/* ============================================================
   CONCEPT ENGINES — editorial two-tone design system
   Paper (cream) ↔ Ink (warm charcoal). Serif display, mono
   labels, humanist-sans body. No images; type + space carry it.
   ============================================================ */

:root {
  /* Two-tone palette (warm) */
  --paper:        #f3efe7;   /* cream base */
  --paper-2:      #ebe6dc;   /* raised cream (cards) */
  --ink:          #1b1915;   /* warm near-black */
  --ink-2:        #24211b;   /* raised charcoal (cards) */

  /* Text */
  --on-paper:       #1b1915;
  --on-paper-soft:  #5f594e;
  --on-paper-faint: #8a8478;
  --on-ink:         #f3efe7;
  --on-ink-soft:    #b6ac9b;
  --on-ink-faint:   #7d7566;

  /* Lines */
  --rule-paper:     rgba(27,25,21,.16);
  --rule-paper-2:   rgba(27,25,21,.09);
  --rule-ink:       rgba(243,239,231,.18);
  --rule-ink-2:     rgba(243,239,231,.09);

  /* Accent — warm ochre, used sparingly */
  --accent:       #9c6b38;
  --accent-soft:  #b98a52;

  /* Type */
  --serif: 'Fraunces', 'Georgia', 'Times New Roman', serif;
  --sans:  'Inter', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --mono:  'IBM Plex Mono', 'SFMono-Regular', ui-monospace, monospace;

  /* Metrics */
  --edge: clamp(22px, 5.2vw, 96px);
  --maxw: 1280px;
  --readw: 68ch;
}

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--on-paper);
  font-family: var(--sans);
  font-weight: 400;
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  font-optical-sizing: auto;
  overflow-x: hidden;
}
::selection { background: var(--ink); color: var(--paper); }
img { max-width: 100%; display: block; }
a { color: inherit; }

/* ---------- Type primitives ---------- */
.eyebrow {
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .3em;
  text-transform: uppercase;
  color: var(--on-paper-faint);
  margin: 0 0 26px;
}
.display {
  font-family: var(--serif);
  font-weight: 400;
  line-height: .98;
  letter-spacing: -.015em;
  margin: 0;
  font-size: clamp(44px, 8vw, 118px);
}
h1, h2, h3 { font-family: var(--serif); font-weight: 400; margin: 0; }
h2.title {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(34px, 5.2vw, 72px);
  line-height: 1.02;
  letter-spacing: -.014em;
  margin: 0 0 28px;
  max-width: 20ch;
}
.deck {
  font-family: var(--serif);
  font-style: italic;
  font-weight: 400;
  font-size: clamp(21px, 2.5vw, 32px);
  line-height: 1.34;
  letter-spacing: -.01em;
  color: var(--on-paper);
  margin: 0 0 30px;
  max-width: 30ch;
}
.lede {
  font-size: clamp(18px, 1.5vw, 21px);
  line-height: 1.6;
  color: var(--on-paper-soft);
  max-width: var(--readw);
  margin: 0 0 34px;
}
p { max-width: var(--readw); }
.prose p { color: var(--on-paper-soft); margin: 0 0 20px; }
strong, b { font-weight: 600; color: var(--on-paper); }
em { font-style: italic; }

/* ---------- Layout ---------- */
.section { padding: clamp(72px, 12vh, 160px) var(--edge); position: relative; }
.wrap { max-width: var(--maxw); margin: 0 auto; width: 100%; }
.wrap-narrow { max-width: 880px; margin: 0 auto; width: 100%; }

/* Ink (dark) sections invert every token */
.ink {
  background: var(--ink);
  color: var(--on-ink);
}
.ink .eyebrow { color: var(--on-ink-faint); }
.ink .deck { color: var(--on-ink); }
.ink .lede { color: var(--on-ink-soft); }
.ink .prose p { color: var(--on-ink-soft); }
.ink strong, .ink b { color: var(--on-ink); }
.ink ::selection { background: var(--paper); color: var(--ink); }

