/* ============================================
   Philip J. Freda, Jr., Ph.D., M.S. - Personal Website
   Premium Dark Mode Theme with Visual Flair
   ============================================ */

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

/* CSS Variables - Premium Dark Theme */
:root {
  --color-bg: #0a0e14;
  --color-bg-secondary: #111820;
  --color-bg-tertiary: #1a2130;
  --color-bg-hover: #242d3d;
  --color-bg-card: linear-gradient(145deg, #131a24 0%, #0f151d 100%);
  --color-border: #2d3848;
  --color-border-light: #1e2836;
  --color-border-glow: rgba(88, 166, 255, 0.3);
  --color-text: #e6edf3;
  --color-text-secondary: #9ba7b4;
  --color-text-muted: #6b7b8c;
  --color-primary: #58a6ff;
  --color-primary-hover: #79c0ff;
  --color-primary-glow: rgba(88, 166, 255, 0.15);
  --color-accent: #7ee787;
  --color-accent-secondary: #a78bfa;
  --color-accent-tertiary: #f472b6;
  --color-gold: #fbbf24;
  --gradient-primary: linear-gradient(135deg, #58a6ff 0%, #a78bfa 100%);
  --gradient-accent: linear-gradient(135deg, #7ee787 0%, #58a6ff 100%);
  --gradient-hero: linear-gradient(135deg, #131a24 0%, #1a2636 50%, #111820 100%);
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;
  --max-width: 1000px;
  --header-height: 64px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 40px rgba(88, 166, 255, 0.15);
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-image:
    radial-gradient(ellipse at 20% 0%, rgba(88, 166, 255, 0.08) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 100%, rgba(126, 231, 135, 0.05) 0%, transparent 50%);
  background-attachment: fixed;
}

/* Links */
a {
  color: var(--color-primary);
  text-decoration: none;
  transition: all var(--transition);
  position: relative;
}

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

/* Animated underline for text links */
.intro-text a, .cta-section a, .timeline-item a, .education-content a, p a {
  background: linear-gradient(to right, var(--color-primary), var(--color-accent-secondary));
  background-size: 0% 2px;
  background-repeat: no-repeat;
  background-position: left bottom;
  transition: background-size var(--transition), color var(--transition);
}

.intro-text a:hover, .cta-section a:hover, .timeline-item a:hover, .education-content a:hover, p a:hover {
  background-size: 100% 2px;
}

/* Container */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ============================================
   Header & Navigation
   ============================================ */
.site-header {
  position: sticky;
  top: 0;
  background: rgba(10, 14, 20, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-border-light);
  z-index: 100;
  height: var(--header-height);
}

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

.site-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
  transition: all var(--transition);
  white-space: nowrap;
  letter-spacing: -0.02em;
}

.site-title:hover {
  color: var(--color-primary);
  text-shadow: 0 0 20px var(--color-primary-glow);
}

.site-nav {
  display: flex;
  gap: 0.25rem;
}

.site-nav a {
  color: var(--color-text-secondary);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  padding: 0.5rem 0.875rem;
  border-radius: var(--radius-md);
  transition: all var(--transition);
  position: relative;
}

.site-nav a::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-md);
  background: var(--gradient-primary);
  opacity: 0;
  transition: opacity var(--transition);
  z-index: -1;
}

.site-nav a:hover {
  color: var(--color-text);
  background: none;
}

.site-nav a:hover::before {
  opacity: 0.15;
}

.site-nav a.active {
  color: var(--color-text);
  background: var(--color-bg-tertiary);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  border-radius: var(--radius-sm);
}

.nav-toggle:hover {
  background: var(--color-bg-tertiary);
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  transition: all 0.3s;
  border-radius: 2px;
}

/* ============================================
   Main Content
   ============================================ */
.site-main {
  flex: 1;
  padding: 3rem 0;
}

.page-title {
  font-size: 2.25rem;
  font-weight: 800;
  margin-bottom: 2rem;
  color: var(--color-text);
  letter-spacing: -0.03em;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  color: var(--color-text);
  font-weight: 700;
  line-height: 1.3;
  margin-top: 2rem;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}

h1 { font-size: 2rem; }
h2 {
  font-size: 1.5rem;
  color: var(--color-primary);
}
h3 {
  font-size: 1.2rem;
  color: var(--color-text);
}
h4 { font-size: 1.1rem; }

