/* ---------- BioAI Lab — design system ---------- */
/* Forest green + cream, editorial-technical */

:root {
  /* Cream / paper — closer to white */
  --cream-50: #fefdfa;
  --cream-100: #f8f5ee;
  --cream-200: #ece5d2;
  --cream-300: #ddd3b8;

  /* Forest greens — brightened */
  --moss-50: #f0f5ed;
  --moss-100: #dde7d3;
  --moss-200: #b4c5a6;
  --moss-400: #7a9670;
  --moss-600: #4d7549;
  --moss-700: #3a5e37;
  --moss-800: #2a4828;
  --moss-900: #1c331c;

  /* Yellow accent — warm sunlit */
  --sun-100: #fcefb8;
  --sun-200: #f7df7e;
  --sun-400: #e8c441;
  --sun-600: #c69a1f;

  /* Accents — same chroma family */
  --ochre: #b8884a;       /* warm earth */
  --terracotta: #b65a3c;  /* alert/highlight */
  --sage: #8a9a7c;        /* secondary */

  /* Theme accent hues for the four research themes */
  --theme-genomics: #4d7549;     /* brighter moss */
  --theme-genomics-soft: #d3e0c7;
  --theme-llm: #3a6e8f;          /* steel blue */
  --theme-llm-soft: #c8dae5;
  --theme-healthcare: #b65a3c;   /* terracotta */
  --theme-healthcare-soft: #e8c5b3;
  --theme-ethics: #c69a1f;       /* sun/ochre */
  --theme-ethics-soft: #f7e6a8;

  /* Functional */
  --ink: #0e1d10;
  --ink-soft: #3a463a;
  --rule: #ddd3b8;
  --paper: #fefdfa;
  --paper-warm: #f5f1e6;

  --serif: 'Fraunces', 'Cormorant Garamond', Georgia, serif;
  --sans: 'Inter Tight', 'Inter', system-ui, sans-serif;
  --mono: 'JetBrains Mono', 'IBM Plex Mono', ui-monospace, monospace;

  --max-w: 1280px;
  --pad-x: clamp(20px, 5vw, 64px);
}

/* ---- Font pairing presets (overridden via [data-fonts] on <html>) ---- */
/* Apple-style: SF-like geometric humanist sans for everything, tight tracking */
html[data-fonts="apple"] {
  --serif: -apple-system, 'SF Pro Display', 'Inter Tight', system-ui, sans-serif;
  --sans:  -apple-system, 'SF Pro Text', 'Inter', system-ui, sans-serif;
}
html[data-fonts="apple"] h1,
html[data-fonts="apple"] h2,
html[data-fonts="apple"] h3 { font-weight: 600; letter-spacing: -0.035em; }
html[data-fonts="apple"] .serif { letter-spacing: -0.035em; font-weight: 600; }

/* Geist (Vercel-ish, very Apple-adjacent) */
html[data-fonts="geist"] {
  --serif: 'Geist', -apple-system, system-ui, sans-serif;
  --sans:  'Geist', -apple-system, system-ui, sans-serif;
}
html[data-fonts="geist"] h1,
html[data-fonts="geist"] h2,
html[data-fonts="geist"] h3 { font-weight: 600; letter-spacing: -0.035em; }
html[data-fonts="geist"] .serif { letter-spacing: -0.035em; font-weight: 600; }

/* Manrope — friendly geometric, rounded terminals */
html[data-fonts="manrope"] {
  --serif: 'Manrope', system-ui, sans-serif;
  --sans:  'Manrope', system-ui, sans-serif;
}
html[data-fonts="manrope"] h1,
html[data-fonts="manrope"] h2,
html[data-fonts="manrope"] h3 { font-weight: 700; letter-spacing: -0.03em; }
html[data-fonts="manrope"] .serif { letter-spacing: -0.03em; font-weight: 700; }

/* DM Sans — clean modern geometric */
html[data-fonts="dmsans"] {
  --serif: 'DM Sans', system-ui, sans-serif;
  --sans:  'DM Sans', system-ui, sans-serif;
}
html[data-fonts="dmsans"] h1,
html[data-fonts="dmsans"] h2,
html[data-fonts="dmsans"] h3 { font-weight: 600; letter-spacing: -0.04em; }
html[data-fonts="dmsans"] .serif { letter-spacing: -0.04em; font-weight: 600; }

