/* ==========================================================================
   Global Styles
   ========================================================================== */

:root {
  /* Colors - Dark Theme with Futuristic Accents */
  --color-bg-primary: #0a0e27;
  --color-bg-secondary: #111733;
  --color-bg-tertiary: #1a1f3a;
  --color-text-primary: #e4e6eb;
  --color-text-secondary: #a0a4b8;
  --color-accent-primary: #00d9ff;
  --color-accent-secondary: #7c3aed;
  --color-accent-tertiary: #06b6d4;
  --color-border: #2a2f45;
  
  /* Glow Effects */
  --glow-subtle: 0 0 20px rgba(0, 217, 255, 0.15);
  --glow-medium: 0 0 30px rgba(0, 217, 255, 0.25);
  --glow-accent: 0 0 40px rgba(124, 58, 237, 0.2);
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-xxl: 4rem;
  
  /* Typography */
  --font-family-main: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.5rem;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-main);
  background: linear-gradient(135deg, var(--color-bg-primary) 0%, var(--color-bg-secondary) 100%);
  color: var(--color-text-primary);
  line-height: 1.6;
  min-height: 100vh;
  background-attachment: fixed;
}

/* ==========================================================================
   Container & Layout
   ========================================================================== */

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

@media (max-width: 768px) {
  .container {
    padding: 0 var(--spacing-md);
  }
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: linear-gradient(180deg, rgba(10, 14, 39, 0.95) 0%, rgba(10, 14, 39, 0.85) 100%);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--glow-subtle);
  transition: background var(--transition-normal);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md) 0;
}

.logo {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  background: linear-gradient(135deg, var(--color-accent-primary), var(--color-accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.logo a {
  text-decoration: none;
  color: inherit;
}

.nav-menu {
  display: flex;
  gap: var(--spacing-lg);
}

.nav-link {
  color: var(--color-text-secondary);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  transition: color var(--transition-fast);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-accent-primary), var(--color-accent-secondary));
  transition: width var(--transition-normal);
}

.nav-link:hover {
  color: var(--color-accent-primary);
}

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

@media (max-width: 768px) {
  .nav-menu {
    gap: var(--spacing-md);
  }
  
  .nav-link {
    font-size: var(--font-size-base);
  }
}

@media (max-width: 640px) {
  .header-content {
    flex-direction: column;
    gap: var(--spacing-md);
    text-align: center;
  }
  
  .nav-menu {
    flex-wrap: wrap;
    justify-content: center;
  }
}

/* ==========================================================================
   Hero Section
   ========================================================================== */

.hero-section {
  padding: var(--spacing-xxl) 0;
  background: radial-gradient(ellipse at bottom right, rgba(124, 58, 237, 0.1) 0%, transparent 50%);
}

.hero-content {
  max-width: 900px;
}

.eyebrow {
  font-size: var(--font-size-lg);
  color: var(--color-accent-primary);
  font-weight: var(--font-weight-medium);
  margin-bottom: var(--spacing-sm);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.hero-title {
  font-size: var(--font-size-4xl);
  font-weight: var(--font-weight-bold);
  line-height: 1.2;
  margin-bottom: var(--spacing-lg);
  background: linear-gradient(135deg, var(--color-accent-primary), var(--color-accent-tertiary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-description {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-lg);
  line-height: 1.8;
}

.hero-actions {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

@media (max-width: 768px) {
  .hero-section {
    padding: var(--spacing-xl) 0;
  }
  
  .hero-title {
    font-size: var(--font-size-3xl);
  }
  
  .hero-description {
    font-size: var(--font-size-base);
  }
}

/* ==========================================================================
   Buttons
   ========================================================================== */

.btn {
  display: inline-block;
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: 8px;
  font-weight: var(--font-weight-semibold);
  text-decoration: none;
  cursor: pointer;
  border: 2px solid;
  transition: all var(--transition-normal);
  font-size: var(--font-size-base);
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-accent-primary), var(--color-accent-tertiary));
  color: var(--color-bg-primary);
  border-color: var(--color-accent-primary);
  box-shadow: var(--glow-subtle);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--glow-medium);
}

.btn-secondary {
  background: transparent;
  color: var(--color-accent-primary);
  border-color: var(--color-accent-primary);
}

.btn-secondary:hover {
  background: rgba(0, 217, 255, 0.1);
  transform: translateY(-2px);
  box-shadow: var(--glow-subtle);
}

/* ==========================================================================
   Section Styles
   ========================================================================== */

.section {
  padding: var(--spacing-xxl) 0;
  border-top: 1px solid var(--color-border);
}

.section h2 {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-md);
  color: var(--color-accent-primary);
}

.section-subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-xl);
}

/* Research Section */
.research-section {
  background: radial-gradient(ellipse at top left, rgba(0, 217, 255, 0.08) 0%, transparent 40%);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-lg);
  margin-top: var(--spacing-lg);
}