/* ---------- Nav ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 20px var(--edge);
  background: color-mix(in srgb, var(--paper) 86%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--rule-paper-2);
}
.nav.on-ink {
  background: color-mix(in srgb, var(--ink) 86%, transparent);
  color: var(--on-ink);
  border-bottom-color: var(--rule-ink-2);
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  text-decoration: none;
  color: inherit;
  background: none; border: none; padding: 0; cursor: pointer;
}
.brand-word {
  font-family: var(--mono);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: .26em;
  text-transform: uppercase;
  white-space: nowrap;
}
.nav-right { display: flex; align-items: center; gap: clamp(18px, 2.4vw, 40px); }
.nav-links {
  display: flex;
  align-items: center;
  gap: clamp(18px, 2.4vw, 40px);
  list-style: none;
  margin: 0; padding: 0;
}
.nav-link {
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: inherit;
  opacity: .68;
  text-decoration: none;
  cursor: pointer;
  background: none; border: none; padding: 4px 0;
  transition: opacity .2s;
  position: relative;
}
.nav-link:hover, .nav-link[aria-current="page"] { opacity: 1; }
.nav-link[aria-current="page"]::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -2px;
  height: 1px; background: currentColor; opacity: .5;
}
.nav-cta {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .18em;
  text-transform: uppercase;
  padding: 9px 20px;
  border: 1px solid currentColor;
  background: none;
  color: inherit;
  cursor: pointer;
  transition: background .2s, color .2s;
}
.nav-cta:hover { background: currentColor; }
.nav-cta:hover .nav-cta-inner { color: var(--paper); }
.on-ink .nav-cta:hover .nav-cta-inner { color: var(--ink); }
.burger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none; border: none; cursor: pointer; padding: 6px;
}
.burger span { display: block; width: 24px; height: 1.5px; background: currentColor; }

/* ---------- CE logo mark ---------- */
.logo-mark { height: 18px; width: auto; display: block; flex-shrink: 0; }
.logo-mark-sm { height: 16px; }

/* ---------- Mobile menu ---------- */
.mobile-menu {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 80;
  background: var(--ink);
  color: var(--on-ink);
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  padding: 0 var(--edge);
}
.mobile-menu.open { display: flex; }
.menu-close {
  position: absolute; top: 20px; right: var(--edge);
  background: none; border: none; color: var(--on-ink);
  font-family: var(--serif); font-size: 40px; line-height: 1; cursor: pointer;
}
.menu-link {
  font-family: var(--serif);
  font-size: clamp(34px, 9vw, 60px);
  line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--on-ink);
  text-decoration: none;
  cursor: pointer;
  padding: 10px 0;
  border: none; border-bottom: 1px solid var(--rule-ink-2);
  background: none; text-align: left; display: block;
}
.menu-link:last-child { border-bottom: none; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 10px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .18em;
  text-transform: uppercase;
  padding: 15px 30px;
  cursor: pointer;
  text-decoration: none;
  transition: background .22s, color .22s, border-color .22s;
  border: 1px solid var(--ink);
}
.btn-solid { background: var(--ink); color: var(--paper); }
.btn-solid:hover { background: transparent; color: var(--ink); }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--rule-paper); }
.btn-ghost:hover { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.ink .btn-solid { background: var(--paper); color: var(--ink); border-color: var(--paper); }
.ink .btn-solid:hover { background: transparent; color: var(--paper); }
.ink .btn-ghost { color: var(--paper); border-color: var(--rule-ink); }
.ink .btn-ghost:hover { background: var(--paper); color: var(--ink); border-color: var(--paper); }
.btn-row { display: flex; flex-wrap: wrap; gap: 14px; }

/* ---------- Hero ---------- */
.hero {
  min-height: 92vh;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding-bottom: clamp(48px, 8vh, 100px);
}
.hero .display { max-width: 15ch; margin-bottom: 30px; }
.hero-foot {
  display: flex; flex-wrap: wrap; gap: 12px 40px;
  align-items: baseline; justify-content: space-between;
  margin-top: clamp(40px, 8vh, 90px);
  padding-top: 22px;
  border-top: 1px solid var(--rule-ink);
}
.hero-foot .meta { font-family: var(--mono); font-size: 12px; letter-spacing: .2em; text-transform: uppercase; color: var(--on-ink-faint); }

/* ---------- Ruled rows (layers / models / phases) ---------- */
.rows { border-top: 1px solid currentColor; }
.rows.on-rule { border-top-color: var(--rule-paper); }
.ink .rows.on-rule { border-top-color: var(--rule-ink); }
.row {
  display: grid;
  grid-template-columns: 3.5rem minmax(0, 1fr) minmax(0, 1.4fr);
  gap: 28px;
  align-items: baseline;
  padding: 26px 0;
  border-bottom: 1px solid var(--rule-paper);
}
.ink .row { border-bottom-color: var(--rule-ink); }
.row-num { font-family: var(--mono); font-size: 13px; letter-spacing: .1em; color: var(--on-paper-faint); }
.ink .row-num { color: var(--on-ink-faint); }
.row-term { font-family: var(--serif); font-size: clamp(22px, 2.4vw, 30px); line-height: 1.1; }
.row-term.strong-term { font-weight: 600; }
.row-desc { font-family: var(--serif); font-style: italic; font-size: clamp(16px, 1.5vw, 20px); line-height: 1.35; color: var(--on-paper-soft); }
.ink .row-desc { color: var(--on-ink-soft); }
.row-desc.plain { font-family: var(--sans); font-style: normal; font-size: 15px; line-height: 1.55; }