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

strong {
  color: var(--color-text);
  font-weight: 600;
}

em {
  color: var(--color-text-secondary);
  font-style: italic;
}

ul, ol {
  margin-bottom: 1.25rem;
  padding-left: 1.5rem;
  color: var(--color-text-secondary);
}

li {
  margin-bottom: 0.5rem;
}

li strong {
  color: var(--color-text);
}

img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
}

hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 2.5rem 0;
}

blockquote {
  border-left: 3px solid var(--color-primary);
  padding-left: 1.5rem;
  margin: 1.5rem 0;
  color: var(--color-text-secondary);
  font-style: italic;
}

/* Hero Quote - Stunning centered quote */
.hero-quote {
  text-align: center;
  font-size: 1.25rem;
  font-style: italic;
  color: var(--color-text-secondary);
  margin: 0 0 3rem 0;
  padding: 2rem 2.5rem;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-left: 4px solid;
  border-image: var(--gradient-accent) 1;
  border-radius: var(--radius-lg);
  position: relative;
  box-shadow: var(--shadow-md);
}

.hero-quote::before {
  content: '"';
  position: absolute;
  top: 10px;
  left: 20px;
  font-size: 4rem;
  font-family: Georgia, serif;
  color: var(--color-primary);
  opacity: 0.2;
  line-height: 1;
}

/* ============================================
   Hero Section - Landing Page
   ============================================ */
.hero-section {
  display: flex;
  align-items: center;
  gap: 2.5rem;
  margin-bottom: 2rem;
  padding: 3rem;
  background: var(--gradient-hero);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.hero-section::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 60%;
  height: 200%;
  background: radial-gradient(ellipse, rgba(88, 166, 255, 0.1) 0%, transparent 70%);
  pointer-events: none;
}

.hero-section::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -10%;
  width: 50%;
  height: 150%;
  background: radial-gradient(ellipse, rgba(126, 231, 135, 0.05) 0%, transparent 70%);
  pointer-events: none;
}

.hero-photo {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid transparent;
  background: linear-gradient(var(--color-bg-secondary), var(--color-bg-secondary)) padding-box,
              var(--gradient-primary) border-box;
  box-shadow: var(--shadow-lg), 0 0 40px rgba(88, 166, 255, 0.2);
  flex-shrink: 0;
  position: relative;
  z-index: 1;
  transition: transform var(--transition-slow);
}

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

/* Hero Logo - rectangular display */
.hero-logo {
  width: 380px;
  height: auto;
  border-radius: var(--radius-lg);
  object-fit: contain;
  flex-shrink: 0;
  position: relative;
  z-index: 1;
  transition: all var(--transition-slow);
  filter: drop-shadow(0 0 30px rgba(88, 166, 255, 0.3));
}

.hero-logo:hover {
  transform: scale(1.02);
  filter: drop-shadow(0 0 40px rgba(88, 166, 255, 0.45));
}

.hero-content {
  position: relative;
  z-index: 1;
  flex: 1;
}

.hero-content h1 {
  font-size: 2rem;
  margin: 0 0 0.5rem 0;
  letter-spacing: -0.03em;
  color: var(--color-text);
  font-weight: 800;
}

.hero-subtitle {
  font-size: 1.15rem;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  font-weight: 600;
  margin: 0;
}

/* Intro Text */
.intro-text {
  margin-bottom: 2.5rem;
}

.intro-text p {
  font-size: 1.05rem;
  line-height: 1.85;
  color: var(--color-text);
}

/* Intro Card Layout */
.intro-card {
  margin-bottom: 2.5rem;
  padding: 2rem;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
}

.intro-card-content {
  display: flex;
  gap: 2rem;
  align-items: stretch;
}

.intro-card-image {
  width: 280px;
  flex-shrink: 0;
  object-fit: cover;
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition);
}

.intro-card-image:hover {
  transform: scale(1.02);
  box-shadow: var(--shadow-md), 0 0 25px rgba(88, 166, 255, 0.12);
  border-color: var(--color-primary);
}

