/* =============================================================
   FM Research Project — site stylesheet
   Bolder scientific-publication aesthetic
   ============================================================= */

@import url('https://fonts.googleapis.com/css2?family=Source+Serif+4:opsz,wght@8..60,400;8..60,500;8..60,600;8..60,700&family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
  /* Type system */
  --font-serif: "Source Serif 4", Georgia, "Times New Roman", serif;
  --font-sans:  "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono:  "JetBrains Mono", ui-monospace, "SF Mono", Monaco, monospace;

  /* Base colors — neutral foundation */
  --c-text:        #0F172A;
  --c-text-mute:   #475569;
  --c-text-soft:   #64748B;
  --c-bg:          #FFFFFF;
  --c-bg-soft:     #F8FAFC;
  --c-bg-deep:     #0F172A;     /* hero / dark sections */
  --c-bg-cream:    #FAF7F2;     /* warm section break */
  --c-border:      #E2E8F0;
  --c-border-strong: #CBD5E1;

  /* Brand / tier palette — carries through from visualizations */
  --c-established: #0D9488;
  --c-emerging:    #7E22CE;
  --c-inferred:    #B45309;
  --c-bridging:    #EA580C;
  --c-intervention:#DC2626;
  --c-trigger:     #64748B;

  --f-established: #CCFBF1;
  --f-emerging:    #F3E8FF;
  --f-inferred:    #FEF3C7;
  --f-bridging:    #FFEDD5;
  --f-intervention:#FEE2E2;

  /* Accent — site brand */
  --c-accent:      #5B21B6;     /* deep violet, cooler than tier purple */
  --c-accent-soft: #EDE9FE;

  /* Layout */
  --max-prose:   720px;
  --max-content: 1080px;
  --max-wide:    1280px;
  --gap-xs: 6px;
  --gap-sm: 12px;
  --gap-md: 20px;
  --gap-lg: 36px;
  --gap-xl: 64px;
  --gap-2xl: 96px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; padding: 0;
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.6;
  color: var(--c-text);
  background: var(--c-bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* =============================================================
   TYPOGRAPHY
   ============================================================= */

h1, h2, h3, h4 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.012em;
  margin: 0 0 var(--gap-md);
  color: var(--c-text);
}
h1 { font-size: clamp(40px, 5.6vw, 64px); font-weight: 700; letter-spacing: -0.022em; }
h2 { font-size: clamp(28px, 3.2vw, 38px); margin-top: var(--gap-xl); }
h3 { font-size: clamp(20px, 2.0vw, 24px); margin-top: var(--gap-lg); }
h4 { font-size: 16px; text-transform: uppercase; letter-spacing: 0.06em; font-family: var(--font-sans); font-weight: 700; color: var(--c-accent); margin-bottom: var(--gap-sm); }

p { margin: 0 0 var(--gap-md); max-width: var(--max-prose); }
p.lede {
  font-size: 21px; line-height: 1.55; color: var(--c-text-mute); font-weight: 400;
  max-width: var(--max-prose);
}
a { color: var(--c-accent); text-decoration: none; border-bottom: 1px solid transparent; transition: border-color 120ms ease; }
a:hover { border-bottom-color: var(--c-accent); }
strong { font-weight: 600; color: var(--c-text); }
em { font-style: italic; }
code { font-family: var(--font-mono); font-size: 0.9em; padding: 1px 5px; background: var(--c-bg-soft); border-radius: 3px; }

ul, ol { padding-left: 1.4em; margin: 0 0 var(--gap-md); max-width: var(--max-prose); }
li { margin-bottom: 6px; }

hr {
  border: 0; border-top: 1px solid var(--c-border);
  margin: var(--gap-lg) 0;
}

blockquote {
  font-family: var(--font-serif);
  font-size: 22px;
  font-style: italic;
  line-height: 1.45;
  color: var(--c-text);
  padding: 0 var(--gap-lg);
  margin: var(--gap-lg) 0;
  border-left: 3px solid var(--c-accent);
  max-width: var(--max-prose);
}
blockquote cite {
  display: block;
  font-style: normal;
  font-size: 14px;
  font-family: var(--font-sans);
  color: var(--c-text-mute);
  margin-top: var(--gap-sm);
}

/* =============================================================
   NAV
   ============================================================= */

