:root {
  --bg: #0c0d10;
  --bg-raised: #131519;
  --bg-card: #16181d;
  --border: #262932;
  --text: #e9e7e0;
  --text-dim: #9a9ca6;
  --text-muted: #8b8d97;
  --accent: #e0a83e;
  --accent-soft: rgba(224, 168, 62, 0.14);
  --serif: Georgia, "Iowan Old Style", "Palatino Linotype", Palatino, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Helvetica, Arial, sans-serif;
  --max: 760px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 18px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
}

/* Nav */
nav.site-nav {
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: rgba(12, 13, 16, 0.9);
  backdrop-filter: blur(8px);
  z-index: 10;
}
nav.site-nav .wrap {
  max-width: 1280px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 18px;
  padding-bottom: 18px;
}
.logo {
  display: inline-flex;
  align-items: center;
  flex: 0 0 auto;
}
.logo:hover { text-decoration: none; }
.logo img {
  display: block;
  width: 357px;
  max-width: 100%;
  height: auto;
  mix-blend-mode: screen;
}
.nav-links a {
  color: var(--text-muted);
  margin-left: 28px;
  font-size: 15px;
}
.nav-links a:hover { color: var(--text); text-decoration: none; }
.nav-links a[aria-current="page"] { color: var(--accent); }
.nav-links .nav-apply {
  margin-left: 22px;
  padding: 7px 12px;
  border: 1px solid rgba(224, 168, 62, 0.42);
  border-radius: 999px;
  color: var(--accent);
  background: rgba(224, 168, 62, 0.08);
  box-shadow: 0 0 16px rgba(224, 168, 62, 0.18), inset 0 0 12px rgba(224, 168, 62, 0.05);
  text-shadow: 0 0 12px rgba(224, 168, 62, 0.55);
  transition: color 160ms ease, background 160ms ease, border-color 160ms ease, box-shadow 160ms ease, transform 160ms ease;
  animation: nav-apply-glow 3.4s ease-in-out infinite;
}
.nav-links .nav-apply:hover {
  color: var(--text);
  border-color: var(--accent);
  background: rgba(224, 168, 62, 0.14);
  box-shadow: 0 0 24px rgba(224, 168, 62, 0.3), inset 0 0 14px rgba(224, 168, 62, 0.08);
  transform: translateY(-1px);
}
.nav-links .nav-apply:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 4px;
}
@keyframes nav-apply-glow {
  0%, 100% { box-shadow: 0 0 13px rgba(224, 168, 62, 0.14), inset 0 0 10px rgba(224, 168, 62, 0.04); }
  50% { box-shadow: 0 0 22px rgba(224, 168, 62, 0.28), inset 0 0 14px rgba(224, 168, 62, 0.08); }
}

/* Applying AQ */
.applying-hero {
  padding: 88px 0 46px;
  border-bottom: 1px solid var(--border);
}
.applying-hero .lede { color: var(--text-dim); }
.applying-section { padding: 72px 0 88px; }
.applying-card {
  position: relative;
  overflow: hidden;
  padding: 44px 46px;
  border: 1px solid rgba(224, 168, 62, 0.28);
  border-radius: 10px;
  background: linear-gradient(135deg, rgba(224, 168, 62, 0.1), var(--bg-card) 48%);
  box-shadow: 0 24px 70px rgba(0, 0, 0, 0.22);
}
.applying-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 46px;
  width: 88px;
  height: 2px;
  background: var(--accent);
  box-shadow: 0 0 18px rgba(224, 168, 62, 0.65);
}
.applying-card p { max-width: 620px; }
.applying-card p:last-of-type { margin-bottom: 30px; }
.applying-contact {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
}
.applying-contact::after {
  content: "→";
  transition: transform 160ms ease;
}
.applying-contact:hover::after { transform: translateX(4px); }