.intro-card-text {
  flex: 1;
  min-width: 0;
}

.intro-card-text p {
  font-size: 1.05rem;
  line-height: 1.85;
  color: var(--color-text);
  text-align: justify;
}

.intro-card-text p:last-child {
  margin-bottom: 0;
}

@media (max-width: 768px) {
  .intro-card {
    padding: 1.5rem;
  }

  .intro-card-content {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .intro-card-image {
    width: 100%;
    max-width: 280px;
    height: auto;
    aspect-ratio: 2 / 3;
  }
}

/* Research Highlights - Premium Cards */
.research-highlights {
  margin-bottom: 2.5rem;
  padding: 2.5rem;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
}

.research-highlights h2 {
  margin-top: 0;
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--color-border);
  font-size: 1.35rem;
}

.research-focus-item {
  margin-bottom: 1.5rem;
  padding: 1.25rem 1.5rem;
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  transition: all var(--transition);
}

.research-focus-item:hover {
  border-color: var(--color-primary);
  background: rgba(88, 166, 255, 0.03);
  transform: translateX(4px);
}

.research-focus-item:last-child {
  margin-bottom: 0;
}

.research-focus-item h3 {
  margin: 0 0 0.75rem 0;
  font-size: 1.05rem;
  color: var(--color-primary);
  font-weight: 600;
}

.research-focus-item ul {
  margin: 0;
  padding-left: 1.25rem;
}

.research-focus-item li {
  margin-bottom: 0.4rem;
  font-size: 0.95rem;
}

.research-focus-item li:last-child {
  margin-bottom: 0;
}

/* CTA Section - Gradient Border */
.cta-section {
  background: var(--color-bg-secondary);
  padding: 1.75rem 2rem;
  border-radius: var(--radius-lg);
  margin-bottom: 3rem;
  position: relative;
  border: 1px solid var(--color-border);
}

.cta-section::before {
  content: '';
  position: absolute;
  inset: -1px;
  border-radius: var(--radius-lg);
  padding: 1px;
  background: var(--gradient-primary);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  opacity: 0.5;
  pointer-events: none;
}

.cta-section p {
  margin: 0;
  font-size: 1.05rem;
  color: var(--color-text-secondary);
  text-align: center;
}

/* Visit Section */
.visit-section {
  margin-top: 1rem;
}

.visit-section h2 {
  text-align: center;
  margin-bottom: 1.5rem;
  font-size: 1.35rem;
}

/* Location Cards - Stunning Hover Effects */
.location-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}

.location-card {
  display: block;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  transition: all var(--transition);
  text-decoration: none;
  position: relative;
}

.location-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--gradient-primary);
  opacity: 0;
  transition: opacity var(--transition);
  z-index: 0;
}

.location-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg), 0 0 30px rgba(88, 166, 255, 0.15);
}

.location-card:hover::before {
  opacity: 0.05;
}

.location-card img {
  width: 100%;
  height: 150px;
  object-fit: cover;
  border-radius: 0;
  transition: transform var(--transition-slow);
  position: relative;
  z-index: 1;
}

.location-card:hover img {
  transform: scale(1.08);
}

.location-card span {
  display: block;
  padding: 1rem;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-text);
  text-align: center;
  position: relative;
  z-index: 1;
  background: var(--color-bg-secondary);
}

/* ============================================
   Research Section
   ============================================ */
.research-section {
  margin-bottom: 2.5rem;
  padding: 2.5rem;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  transition: all var(--transition);
  box-shadow: var(--shadow-sm);
}

.research-section:hover {
  border-color: var(--color-border-glow);
  box-shadow: var(--shadow-md);
}

.research-section h2 {
  margin-top: 0;
  margin-bottom: 1.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--color-border);
}

.research-flex {
  display: flex;
  gap: 2rem;
  align-items: flex-start;
}

.research-flex img {
  width: 280px;
  flex-shrink: 0;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  transition: all var(--transition);
}

.research-flex img:hover {
  transform: scale(1.03);
  box-shadow: var(--shadow-md);
}