.research-card {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: var(--spacing-lg);
  transition: all var(--transition-normal);
  backdrop-filter: blur(10px);
}

.research-card h3 {
  font-size: var(--font-size-lg);
  color: var(--color-accent-primary);
  margin-bottom: var(--spacing-sm);
}

.research-card p {
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.research-card:hover {
  background: rgba(255, 255, 255, 0.06);
  border-color: var(--color-accent-primary);
  transform: translateY(-4px);
  box-shadow: var(--glow-accent);
}

/* Publications Section */
.publications-section {
  background: radial-gradient(ellipse at bottom left, rgba(124, 58, 237, 0.08) 0%, transparent 40%);
}

.publication-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.publication-item {
  background: rgba(255, 255, 255, 0.02);
  border-left: 4px solid var(--color-accent-primary);
  border-radius: 8px;
  padding: var(--spacing-lg);
  transition: all var(--transition-normal);
}

.publication-item h3 {
  font-size: var(--font-size-lg);
  color: var(--color-accent-tertiary);
  margin-bottom: var(--spacing-xs);
}

.publication-meta {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-sm);
}

.publication-description {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
  line-height: 1.7;
}

.publication-links {
  display: flex;
  gap: var(--spacing-md);
}

.link-icon {
  color: var(--color-accent-primary);
  text-decoration: none;
  font-weight: var(--font-weight-semibold);
  transition: color var(--transition-fast);
}

.link-icon:hover {
  color: var(--color-accent-tertiary);
}

.publication-item:hover {
  background: rgba(255, 255, 255, 0.05);
  border-left-color: var(--color-accent-tertiary);
}

/* Service Section */
.service-section {
  background: radial-gradient(ellipse at top right, rgba(6, 182, 212, 0.08) 0%, transparent 40%);
}

.service-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
}

.service-card {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: var(--spacing-lg);
  transition: all var(--transition-normal);
  backdrop-filter: blur(10px);
}

.service-card h3 {
  font-size: var(--font-size-lg);
  color: var(--color-accent-tertiary);
  margin-bottom: var(--spacing-md);
}

.service-card ul {
  list-style: none;
}

.service-card li {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-sm);
  padding-left: var(--spacing-md);
  position: relative;
}

.service-card li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--color-accent-primary);
}

.service-card:hover {
  background: rgba(255, 255, 255, 0.06);
  border-color: var(--color-accent-tertiary);
  transform: translateY(-4px);
  box-shadow: var(--glow-accent);
}

/* Links Section */
.links-section {
  background: radial-gradient(ellipse at center, rgba(0, 217, 255, 0.05) 0%, transparent 50%);
}

.links-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: var(--spacing-lg);
}

.link-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-lg);
  background: rgba(255, 255, 255, 0.03);
  border: 2px solid var(--color-border);
  border-radius: 12px;
  text-decoration: none;
  color: var(--color-text-primary);
  transition: all var(--transition-normal);
  backdrop-filter: blur(10px);
}

.link-card .link-icon {
  font-size: 2rem;
}

.link-label {
  font-weight: var(--font-weight-semibold);
  font-size: var(--font-size-base);
}

.link-card:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--color-accent-primary);
  transform: translateY(-6px);
  box-shadow: var(--glow-medium);
}

@media (max-width: 768px) {
  .links-grid {
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  }
  
  .section {
    padding: var(--spacing-xl) 0;
  }
  
  .section h2 {
    font-size: var(--font-size-2xl);
  }
}

/* ==========================================================================
   Footer
   ========================================================================== */

.footer {
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-xl) 0;
  margin-top: var(--spacing-xxl);
  text-align: center;
  background: rgba(10, 14, 39, 0.5);
}

.footer p {
  color: var(--color-text-secondary);
  font-size: var(--font-size-base);
}

.footer a {
  color: var(--color-accent-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

/* ==========================================================================
   Responsive Design
   ========================================================================== */

@media (max-width: 768px) {
  :root {
    --font-size-4xl: 1.875rem;
    --font-size-3xl: 1.5rem;
  }
  
  .hero-actions {
    flex-direction: column;
  }
  
  .btn {
    width: 100%;
    text-align: center;
  }
}

@media (max-width: 640px) {
  :root {
    --spacing-xl: 2rem;
    --spacing-xxl: 3rem;
  }
  
  .service-grid {
    grid-template-columns: 1fr;
  }
  
  .publication-item {
    padding: var(--spacing-md);
  }
}

/* ==========================================================================
   Accessibility
   ========================================================================== */

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* High contrast mode support */
@media (prefers-contrast: more) {
  :root {
    --color-accent-primary: #00e5ff;
    --color-border: #4a4f65;
  }
}