/* ============================================================
   site.css — Nicholas Goble · Idea Lab
   Palette extracted from the trust integral explorer (iris+emerald).
   Sky is the bridge color. Each lecture gets one accent.
   ============================================================ */

:root {
  /* Surfaces */
  --bg:        #fafaf6;
  --panel:     #ffffff;
  --panel-2:   #f5f5f0;
  --ink:       #18181b;
  --ink-soft:  #3f3f46;
  --muted:     #6b7280;
  --border:    #e5e7eb;
  --border-2:  #d4d4d8;

  /* Topic accents (used per-card via [data-accent]) */
  --sky:        #38bdf8;
  --sky-text:   #0369a1;
  --sky-soft:   rgba(56, 189, 248, 0.10);

  --indigo:        #6366f1;
  --indigo-text:   #3730a3;
  --indigo-soft:   rgba(99, 102, 241, 0.10);

  --saffron:        #fbbf24;
  --saffron-text:   #92400e;
  --saffron-soft:   rgba(251, 191, 36, 0.12);

  --emerald:        #1f8d20;
  --emerald-text:   #065f46;
  --emerald-soft:   rgba(31, 141, 32, 0.10);

  --pink:           #f472b6;
  --pink-text:      #9d174d;

  /* Type */
  --serif: 'Charter', 'Iowan Old Style', 'Palatino Linotype', Georgia, serif;
  --sans:  -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Inter', system-ui, sans-serif;
  --mono:  ui-monospace, 'SF Mono', 'JetBrains Mono', Menlo, Consolas, monospace;
}

*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
a.inline { color: var(--ink); border-bottom: 1px solid var(--border-2); }
a.inline:hover { border-bottom-color: var(--ink); }

::selection { background: var(--saffron); color: var(--ink); }

/* ============================================================
   Layout
   ============================================================ */

.wrap {
  max-width: 1180px;
  margin: 0 auto;
  padding: 36px 32px 96px;
}

.wrap-narrow {
  max-width: 760px;
  margin: 0 auto;
  padding: 28px 28px 96px;
}

/* ============================================================
   Site header (small, present on every page)
   ============================================================ */

.site-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 18px;
  margin-bottom: 36px;
  border-bottom: 1px solid var(--border);
}
.site-header .brand {
  font-family: var(--serif);
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--ink);
}
.site-header .brand a:hover { color: var(--indigo-text); }
.site-header nav {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  display: flex;
  gap: 18px;
}
.site-header nav a:hover { color: var(--ink); }

/* ============================================================
   Hero (homepage only)
   ============================================================ */

.hero {
  padding: 48px 0 56px;
  max-width: 760px;
}
.hero .kicker {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 14px;
}
.hero h1 {
  font-family: var(--serif);
  font-size: 56px;
  font-weight: 600;
  line-height: 1.02;
  letter-spacing: -0.02em;
  margin: 0 0 18px;
  color: var(--ink);
}
.hero .tagline {
  font-family: var(--serif);
  font-size: 22px;
  font-style: italic;
  line-height: 1.4;
  color: var(--ink-soft);
  max-width: 580px;
  margin: 0 0 8px;
}
.hero .sub {
  color: var(--muted);
  font-size: 14.5px;
  max-width: 600px;
  margin: 14px 0 0;
}

/* ============================================================
   Card grid (homepage)
   ============================================================ */

.grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  margin-top: 8px;
}
@media (max-width: 720px) {
  .grid { grid-template-columns: 1fr; gap: 18px; }
}

.card {
  display: flex;
  flex-direction: column;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  overflow: hidden;
  text-decoration: none;
  color: inherit;
  transition: transform 220ms ease, border-color 220ms ease, box-shadow 220ms ease;
  position: relative;
}
.card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--card-accent, var(--ink));
  opacity: 0.75;
}
.card:hover {
  transform: translateY(-3px);
  border-color: var(--card-accent, var(--ink));
  box-shadow: 0 10px 28px rgba(15, 23, 42, 0.07);
}
.card:hover::before { opacity: 1; }

.card .preview {
  position: relative;
  aspect-ratio: 16 / 10;
  background: var(--card-accent-soft, var(--panel-2));
  border-bottom: 1px solid var(--border);
  overflow: hidden;
}
.card .preview iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 200%;
  height: 200%;
  transform: scale(0.5);
  transform-origin: top left;
  border: 0;
  pointer-events: none;
  background: var(--panel);
}
.card .preview .veil {
  /* Sits above the iframe to mute its busyness and ensure click goes to <a>. */
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg,
    rgba(250, 250, 246, 0.0) 0%,
    rgba(250, 250, 246, 0.0) 55%,
    rgba(250, 250, 246, 0.55) 100%);
  pointer-events: none;
}