.research-flex p {
  margin: 0;
  text-align: justify;
}

.research-flex-reverse {
  flex-direction: row-reverse;
}

/* ============================================
   Timeline - Stunning Visual Design
   ============================================ */
.timeline {
  position: relative;
  padding-left: 2.5rem;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 6px;
  top: 0;
  bottom: 0;
  width: 3px;
  background: linear-gradient(to bottom,
    var(--color-primary) 0%,
    var(--color-accent-secondary) 50%,
    var(--color-accent) 100%);
  border-radius: 2px;
}

.timeline-item {
  position: relative;
  margin-bottom: 1.5rem;
  padding: 1.5rem 2rem;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: all var(--transition);
  box-shadow: var(--shadow-sm);
}

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

.timeline-item::before {
  content: '';
  position: absolute;
  left: -2.5rem;
  top: 1.75rem;
  width: 14px;
  height: 14px;
  background: var(--color-bg);
  border: 3px solid var(--color-primary);
  border-radius: 50%;
  transform: translateX(-6px);
  transition: all var(--transition);
  box-shadow: 0 0 0 4px var(--color-bg);
}

.timeline-item:hover::before {
  background: var(--color-primary);
  box-shadow: 0 0 0 4px var(--color-bg), 0 0 20px var(--color-primary);
}

.timeline-date {
  display: inline-block;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 0.75rem;
  font-size: 0.9rem;
  padding: 0.25rem 0.75rem;
  background: rgba(88, 166, 255, 0.1);
  border-radius: var(--radius-sm);
}

.timeline-item p {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.7;
}

.timeline-item p + p {
  margin-top: 0.75rem;
}

/* Timeline with images */
.timeline-content-wrapper {
  display: flex;
  gap: 1.5rem;
  align-items: flex-start;
}

.timeline-content-wrapper > div {
  flex: 1;
}

.timeline-image {
  width: 180px;
  height: 120px;
  object-fit: cover;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  flex-shrink: 0;
  transition: all var(--transition);
}

.timeline-image:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-md);
}

/* ============================================
   Education - Premium Cards
   ============================================ */
.education-card {
  display: flex;
  gap: 2rem;
  padding: 2rem;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  margin-bottom: 1.5rem;
  transition: all var(--transition);
  box-shadow: var(--shadow-sm);
}

.education-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.education-image {
  flex-shrink: 0;
  width: 300px;
}

.education-image img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  transition: all var(--transition);
}

.education-card:hover .education-image img {
  transform: scale(1.03);
}

.education-content {
  flex: 1;
}

.education-card h3 {
  margin: 0 0 0.5rem 0;
  color: var(--color-text);
  font-size: 1.15rem;
  font-weight: 700;
}

.education-institution {
  color: var(--color-primary);
  font-weight: 600;
  margin-bottom: 0.25rem;
  font-size: 1rem;
}

.education-dates {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-bottom: 1rem;
  padding: 0.2rem 0.6rem;
  background: rgba(88, 166, 255, 0.1);
  border-radius: var(--radius-sm);
  display: inline-block;
}

.education-content p {
  text-align: justify;
}

.education-content p:last-child {
  margin-bottom: 0;
}

/* ============================================
   Publications
   ============================================ */
.publications-section {
  margin-bottom: 2.5rem;
}

.publications-section h2 {
  margin-bottom: 1.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--color-border);
}

.publication-item {
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--color-border-light);
  transition: all var(--transition);
}

.publication-item:hover {
  padding-left: 0.75rem;
  border-left: 3px solid var(--color-primary);
}

.publication-item:last-child {
  border-bottom: none;
}

.publication-item p {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.75;
}

.publication-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  background: var(--gradient-primary);
  color: var(--color-bg);
  font-weight: 700;
  font-size: 0.8rem;
  border-radius: 50%;
  margin-right: 0.75rem;
}

/* ============================================
   Photo Gallery
   ============================================ */
.photo-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.photo-item {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-lg);
  aspect-ratio: 16/10;
  border: 1px solid var(--color-border);
  transition: all var(--transition);
  cursor: pointer;
}

.photo-item:hover {
  border-color: var(--color-primary);
  transform: scale(1.02);
  box-shadow: var(--shadow-lg);
}

.photo-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 0;
  transition: transform var(--transition-slow);
}