/* AQ Capture */
.capture-hero {
  padding: 88px 0 52px;
  border-bottom: 1px solid var(--border);
}
.capture-hero .lede { color: var(--text-dim); }
.capture-rule {
  position: relative;
  margin-top: 38px;
  padding: 22px 24px 22px 27px;
  background: linear-gradient(135deg, var(--accent-soft), rgba(22, 24, 29, 0.86) 58%);
  border: 1px solid rgba(224, 168, 62, 0.3);
  border-left: 3px solid var(--accent);
  border-radius: 4px;
}
.capture-rule p { margin: 0; color: var(--text); font-size: 16px; }
.capture-section { padding: 64px 0; }
.capture-section + .capture-section { border-top: 1px solid var(--border); }
.capture-section h2 { margin: 0 0 24px; }
.capture-practice {
  display: grid;
  grid-template-columns: 42px 1fr;
  gap: 18px;
  padding: 26px 0;
  border-top: 1px solid var(--border);
}
.capture-practice:last-child { border-bottom: 1px solid var(--border); }
.capture-number {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  margin-top: 2px;
  border: 1px solid rgba(224, 168, 62, 0.5);
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
}
.capture-practice h3 { margin: 0 0 6px; font-size: 20px; }
.capture-practice p { margin: 0; color: var(--text-dim); font-size: 16px; }
.capture-not-list { list-style: none; margin: 0; padding: 0; }
.capture-not-list li {
  position: relative;
  padding: 15px 0 15px 34px;
  border-top: 1px solid var(--border);
  color: var(--text-dim);
  font-size: 16px;
}
.capture-not-list li:last-child { border-bottom: 1px solid var(--border); }
.capture-not-list li::before {
  content: "×";
  position: absolute;
  top: 13px;
  left: 4px;
  color: var(--accent);
  font-size: 20px;
  line-height: 1;
}
.capture-not-list strong { color: var(--text); }
.capture-signals {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
}
.capture-signal {
  min-height: 178px;
  padding: 22px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 6px;
}
.capture-signal-label {
  margin-bottom: 10px;
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
.capture-signal p { margin: 0; color: var(--text-dim); font-size: 15px; }
.capture-closing {
  padding: 40px 0 72px;
  border-top: 1px solid var(--border);
}
.capture-equation {
  margin: 0 0 14px;
  color: var(--accent);
  font-family: var(--serif);
  font-size: 24px;
  font-weight: 700;
}
.capture-closing p:last-child { margin: 0; color: var(--text-dim); }

/* Hero */
header.hero {
  padding: 96px 0 64px;
  border-bottom: 1px solid var(--border);
}
.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.14em;
  font-size: 13px;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 20px;
}
h1 {
  font-family: var(--serif);
  font-size: 56px;
  line-height: 1.08;
  margin: 0 0 16px;
  font-weight: 700;
  letter-spacing: -0.01em;
}
.subhead {
  font-family: var(--serif);
  font-size: 26px;
  color: var(--text-dim);
  margin: 0 0 28px;
  font-style: italic;
  line-height: 1.35;
}
.lede {
  font-size: 20px;
  color: var(--text);
  max-width: 620px;
}
.lede strong { color: var(--accent); font-weight: 600; }
.hero-actions {
  display: flex;
  align-items: center;
  gap: 18px;
  margin-top: 32px;
}
.hero-btn {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  padding: 15px 24px;
  box-shadow: 0 10px 28px rgba(224, 168, 62, 0.16);
  transition: transform 160ms ease, box-shadow 160ms ease, background 160ms ease;
}
.hero-btn span {
  font-size: 19px;
  line-height: 1;
  transition: transform 160ms ease;
}
.hero-btn:hover {
  opacity: 1;
  transform: translateY(-2px);
  box-shadow: 0 14px 34px rgba(224, 168, 62, 0.24);
}
.hero-btn:hover span { transform: translateX(3px); }
.hero-btn:active { transform: translateY(0); }
.hero-btn:focus-visible {
  outline: 3px solid var(--text);
  outline-offset: 4px;
}
.hero-action-note {
  color: var(--text-muted);
  font-size: 14px;
}

