/* ==========================================================================
   Defense AI Weekly - Tactical Dark Theme
   Distinct visual identity: military-inspired, command-center aesthetic
   ========================================================================== */

/* --------------------------------------------------------------------------
   Custom Properties - Defense/Military Palette
   -------------------------------------------------------------------------- */

:root {
  /* Defense-oriented color palette */
  --def-bg-primary: #0d1117;
  --def-bg-secondary: #161b22;
  --def-bg-tertiary: #21262d;
  --def-bg-card: #1c2128;
  --def-bg-hover: #262c36;
  
  --def-text-primary: #e6edf3;
  --def-text-secondary: #8b949e;
  --def-text-muted: #6e7681;
  
  --def-border: #30363d;
  --def-border-light: #3d444d;
  
  /* Accent colors - tactical gold/amber */
  --def-accent-primary: #d4a574;
  --def-accent-secondary: #e8c49a;
  --def-accent-glow: rgba(212, 165, 116, 0.15);
  
  /* Status indicators */
  --def-success: #3fb950;
  --def-alert: #f85149;
  --def-info: #58a6ff;
  
  /* Typography */
  --def-font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --def-font-mono: 'JetBrains Mono', 'Fira Code', ui-monospace, monospace;
  --def-font-display: 'Bebas Neue', Impact, sans-serif;
  
  /* Spacing scale */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  
  /* Layout */
  --max-w: 1280px;
  --content-w: 860px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  
  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --duration-fast: 150ms;
  --duration-base: 250ms;
}

/* --------------------------------------------------------------------------
   Base Reset
   -------------------------------------------------------------------------- */

*, *::before, *::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  margin: 0;
  font-family: var(--def-font-primary);
  font-size: 16px;
  line-height: 1.6;
  color: var(--def-text-primary);
  background-color: var(--def-bg-primary);
}

/* Subtle grid overlay for command-center feel */
body::after {
  content: '';
  position: fixed;
  inset: 0;
  background-image: 
    linear-gradient(rgba(212, 165, 116, 0.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(212, 165, 116, 0.02) 1px, transparent 1px);
  background-size: 40px 40px;
  pointer-events: none;
  z-index: -1;
}

a {
  color: var(--def-accent-secondary);
  text-decoration: none;
  transition: color var(--duration-fast);
}

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

h1, h2, h3, h4 {
  margin: 0 0 var(--space-md);
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

p { margin: 0 0 var(--space-md); }

/* --------------------------------------------------------------------------
   Header - Top Nav with Dropdowns
   -------------------------------------------------------------------------- */

.def-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(13, 17, 23, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--def-border);
}

.def-nav {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 var(--space-lg);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.def-logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: var(--def-font-display);
  font-size: 1.5rem;
  letter-spacing: 0.05em;
  color: var(--def-text-primary);
}

.def-logo__icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, var(--def-accent-primary), var(--def-accent-secondary));
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
}

.def-logo:hover {
  color: var(--def-text-primary);
}

.def-menu {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
  list-style: none;
  margin: 0;
  padding: 0;
}

.def-menu__item {
  position: relative;
}

.def-menu__link {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-sm) 0;
  color: var(--def-text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color var(--duration-fast);
}

.def-menu__link:hover {
  color: var(--def-text-primary);
}

.def-menu__link::after {
  content: '▾';
  font-size: 0.7rem;
  opacity: 0.6;
}

/* Dropdown */
.def-dropdown {
  display: none;
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  min-width: 200px;
  background: var(--def-bg-secondary);
  border: 1px solid var(--def-border);
  border-radius: var(--radius-md);
  padding: var(--space-sm);
  box-shadow: 0 8px 32px rgba(0,0,0,0.4);
  z-index: 200;
}

.def-menu__item:hover .def-dropdown,
.def-menu__item:focus-within .def-dropdown {
  display: block;
}

.def-dropdown__item {
  display: block;
  padding: var(--space-sm) var(--space-md);
  color: var(--def-text-secondary);
  font-size: 0.875rem;
  border-radius: var(--radius-sm);
  transition: all var(--duration-fast);
}

.def-dropdown__item:hover {
  background: var(--def-bg-hover);
  color: var(--def-text-primary);
}

/* --------------------------------------------------------------------------
   Main Layout
   -------------------------------------------------------------------------- */

.def-main {
  min-height: calc(100vh - 200px);
}

.def-article {
  max-width: 800px;
  margin: 0 auto;
  padding: var(--space-2xl) var(--space-lg);
}

/* --------------------------------------------------------------------------
   Hero - Publication Landing
   -------------------------------------------------------------------------- */

.def-hero {
  padding: var(--space-3xl) var(--space-lg);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.def-hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 400px;
  background: radial-gradient(ellipse, var(--def-accent-glow) 0%, transparent 70%);
  pointer-events: none;
}

.def-hero__badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-xs) var(--space-md);
  background: var(--def-bg-secondary);
  border: 1px solid var(--def-border);
  border-radius: 100px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--def-accent-primary);
  margin-bottom: var(--space-lg);
}

.def-hero__title {
  font-family: var(--def-font-display);
  font-size: clamp(2.5rem, 6vw, 4rem);
  letter-spacing: 0.02em;
  margin-bottom: var(--space-md);
  color: var(--def-text-primary);
}

.def-hero__title span {
  color: var(--def-accent-primary);
}

.def-hero__tagline {
  font-size: 1.25rem;
  color: var(--def-text-secondary);
  max-width: 600px;
  margin: 0 auto var(--space-lg);
}