/* Plus Jakarta — slightly warmer Apple-feel */
html[data-fonts="jakarta"] {
  --serif: 'Plus Jakarta Sans', system-ui, sans-serif;
  --sans:  'Plus Jakarta Sans', system-ui, sans-serif;
}
html[data-fonts="jakarta"] h1,
html[data-fonts="jakarta"] h2,
html[data-fonts="jakarta"] h3 { font-weight: 700; letter-spacing: -0.03em; }
html[data-fonts="jakarta"] .serif { letter-spacing: -0.03em; font-weight: 700; }

/* Editorial — Instrument Serif headings + Inter body (mixed elegant) */
html[data-fonts="editorial"] {
  --serif: 'Instrument Serif', 'Fraunces', Georgia, serif;
  --sans:  'Inter', system-ui, sans-serif;
}
html[data-fonts="editorial"] h1,
html[data-fonts="editorial"] h2,
html[data-fonts="editorial"] h3 { font-weight: 400; letter-spacing: -0.02em; }
html[data-fonts="editorial"] .serif { font-weight: 400; letter-spacing: -0.02em; }

* { box-sizing: border-box; }

html, body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
button { font-family: inherit; cursor: pointer; }

/* Editorial type */
.serif { font-family: var(--serif); font-weight: 400; letter-spacing: -0.01em; }
.mono  { font-family: var(--mono); font-weight: 400; }
.upper-mono {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--ink-soft);
}

h1, h2, h3, h4 { margin: 0; font-weight: 500; letter-spacing: -0.02em; text-wrap: balance; }
p { margin: 0 0 1em; text-wrap: pretty; }

/* ---------- Site chrome ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(250, 250, 250, 0.88);
  backdrop-filter: saturate(140%) blur(10px);
  -webkit-backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--rule);
}
.site-header__inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 14px var(--pad-x);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--serif);
  font-size: 19px;
  letter-spacing: -0.01em;
  color: var(--moss-800);
}
.brand__mark {
  width: 32px; height: 32px;
  display: grid; place-items: center;
  background: var(--moss-700);
  color: var(--cream-100);
  border-radius: 4px;
  font-family: var(--mono);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0;
}
.brand__name strong { font-weight: 500; }
.brand__name em {
  font-style: normal;
  color: var(--moss-400);
  margin-left: 4px;
}
.nav { display: flex; gap: 28px; align-items: center; }
.nav a {
  font-size: 14px;
  color: var(--ink-soft);
  padding: 6px 0;
  border-bottom: 1px solid transparent;
  transition: color .15s, border-color .15s;
}
.nav a:hover { color: var(--moss-700); }
.nav a.active { color: var(--moss-800); border-bottom-color: var(--moss-700); }
.nav a.nav__cta {
  font-size: 13px;
  padding: 8px 14px;
  background: var(--moss-800);
  color: var(--cream-50);
  border-radius: 999px;
  border: 1px solid var(--moss-800);
  transition: background .15s;
  white-space: nowrap;
}
.nav a.nav__cta:hover { background: var(--moss-700); color: var(--cream-50); }

/* ---------- Footer ---------- */
.site-footer {
  margin-top: 100px;
  background: var(--moss-900);
  color: var(--cream-200);
  padding: 64px var(--pad-x) 32px;
}
.site-footer__inner {
  max-width: var(--max-w);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
}
.site-footer h4 {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--sun-200);
  margin-bottom: 14px;
  font-weight: 500;
}
.site-footer ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 8px; }
.site-footer a { color: var(--cream-200); font-size: 14px; }
.site-footer a:hover { color: var(--cream-50); }
.site-footer__brand p { color: var(--moss-200); font-size: 13px; max-width: 320px; }
.site-footer__brand .brand__name { color: var(--cream-50); }
.site-footer__bottom {
  max-width: var(--max-w);
  margin: 48px auto 0;
  padding-top: 24px;
  border-top: 1px solid var(--moss-700);
  display: flex;
  justify-content: space-between;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--moss-200);
}

