/* ═══════════════════════════════════════════════════════════
   Knowik — NVIDIA Developer Blog Inspired Theme
   ═══════════════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');
@import url('https://fonts.googleapis.com/css2?family=Montserrat:wght@900&display=swap');

/* ── Variables (Default Dark Theme) ───────────────────────── */
:root {
  --bg-primary:   #111111;
  --bg-secondary: #1A1A1A;
  --bg-card:      #1A1A1A;
  --border-card:  #333333;
  --accent-primary: #76B900; /* NVIDIA Green */
  --accent-hover:   #88D100;
  --nav-bg:       #000000;
  --nav-text:     #FFFFFF;
  --text-primary: #FFFFFF;
  --text-secondary:#A3A3A3;
  --text-muted:   #737373;
  --font:         'Inter', system-ui, -apple-system, sans-serif;
  --radius:       0px; /* Flat design */
  --shadow-card:  0 1px 3px rgba(0,0,0,0.5);
  --shadow-hover: 0 4px 12px rgba(0,0,0,0.7);
  --transition:   0.2s ease-in-out;
}

/* Light Theme Overrides */
[data-theme="light"] {
  --bg-primary:   #F3F4F6;
  --bg-secondary: #FFFFFF;
  --bg-card:      #FFFFFF;
  --border-card:  #E5E7EB;
  --nav-bg:       #000000;
  --nav-text:     #FFFFFF;
  --text-primary: #111827;
  --text-secondary:#4B5563;
  --text-muted:   #6B7280;
  --shadow-card:  0 1px 3px rgba(0,0,0,0.1);
  --shadow-hover: 0 4px 12px rgba(0,0,0,0.15);
}

/* ── Reset ────────────────────────────────────────────────── */
*, *::before, *::after { margin:0; padding:0; box-sizing:border-box; }
html { scroll-behavior:smooth; }

body {
  font-family: var(--font);
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  line-height: 1.6;
}

/* ── Typography ───────────────────────────────────────────── */
h1, h2, h3, h4 { 
  line-height: 1.2; 
  font-weight: 700; 
  color: var(--text-primary);
}
a { color: inherit; text-decoration: none; transition: color var(--transition); }
p { color: var(--text-secondary); }
img { max-width: 100%; height: auto; display: block; }

.gradient-text {
  color: var(--accent-primary);
}

/* ── Navbar ───────────────────────────────────────────────── */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
  height: 64px;
  background: var(--nav-bg);
  border-bottom: 3px solid var(--accent-primary);
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo-icon {
  width: 28px;
  height: 28px;
  object-fit: contain;
}

.nav-logo span {
  font-family: 'Montserrat', sans-serif;
  font-size: 1.5rem;
  font-weight: 900;
  color: #FFFFFF;
  letter-spacing: -0.04em;
  line-height: 1;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
  list-style: none;
}

.nav-links a {
  font-size: 0.95rem;
  font-weight: 600;
  color: #D1D5DB;
  text-transform: uppercase;
}

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

.live-badge {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.8rem;
  font-weight: 700;
  color: #EF4444;
  text-transform: uppercase;
}

.live-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: #EF4444;
  animation: pulse-red 1.5s ease-in-out infinite;
}

@keyframes pulse-red {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.7; transform: scale(1.1); }
}

/* ── Ticker Bar ───────────────────────────────────────────── */
.ticker {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.5rem 2rem;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-card);
  font-size: 0.85rem;
  color: var(--text-primary);
  overflow: hidden;
}

.ticker-label {
  flex-shrink: 0;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 0.75rem;
  text-transform: uppercase;
  background: var(--accent-primary);
  padding: 3px 8px;
}

.ticker-content { display: flex; gap: 2rem; }
.ticker-sep { color: var(--border-card); }

/* ── Main layout ──────────────────────────────────────────── */
main {
  max-width: 1280px;
  margin: 0 auto;
  padding: 2.5rem 2rem 4rem;
}

/* ── Hero Section ─────────────────────────────────────────── */
.hero-section { margin-bottom: 4rem; }

.hero-card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  box-shadow: var(--shadow-card);
  transition: box-shadow var(--transition);
  min-height: 400px;
}

.hero-card:hover { 
  box-shadow: var(--shadow-hover); 
}

.hero-content {
  padding: 3rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 1.25rem;
}