/* Sections */
section {
  padding: 64px 0;
  border-bottom: 1px solid var(--border);
}
section.no-border { border-bottom: none; }
h2 {
  font-family: var(--serif);
  font-size: 32px;
  margin: 0 0 28px;
  font-weight: 700;
}
h3 {
  font-family: var(--serif);
  font-size: 22px;
  margin: 0 0 10px;
  font-weight: 700;
}
p { margin: 0 0 18px; }
.section-kicker {
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 12px;
  color: var(--text-muted);
  font-weight: 600;
  margin-bottom: 12px;
}

/* Equation block */
.equation {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 40px 32px;
  text-align: center;
  margin: 8px 0 32px;
}
.equation .formula {
  font-family: var(--serif);
  font-size: 30px;
  color: var(--accent);
  font-weight: 700;
  letter-spacing: 0.01em;
}
.equation-terms {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 8px;
}
.equation-terms div {
  border-top: 1px solid var(--border);
  padding-top: 16px;
  text-align: left;
}
.equation-terms .term {
  font-weight: 700;
  color: var(--text);
  display: block;
  margin-bottom: 6px;
  font-family: var(--serif);
}
.equation-terms p { margin: 0; font-size: 15px; color: var(--text-muted); }

/* Capability list */
.capabilities {
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: cap;
}
.capabilities li {
  counter-increment: cap;
  display: flex;
  gap: 20px;
  padding: 18px 0;
  border-top: 1px solid var(--border);
}
.capabilities li:first-child { border-top: none; }
.capabilities li::before {
  content: counter(cap, decimal-leading-zero);
  font-family: var(--serif);
  color: var(--accent);
  font-size: 15px;
  font-weight: 700;
  flex-shrink: 0;
  padding-top: 2px;
}
.capabilities strong { display: block; font-size: 17px; margin-bottom: 2px; }
.capabilities span.desc { color: var(--text-muted); font-size: 16px; }

/* Two-column check/x lists */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}
.list-block h3 { margin-bottom: 14px; }
.list-block ul { list-style: none; padding: 0; margin: 0; }
.list-block li {
  padding: 9px 0;
  font-size: 16px;
  border-top: 1px solid var(--border);
  padding-left: 26px;
  position: relative;
}
.list-block li:first-child { border-top: none; }
.list-block.yes li::before {
  content: "✓";
  color: var(--accent);
  position: absolute;
  left: 0;
  font-weight: 700;
}
.list-block.no li::before {
  content: "✕";
  color: #6b6d76;
  position: absolute;
  left: 0;
}
.list-block.no li { color: var(--text-muted); }

/* Maturity model */
.levels { display: flex; flex-direction: column; gap: 0; }
.level {
  display: grid;
  grid-template-columns: 90px 1fr;
  gap: 24px;
  padding: 22px 0;
  border-top: 1px solid var(--border);
  align-items: start;
}
.level:first-child { border-top: none; }
.level .tag {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 15px;
  color: var(--accent);
  background: var(--accent-soft);
  border-radius: 6px;
  padding: 6px 10px;
  text-align: center;
  height: fit-content;
}
.level h3 { margin: 0 0 6px; font-size: 19px; }
.level p { margin: 0; color: var(--text-muted); font-size: 16px; }

/* Essays teaser / list */
.essay-list { display: flex; flex-direction: column; }
.essay-row {
  display: block;
  padding: 22px 0;
  border-top: 1px solid var(--border);
}
.essay-row:first-child { border-top: none; }
.essay-row:hover { text-decoration: none; }
.essay-row .essay-title {
  font-family: var(--serif);
  font-size: 21px;
  color: var(--text);
  font-weight: 700;
  margin-bottom: 6px;
}
.essay-row:hover .essay-title { color: var(--accent); }
.essay-row .essay-dek { color: var(--text-muted); font-size: 16px; margin: 0; }
.essay-row.soon { opacity: 0.5; cursor: default; }
.essay-row.soon .essay-title::after {
  content: " — coming soon";
  font-family: var(--sans);
  font-size: 13px;
  font-weight: 400;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* CTA */
.cta-box {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 40px;
  text-align: center;
}
.cta-box h2 { margin-bottom: 14px; }
.cta-box p { color: var(--text-muted); max-width: 480px; margin: 0 auto 24px; }
.btn {
  display: inline-block;
  background: var(--accent);
  color: #14140f;
  font-weight: 700;
  padding: 13px 26px;
  border-radius: 6px;
  font-size: 15px;
}
.btn:hover { text-decoration: none; opacity: 0.9; }

