:root {
  /* Deep Navy Color Palette */
  --primary-dark: #1a1a2e;
  --primary-medium: #16213e;
  --primary-light: #0f3460;
  --accent-gold: #e94560;
  --accent-warm: #f39c12;
  --text-light: #f8f9fa;
  --text-muted: #a8b2d1;
  --text-dark: #1a1a2e;
  --bg-light: #ffffff;
  --bg-off-white: #f8f9fa;
  --berkeley-blue: #003262;
  --berkeley-gold: #fdb515;

  /* Typography */
  --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  /* Spacing */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 2rem;
  --space-lg: 4rem;
  --space-xl: 8rem;

  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-medium: 0.3s ease;
  --transition-slow: 0.5s ease;

  /* Shadows */
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.2);
}

/* 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);
  line-height: 1.7;
  color: var(--text-dark);
  background-color: var(--bg-light);
  overflow-x: hidden;
}

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

h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
}

h2 {
  font-size: clamp(1.8rem, 3vw, 2.5rem);
}

h3 {
  font-size: clamp(1.3rem, 2vw, 1.75rem);
}

h4 {
  font-size: 1.25rem;
}

p {
  margin-bottom: var(--space-sm);
  color: var(--text-muted);
}

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

a:hover {
  color: var(--accent-gold);
}

/* Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

section {
  padding: var(--space-lg) 0;
}

/* Navigation */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(26, 26, 46, 0.95);
  backdrop-filter: blur(10px);
  padding: var(--space-sm) 0;
  transition: all var(--transition-medium);
}

.navbar.scrolled {
  padding: var(--space-xs) 0;
  box-shadow: var(--shadow-md);
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

.nav-logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-light);
  letter-spacing: -0.5px;
}

.nav-logo:hover {
  color: var(--berkeley-gold);
}

.nav-links {
  display: flex;
  gap: var(--space-md);
  list-style: none;
}

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

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

.nav-links a:hover {
  color: var(--text-light);
}

.nav-links a:hover::after {
  width: 100%;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 10px;
}

.nav-toggle span {
  width: 25px;
  height: 2px;
  background: var(--text-light);
  transition: all var(--transition-fast);
}

/* Hero Section */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary-medium) 50%, var(--primary-light) 100%);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="50" cy="50" r="1" fill="rgba(255,255,255,0.03)"/></svg>');
  background-size: 50px 50px;
}

.hero-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-lg);
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-text h1 {
  color: var(--text-light);
  margin-bottom: var(--space-xs);
}

.hero-text .title {
  color: var(--berkeley-gold);
  font-size: 1.25rem;
  font-weight: 500;
  margin-bottom: var(--space-sm);
  display: block;
}

.hero-text .tagline {
  color: var(--text-muted);
  font-size: 1.15rem;
  line-height: 1.8;
  margin-bottom: var(--space-md);
}

.hero-cta {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 0.875rem 1.75rem;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: all var(--transition-medium);
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: var(--berkeley-gold);
  color: var(--primary-dark);
}

.btn-primary:hover {
  background: #ffc233;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  color: var(--primary-dark);
}

.btn-secondary {
  background: transparent;
  color: var(--text-light);
  border: 2px solid var(--text-muted);
}

.btn-secondary:hover {
  border-color: var(--text-light);
  background: rgba(255, 255, 255, 0.1);
  color: var(--text-light);
}

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

.hero-image img {
  width: 350px;
  height: 350px;
  border-radius: 50%;
  object-fit: cover;
  object-position: center 20%;
  border: 4px solid rgba(255, 255, 255, 0.1);
  box-shadow: var(--shadow-lg);
  transition: transform var(--transition-medium);
}

.hero-image img:hover {
  transform: scale(1.02);
}

/* Section Headers */
.section-header {
  text-align: center;
  margin-bottom: var(--space-lg);
}

.section-header h2 {
  color: var(--primary-dark);
  position: relative;
  display: inline-block;
}

.section-header h2::after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 3px;
  background: var(--berkeley-gold);
  border-radius: 2px;
}

.section-header p {
  max-width: 600px;
  margin: var(--space-md) auto 0;
}

/* About Section */
.about {
  background: var(--bg-off-white);
}

.about-content {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: var(--space-lg);
  align-items: start;
}