.site-nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(140%) blur(8px);
  -webkit-backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid var(--c-border);
}
.nav-inner {
  max-width: var(--max-wide);
  margin: 0 auto;
  padding: 14px 28px;
  display: flex; align-items: center; gap: var(--gap-lg);
}
.nav-brand {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 18px;
  color: var(--c-text);
  border-bottom: 0;
  letter-spacing: -0.01em;
}
.nav-brand:hover { border-bottom: 0; color: var(--c-accent); }
.nav-brand .accent { color: var(--c-accent); }
.nav-links {
  display: flex; gap: var(--gap-md); align-items: center;
  margin-left: auto;
  list-style: none; padding: 0; margin-bottom: 0;
}
.nav-links a {
  color: var(--c-text-mute);
  font-size: 14.5px; font-weight: 500;
  border-bottom: 0;
  padding: 6px 2px;
  position: relative;
}
.nav-links a:hover { color: var(--c-text); }
.nav-links a.active { color: var(--c-accent); font-weight: 600; }
.nav-links a.active::after {
  content: "";
  position: absolute; left: 0; right: 0; bottom: -16px;
  height: 2px; background: var(--c-accent);
}

/* =============================================================
   HERO
   ============================================================= */

.hero {
  background: var(--c-bg-deep);
  color: #F8FAFC;
  padding: var(--gap-2xl) 28px;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute; inset: 0;
  background:
    radial-gradient(circle at 18% 30%, rgba(126, 34, 206, 0.22), transparent 50%),
    radial-gradient(circle at 82% 70%, rgba(13, 148, 136, 0.18), transparent 50%);
  pointer-events: none;
}
.hero-inner {
  position: relative;
  max-width: var(--max-content);
  margin: 0 auto;
}
.hero h1 { color: #FFFFFF; margin-bottom: var(--gap-md); }
.hero h1 .accent { color: #C4B5FD; }
.hero .lede { color: #CBD5E1; max-width: 720px; }
.hero strong, .hero .lede strong { color: #FFFFFF; font-weight: 600; }
.hero em, .hero .lede em { color: #E2E8F0; }
.hero .eyebrow {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: #C4B5FD;
  margin-bottom: var(--gap-md);
  padding: 4px 10px;
  border: 1px solid rgba(196, 181, 253, 0.4);
  border-radius: 999px;
}
.hero-cta {
  display: flex; gap: var(--gap-md); flex-wrap: wrap;
  margin-top: var(--gap-lg);
}
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 22px;
  border-radius: 8px;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 15px;
  text-decoration: none;
  border-bottom: 0;
  transition: transform 120ms ease, background 120ms ease, color 120ms ease;
  cursor: pointer;
}
.btn:hover { transform: translateY(-1px); border-bottom: 0; }
.btn-primary {
  background: #FFFFFF; color: var(--c-bg-deep);
}
.btn-primary:hover { background: var(--c-accent-soft); }
.btn-secondary {
  background: transparent; color: #F8FAFC; border: 1px solid rgba(248, 250, 252, 0.4);
}
.btn-secondary:hover { background: rgba(255,255,255,0.08); color: #FFFFFF; }
.btn-accent {
  background: var(--c-accent); color: #FFFFFF;
}
.btn-accent:hover { background: #4C1D95; color: #FFFFFF; }

.hero-stats {
  display: flex; gap: var(--gap-xl); flex-wrap: wrap;
  margin-top: var(--gap-xl);
  padding-top: var(--gap-lg);
  border-top: 1px solid rgba(255,255,255,0.1);
}
.hero-stat-num {
  font-family: var(--font-serif);
  font-size: 36px; font-weight: 700;
  color: #FFFFFF;
  line-height: 1;
}
.hero-stat-label {
  font-size: 12px; font-weight: 500;
  color: #94A3B8;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-top: 4px;
}

/* =============================================================
   SECTIONS
   ============================================================= */

.section {
  padding: var(--gap-2xl) 28px;
}
.section-inner {
  max-width: var(--max-content);
  margin: 0 auto;
}
.section-wide-inner {
  max-width: var(--max-wide);
  margin: 0 auto;
}
.section.tinted { background: var(--c-bg-soft); }
.section.cream  { background: var(--c-bg-cream); }
.section.dark   { background: var(--c-bg-deep); color: #F8FAFC; }
.section.dark h2, .section.dark h3, .section.dark h4 { color: #FFFFFF; }
.section.dark h4 { color: #C4B5FD; }
.section.dark p { color: #CBD5E1; }
.section.dark a { color: #C4B5FD; }
.section.dark a:hover { border-bottom-color: #C4B5FD; }

