/* ZeravaTech — design tokens
   Paper #FAFAF8 · Ink #141D2B · Viridian #0E7C66 · Amber #B65A1E
   Display: STIX Two Text · Body: IBM Plex Sans · Utility: IBM Plex Mono */

:root {
  --paper: #FAFAF8;
  --ink: #141D2B;
  --ink-soft: #3A4454;
  --muted: #5A6472;
  --viridian: #0E7C66;
  --viridian-dark: #0A5F4F;
  --viridian-tint: #E8F2EF;
  --amber: #B65A1E;
  --hairline: #DFE3DC;
  --card: #FFFFFF;
  --display: "STIX Two Text", Georgia, serif;
  --body: "IBM Plex Sans", -apple-system, "Segoe UI", sans-serif;
  --mono: "IBM Plex Mono", "SF Mono", Consolas, monospace;
  --maxw: 1080px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--body);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 28px; }

a { color: var(--viridian-dark); text-decoration: none; }
a:hover { text-decoration: underline; }
a:focus-visible, button:focus-visible {
  outline: 2px solid var(--viridian);
  outline-offset: 3px;
  border-radius: 2px;
}

/* ---------- header ---------- */
header {
  border-bottom: 1px solid var(--hairline);
  background: rgba(250, 250, 248, 0.92);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 50;
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 66px;
}
.brand {
  font-family: var(--display);
  font-weight: 600;
  font-size: 20px;
  letter-spacing: 0.01em;
  color: var(--ink);
  display: flex;
  align-items: center;
  gap: 10px;
}
.brand:hover { text-decoration: none; }
.brand .mark { flex: 0 0 auto; display: block; }
.nav-links { display: flex; gap: 26px; align-items: center; }
.nav-links a {
  font-size: 14.5px;
  color: var(--ink-soft);
  font-weight: 500;
}
.nav-links a:hover { color: var(--ink); text-decoration: none; }
.nav-cta {
  border: 1.5px solid var(--ink);
  padding: 8px 16px;
  border-radius: 3px;
  color: var(--ink) !important;
  font-weight: 600 !important;
  transition: background 0.15s, color 0.15s;
}
.nav-cta:hover { background: var(--ink); color: var(--paper) !important; }
@media (max-width: 760px) { .nav-links a:not(.nav-cta) { display: none; } }

/* ---------- shared section furniture ---------- */
section { padding: 88px 0; border-bottom: 1px solid var(--hairline); }
.eyebrow {
  font-family: var(--mono);
  font-size: 12.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--viridian-dark);
  margin-bottom: 18px;
}
h2 {
  font-family: var(--display);
  font-weight: 600;
  font-size: clamp(28px, 4vw, 38px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  max-width: 21ch;
  margin-bottom: 22px;
}
.lede { font-size: 19px; color: var(--ink-soft); max-width: 62ch; }

/* ---------- hero ---------- */
.hero { padding: 96px 0 100px; border-bottom: 1px solid var(--hairline); }
.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  gap: 64px;
  align-items: center;
}
@media (max-width: 880px) { .hero-grid { grid-template-columns: 1fr; gap: 48px; } }
.hero h1 {
  font-family: var(--display);
  font-weight: 600;
  font-size: clamp(34px, 5vw, 52px);
  line-height: 1.14;
  letter-spacing: -0.015em;
  margin-bottom: 26px;
}
.hero h1 em { font-style: italic; color: var(--viridian-dark); }
.hero p.sub { font-size: 19px; color: var(--ink-soft); max-width: 54ch; margin-bottom: 36px; }
.hero-ctas { display: flex; gap: 14px; flex-wrap: wrap; }
.btn {
  display: inline-block;
  font-weight: 600;
  font-size: 15.5px;
  padding: 13px 24px;
  border-radius: 3px;
  transition: transform 0.12s, background 0.15s;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn-primary { background: var(--ink); color: var(--paper); }
.btn-primary:hover { background: #202c3f; }
.btn-ghost { border: 1.5px solid var(--hairline); color: var(--ink); background: var(--card); }
.btn-ghost:hover { border-color: var(--ink-soft); }
.hero-note {
  margin-top: 26px;
  font-family: var(--mono);
  font-size: 13px;
  color: var(--muted);
}
.hero-note a { color: var(--muted); text-decoration: underline; }

/* simplex figure */
.simplex-card {
  background: var(--card);
  border: 1px solid var(--hairline);
  border-radius: 6px;
  padding: 28px 26px 20px;
}
.simplex-card figcaption {
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--muted);
  line-height: 1.6;
  margin-top: 14px;
  border-top: 1px solid var(--hairline);
  padding-top: 14px;
}
.simplex-card .eq { color: var(--ink); font-weight: 500; }

/* ---------- claim strip ---------- */
.claims {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--hairline);
  border: 1px solid var(--hairline);
  border-radius: 6px;
  overflow: hidden;
  margin-top: 56px;
}
@media (max-width: 760px) { .claims { grid-template-columns: 1fr; } }
.claim { background: var(--card); padding: 26px 26px 24px; }
.claim .num {
  font-family: var(--display);
  font-size: 34px;
  font-weight: 600;
  color: var(--viridian-dark);
  line-height: 1.1;
}
.claim .lbl { font-size: 14.5px; color: var(--ink-soft); margin-top: 6px; }
.claim .src { font-family: var(--mono); font-size: 11.5px; color: var(--muted); margin-top: 12px; }
.claim .src a { color: var(--muted); text-decoration: underline; }