.hero-image {
  position: relative;
  overflow: hidden;
  border-left: 1px solid var(--border-card);
}

.hero-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-title {
  font-size: clamp(2rem, 3.5vw, 2.75rem);
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--text-primary);
  font-weight: 500;
}

.hero-excerpt {
  font-size: 1rem;
  color: var(--text-secondary);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ── Empty State ──────────────────────────────────────────── */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 6rem 2rem;
  text-align: center;
  gap: 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border-card);
}

.empty-spinner {
  width: 50px; height: 50px;
  border: 4px solid var(--border-card);
  border-top-color: var(--accent-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

.empty-state h2 { font-size: 1.75rem; color: var(--text-primary); }
.empty-state p { font-size: 1.1rem; color: var(--text-secondary); }

/* ── Section Heading ──────────────────────────────────────── */
.section-heading {
  margin-bottom: 2rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--nav-bg);
}

.section-heading h2 {
  font-size: 1.5rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-primary);
}

.section-line {
  display: none;
}

/* ── Story Grid ───────────────────────────────────────────── */
.stories-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

/* ── Story Card ───────────────────────────────────────────── */
.story-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  display: flex;
  flex-direction: column;
  transition: transform var(--transition), box-shadow var(--transition);
}

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

.card-image {
  width: 100%;
  height: 200px;
  overflow: hidden;
  border-bottom: 1px solid var(--border-card);
}

.card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
}

.story-card:hover .card-image img { 
  transform: scale(1.05); 
}

.card-image-overlay {
  display: none;
}

.card-content {
  padding: 1.5rem;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.card-content h3 {
  font-size: 1.15rem;
  font-weight: 700;
  line-height: 1.4;
}

.card-content h3 a {
  color: var(--text-primary);
}

.card-content h3 a:hover { 
  color: var(--accent-primary); 
}

.card-excerpt {
  font-size: 0.95rem;
  color: var(--text-secondary);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  flex: 1;
}

.card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 1rem;
  margin-top: auto;
}

.timestamp {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
}

.read-more {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-primary);
  text-transform: uppercase;
}

.read-more:hover { 
  color: var(--accent-primary); 
}

/* ── Category Badges ──────────────────────────────────────── */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 4px 8px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  background: var(--nav-bg);
  color: #FFFFFF;
}

.badge-ai-ml { background: #000000; }
.badge-technology { background: #333333; }
.badge-politics { background: #555555; }

/* ── Buttons & Toggles ────────────────────────────────────── */
.theme-toggle {
  background: transparent;
  border: none;
  color: #FFFFFF;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8px;
  border-radius: 50%;
  transition: background var(--transition);
  margin-left: 1rem;
}

.theme-toggle:hover {
  background: rgba(255, 255, 255, 0.1);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
  fill: currentColor;
}

[data-theme="light"] .icon-moon { display: block; }
[data-theme="light"] .icon-sun { display: none; }

:root:not([data-theme="light"]) .icon-moon { display: none; }
:root:not([data-theme="light"]) .icon-sun { display: block; }

.btn-primary {
  display: inline-flex;
  align-items: center;
  padding: 0.75rem 1.5rem;
  font-family: var(--font);
  font-size: 0.95rem;
  font-weight: 700;
  background: var(--accent-primary);
  color: #000000;
  border: none;
  cursor: pointer;
  text-transform: uppercase;
  transition: background var(--transition);
  width: fit-content;
}

.btn-primary:hover {
  background: var(--accent-hover);
}

.btn-back {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  padding: 0.5rem 1rem;
  border: 2px solid var(--border-card);
  background: var(--bg-card);
  text-transform: uppercase;
}

.btn-back:hover { 
  border-color: var(--text-primary);
}

/* ── Story Page ───────────────────────────────────────────── */
.story-hero {
  position: relative;
  width: 100%;
  max-height: 500px;
  overflow: hidden;
  margin-bottom: 3rem;
  background: #000;
}

.story-hero img {
  width: 100%;
  height: 500px;
  object-fit: cover;
  opacity: 0.85;
}

.story-hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(0,0,0,0.8) 0%, transparent 100%);
}