/* ---------- Two-column split ---------- */
.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(32px, 6vw, 96px);
  align-items: start;
}
.split.top { align-items: start; }
.col-label {
  font-family: var(--mono);
  font-size: 12px; letter-spacing: .22em; text-transform: uppercase;
  color: var(--on-paper-faint);
  padding-bottom: 14px; margin-bottom: 22px;
  border-bottom: 1px solid var(--rule-paper);
}
.ink .col-label { color: var(--on-ink-faint); border-bottom-color: var(--rule-ink); }

/* Flow list (arrow-connected steps) */
.flow { list-style: none; margin: 0; padding: 0; }
.flow li { font-size: clamp(17px, 1.6vw, 20px); line-height: 1.5; padding: 6px 0; }
.flow li.arrow { color: var(--on-paper-faint); font-family: var(--mono); font-size: 15px; }
.ink .flow li.arrow { color: var(--on-ink-faint); }
.flow li.emph { font-weight: 600; }

/* ---------- Card grid ---------- */
.grid {
  display: grid;
  grid-template-columns: repeat(var(--cols, 3), 1fr);
  gap: 1px;
  background: var(--rule-paper);
  border: 1px solid var(--rule-paper);
}
.ink .grid { background: var(--rule-ink); border-color: var(--rule-ink); }
.card {
  background: var(--paper);
  padding: clamp(26px, 2.6vw, 40px);
  display: flex; flex-direction: column;
  min-height: 260px;
}
.ink .card { background: var(--ink); }
a.card { text-decoration: none; color: inherit; transition: background .25s; }
a.card:hover { background: var(--paper-2); }
.ink a.card:hover { background: var(--ink-2); }
.card-num { font-family: var(--mono); font-size: 12px; letter-spacing: .16em; color: var(--on-paper-faint); margin-bottom: auto; }
.ink .card-num { color: var(--on-ink-faint); }
.card-title { font-family: var(--serif); font-size: clamp(23px, 2vw, 29px); line-height: 1.06; margin: 32px 0 12px; letter-spacing: -.01em; }
.card-desc { font-size: 15px; line-height: 1.58; color: var(--on-paper-soft); margin: 0; }
.ink .card-desc { color: var(--on-ink-soft); }
.card-more { font-family: var(--mono); font-size: 11px; letter-spacing: .16em; text-transform: uppercase; color: var(--accent); margin-top: 20px; }

/* ---------- Feature block (label · big statement) ---------- */
.statement {
  font-family: var(--serif);
  font-size: clamp(30px, 4.6vw, 66px);
  line-height: 1.05;
  letter-spacing: -.015em;
  max-width: 20ch;
  margin: 0;
}
.statement em { font-style: italic; }

/* Pull quote */
.pull {
  font-family: var(--serif);
  font-style: italic;
  font-size: clamp(24px, 3.4vw, 44px);
  line-height: 1.24;
  letter-spacing: -.012em;
  max-width: 24ch;
  margin: 0 auto;
  text-align: center;
}

/* Callout / code panel */
.panel {
  border: 1px solid var(--rule-ink);
  padding: clamp(24px, 2.6vw, 38px);
}
.ink .panel { border-color: var(--rule-ink); }
.panel .code {
  font-family: var(--mono); font-size: clamp(14px, 1.3vw, 16px); line-height: 1.9;
  white-space: pre-wrap; margin: 0;
}
.panel .code .kw { color: var(--on-ink-faint); }
.ink .panel .code .kw { color: var(--on-ink-faint); }

/* Stats */
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: clamp(28px, 4vw, 60px); }
.stat { border-top: 1px solid var(--rule-paper); padding-top: 20px; }
.ink .stat { border-top-color: var(--rule-ink); }
.stat-value { font-family: var(--serif); font-size: clamp(42px, 5vw, 68px); line-height: .95; letter-spacing: -.02em; }
.stat-label { font-family: var(--mono); font-size: 12px; letter-spacing: .14em; text-transform: uppercase; color: var(--on-paper-faint); margin-top: 12px; }
.ink .stat-label { color: var(--on-ink-faint); }