/* Footer */
footer {
  padding: 40px 0 64px;
  color: var(--text-muted);
  font-size: 14px;
}
footer a { color: var(--text-muted); }
footer .foot-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}

/* Detailed maturity model page */
.level-full {
  padding: 44px 0;
  border-top: 1px solid var(--border);
}
.level-full:first-child { border-top: none; padding-top: 0; }
.level-full-head {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 8px;
}
.level-full-head .tag {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 15px;
  color: var(--accent);
  background: var(--accent-soft);
  border-radius: 6px;
  padding: 6px 12px;
}
.level-full-head h3 { margin: 0; font-size: 26px; }
.level-full .summary {
  font-family: var(--serif);
  font-style: italic;
  font-size: 19px;
  color: var(--text-dim);
  margin: 0 0 24px;
}
.subheading {
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-size: 12px;
  color: var(--accent);
  font-weight: 700;
  margin: 22px 0 10px;
}
.level-full ul.plain-list {
  list-style: none;
  padding: 0;
  margin: 0 0 4px;
}
.level-full ul.plain-list li {
  padding: 8px 0 8px 20px;
  position: relative;
  font-size: 16px;
  color: var(--text);
  border-top: 1px solid var(--border);
}
.level-full ul.plain-list li:first-child { border-top: none; }
.level-full ul.plain-list li::before {
  content: "—";
  position: absolute;
  left: 0;
  color: var(--text-muted);
}
.level-full p.trap-text,
.level-full p.next-text {
  font-size: 16px;
  color: var(--text-muted);
  margin: 0;
}

/* Dimensions and playbook */
.content-hero {
  padding: 88px 0 54px;
  border-bottom: 1px solid var(--border);
}
.content-hero .lede { color: var(--text-dim); }
.content-hero .hero-actions { margin-top: 28px; }
.dimension-stack { padding: 28px 0 84px; }
.dimension-card {
  display: grid;
  grid-template-columns: minmax(220px, 0.72fr) minmax(0, 1.8fr);
  gap: 52px;
  padding: 56px 0;
  border-bottom: 1px solid var(--border);
}
.dimension-card:first-child { border-top: 1px solid var(--border); }
.dimension-card h2 { margin: 4px 0 14px; }
.dimension-card .dimension-code {
  color: var(--accent);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}
.dimension-card .dimension-root {
  display: inline-block;
  margin-top: 2px;
  color: var(--accent);
  font-family: var(--serif);
  font-size: 15px;
  font-style: italic;
}
.dimension-card .dimension-intro { color: var(--text-dim); font-size: 16px; }
.aq-table-wrap { overflow-x: auto; }
.aq-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  line-height: 1.55;
}
.aq-table th,
.aq-table td {
  padding: 15px 16px;
  border-bottom: 1px solid var(--border);
  text-align: left;
  vertical-align: top;
}
.aq-table th {
  color: var(--accent);
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
.aq-table td:first-child { min-width: 118px; color: var(--text); font-weight: 700; }
.aq-table tbody tr:hover { background: rgba(224, 168, 62, 0.045); }
.engineering-lens,
.boundary-line,
.metrics-note {
  position: relative;
  padding: 34px 36px;
  border: 1px solid rgba(224, 168, 62, 0.3);
  background: linear-gradient(125deg, rgba(224, 168, 62, 0.1), var(--bg-card) 60%);
}
.engineering-lens { margin: 18px 0 84px; }
.engineering-lens h2,
.boundary-line h2 { margin: 0 0 14px; }
.engineering-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 30px;
  margin-top: 22px;
}
.engineering-item { padding: 18px 0; border-top: 1px solid var(--border); }
.engineering-item strong { display: block; margin-bottom: 5px; color: var(--accent); }
.engineering-item p { margin: 0; color: var(--text-dim); font-size: 15px; }
.boundary-line { margin: 10px 0 34px; border-left: 4px solid var(--accent); }
.boundary-label {
  color: var(--accent);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}
.boundary-line p:last-child { margin-bottom: 0; }
.dimension-link-row { display: flex; gap: 14px; flex-wrap: wrap; margin-top: 26px; }
.metrics-section { padding: 74px 0 88px; border-top: 1px solid var(--border); }
.metrics-note { margin: 24px 0 28px; padding: 22px 26px; color: var(--text-dim); font-style: italic; }
.metric-footnote { margin-top: 18px; color: var(--text-muted); font-size: 14px; }
.playbook-loop { padding: 64px 0 88px; }
.playbook-step {
  display: grid;
  grid-template-columns: 62px minmax(0, 1fr);
  gap: 24px;
  padding: 30px 0;
  border-top: 1px solid var(--border);
}
.playbook-step:last-child { border-bottom: 1px solid var(--border); }
.playbook-number {
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  border: 1px solid rgba(224, 168, 62, 0.48);
  border-radius: 50%;
  color: var(--accent);
  font-family: var(--serif);
  font-size: 20px;
}
.playbook-step h2 { margin: 3px 0 8px; font-size: 25px; }
.playbook-step p { margin: 0; color: var(--text-dim); }
.playbook-close { margin-top: 46px; padding: 34px 36px; background: var(--bg-card); border: 1px solid var(--border); }
.playbook-close p { margin: 0; font-family: var(--serif); font-size: 22px; color: var(--text); }
.trap-diagnosis { display: block; margin-top: 12px; color: var(--accent); }
.aq-zero .tag { border-color: rgba(255, 107, 107, 0.45); color: #ff8b83; }