.photo-item:hover img {
  transform: scale(1.1);
}

.photo-caption {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 1.25rem;
  background: linear-gradient(transparent, rgba(0, 0, 0, 0.9));
  color: white;
  font-size: 0.9rem;
  font-weight: 500;
  transform: translateY(100%);
  transition: transform var(--transition);
}

.photo-item:hover .photo-caption {
  transform: translateY(0);
}

/* ============================================
   Buttons
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  background: var(--gradient-primary);
  color: var(--color-bg);
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.9rem;
  text-decoration: none;
  transition: all var(--transition);
  margin-right: 0.75rem;
  margin-bottom: 0.75rem;
  border: none;
  cursor: pointer;
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(88, 166, 255, 0.3);
  color: var(--color-bg);
}

.btn-outline {
  background: var(--gradient-primary);
  border: none;
  color: var(--color-bg);
}

.btn-outline:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(88, 166, 255, 0.3);
  color: var(--color-bg);
}

/* ============================================
   PDF Embed
   ============================================ */
.pdf-embed {
  width: 100%;
  height: 800px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-bg-secondary);
}

/* ============================================
   Teaching Page Styles
   ============================================ */
.hero-image-container {
  margin: 2rem 0;
  text-align: center;
}

.hero-banner {
  max-width: 500px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-md);
}

/* Articles Grid */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
  margin: 1.5rem 0 2rem 0;
  padding: 2rem;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
}

.article-column {
  padding: 0;
}

.article-list {
  margin: 0;
  padding-left: 2rem;
  list-style-position: outside;
}

.article-list li {
  margin-bottom: 0.75rem;
  padding-left: 0.5rem;
  font-size: 0.9rem;
  line-height: 1.5;
}

.article-list li::marker {
  color: var(--color-primary);
  font-weight: 600;
}

.article-list a {
  color: var(--color-text-secondary);
  transition: color var(--transition);
}

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

/* Video Grid */
.video-grid {
  display: grid;
  gap: 2rem;
}

.video-item {
  padding: 1.5rem;
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
}

.video-item h3 {
  margin: 0 0 1rem 0;
  font-size: 1rem;
  color: var(--color-primary);
}

.video-wrapper {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
  border-radius: var(--radius-md);
}

.video-wrapper iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: none;
  border-radius: var(--radius-md);
}

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

.footer-content {
  text-align: center;
}

.contact-links {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.contact-links a {
  color: var(--color-text-secondary);
  padding: 0.75rem;
  border-radius: var(--radius-md);
  transition: all var(--transition);
  background: var(--color-bg-tertiary);
  border: 1px solid var(--color-border);
}

.contact-links a:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  transform: translateY(-3px);
  box-shadow: 0 8px 20px rgba(88, 166, 255, 0.2);
}

.contact-links svg {
  width: 22px;
  height: 22px;
  display: block;
}

.copyright {
  color: var(--color-text-muted);
  font-size: 0.85rem;
  margin: 0;
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-bg-secondary);
    flex-direction: column;
    padding: 1rem;
    gap: 0.25rem;
    border-bottom: 1px solid var(--color-border);
    display: none;
  }

  .site-nav.active {
    display: flex;
  }

  .site-nav a {
    padding: 0.875rem 1rem;
  }

  .hero-section {
    flex-direction: column;
    text-align: center;
    padding: 2rem 1.5rem;
  }

  .hero-photo {
    width: 150px;
    height: 150px;
  }

  .hero-logo {
    width: 220px;
    height: auto;
  }

  .hero-content h1 {
    font-size: 1.5rem;
  }

  .location-cards {
    grid-template-columns: 1fr;
  }

  .education-card {
    flex-direction: column;
  }

  .education-image {
    width: 100%;
  }

  .education-image img {
    height: 200px;
  }

  .research-flex,
  .research-flex-reverse {
    flex-direction: column;
  }

  .research-flex img {
    width: 100%;
    max-width: 250px;
    margin: 0 auto;
  }