/* ---------- how it works ---------- */
.tiers { display: grid; gap: 0; margin-top: 48px; border-top: 1px solid var(--hairline); }
.tier {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 40px;
  padding: 34px 0;
  border-bottom: 1px solid var(--hairline);
}
@media (max-width: 700px) { .tier { grid-template-columns: 1fr; gap: 10px; } }
.tier .t-name { font-family: var(--mono); font-size: 14px; font-weight: 600; color: var(--ink); letter-spacing: 0.02em; }
.tier .t-name span { display: block; color: var(--viridian-dark); font-size: 12px; margin-top: 4px; font-weight: 400; }
.tier p { color: var(--ink-soft); max-width: 64ch; }

/* ---------- research ---------- */
.papers { display: grid; gap: 14px; margin-top: 44px; }
.paper {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 24px;
  align-items: center;
  background: var(--card);
  border: 1px solid var(--hairline);
  border-radius: 6px;
  padding: 22px 26px;
  transition: border-color 0.15s;
}
.paper:hover { border-color: var(--viridian); text-decoration: none; }
@media (max-width: 600px) { .paper { grid-template-columns: 1fr; gap: 10px; } }
.paper .p-title { font-family: var(--display); font-size: 19px; font-weight: 600; color: var(--ink); }
.paper .p-meta { font-family: var(--mono); font-size: 12.5px; color: var(--muted); margin-top: 5px; }
.paper .p-go { font-family: var(--mono); font-size: 13px; color: var(--viridian-dark); white-space: nowrap; }
.disclosure {
  margin-top: 36px;
  background: var(--viridian-tint);
  border: 1px solid #CDE4DE;
  border-radius: 6px;
  padding: 22px 26px;
  font-size: 15.5px;
  color: var(--ink-soft);
  max-width: 100%;
}
.disclosure strong { color: var(--ink); }

/* ---------- verticals ---------- */
.verticals { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; margin-top: 48px; }
@media (max-width: 760px) { .verticals { grid-template-columns: 1fr; } }
.vertical {
  background: var(--card);
  border: 1px solid var(--hairline);
  border-radius: 6px;
  padding: 34px 30px;
}
.vertical .v-tag {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--amber);
  margin-bottom: 14px;
}
.vertical h3 { font-family: var(--display); font-size: 24px; font-weight: 600; margin-bottom: 14px; }
.vertical p { color: var(--ink-soft); font-size: 16px; margin-bottom: 14px; }
.vertical ul { list-style: none; margin: 18px 0 22px; }
.vertical li {
  padding: 9px 0 9px 26px;
  position: relative;
  font-size: 15.5px;
  color: var(--ink-soft);
  border-top: 1px solid var(--hairline);
}
.vertical li::before {
  content: "—";
  position: absolute;
  left: 0;
  color: var(--viridian);
  font-family: var(--mono);
}
.vertical .v-link { font-weight: 600; font-size: 15px; }

/* ---------- FAQ ---------- */
.faq { margin-top: 40px; border-top: 1px solid var(--hairline); }
.faq details { border-bottom: 1px solid var(--hairline); }
.faq summary {
  cursor: pointer;
  padding: 22px 36px 22px 0;
  font-family: var(--display);
  font-size: 19px;
  font-weight: 600;
  list-style: none;
  position: relative;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  position: absolute;
  right: 4px;
  top: 20px;
  font-family: var(--mono);
  font-size: 20px;
  color: var(--viridian-dark);
  transition: transform 0.15s;
}
.faq details[open] summary::after { transform: rotate(45deg); }
.faq details p { padding: 0 0 24px; color: var(--ink-soft); max-width: 70ch; }

/* ---------- contact ---------- */
.contact-band { background: var(--ink); color: var(--paper); border-bottom: none; }
.contact-band .eyebrow { color: #6FBFAE; }
.contact-band h2 { color: var(--paper); }
.contact-band p { color: #B9C2CF; max-width: 58ch; }
.contact-band .btn-primary { background: var(--paper); color: var(--ink); margin-top: 30px; }
.contact-band .btn-primary:hover { background: #E8EAE5; }
.contact-band .alt {
  margin-top: 22px;
  font-family: var(--mono);
  font-size: 13.5px;
  color: #8C97A6;
}
.contact-band .alt a { color: #B9C2CF; text-decoration: underline; }

/* ---------- footer ---------- */
footer { padding: 44px 0 56px; font-size: 14px; color: var(--muted); }
.foot-grid { display: flex; justify-content: space-between; gap: 30px; flex-wrap: wrap; }
.foot-links { display: flex; gap: 22px; flex-wrap: wrap; }
.foot-links a { color: var(--muted); }
.foot-links a:hover { color: var(--ink); }
.foot-legal { margin-top: 18px; font-family: var(--mono); font-size: 12px; color: var(--muted); }

/* ---------- legal pages ---------- */
.legal-page { padding: 72px 0 100px; }
.legal-page h1 { font-family: var(--display); font-size: 36px; font-weight: 600; margin-bottom: 8px; }
.legal-page .updated { font-family: var(--mono); font-size: 13px; color: var(--muted); margin-bottom: 44px; }
.legal-page h2 { font-size: 22px; margin: 40px 0 12px; max-width: none; }
.legal-page p, .legal-page li { color: var(--ink-soft); max-width: 74ch; margin-bottom: 14px; }
.legal-page ul { padding-left: 22px; }

/* subtle rise on load for hero (respects reduced motion via global rule) */
@keyframes rise { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
.hero h1, .hero .sub, .hero-ctas, .hero-note { animation: rise 0.55s ease both; }
.hero .sub { animation-delay: 0.08s; }
.hero-ctas { animation-delay: 0.16s; }
.hero-note { animation-delay: 0.24s; }