@media (max-width: 760px) {
  .dimension-card { grid-template-columns: 1fr; gap: 20px; padding: 44px 0; }
  .engineering-grid { grid-template-columns: 1fr; }
  .engineering-lens, .boundary-line { padding: 28px 24px; }
  .playbook-step { grid-template-columns: 48px minmax(0, 1fr); gap: 16px; }
}

/* Article pages */
article.essay { padding: 72px 0 40px; }
.essay-meta {
  color: var(--text-muted);
  font-size: 14px;
  margin-bottom: 18px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
article.essay h1 { font-size: 42px; margin-bottom: 22px; }
article.essay .dek {
  font-family: var(--serif);
  font-style: italic;
  font-size: 22px;
  color: var(--text-dim);
  margin-bottom: 36px;
}
article.essay .body p { font-size: 19px; }
article.essay .body h3 { margin-top: 36px; }
.back-link { display: inline-block; margin-bottom: 8px; font-size: 14px; }

/* Framework sandbox */
.sandbox-wrap {
  width: min(1120px, calc(100% - 48px));
  margin: 0 auto;
}
.sandbox-hero {
  position: relative;
  overflow: hidden;
  padding: 88px 0 64px;
  border-bottom: 1px solid var(--border);
  background:
    radial-gradient(circle at 82% 20%, rgba(224, 168, 62, 0.12), transparent 28%),
    linear-gradient(135deg, rgba(255,255,255,0.025) 0 1px, transparent 1px 24px);
  background-size: auto, 24px 24px;
}
.sandbox-hero::after {
  content: "AQ";
  position: absolute;
  right: -0.04em;
  bottom: -0.32em;
  color: rgba(233, 231, 224, 0.025);
  font-family: var(--serif);
  font-size: clamp(170px, 28vw, 360px);
  font-weight: 700;
  line-height: 1;
  pointer-events: none;
}
.sandbox-hero .sandbox-wrap {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(320px, 0.65fr);
  gap: 72px;
  align-items: end;
}
.sandbox-hero-copy .lede { margin-bottom: 0; }
.sandbox-map {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  border: 1px solid var(--border);
  background: rgba(12, 13, 16, 0.72);
  box-shadow: 0 24px 70px rgba(0,0,0,0.2);
}
.sandbox-map div {
  min-height: 118px;
  padding: 22px;
  border-right: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}
.sandbox-map div:nth-child(2n) { border-right: 0; }
.sandbox-map div:nth-child(n+3) { border-bottom: 0; }
.sandbox-map strong {
  color: var(--accent);
  font-family: var(--serif);
  font-size: 34px;
  line-height: 1;
}
.sandbox-map span {
  color: var(--text-muted);
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
.sandbox-main { padding: 0 0 96px; }
.sandbox-toolbar {
  min-height: 76px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.sandbox-toolbar p { margin: 0; color: var(--text-muted); font-size: 14px; }
.sandbox-toolbar strong { color: var(--text); }
.sandbox-pulse {
  display: inline-block;
  width: 7px;
  height: 7px;
  margin-right: 10px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 5px var(--accent-soft);
}
.sandbox-toggle-all {
  border: 0;
  padding: 9px 0;
  color: var(--accent);
  background: transparent;
  font: 600 13px var(--sans);
  cursor: pointer;
}
.sandbox-toggle-all:hover { color: var(--text); }
.sandbox-toggle-all:focus-visible,
.sandbox-step-button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 4px;
}
.sandbox-layer {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 72px;
  padding: 82px 0;
  border-bottom: 1px solid var(--border);
}
.layer-intro {
  display: grid;
  grid-template-columns: 40px 1fr;