.section-header {
  margin-bottom: var(--gap-xl);
}
.section-header h4 { margin-bottom: 8px; }

/* Two-col layout for sections */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--gap-xl);
  align-items: start;
}
@media (max-width: 820px) {
  .two-col { grid-template-columns: 1fr; gap: var(--gap-lg); }
}

/* =============================================================
   CARDS
   ============================================================= */

.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--gap-md);
  max-width: var(--max-wide);
}

.card {
  background: var(--c-bg);
  border: 1px solid var(--c-border);
  border-radius: 12px;
  padding: var(--gap-lg);
  transition: transform 140ms ease, box-shadow 140ms ease, border-color 140ms ease;
  display: flex; flex-direction: column;
}
.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.08);
  border-color: var(--c-border-strong);
}
.card h3 {
  font-size: 22px;
  margin-top: 0;
  margin-bottom: var(--gap-sm);
}
.card p {
  color: var(--c-text-mute);
  font-size: 15px;
  margin-bottom: var(--gap-md);
  max-width: none;
  flex: 1;
}
.card-link {
  font-weight: 600; font-size: 14px;
  color: var(--c-accent);
  border-bottom: 0;
  display: inline-flex; align-items: center; gap: 4px;
  margin-top: auto;
}
.card-link::after { content: "→"; transition: transform 160ms ease; }
.card:hover .card-link::after { transform: translateX(3px); }

.card.featured {
  background: var(--c-bg-deep);
  color: #F8FAFC;
  border-color: var(--c-bg-deep);
}
.card.featured h3 { color: #FFFFFF; }
.card.featured p { color: #CBD5E1; }
.card.featured .card-link { color: #C4B5FD; }

.card-eyebrow {
  font-size: 11px; font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--c-accent);
  margin-bottom: var(--gap-sm);
}
.card.featured .card-eyebrow { color: #C4B5FD; }

/* Visualization preview cards — large CTAs */
.viz-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--gap-md);
  margin-top: var(--gap-lg);
}
@media (max-width: 820px) {
  .viz-cards { grid-template-columns: 1fr; }
}
.viz-card {
  background: var(--c-bg);
  border: 1px solid var(--c-border);
  border-radius: 16px;
  padding: var(--gap-xl);
  display: flex; flex-direction: column;
  position: relative;
  overflow: hidden;
  transition: transform 140ms ease, box-shadow 140ms ease;
  text-decoration: none;
  border-bottom: 0;
  color: inherit;
}
.viz-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 32px rgba(15, 23, 42, 0.10);
  border-bottom: 0;
}
.viz-card.mechanism::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 4px;
  background: linear-gradient(90deg, var(--c-emerging), var(--c-established));
}
.viz-card.ontology::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 4px;
  background: linear-gradient(90deg, var(--c-bridging), var(--c-emerging));
}
.viz-card h3 { font-size: 26px; margin: 0 0 var(--gap-sm); }
.viz-card .viz-meta {
  font-size: 12px;
  color: var(--c-text-mute);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--gap-md);
  font-weight: 600;
}
.viz-card p { color: var(--c-text-mute); font-size: 15.5px; margin-bottom: var(--gap-md); }
.viz-card .stats-row {
  display: flex; gap: var(--gap-md); flex-wrap: wrap;
  padding-top: var(--gap-md);
  margin-top: auto;
  border-top: 1px solid var(--c-border);
}
.viz-card .stat-pill {
  font-size: 13px;
  color: var(--c-text-mute);
}
.viz-card .stat-pill strong {
  display: inline-block;
  font-family: var(--font-serif);
  font-size: 22px;
  font-weight: 700;
  color: var(--c-text);
  margin-right: 4px;
}

/* =============================================================
   TIER BADGES (shared with visualizations)
   ============================================================= */

.badge {
  display: inline-block;
  font-size: 11px; font-weight: 600;
  text-transform: uppercase; letter-spacing: 0.06em;
  padding: 3px 9px;
  border-radius: 4px;
  font-family: var(--font-sans);
}
.badge.established { background: var(--f-established); color: var(--c-established); }
.badge.emerging    { background: var(--f-emerging);    color: var(--c-emerging); }
.badge.inferred    { background: var(--f-inferred);    color: var(--c-inferred); }
.badge.bridging    { background: var(--f-bridging);    color: var(--c-bridging); }
.badge.intervention{ background: var(--f-intervention); color: var(--c-intervention); }
.badge.outline {
  background: transparent;
  border: 1px solid currentColor;
}