.card .body {
  padding: 18px 20px 22px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.card .meta {
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--card-accent, var(--muted));
  font-weight: 600;
}
.card h2 {
  font-family: var(--serif);
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.15;
  margin: 0;
  color: var(--ink);
}
.card .sub {
  font-size: 14.5px;
  color: var(--muted);
  line-height: 1.5;
  margin: 6px 0 0;
}

/* Per-card accent colors */
.card[data-accent="sky"]     { --card-accent: var(--sky-text);     --card-accent-soft: var(--sky-soft); }
.card[data-accent="indigo"]  { --card-accent: var(--indigo-text);  --card-accent-soft: var(--indigo-soft); }
.card[data-accent="saffron"] { --card-accent: var(--saffron-text); --card-accent-soft: var(--saffron-soft); }
.card[data-accent="emerald"] { --card-accent: var(--emerald-text); --card-accent-soft: var(--emerald-soft); }

/* ============================================================
   Lecture page
   ============================================================ */

.lecture-meta {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent, var(--muted));
  font-weight: 600;
  margin-bottom: 12px;
}

.lecture-title {
  font-family: var(--serif);
  font-size: 44px;
  font-weight: 600;
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin: 0 0 18px;
  color: var(--ink);
}

.lecture-lead {
  font-family: var(--serif);
  font-size: 20px;
  font-style: italic;
  line-height: 1.5;
  color: var(--ink-soft);
  margin: 0 0 28px;
  max-width: 680px;
}

/* Full-bleed embed for the lecture's headline interactive. */
.lecture-embed {
  margin: 32px 0 40px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  overflow: hidden;
  /* Pull slightly beyond the narrow column for visual punch. */
  margin-left: -40px;
  margin-right: -40px;
}
@media (max-width: 820px) {
  .lecture-embed { margin-left: 0; margin-right: 0; }
}
.lecture-embed iframe {
  display: block;
  width: 100%;
  height: 640px;
  border: 0;
  background: var(--panel);
}
.lecture-embed .caption {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  padding: 10px 16px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  gap: 12px;
}
.lecture-embed .caption a:hover { color: var(--ink); }

/* Prose body */
.prose { max-width: 680px; }
.prose h2 {
  font-family: var(--serif);
  font-size: 28px;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 48px 0 12px;
  line-height: 1.2;
  color: var(--ink);
}
.prose h2::before {
  content: '§ ';
  color: var(--accent, var(--muted));
  font-family: var(--mono);
  font-size: 0.7em;
  font-weight: 400;
  vertical-align: 0.15em;
  margin-right: 4px;
}
.prose h3 {
  font-family: var(--serif);
  font-size: 20px;
  font-weight: 600;
  margin: 28px 0 8px;
  color: var(--ink);
}
.prose p { margin: 0 0 16px; font-size: 16.5px; line-height: 1.65; color: var(--ink-soft); }
.prose p.draft {
  color: var(--muted);
  font-style: italic;
  border-left: 2px solid var(--border-2);
  padding-left: 14px;
}
.prose ul, .prose ol { padding-left: 22px; margin: 0 0 16px; color: var(--ink-soft); }
.prose li { margin-bottom: 6px; line-height: 1.6; }
.prose code {
  font-family: var(--mono);
  font-size: 0.92em;
  background: var(--panel-2);
  padding: 1px 6px;
  border-radius: 4px;
}
.prose blockquote {
  margin: 18px 0;
  padding: 4px 18px;
  border-left: 3px solid var(--accent, var(--border-2));
  color: var(--ink-soft);
  font-family: var(--serif);
  font-style: italic;
}

/* Accent assignment per lecture (set on <body data-accent>) */
body[data-accent="sky"]     { --accent: var(--sky-text); }
body[data-accent="indigo"]  { --accent: var(--indigo-text); }
body[data-accent="saffron"] { --accent: var(--saffron-text); }
body[data-accent="emerald"] { --accent: var(--emerald-text); }

/* Prev / next nav at end of a lecture */
.lecture-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 56px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}
.lecture-nav a {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--panel);
  transition: border-color 180ms ease, transform 180ms ease;
}
.lecture-nav a:hover { border-color: var(--ink); transform: translateY(-2px); }
.lecture-nav a.next { text-align: right; }
.lecture-nav .dir {
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
}
.lecture-nav .label {
  font-family: var(--serif);
  font-size: 18px;
  font-weight: 600;
  color: var(--ink);
}
.lecture-nav a.disabled {
  opacity: 0.4;
  pointer-events: none;
}

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

.site-footer {
  margin-top: 72px;
  padding-top: 22px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  display: flex;
  justify-content: space-between;
  gap: 16px;
}