/* Third Information Lab — single page, vanilla CSS, no build.
   Palette shared with Material & Meaning (family, not merge):
   charcoal #1c1b1a · slate #3a3d42 · bone #e9e4d8 · gold #d8a24a */

:root {
  --charcoal: #1c1b1a;
  --slate: #3a3d42;
  --bone: #e9e4d8;
  --gold: #d8a24a;
  --serif: "Spectral", "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, "Times New Roman", serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --maxw: 1120px;
  --measure: 62ch;
  --pad: clamp(1.25rem, 5vw, 3rem);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bone);
  color: var(--charcoal);
  font-family: var(--sans);
  font-size: clamp(1rem, 0.96rem + 0.2vw, 1.0625rem);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

.wrap {
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--pad);
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 100;
  background: var(--charcoal);
  color: var(--bone);
  font-family: var(--mono);
  font-size: 0.8rem;
  padding: 0.6rem 1rem;
  text-decoration: none;
}
.skip-link:focus { left: 0.5rem; top: 0.5rem; }

a {
  color: var(--charcoal);
  text-decoration: underline;
  text-decoration-color: var(--gold);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
a:hover { text-decoration-thickness: 2px; }

:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 3px;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--bone);
  border-top: 2px solid var(--gold);
}
.site-header::after {
  content: "";
  display: block;
  height: 1px;
  background: var(--slate);
  opacity: 0.35;
}
.header-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem 1.5rem;
  padding-block: 0.9rem;
}
.wordmark {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 1.05rem;
  letter-spacing: 0.01em;
  text-decoration: none;
  color: var(--charcoal);
}
.wordmark:hover { text-decoration: none; color: var(--charcoal); }
.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem 1.15rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.site-nav a {
  text-decoration: none;
  color: var(--slate);
}
.site-nav a:hover { color: var(--charcoal); text-decoration: underline; text-decoration-color: var(--gold); }

/* Sections */
.section {
  padding-block: clamp(2.75rem, 6vw, 4.5rem);
  border-bottom: 1px solid rgba(58, 61, 66, 0.25);
}
.section--alt { background: #e4dfd3; }
.section--hero { padding-top: clamp(3rem, 7vw, 5rem); }
.section--footer { border-bottom: 0; }

.grid-gutter {
  display: grid;
  grid-template-columns: minmax(0, 10rem) minmax(0, 1fr);
  gap: clamp(1.25rem, 3vw, 2.5rem);
}
@media (max-width: 720px) {
  .grid-gutter { grid-template-columns: 1fr; }
}

.sec-num {
  display: block;
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  color: var(--gold);
  margin-bottom: 0.35rem;
}
.eyebrow {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--slate);
}

.hero-title, .sec-title {
  font-family: var(--serif);
  font-weight: 400;
  line-height: 1.22;
  margin: 0 0 1rem;
  max-width: 22ch;
}
.hero-title { font-size: clamp(1.65rem, 1.2rem + 1.8vw, 2.35rem); max-width: 28ch; }
.sec-title { font-size: clamp(1.4rem, 1.15rem + 1vw, 1.85rem); }

.lead {
  font-family: var(--serif);
  font-size: clamp(1.1rem, 1rem + 0.4vw, 1.25rem);
  line-height: 1.5;
  max-width: var(--measure);
  margin: 0 0 1.5rem;
}

.prose {
  max-width: var(--measure);
  margin: 0 0 1rem;
}
.prose.muted { color: var(--slate); margin-top: 1.25rem; }

.callout {
  max-width: var(--measure);
  border-left: 2px solid var(--gold);
  padding: 0.85rem 0 0.85rem 1.15rem;
  margin: 1.5rem 0 0;
}
.callout--quiet { border-left-color: var(--slate); opacity: 0.95; }
.callout-label {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--slate);
  margin: 0 0 0.4rem;
}
.callout-text {
  font-family: var(--serif);
  font-size: 1.05rem;
  line-height: 1.45;
  margin: 0;
}

.content-block { margin-top: 1.75rem; }

/* Cards */
.cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin-top: 2rem;
}
@media (max-width: 800px) {
  .cards { grid-template-columns: 1fr; }
}
.card {
  border: 1px solid rgba(58, 61, 66, 0.35);
  padding: 1.25rem 1.2rem 1.35rem;
  background: var(--bone);
}
.card--accent {
  border-color: var(--gold);
  background: #f0ebe0;
}
.card-title {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 1.2rem;
  margin: 0 0 0.25rem;
}
.card-kicker {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--gold);
  margin: 0 0 0.75rem;
}
.card p:last-child { margin: 0; font-size: 0.95rem; color: var(--slate); }

/* Lists */
.strand-list {
  max-width: var(--measure);
  margin: 0;
  padding-left: 1.2rem;
}
.strand-list li { margin-bottom: 1rem; }
.strand-list strong { font-weight: 600; }

.plain-list {
  max-width: var(--measure);
  margin: 0;
  padding-left: 1.2rem;
}
.plain-list li { margin-bottom: 0.65rem; }

/* Footer */
.site-footer {
  background: var(--charcoal);
  color: var(--bone);
  padding: 1.5rem 0;
}
.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.5rem 1.5rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
}
.site-footer p { margin: 0; }
.footer-note { opacity: 0.65; }
.site-footer a { color: var(--bone); text-decoration-color: var(--gold); }