  gap: 16px;
  align-content: start;
  position: sticky;
  top: 124px;
  height: fit-content;
}
.layer-number {
  color: var(--accent);
  font: 700 13px var(--sans);
  letter-spacing: 0.1em;
  padding-top: 3px;
}
.layer-intro h2 { font-size: 29px; margin-bottom: 14px; }
.layer-intro p { color: var(--text-muted); font-size: 15px; line-height: 1.6; }
.sandbox-accordions { border-top: 1px solid var(--border); }
.sandbox-step { border-bottom: 1px solid var(--border); }
.sandbox-step h3 { margin: 0; }
.sandbox-step-button {
  width: 100%;
  min-height: 92px;
  border: 0;
  padding: 0 4px;
  display: grid;
  grid-template-columns: 52px 1fr 32px;
  gap: 18px;
  align-items: center;
  color: var(--text);
  background: transparent;
  text-align: left;
  cursor: pointer;
  transition: background 160ms ease, padding 160ms ease;
}
.sandbox-step-button:hover { background: rgba(255,255,255,0.018); padding: 0 12px; }
.step-index {
  color: var(--text-muted);
  font: 600 12px var(--sans);
  letter-spacing: 0.1em;
}
.step-title { display: flex; align-items: baseline; gap: 16px; }
.step-title strong {
  font: 700 22px var(--serif);
  transition: color 160ms ease;
}
.step-title small { color: var(--text-muted); font: 400 13px var(--sans); }
.sandbox-step-button:hover .step-title strong,
.sandbox-step.is-open .step-title strong { color: var(--accent); }
.step-mark {
  width: 28px;
  height: 28px;
  border: 1px solid var(--border);
  border-radius: 50%;
  position: relative;
  transition: border-color 160ms ease, transform 220ms ease, background 160ms ease;
}
.step-mark::before,
.step-mark::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  width: 10px;
  height: 1px;
  background: var(--text-muted);
  transform: translate(-50%, -50%);
}
.step-mark::after { transform: translate(-50%, -50%) rotate(90deg); }
.sandbox-step.is-open .step-mark {
  border-color: var(--accent);
  background: var(--accent-soft);
  transform: rotate(45deg);
}
.sandbox-step.is-open .step-mark::before,
.sandbox-step.is-open .step-mark::after { background: var(--accent); }
.sandbox-step-panel {
  padding: 4px 52px 32px 74px;
  animation: sandbox-reveal 220ms ease both;
}
@keyframes sandbox-reveal {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}
.step-panel-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 32px;
  padding: 24px;
  border-left: 2px solid var(--accent);
  background: var(--bg-raised);
}
.panel-label {
  display: block;
  margin-bottom: 8px;
  color: var(--accent);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}
.step-panel-grid p { margin: 0; color: var(--text-dim); font-size: 14px; line-height: 1.65; }
.step-connection {
  padding: 15px 24px;
  border: 1px solid var(--border);
  border-top: 0;
  color: var(--text-dim);
  font-size: 13px;
}
.step-connection span {
  margin-right: 12px;
  color: var(--text-muted);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
.sandbox-next {
  margin-top: 80px;
  padding: 44px;
  border: 1px solid var(--border);
  background: linear-gradient(115deg, var(--bg-card), rgba(224, 168, 62, 0.08));
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 48px;
}
.sandbox-next h2 { margin-bottom: 10px; }
.sandbox-next p { max-width: 590px; margin: 0; color: var(--text-muted); font-size: 16px; }
.sandbox-next .btn { flex: 0 0 auto; }