/* Section header (eyebrow + title + deck) helper spacing */
.section-head { margin-bottom: clamp(44px, 7vh, 84px); max-width: 34ch; }
.section-head.wide { max-width: 46ch; }

/* Lead-in for a big block */
.kicker-row {
  display: flex; align-items: baseline; justify-content: space-between;
  flex-wrap: wrap; gap: 16px;
  padding-bottom: 22px; margin-bottom: clamp(40px, 6vh, 72px);
  border-bottom: 1px solid var(--rule-paper);
}
.ink .kicker-row { border-bottom-color: var(--rule-ink); }

/* ---------- Footer ---------- */
.footer { background: var(--ink); color: var(--on-ink); padding: clamp(56px, 8vh, 96px) var(--edge) 0; }
.footer-grid { max-width: var(--maxw); margin: 0 auto; display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 40px; }
.footer-brand { display: flex; align-items: center; gap: 12px; margin-bottom: 18px; }
.footer-tag { color: var(--on-ink-soft); font-size: 14px; line-height: 1.6; max-width: 32ch; margin: 0; }
.footer-col h4 { font-family: var(--mono); font-size: 11px; font-weight: 500; letter-spacing: .18em; text-transform: uppercase; color: var(--on-ink-faint); margin: 0 0 18px; }
.footer-col a, .footer-col button {
  display: block; font-family: var(--sans); font-size: 15px; color: var(--on-ink-soft);
  text-decoration: none; margin-bottom: 11px; cursor: pointer;
  background: none; border: none; padding: 0; text-align: left; transition: color .2s;
}
.footer-col a:hover, .footer-col button:hover { color: var(--on-ink); }
.footer-bottom { max-width: var(--maxw); margin: 40px auto 0; padding: 22px 0; border-top: 1px solid var(--rule-ink-2);
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px; }
.footer-meta { font-family: var(--mono); font-size: 11px; letter-spacing: .08em; color: var(--on-ink-faint); }

/* ---------- Schedule modal ---------- */
.modal {
  display: none; position: fixed; inset: 0; z-index: 100;
  align-items: center; justify-content: center;
  padding: clamp(14px, 4vw, 44px);
  background: rgba(15,13,10,.72); backdrop-filter: blur(6px);
}
.modal.open { display: flex; }
.modal-panel {
  position: relative; width: 100%; max-width: 920px; height: min(86vh, 760px);
  background: var(--paper); border: 1px solid var(--rule-ink);
  display: flex; flex-direction: column; overflow: hidden;
  box-shadow: 0 40px 120px rgba(0,0,0,.5);
}
.modal-head { display: flex; align-items: center; justify-content: space-between;
  padding: 16px clamp(18px, 3vw, 28px); border-bottom: 1px solid var(--rule-paper); flex-shrink: 0; }
.modal-title { font-family: var(--mono); font-size: 12px; letter-spacing: .22em; text-transform: uppercase; color: var(--on-paper-soft); }
.modal-close { background: none; border: none; color: var(--on-paper-soft); font-family: var(--serif); font-size: 30px; line-height: 1; cursor: pointer; padding: 0 4px; }
.modal-close:hover { color: var(--ink); }
.modal-body { flex: 1; min-height: 0; background: #fff; }
.modal-body iframe { width: 100%; height: 100%; border: 0; display: block; }
.modal-fallback { height: 100%; display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center; gap: 22px; padding: 40px; }

/* ---------- Reveal on scroll ---------- */
[data-reveal] { opacity: 0; transform: translateY(24px); transition: opacity .8s cubic-bezier(.2,.7,.2,1), transform .8s cubic-bezier(.2,.7,.2,1); }
[data-reveal].in { opacity: 1; transform: none; }
[data-reveal][data-delay="1"] { transition-delay: .08s; }
[data-reveal][data-delay="2"] { transition-delay: .16s; }
[data-reveal][data-delay="3"] { transition-delay: .24s; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .nav-links { display: none; }
  .nav-cta { display: none; }
  .burger { display: inline-flex; }
  .split { grid-template-columns: 1fr; }
  .grid { grid-template-columns: 1fr !important; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .row { grid-template-columns: 2.4rem 1fr; }
  .row-desc { grid-column: 1 / -1; padding-left: calc(2.4rem + 28px); margin-top: -6px; }
}
@media (max-width: 560px) {
  body { font-size: 16px; }
  .footer-grid { grid-template-columns: 1fr; }
  .row-desc { padding-left: 0; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  [data-reveal] { transition: none; opacity: 1; transform: none; }
  * { animation-duration: .001ms !important; animation-iteration-count: 1 !important; }
}