.def-hero__meta {
  display: flex;
  justify-content: center;
  gap: var(--space-xl);
  font-size: 0.875rem;
  color: var(--def-text-muted);
}

/* --------------------------------------------------------------------------
   Content Sections
   -------------------------------------------------------------------------- */

.def-section {
  padding: var(--space-2xl) var(--space-lg);
}

.def-section--centered {
  text-align: center;
}

.def-section__header {
  margin-bottom: var(--space-xl);
}

.def-section__title {
  font-size: 1.75rem;
  margin-bottom: var(--space-sm);
}

.def-section__subtitle {
  color: var(--def-text-secondary);
  font-size: 1rem;
}

/* --------------------------------------------------------------------------
   Cards - Digest Style
   -------------------------------------------------------------------------- */

.def-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: var(--space-lg);
  max-width: var(--max-w);
  margin: 0 auto;
}

.def-card {
  background: var(--def-bg-secondary);
  border: 1px solid var(--def-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  transition: all var(--duration-base) var(--ease-out);
}

.def-card:hover {
  border-color: var(--def-accent-primary);
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

.def-card__category {
  display: inline-block;
  padding: var(--space-xs) var(--space-sm);
  background: var(--def-bg-tertiary);
  border-radius: var(--radius-sm);
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--def-accent-primary);
  margin-bottom: var(--space-md);
}

.def-card__title {
  font-size: 1.125rem;
  margin-bottom: var(--space-sm);
  color: var(--def-text-primary);
}

.def-card__excerpt {
  font-size: 0.9rem;
  color: var(--def-text-secondary);
  line-height: 1.6;
}

.def-card__meta {
  display: flex;
  gap: var(--space-md);
  margin-top: var(--space-md);
  padding-top: var(--space-md);
  border-top: 1px solid var(--def-border);
  font-size: 0.8rem;
  color: var(--def-text-muted);
}

/* --------------------------------------------------------------------------
   About Content Block
   -------------------------------------------------------------------------- */

.def-content {
  max-width: var(--content-w);
  margin: 0 auto;
  padding: var(--space-2xl) var(--space-lg);
}

.def-content__title {
  font-size: 2rem;
  margin-bottom: var(--space-lg);
}

.def-content p {
  color: var(--def-text-secondary);
  line-height: 1.8;
  font-size: 1.05rem;
}

/* --------------------------------------------------------------------------
   Topic Pills
   -------------------------------------------------------------------------- */

.def-topics {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin: var(--space-lg) 0;
}

.def-pill {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-md);
  background: var(--def-bg-tertiary);
  border: 1px solid var(--def-border);
  border-radius: 100px;
  font-size: 0.85rem;
  color: var(--def-text-secondary);
  transition: all var(--duration-fast);
}

.def-pill:hover {
  border-color: var(--def-accent-primary);
  color: var(--def-accent-primary);
}

.def-pill__icon {
  font-size: 1rem;
}

/* --------------------------------------------------------------------------
   Footer - Different from Starter
   -------------------------------------------------------------------------- */

.def-footer {
  background: var(--def-bg-secondary);
  border-top: 1px solid var(--def-border);
  padding: var(--space-2xl) var(--space-lg);
}

.def-footer__inner {
  max-width: var(--max-w);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-xl);
}

.def-footer__brand {
  max-width: 300px;
}

.def-footer__logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: var(--def-font-display);
  font-size: 1.25rem;
  letter-spacing: 0.05em;
  color: var(--def-text-primary);
  margin-bottom: var(--space-md);
}

.def-footer__desc {
  font-size: 0.875rem;
  color: var(--def-text-muted);
  line-height: 1.7;
}

.def-footer__col-title {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--def-accent-primary);
  margin-bottom: var(--space-md);
}

.def-footer__links {
  list-style: none;
  padding: 0;
  margin: 0;
}

.def-footer__links li {
  margin-bottom: var(--space-sm);
}

.def-footer__links a {
  font-size: 0.875rem;
  color: var(--def-text-secondary);
}

.def-footer__links a:hover {
  color: var(--def-text-primary);
}

.def-footer__bottom {
  max-width: var(--max-w);
  margin: var(--space-xl) auto 0;
  padding-top: var(--space-lg);
  border-top: 1px solid var(--def-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
  color: var(--def-text-muted);
}

.def-footer__legal {
  display: flex;
  gap: var(--space-lg);
}

/* --------------------------------------------------------------------------
   Responsive
   -------------------------------------------------------------------------- */

@media (max-width: 768px) {
  .def-nav {
    flex-direction: column;
    height: auto;
    padding: var(--space-md);
    gap: var(--space-md);
  }
  
  .def-menu {
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--space-md);
  }
  
  .def-menu__item {
    position: static;
  }
  
  .def-dropdown {
    display: block;
    position: static;
    transform: none;
    box-shadow: none;
    border: none;
    background: transparent;
    padding-left: var(--space-md);
    opacity: 1;
    visibility: visible;
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--duration-base) var(--ease-out);
  }
  
  .def-menu__item:focus-within .def-dropdown,
  .def-menu__item:hover .def-dropdown {
    max-height: 400px;
    visibility: visible;
    opacity: 1;
  }
  
  .def-footer__inner {
    grid-template-columns: 1fr 1fr;
  }
  
  .def-footer__brand {
    grid-column: span 2;
  }
  
  .def-footer__bottom {
    flex-direction: column;
    gap: var(--space-md);
    text-align: center;
  }
}