@media (max-width: 820px) {
  nav.site-nav .wrap {
    flex-wrap: wrap;
    gap: 12px 0;
    padding-top: 14px;
    padding-bottom: 14px;
  }
  .logo img { width: 315px; }
  .nav-links {
    display: flex;
    width: 100%;
    justify-content: flex-start;
    flex-wrap: wrap;
    gap: 8px 20px;
  }
  .nav-links a {
    margin-left: 0;
    font-size: 13px;
  }
  .nav-links .nav-apply { margin-left: 0; }
  .sandbox-hero .sandbox-wrap { grid-template-columns: 1fr; gap: 44px; }
  .sandbox-map { max-width: 520px; }
  .sandbox-layer { grid-template-columns: 1fr; gap: 28px; padding: 64px 0; }
  .layer-intro { position: static; max-width: 560px; }
}

@media (max-width: 640px) {
  h1 { font-size: 38px; }
  .subhead { font-size: 20px; }
  .hero-actions { align-items: flex-start; flex-direction: column; gap: 10px; }
  .equation-terms { grid-template-columns: 1fr; }
  .two-col { grid-template-columns: 1fr; }
  .level { grid-template-columns: 70px 1fr; }
  article.essay h1 { font-size: 30px; }
  section { padding: 44px 0; }
  header.hero { padding: 64px 0 44px; }
  .sandbox-wrap { width: min(100% - 32px, 1120px); }
  .sandbox-hero { padding: 64px 0 48px; }
  .sandbox-hero .subhead { margin-bottom: 20px; }
  .sandbox-map div { min-height: 96px; padding: 16px; }
  .sandbox-map strong { font-size: 28px; }
  .sandbox-toolbar { min-height: 68px; }
  .sandbox-toolbar p { max-width: 220px; line-height: 1.45; }
  .sandbox-layer { padding: 52px 0; }
  .sandbox-step-button { min-height: 82px; grid-template-columns: 34px 1fr 28px; gap: 10px; }
  .step-title { display: block; }
  .step-title strong { display: block; font-size: 19px; }
  .step-title small { display: block; margin-top: 3px; }
  .sandbox-step-panel { padding: 0 0 24px 44px; }
  .step-panel-grid { grid-template-columns: 1fr; gap: 22px; padding: 20px; }
  .step-connection { padding: 14px 20px; }
  .step-connection span { display: block; margin: 0 0 4px; }
  .sandbox-next { margin-top: 56px; padding: 30px 24px; align-items: flex-start; flex-direction: column; gap: 24px; }
  .capture-hero { padding: 64px 0 42px; }
  .capture-section { padding: 48px 0; }
  .capture-signals { grid-template-columns: 1fr; }
  .capture-signal { min-height: auto; }
  .applying-hero { padding: 64px 0 42px; }
  .applying-section { padding: 48px 0 64px; }
  .applying-card { padding: 34px 26px; }
  .applying-card::before { left: 26px; }
}

@media (prefers-reduced-motion: reduce) {
  .sandbox-step-panel { animation: none; }
  .nav-links .nav-apply { animation: none; }
}