.story-hero-meta {
  position: absolute;
  bottom: 2.5rem;
  left: 2.5rem;
  right: 2.5rem;
  max-width: 900px;
  margin: 0 auto;
}

.story-hero-meta h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  color: #FFFFFF;
  margin-top: 1rem;
}

.story-container {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 1rem;
}

.story-header { margin-bottom: 2rem; }

.story-subtitle {
  font-size: 1.25rem;
  color: var(--text-primary);
  font-weight: 500;
  margin-bottom: 1.5rem;
}

.story-byline {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
}

.byline-dot { color: var(--border-card); }

.story-divider {
  height: 1px;
  background: var(--border-card);
  margin: 2.5rem 0;
  border: none;
}

/* Article body typography */
.story-body {
  font-size: 1.1rem;
  line-height: 1.8;
  color: var(--text-primary);
}

.story-body p { margin-bottom: 1.75rem; }
.story-body strong { font-weight: 700; }
.story-body em { font-style: italic; }

.story-body p:first-child {
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--text-primary);
}

/* ── Tags ─────────────────────────────────────────────────── */
.tags-section { margin: 3rem 0; }
.tags-label { font-size: 0.9rem; font-weight: 700; color: var(--text-primary); text-transform: uppercase; margin-bottom: 1rem; }
.tags-list { display: flex; flex-wrap: wrap; gap: 0.5rem; }

.tag {
  padding: 6px 12px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  background: var(--bg-primary);
  border: 1px solid var(--border-card);
}

.tag:hover {
  background: var(--border-card);
}

/* ── Related Stories ──────────────────────────────────────── */
.related-section { margin-top: 4rem; padding-top: 3rem; border-top: 2px solid var(--border-card); }
.related-section h3 { font-size: 1.5rem; text-transform: uppercase; margin-bottom: 2rem; color: var(--text-primary); }
.related-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; }

/* ── Category Page ────────────────────────────────────────── */
.category-header {
  padding: 4rem 2rem 3rem;
  margin-bottom: 3rem;
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  text-align: center;
}

.category-icon { font-size: 3rem; margin-bottom: 1rem; color: var(--accent-primary); }
.category-header h1 { font-size: 2.5rem; text-transform: uppercase; margin-bottom: 0.5rem; }
.category-count { font-size: 1rem; font-weight: 600; color: var(--text-muted); text-transform: uppercase; }

/* ── Footer ───────────────────────────────────────────────── */
.site-footer {
  margin-top: 5rem;
  padding: 3rem 2rem;
  background: var(--nav-bg);
  color: #FFFFFF;
}

.footer-inner { display: flex; align-items: center; justify-content: center; gap: 1.5rem; flex-wrap: wrap; }
.footer-logo { font-weight: 700; font-size: 1.25rem; }
.footer-logo span { color: var(--accent-primary); }
.footer-sep { color: #333333; }

/* ── Loading Skeleton ─────────────────────────────────────── */
.skeleton {
  background: linear-gradient(90deg, #F3F4F6 25%, #E5E7EB 50%, #F3F4F6 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}

@keyframes shimmer { to { background-position: -200% 0; } }
.skeleton-img  { width: 100%; height: 200px; }
.skeleton-text { height: 16px; margin-bottom: 12px; }
.skeleton-text.wide  { width: 100%; }
.skeleton-text.short { width: 60%; }

/* ── Responsive ───────────────────────────────────────────── */
@media (max-width: 1024px) {
  .stories-grid { grid-template-columns: repeat(2, 1fr); }
  .related-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .navbar { padding: 0 1rem; }
  .nav-links { gap: 1.5rem; }
  main { padding: 1.5rem 1rem 3rem; }

  .hero-card {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .hero-image { height: 250px; order: -1; border-left: none; border-bottom: 1px solid var(--border-card); }
  .hero-content { padding: 2rem; }

  .stories-grid { grid-template-columns: 1fr; }
  .related-grid { grid-template-columns: 1fr; }

  .story-hero img { height: 350px; }
  .story-hero-meta { bottom: 1.5rem; left: 1.5rem; right: 1.5rem; }
  .story-hero-meta h1 { font-size: 1.75rem; }
}

@media (max-width: 480px) {
  .nav-links { display: none; }
  .hero-title { font-size: 1.75rem; }
  .ticker-content { display: none; }
}