/* =============================================================
   FOOTER
   ============================================================= */

footer.site-footer {
  background: var(--c-bg-deep);
  color: #CBD5E1;
  padding: var(--gap-xl) 28px;
  margin-top: var(--gap-2xl);
}
footer.site-footer .footer-inner {
  max-width: var(--max-wide);
  margin: 0 auto;
}
footer.site-footer h4 {
  color: #FFFFFF;
  font-family: var(--font-sans);
  font-size: 13px; font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--gap-sm);
}
footer.site-footer p { color: #94A3B8; font-size: 14px; max-width: 580px; }
footer.site-footer a { color: #C4B5FD; }
footer.site-footer .footer-cols {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1fr;
  gap: var(--gap-xl);
}
@media (max-width: 880px) {
  footer.site-footer .footer-cols { grid-template-columns: 1fr 1fr; gap: var(--gap-lg); }
}
@media (max-width: 520px) {
  footer.site-footer .footer-cols { grid-template-columns: 1fr; gap: var(--gap-lg); }
}
footer.site-footer .footer-contact {
  font-size: 15px;
  color: #FFFFFF;
  font-weight: 600;
  border-bottom: 0;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
footer.site-footer .footer-contact:hover { color: #C4B5FD; border-bottom: 0; }
footer.site-footer .footer-contact::after {
  content: "→";
  transition: transform 140ms ease;
}
footer.site-footer .footer-contact:hover::after { transform: translateX(3px); }
footer.site-footer .footer-contact-note {
  font-size: 13px;
  color: #94A3B8;
  margin-top: 8px;
  display: block;
  max-width: none;
}
footer.site-footer ul { list-style: none; padding: 0; margin: 0; }
footer.site-footer li { margin-bottom: 8px; font-size: 14px; }
footer.site-footer .footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding-top: var(--gap-md);
  margin-top: var(--gap-lg);
  font-size: 12px;
  color: #64748B;
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: var(--gap-sm);
}

/* =============================================================
   AUDIENCE TIER MARKERS — for layered navigation
   ============================================================= */

.audience-marker {
  display: inline-flex; align-items: center; gap: 4px;
  font-size: 11px; font-weight: 600;
  padding: 2px 8px;
  border-radius: 3px;
  text-transform: uppercase; letter-spacing: 0.06em;
  margin-bottom: var(--gap-sm);
}
.audience-marker.lay        { background: #DBEAFE; color: #1D4ED8; }
.audience-marker.researcher { background: var(--f-emerging); color: var(--c-emerging); }
.audience-marker.funder     { background: var(--f-established); color: var(--c-established); }

/* =============================================================
   PROSE / CONTENT PAGES
   ============================================================= */

.prose {
  max-width: var(--max-prose);
  margin: 0 auto;
}
.prose-wide {
  max-width: var(--max-content);
  margin: 0 auto;
}

/* Stat callouts inside prose */
.stat-callout {
  display: flex; align-items: baseline; gap: var(--gap-md);
  padding: var(--gap-md);
  background: var(--c-bg-soft);
  border-left: 3px solid var(--c-accent);
  border-radius: 0 8px 8px 0;
  margin: var(--gap-lg) 0;
  max-width: var(--max-prose);
}
.stat-callout .num {
  font-family: var(--font-serif);
  font-size: 44px; font-weight: 700;
  color: var(--c-accent);
  line-height: 1;
}
.stat-callout .label {
  font-size: 15px;
  color: var(--c-text-mute);
}

/* =============================================================
   EMBEDDED VISUALIZATIONS
   ============================================================= */
.viz-embed {
  max-width: var(--max-wide);
  margin: 0 auto;
  padding: 0 16px;
}

/* =============================================================
   UTILITIES
   ============================================================= */

.muted { color: var(--c-text-mute); }
.center { text-align: center; }
.mb-sm { margin-bottom: var(--gap-sm); }
.mb-md { margin-bottom: var(--gap-md); }
.mb-lg { margin-bottom: var(--gap-lg); }
.mt-lg { margin-top: var(--gap-lg); }