.about-text p {
  color: var(--text-dark);
  font-size: 1.1rem;
}

.about-highlights {
  background: var(--bg-light);
  padding: var(--space-md);
  border-radius: 12px;
  box-shadow: var(--shadow-sm);
}

.about-highlights h3 {
  color: var(--primary-dark);
  margin-bottom: var(--space-sm);
  font-size: 1.1rem;
}

.highlight-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-sm);
  padding: var(--space-sm) 0;
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

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

.highlight-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
}

.highlight-text {
  font-size: 0.95rem;
  color: var(--text-dark);
}

.highlight-text strong {
  display: block;
  margin-bottom: 2px;
}

/* Skills Grid */
.skills-section {
  padding: var(--space-lg) 0;
}

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

.skill-card {
  background: var(--bg-light);
  padding: var(--space-md);
  border-radius: 12px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-medium);
  border: 1px solid rgba(0, 0, 0, 0.05);
}

.skill-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.skill-card h4 {
  color: var(--primary-dark);
  margin-bottom: var(--space-xs);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.skill-card .icon {
  font-size: 1.25rem;
}

.skill-card p {
  font-size: 0.95rem;
  margin-bottom: 0;
}

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

.skill-tag {
  background: rgba(0, 50, 98, 0.1);
  color: var(--berkeley-blue);
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 500;
}

/* Publications Section */
.publications {
  background: var(--bg-off-white);
}

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

.publication-card {
  background: var(--bg-light);
  padding: var(--space-md);
  border-radius: 12px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-medium);
  border-left: 4px solid var(--berkeley-blue);
}

.publication-card:hover {
  transform: translateX(4px);
  box-shadow: var(--shadow-md);
}

.publication-card .venue {
  color: var(--berkeley-blue);
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: var(--space-xs);
}

.publication-card h4 {
  color: var(--primary-dark);
  margin-bottom: var(--space-xs);
  font-size: 1.15rem;
}

.publication-card .authors {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: var(--space-sm);
}

.publication-card .abstract {
  font-size: 0.95rem;
  color: var(--text-dark);
  line-height: 1.7;
}

.publication-card .links {
  margin-top: var(--space-sm);
  display: flex;
  gap: var(--space-sm);
}

.publication-card .links a {
  font-size: 0.9rem;
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

/* Contact Section */
.contact {
  background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary-medium) 100%);
  color: var(--text-light);
}

.contact .section-header h2 {
  color: var(--text-light);
}

.contact .section-header p {
  color: var(--text-muted);
}

.contact-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-md);
  max-width: 800px;
  margin: 0 auto;
}

.contact-item {
  text-align: center;
  padding: var(--space-md);
}

.contact-item .icon {
  font-size: 2.5rem;
  margin-bottom: var(--space-sm);
  display: block;
}

.contact-item h4 {
  color: var(--text-light);
  margin-bottom: var(--space-xs);
}

.contact-item a {
  color: var(--text-muted);
  transition: color var(--transition-fast);
}

.contact-item a:hover {
  color: var(--berkeley-gold);
}

/* Footer */
.footer {
  background: var(--primary-dark);
  color: var(--text-muted);
  text-align: center;
  padding: var(--space-md) 0;
  font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 968px) {
  .hero-content {
    grid-template-columns: 1fr;
    text-align: center;
    padding-top: 100px;
  }

  .hero-image {
    order: -1;
  }

  .hero-image img {
    width: 280px;
    height: 280px;
  }

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

  .about-content {
    grid-template-columns: 1fr;
  }

  .about-highlights {
    order: -1;
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--primary-dark);
    flex-direction: column;
    padding: var(--space-md);
    gap: var(--space-sm);
    text-align: center;
  }

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

  .nav-toggle {
    display: flex;
  }

  section {
    padding: var(--space-md) 0;
  }

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

/* Animations */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-in {
  animation: fadeInUp 0.6s ease forwards;
  opacity: 0;
}

.animate-delay-1 {
  animation-delay: 0.1s;
}

.animate-delay-2 {
  animation-delay: 0.2s;
}

.animate-delay-3 {
  animation-delay: 0.3s;
}

.animate-delay-4 {
  animation-delay: 0.4s;
}

/* Utility Classes */
.text-center {
  text-align: center;
}

.text-light {
  color: var(--text-light);
}

.mb-0 {
  margin-bottom: 0;
}

.mt-md {
  margin-top: var(--space-md);
}