  .page-title {
    font-size: 1.75rem;
  }

  .photo-gallery {
    grid-template-columns: 1fr;
  }

  .timeline {
    padding-left: 2rem;
  }

  .timeline-item::before {
    left: -2rem;
  }

  .timeline-content-wrapper {
    flex-direction: column;
  }

  .timeline-image {
    width: 100%;
    height: 180px;
  }

  .research-highlights {
    padding: 1.5rem;
  }

  .research-focus-item {
    padding: 1rem;
  }

  .articles-grid {
    grid-template-columns: 1fr;
    padding: 1.5rem;
  }

  .research-flex img {
    width: 100%;
    max-width: 280px;
  }
}

/* ============================================
   Scrollbar
   ============================================ */
::-webkit-scrollbar {
  width: 10px;
}

::-webkit-scrollbar-track {
  background: var(--color-bg);
}

::-webkit-scrollbar-thumb {
  background: var(--color-bg-tertiary);
  border-radius: 5px;
  border: 2px solid var(--color-bg);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-bg-hover);
}

/* ============================================
   Selection
   ============================================ */
::selection {
  background: var(--color-primary);
  color: var(--color-bg);
}

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

.hero-section,
.hero-quote,
.intro-text,
.research-highlights,
.cta-section,
.visit-section {
  animation: fadeInUp 0.6s ease-out;
}

.research-highlights {
  animation-delay: 0.1s;
}

.cta-section {
  animation-delay: 0.2s;
}

.visit-section {
  animation-delay: 0.3s;
}

/* ============================================
   People Page
   ============================================ */
.people-section {
  margin-bottom: 3rem;
}

.person-card {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 2.5rem;
  background: var(--color-surface);
  border-radius: 16px;
  padding: 2.5rem;
  margin-bottom: 2rem;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.person-card.principal-investigator {
  background: linear-gradient(135deg, var(--color-surface) 0%, rgba(99, 102, 241, 0.1) 100%);
  border: 1px solid rgba(99, 102, 241, 0.2);
}

.person-image img {
  width: 280px;
  height: 280px;
  object-fit: cover;
  border-radius: 12px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.person-info h2 {
  font-size: 1.8rem;
  margin-bottom: 0.5rem;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.person-title {
  font-size: 1.2rem;
  color: var(--color-primary);
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.person-affiliation {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
  margin-bottom: 1.5rem;
}

.person-bio {
  margin-bottom: 1.5rem;
}

.person-bio p {
  color: var(--color-text);
  line-height: 1.8;
  margin-bottom: 1rem;
  text-align: justify;
}

.person-interests {
  margin-bottom: 1.5rem;
}

.person-interests h3 {
  font-size: 1.1rem;
  color: var(--color-text);
  margin-bottom: 0.75rem;
}

.person-interests ul {
  list-style: none;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.person-interests li {
  background: rgba(99, 102, 241, 0.15);
  color: var(--color-primary-light);
  padding: 0.4rem 0.8rem;
  border-radius: 20px;
  font-size: 0.85rem;
}

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

.person-links .btn {
  padding: 0.6rem 1.2rem;
  font-size: 0.9rem;
}

/* Join Section */
.join-section {
  background: var(--color-surface);
  border-radius: 16px;
  padding: 2.5rem;
  text-align: center;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.join-section h2 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.join-section p {
  color: var(--color-text);
  max-width: 700px;
  margin: 0 auto;
  line-height: 1.8;
}

.join-section a {
  color: var(--color-primary);
  text-decoration: none;
  font-weight: 500;
}

.join-section a:hover {
  text-decoration: underline;
}

/* Responsive for People Page */
@media (max-width: 768px) {
  .person-card {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .person-image {
    display: flex;
    justify-content: center;
  }

  .person-image img {
    width: 200px;
    height: 200px;
  }

  .person-interests ul {
    justify-content: center;
  }

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

/* ============================================
   Person Page Links (nested pages)
   ============================================ */
.person-pages {
  margin-top: 2.5rem;
  padding-top: 2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.person-pages h3 {
  font-size: 1.3rem;
  color: var(--color-text);
  margin-bottom: 1.5rem;
  text-align: center;
}

.person-page-links {
  display: grid !important;
  grid-template-columns: repeat(3, 1fr) !important;
  gap: 1.25rem !important;
}