/* ---------- Pills / tags ---------- */
.tag {
  display: inline-block;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  padding: 3px 9px;
  border: 1px solid var(--moss-200);
  background: var(--cream-50);
  color: var(--moss-700);
  border-radius: 4px;
  cursor: pointer;
  transition: background .12s, border-color .12s, color .12s;
}
.tag:hover { background: var(--moss-100); border-color: var(--moss-400); }
.tag--active {
  background: var(--moss-800);
  color: var(--cream-50);
  border-color: var(--moss-800);
}
.tag--theme-genomics { border-color: var(--theme-genomics-soft); color: var(--theme-genomics); }
.tag--theme-llm-agents { border-color: var(--theme-llm-soft); color: var(--theme-llm); }
.tag--theme-healthcare { border-color: var(--theme-healthcare-soft); color: var(--theme-healthcare); }
.tag--theme-ethics { border-color: var(--theme-ethics-soft); color: var(--theme-ethics); }

.tag--keyword {
  background: transparent;
  cursor: default;
  pointer-events: none;
}
.tag--keyword:hover { background: transparent; border-color: var(--moss-300); }

/* ---------- Section primitives ---------- */
.section {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 80px var(--pad-x);
}
.section--tight { padding: 56px var(--pad-x); }
.section--full {
  max-width: none;
  background: var(--moss-900);
  color: var(--cream-100);
  padding: 96px var(--pad-x);
}
.section--paper-warm { background: var(--paper-warm); }

.section-head {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 48px;
  align-items: baseline;
  margin-bottom: 48px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--rule);
}
.section-head__num {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--moss-600);
}
.section-head__title {
  font-family: var(--serif);
  font-size: clamp(32px, 4vw, 52px);
  line-height: 1.05;
}
.section-head__sub {
  margin-top: 12px;
  font-family: var(--sans);
  font-size: 16px;
  color: var(--ink-soft);
  max-width: 60ch;
}

@media (max-width: 720px) {
  .section-head { grid-template-columns: 1fr; gap: 12px; }
  .nav { gap: 14px; }
  .nav a:not(.nav__cta) { display: none; }
  .site-footer__inner { grid-template-columns: 1fr 1fr; }
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  border: 1px solid transparent;
  transition: background .15s, border-color .15s, color .15s;
  cursor: pointer;
}
.btn--primary { background: var(--moss-800); color: var(--cream-50); border-color: var(--moss-800); }
.btn--primary:hover { background: var(--moss-700); }
.btn--ghost { background: transparent; color: var(--moss-800); border-color: var(--moss-300, var(--moss-200)); }
.btn--ghost:hover { background: var(--cream-100); border-color: var(--moss-400); }
.btn__arrow {
  display: inline-block;
  transition: transform .2s;
}
.btn:hover .btn__arrow { transform: translateX(3px); }

/* ---------- Utility ---------- */
.divider-rule {
  height: 1px;
  background: var(--rule);
  margin: 48px 0;
}
.kbd {
  font-family: var(--mono);
  font-size: 11px;
  padding: 2px 6px;
  border: 1px solid var(--rule);
  border-radius: 3px;
  background: var(--cream-100);
  color: var(--ink-soft);
}

/* placeholder image — striped subtle */
.ph {
  background-color: var(--cream-200);
  background-image: repeating-linear-gradient(
    135deg,
    var(--cream-200) 0,
    var(--cream-200) 11px,
    var(--cream-300) 11px,
    var(--cream-300) 12px
  );
  display: grid;
  place-items: center;
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.02em;
}
.ph--moss {
  background-color: var(--moss-700);
  background-image: repeating-linear-gradient(
    135deg,
    var(--moss-700) 0,
    var(--moss-700) 11px,
    var(--moss-800) 11px,
    var(--moss-800) 12px
  );
  color: var(--moss-200);
}

/* ---------- DNA / network background motif ---------- */
.motif-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--moss-100) 1px, transparent 1px),
    linear-gradient(90deg, var(--moss-100) 1px, transparent 1px);
  background-size: 40px 40px;
  opacity: 0.4;
  pointer-events: none;
  mask-image: radial-gradient(ellipse at center, black 30%, transparent 70%);
  -webkit-mask-image: radial-gradient(ellipse at center, black 30%, transparent 70%);
}
