/* CSS Custom Properties */
:root {
  /* Colors */
  --color-primary: #1a365d;
  --color-secondary: #4a5568;
  --color-accent: #d69e2e;
  --color-bg: #ffffff;
  --color-bg-alt: #f7fafc;
  --color-text: #2d3748;
  --color-text-light: #718096;
  --color-border: #e2e8f0;
  
  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, "Courier New", monospace;
  
  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  
  /* Layout */
  --max-width: 900px;
  --border-radius: 8px;
}

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

/* Base */
html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-primary);
}

h1 { font-size: 2rem; }
h2 { font-size: 1.5rem; margin-top: var(--space-2xl); margin-bottom: var(--space-lg); }
h3 { font-size: 1.25rem; }

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

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--color-accent);
  text-decoration: underline;
}

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

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

/* Utilities */
.text-muted { color: var(--color-text-light); }
.font-mono { font-family: var(--font-mono); }

/* Header / Hero Section */
.hero {
  padding: var(--space-2xl) 0;
  border-bottom: 1px solid var(--color-border);
  background-color: var(--color-bg);
}

.hero-content {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--space-xl);
  align-items: center;
}

.hero-photo {
  width: 150px;
  height: 150px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--color-border);
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.hero-info h1 {
  font-size: 2.5rem;
  margin-bottom: var(--space-sm);
  color: var(--color-primary);
}

.hero-title {
  font-size: 1.125rem;
  color: var(--color-secondary);
  margin-bottom: var(--space-md);
  font-weight: 500;
}

.hero-affiliation {
  font-size: 1rem;
  color: var(--color-text-light);
  margin-bottom: var(--space-md);
}

.hero-contact {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  font-size: 0.95rem;
}

.hero-contact span {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

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

.hero-links a {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-md);
  background-color: var(--color-bg-alt);
  border-radius: var(--border-radius);
  font-size: 0.9rem;
  font-weight: 500;
  transition: all 0.2s ease;
}

.hero-links a:hover {
  background-color: var(--color-primary);
  color: white;
  text-decoration: none;
}

/* Mobile responsive */
@media (max-width: 640px) {
  .hero-content {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .hero-photo {
    width: 120px;
    height: 120px;
    margin: 0 auto;
  }
  
  .hero-info h1 {
    font-size: 2rem;
  }
  
  .hero-contact {
    justify-content: center;
  }
  
  .hero-links {
    justify-content: center;
  }
}

/* About / Research Section */
.about {
  background-color: var(--color-bg-alt);
}

.about-content {
  max-width: 800px;
}

.about-text {
  font-size: 1.05rem;
  line-height: 1.7;
  margin-bottom: var(--space-lg);
}

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

.research-tag {
  display: inline-block;
  padding: var(--space-xs) var(--space-md);
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 20px;
  font-size: 0.9rem;
  color: var(--color-secondary);
  font-weight: 500;
}

.research-tag:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

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

.pub-year {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-primary);
  margin: var(--space-xl) 0 var(--space-md) 0;
  padding-bottom: var(--space-sm);
  border-bottom: 2px solid var(--color-border);
}

.pub-year:first-child {
  margin-top: 0;
}

.pub-list {
  list-style: none;
  padding: 0;
}

.pub-item {
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border);
}

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

.pub-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-xs);
  line-height: 1.4;
}

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

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

.pub-authors {
  font-size: 0.95rem;
  color: var(--color-text-light);
  margin-bottom: var(--space-xs);
}

.pub-venue {
  font-size: 0.9rem;
  color: var(--color-secondary);
  font-style: italic;
}

.pub-venue strong {
  font-style: normal;
  color: var(--color-primary);
}

.pub-award {
  display: inline-block;
  margin-left: var(--space-sm);
  padding: 2px 8px;
  background-color: var(--color-accent);
  color: white;
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: 4px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.pub-links {
  margin-top: var(--space-sm);
  display: flex;
  gap: var(--space-md);
  font-size: 0.9rem;
}

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

.pub-links a:hover {
  color: var(--color-accent);
}

/* Footer */
.footer {
  background-color: var(--color-bg-alt);
  padding: var(--space-xl) 0;
  border-top: 1px solid var(--color-border);
  text-align: center;
  color: var(--color-text-light);
  font-size: 0.9rem;
}

.footer a {
  color: var(--color-secondary);
}

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