.page-link-card {
  display: flex !important;
  flex-direction: column !important;
  align-items: center !important;
  text-align: center !important;
  padding: 1.75rem 1.5rem !important;
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.08) 0%, rgba(139, 92, 246, 0.05) 100%) !important;
  border: 1px solid rgba(99, 102, 241, 0.2) !important;
  border-radius: 16px !important;
  text-decoration: none !important;
  transition: all 0.3s ease !important;
  min-height: 140px !important;
  justify-content: center !important;
}

.page-link-card:hover {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.2) 0%, rgba(139, 92, 246, 0.15) 100%) !important;
  border-color: rgba(99, 102, 241, 0.5) !important;
  transform: translateY(-4px) !important;
  box-shadow: 0 8px 25px rgba(99, 102, 241, 0.2) !important;
}

.page-link-icon {
  font-size: 2.5rem !important;
  margin-bottom: 0.75rem !important;
  display: block !important;
}

.page-link-title {
  font-size: 1.1rem !important;
  font-weight: 600 !important;
  color: var(--color-text) !important;
  margin-bottom: 0.4rem !important;
  display: block !important;
}

.page-link-desc {
  font-size: 0.85rem !important;
  color: var(--color-text-secondary) !important;
  line-height: 1.4 !important;
  display: block !important;
}

@media (max-width: 900px) {
  .person-page-links {
    grid-template-columns: repeat(2, 1fr) !important;
  }
}

@media (max-width: 600px) {
  .person-page-links {
    grid-template-columns: 1fr !important;
  }

  .page-link-card {
    min-height: auto !important;
    padding: 1.25rem !important;
  }
}

/* ===================================
   Subpage Navigation
   =================================== */

.subpage-nav {
  margin-bottom: 2.5rem;
}

.subpage-nav-container {
  display: inline-flex;
  align-items: center;
  gap: 0;
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 0.35rem;
  box-shadow: var(--shadow-sm), inset 0 1px 0 rgba(255, 255, 255, 0.03);
}

.subpage-nav-back {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.6rem 1rem;
  color: var(--color-text-secondary);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  transition: all var(--transition);
  border-radius: var(--radius-md);
  background: transparent;
}

.subpage-nav-back:hover {
  color: var(--color-text);
  background: var(--color-bg-hover);
}

.subpage-nav-back svg {
  transition: transform var(--transition);
  opacity: 0.7;
}

.subpage-nav-back:hover svg {
  transform: translateX(-2px);
  opacity: 1;
}

.subpage-nav-divider {
  width: 1px;
  height: 1.5rem;
  background: var(--color-border);
  margin: 0 0.25rem;
}

.subpage-nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.subpage-nav-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.6rem 1rem;
  background: transparent;
  border: none;
  border-radius: var(--radius-md);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: all var(--transition);
  position: relative;
}

.subpage-nav-link:hover {
  color: var(--color-text);
  background: var(--color-bg-hover);
}

.subpage-nav-link.active {
  color: var(--color-text);
  background: var(--color-bg-tertiary);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2), inset 0 1px 0 rgba(255, 255, 255, 0.05);
}

.subpage-nav-link.active::before {
  content: '';
  position: absolute;
  bottom: 0.35rem;
  left: 50%;
  transform: translateX(-50%);
  width: 1rem;
  height: 2px;
  background: var(--gradient-primary);
  border-radius: 1px;
}

@media (max-width: 768px) {
  .subpage-nav-container {
    flex-wrap: wrap;
    width: 100%;
  }

  .subpage-nav-back {
    padding: 0.5rem 0.875rem;
    font-size: 0.8125rem;
  }

  .subpage-nav-links {
    flex-wrap: wrap;
  }

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

@media (max-width: 480px) {
  .subpage-nav-container {
    padding: 0.25rem;
  }

  .subpage-nav-back {
    width: 100%;
    justify-content: center;
  }

  .subpage-nav-divider {
    display: none;
  }

  .subpage-nav-links {
    width: 100%;
    justify-content: center;
    border-top: 1px solid var(--color-border);
    padding-top: 0.25rem;
    margin-top: 0.25rem;
  }

  .subpage-nav-link {
    flex: 1;
    min-width: fit-content;
  }
}