/* ===== Design Tokens — macOS Dark Mode ===== */
:root {
  --bg: #000000;
  --surface: #1d1d1f;
  --surface-hover: #2a2a2c;
  --border: #38383a;
  --border-hover: #0a84ff;
  --text: #f5f5f7;
  --text-muted: #98989d;
  --text-dim: #6e6e73;
  --accent: #0a84ff;
  --accent-glow: rgba(10, 132, 255, 0.15);
  --radius: 16px;
  --shadow: 0 2px 12px rgba(0, 0, 0, 0.4);
  --shadow-hover: 0 0 0 1px rgba(100, 148, 237, 0.5), 0 8px 32px rgba(100, 148, 237, 0.2);
  --transition: 300ms cubic-bezier(.22, .61, .36, 1);
  --font: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  overflow-x: hidden;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

/* ===== Layout ===== */
main {
  position: relative;
  z-index: 2;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 28px;
}

/* ===== Hero ===== */
.hero {
  padding: 100px 0 72px;
  text-align: center;
}
.hero-sub {
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 20px;
  font-weight: 500;
}
.hero-title {
  font-size: clamp(64px, 12vw, 108px);
  font-weight: 800;
  letter-spacing: -0.04em;
  background: linear-gradient(135deg, #f5f5f7 0%, #0a84ff 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 20px;
}
.hero-desc {
  font-size: 16px;
  color: var(--text-muted);
  max-width: 440px;
  margin: 0 auto 28px;
  line-height: 1.75;
  font-weight: 400;
}
.hero-meta {
  font-size: 13px;
  color: var(--text-dim);
  font-weight: 400;
  letter-spacing: 0.01em;
}
.hero-meta .video-count {
  font-weight: 700;
  color: var(--text);
}

/* ===== Videos Grid ===== */
.videos-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 18px;
  padding-bottom: 80px;
}

/* ===== Video Card ===== */
.video-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  cursor: pointer;
  transition:
    transform var(--transition),
    box-shadow var(--transition),
    border-color var(--transition);
  box-shadow: var(--shadow);
}
.video-card.revealed {
  opacity: 1;
  transform: translateY(0);
  transition: opacity 600ms ease, transform 600ms cubic-bezier(.22, .61, .36, 1);
}
/* Hover: Cornflower blue glow */
.video-card:hover {
  transform: translateY(-6px) scale(1.015);
  border-color: var(--border-hover);
  box-shadow: var(--shadow-hover);
}
.video-card:hover .card-thumb img {
  transform: scale(1.04);
}
.video-card:hover .card-play {
  opacity: 1;
}

.card-thumb {
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: #2a2a2c;
}
.card-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 500ms cubic-bezier(.22, .61, .36, 1);
}
.card-play {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.6);
  opacity: 0;
  transition: opacity var(--transition);
}
.card-play svg {
  width: 52px;
  height: 52px;
  filter: drop-shadow(0 4px 12px rgba(0,0,0,0.3));
  opacity: 0.9;
}

.card-body { padding: 18px 20px 20px; }
.card-number {
  font-size: 10px;
  color: var(--text-dim);
  letter-spacing: 0.12em;
  margin-bottom: 8px;
  font-weight: 500;
  text-transform: uppercase;
}
.card-title {
  font-size: 14.5px;
  font-weight: 600;
  line-height: 1.5;
  color: var(--text);
  margin-bottom: 8px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  letter-spacing: -0.01em;
}
.card-summary {
  font-size: 12.5px;
  color: var(--text-muted);
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-bottom: 12px;
  font-weight: 400;
}
.card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
}
.card-tag {
  font-size: 10.5px;
  padding: 2px 9px;
  border-radius: 20px;
  background: rgba(10, 132, 255, 0.1);
  color: #0a84ff;
  border: 1px solid rgba(10, 132, 255, 0.25);
  letter-spacing: 0.03em;
  font-weight: 500;
}

/* ===== Quote Card ===== */
.quote-card {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px 24px;
  margin-top: 0;
  position: relative;
  overflow: hidden;
}
.quote-card::before {
  content: '"';
  position: absolute;
  top: -8px; left: 16px;
  font-size: 96px;
  font-weight: 800;
  color: rgba(10, 132, 255, 0.08);
  line-height: 1;
  pointer-events: none;
}
.quote-text {
  font-size: 14.5px;
  font-weight: 500;
  color: var(--text);
  line-height: 1.6;
  margin-bottom: 8px;
  font-style: italic;
}
.quote-source {
  font-size: 11.5px;
  color: var(--text-dim);
  font-weight: 400;
}

/* ===== Footer ===== */
.footer {
  text-align: center;
  padding: 40px 0 60px;
  font-size: 12px;
  color: var(--text-dim);
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  font-weight: 400;
}

/* ===== Responsive ===== */
@media (max-width: 640px) {
  .hero { padding: 72px 0 48px; }
  .videos-grid { grid-template-columns: 1fr; }
  .card-body { padding: 16px 18px 18px; }
}

/* ===== Theme accents ===== */
.theme-ai  { --card-accent: rgba(10, 132, 255, 0.06); }
.theme-bio { --card-accent: rgba(48, 209, 88, 0.06); }
.theme-mind{ --card-accent: rgba(175, 82, 222, 0.06); }
.theme-civ { --card-accent: rgba(255, 159, 10, 0.06); }