass);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: 32px;
  box-shadow: var(--card-shadow);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

.bio-text {
  color: var(--text-secondary);
  font-size: 1.05rem;
  line-height: 1.75;
  margin-bottom: 28px;
  text-align: justify;
}

/* Affiliation logos */
.affiliation-logos {
  display: flex;
  gap: 20px;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.aff-logo {
  height: 36px;
  object-fit: contain;
  filter: grayscale(100%);
  opacity: 0.7;
  transition: var(--transition-smooth);
}

.aff-logo:hover,
.affiliation-logos a:hover .aff-logo {
  filter: grayscale(0%);
  opacity: 1;
}

/* Buttons */
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: var(--accent-gradient);
  color: #ffffff;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  padding: 12px 28px;
  border-radius: var(--border-radius-md);
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
  transition: var(--transition-smooth);
  border: none;
  cursor: pointer;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.45);
}

.btn-primary svg {
  width: 18px;
  height: 18px;
}

/* --- News Timeline --- */
.news-timeline {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin-top: 10px;
}

.news-item {
  display: flex;
  gap: 16px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
  transition: var(--transition-smooth);
}

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

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

.news-tag {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: var(--border-radius-sm);
  align-self: flex-start;
  flex-shrink: 0;
  letter-spacing: 0.5px;
}

.news-tag.recruitment {
  background-color: rgba(239, 68, 68, 0.1);
  color: #ef4444;
}

.news-tag.project {
  background-color: rgba(16, 185, 129, 0.1);
  color: #10b981;
}

.news-tag.talk {
  background-color: rgba(245, 158, 11, 0.1);
  color: #f59e0b;
}

.news-tag.conference {
  background-color: rgba(98, 193, 229, 0.1);
  color: #1c96c5;
}

.news-info {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.news-desc {
  color: var(--text-primary);
  font-size: 0.95rem;
  font-weight: 500;
}

.news-desc a {
  color: var(--accent-color);
  text-decoration: none;
  transition: var(--transition-smooth);
}

.news-desc a:hover {
  text-decoration: underline;
}

.news-date {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* --- PAIR Lab Page Styling --- */
.lab-hero {
  padding-top: 130px;
  padding-bottom: 40px;
  text-align: center;
}

.lab-logo-container {
  display: flex;
  justify-content: center;
  margin-bottom: 20px;
}

.lab-title-desc {
  max-width: 700px;
  margin: 0 auto;
  font-size: 1.25rem;
  color: var(--text-secondary);
  font-style: italic;
  line-height: 1.7;
}

.lab-section {
  padding: 40px 0;
}

/* Grid System for Projects & Members */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.card-glass {
  background: var(--bg-glass);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: 24px;
  box-shadow: var(--card-shadow);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  transition: var(--transition-smooth);
}

.card-glass:hover {
  border-color: var(--border-hover);
  transform: translateY(-4px);
}

/* Members Card */
.member-card {
  text-align: center;
  padding: 30px 20px;
}

.member-avatar {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  background-color: var(--border-color);
  margin: 0 auto 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 2px solid var(--border-color);
}

.member-avatar svg {
  width: 40px;
  height: 40px;
  color: var(--text-secondary);
}

.member-name {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.member-role {
  font-size: 0.85rem;
  color: var(--accent-color);
  font-weight: 500;
}

/* Projects Card */
.project-card {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  padding: 0;
}

.project-img-wrapper {
  height: 160px;
  width: 100%;
  overflow: hidden;
  border-bottom: 1px solid var(--border-color);
  background-color: #1e293b;
  position: relative;
}

.project-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition-smooth);
}

.project-card:hover .project-img {
  transform: scale(1.05);
}

.project-card-body {
  padding: 24px;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.project-card-tag {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--accent-secondary);
  letter-spacing: 0.5px;
  margin-bottom: 8px;
}

.project-card-title {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 600;
  line-height: 1.4;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.project-card-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 16px;
  flex-grow: 1;
}

.project-card-meta {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
  display: flex;
  justify-content: space-between;
  border-top: 1px solid var(--border-color);
  padding-top: 12px;
}

/* Previous Projects List/Table */
.table-container {
  width: 100%;
  overflow-x: auto;
}

table.project-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.9rem;
}

table.project-table th {
  padding: 12px 16px;
  border-bottom: 2px solid var(--border-color);
  color: var(--text-primary);
  font-family: var(--font-heading);
  font-weight: 600;
}

table.project-table td {
  padding: 16px;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-secondary);
}

table.project-table tr:hover td {
  color: var(--text-primary);
  background-color: rgba(255, 255, 255, 0.02);
}

table.project-table .role-badge {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: var(--border-radius-sm);
  display: inline-block;
}

table.project-table .role-badge.pi {
  background-color: rgba(99, 102, 241, 0.1);
  color: var(--accent-color);
}

table.project-table .role-badge.co-i {
  background-color: rgba(20, 184, 166, 0.1);
  color: var(--accent-secondary);
}

/* Papers (Publications) styling */
.papers-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.paper-item {
  padding: 16px 20px;
  border-left: 3px solid var(--accent-color);
  transition: var(--transition-smooth);
}

.paper-item:hover {
  background-color: rgba(255, 255, 255, 0.015);
}

.paper-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 4px;
}

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

.paper-venue {
  font-size: 0.8rem;
  font-style: italic;
  color: var(--text-muted);
}

/* --- Footer --- */
footer.site-footer {
  border-top: 1px solid var(--border-color);
  padding: 40px 0;
  background-color: var(--bg-secondary);
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 80px;
}

footer.site-footer a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: var(--transition-smooth);
}

footer.site-footer a:hover {
  color: var(--text-primary);
}

/* --- Responsive Adjustments --- */
@media (max-width: 900px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .profile-card {
    position: relative;
    top: 0;
    width: 100%;
  }

  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .burger {
    display: block;
  }

  .nav-menu {
    position: fixed;
    top: 70px;
    right: -100%;
    width: 100%;
    height: calc(100vh - 70px);
    background-color: var(--bg-secondary);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 40px;
    transition: var(--transition-smooth);
    border-top: 1px solid var(--border-color);
  }

  .nav-menu.active {
    right: 0;
  }

  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
  }
}