:root {
  --paper: #faf8f1;
  --paper-deep: #f1ecdf;
  --paper-white: #fffdf8;
  --ink: #171918;
  --muted: #5e625f;
  --line: rgba(23, 25, 24, 0.14);
  --green: #76c487;
  --yellow: #f6bd45;
  --coral: #f58d7b;
  --blue: #7db6ed;
  --dot: rgba(112, 176, 235, 0.22);
  --shadow: 0 28px 80px rgba(45, 43, 36, 0.12);
  --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  --sans: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --max: 1180px;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  background: var(--paper);
}

body {
  margin: 0;
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.6;
  background-color: var(--paper);
  background-image:
    radial-gradient(circle at 1px 1px, var(--dot) 1.2px, transparent 1.3px),
    linear-gradient(180deg, rgba(255,255,255,.52), rgba(245,240,228,.28));
  background-size: 22px 22px, 100% 100%;
  min-height: 100vh;
}

img { max-width: 100%; display: block; }
a { color: inherit; }
button, input { font: inherit; }

::selection { background: rgba(125, 182, 237, 0.35); }

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 100;
  transform: translateY(-160%);
  padding: 10px 14px;
  background: var(--ink);
  color: white;
  border-radius: 8px;
}
.skip-link:focus { transform: none; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(250, 248, 241, 0.86);
  border-bottom: 1px solid rgba(23, 25, 24, 0.09);
  backdrop-filter: blur(18px) saturate(1.3);
}

.nav-wrap {
  width: min(calc(100% - 40px), var(--max));
  min-height: 72px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  text-decoration: none;
  font-family: var(--mono);
  font-size: 15px;
  font-weight: 750;
  letter-spacing: -0.02em;
  white-space: nowrap;
}
.brand img {
  width: 41px;
  height: 41px;
  border-radius: 11px;
  box-shadow: 0 8px 22px rgba(69, 58, 35, .13);
}

.site-nav { display: flex; align-items: center; gap: 7px; }
.site-nav a {
  padding: 9px 12px;
  border-radius: 999px;
  color: #414542;
  text-decoration: none;
  font-size: 14px;
  font-weight: 700;
}
.site-nav a:hover, .site-nav a[aria-current="page"] { background: rgba(125, 182, 237, .14); color: var(--ink); }
.site-nav .nav-download { background: var(--ink); color: white; padding-inline: 16px; }
.site-nav .nav-download:hover { background: #353937; color: white; }
.site-nav a.nav-store-badge {
  display: inline-flex;
  align-items: center;
  padding: 4px;
  border-radius: 8px;
  background: transparent;
}
.site-nav a.nav-store-badge:hover { background: transparent; }
.nav-store-badge img { width: auto; height: 40px; max-width: none; }

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(255,255,255,.55);
  color: var(--ink);
  cursor: pointer;
}

.container { width: min(calc(100% - 40px), var(--max)); margin-inline: auto; }
.narrow { width: min(calc(100% - 40px), 780px); margin-inline: auto; }

.eyebrow {
  margin: 0 0 18px;
  color: #4f6f8d;
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: .13em;
  text-transform: uppercase;
}

h1, h2, h3 { line-height: 1.08; letter-spacing: -0.045em; text-wrap: balance; }
h1 { margin: 0; font-family: var(--mono); font-size: clamp(44px, 7vw, 88px); font-weight: 520; }
h2 { margin: 0; font-size: clamp(34px, 5vw, 60px); font-weight: 760; }
h3 { margin: 0; font-size: 24px; font-weight: 760; }
p { text-wrap: pretty; }

.hero {
  position: relative;
  overflow: hidden;
  padding: clamp(72px, 10vw, 130px) 0 94px;
}

.hero::before,
.article-hero::before {
  content: "O(1)   O(n)   O(log n)   O(V + E)";
  position: absolute;
  z-index: -1;
  top: 56px;
  left: 50%;
  transform: translateX(-50%) rotate(-4deg);
  width: 1400px;
  color: rgba(118, 196, 135, .08);
  font-family: var(--mono);
  font-size: clamp(68px, 10vw, 150px);
  font-weight: 800;
  letter-spacing: -0.09em;
  white-space: nowrap;
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.12fr) minmax(330px, .88fr);
  align-items: center;
  gap: clamp(44px, 8vw, 112px);
}

.hero-copy { position: relative; z-index: 2; }
.hero-copy .lede {
  max-width: 660px;
  margin: 26px 0 0;
  color: var(--muted);
  font-size: clamp(18px, 2vw, 23px);
  line-height: 1.55;
}

.accent-word { position: relative; display: inline-block; }
.accent-word::after {
  content: "";
  position: absolute;
  z-index: -1;
  left: -.02em;
  right: -.02em;
  bottom: .03em;
  height: .17em;
  border-radius: 999px;
  background: var(--yellow);
  transform: rotate(-1.5deg);
}

.cta-row { display: flex; flex-wrap: wrap; align-items: center; gap: 14px; margin-top: 34px; }
.button {
  min-height: 54px;
  padding: 14px 21px;
  border: 1px solid var(--ink);
  border-radius: 14px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 11px;
  background: var(--ink);
  color: white;
  text-decoration: none;
  font-weight: 800;
  box-shadow: 0 12px 28px rgba(23,25,24,.14);
  transition: transform .2s ease, box-shadow .2s ease;
}
.button:hover { transform: translateY(-2px); box-shadow: 0 18px 36px rgba(23,25,24,.18); }
.button.secondary { color: var(--ink); background: rgba(255,255,255,.45); box-shadow: none; }
.button.small { min-height: 44px; padding: 10px 16px; border-radius: 12px; font-size: 14px; }
.button.secondary.app-store-companion {
  min-height: 48px;
  padding-block: 0;
  background: var(--paper-white);
}

.app-store-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px;
  margin: -10px;
  border-radius: 12px;
  text-decoration: none;
}
.app-store-badge img { width: auto; height: 48px; max-width: none; }
.app-store-badge:focus-visible,
.nav-store-badge:focus-visible { outline: 3px solid var(--blue); outline-offset: 3px; }

.trust-line { margin: 20px 0 0; color: #727773; font-family: var(--mono); font-size: 12px; }
.trust-line span + span::before { content: "•"; padding: 0 9px; color: var(--blue); }

.hero-visual { position: relative; min-height: 620px; display: grid; place-items: center; }
.phone-shell {
  position: relative;
  width: min(365px, 86vw);
  padding: 11px;
  overflow: hidden;
  border-radius: 56px;
  background: #2f3231;
  box-shadow: 0 42px 100px rgba(35, 37, 35, .24), 0 0 0 1px rgba(0,0,0,.15);
  transform: rotate(3.2deg);
}
.phone-shell::before {
  content: "";
  position: absolute;
  z-index: 2;
  top: 23px;
  left: 50%;
  width: 88px;
  height: 24px;
  border-radius: 20px;
  background: #080908;
  transform: translateX(-50%);
}
.phone-shell img {
  width: 100%;
  height: auto;
  aspect-ratio: 945 / 2052;
  object-fit: contain;
  border-radius: 45px;
}
.float-note {
  position: absolute;
  padding: 15px 17px;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: rgba(255,253,248,.91);
  box-shadow: var(--shadow);
  font-family: var(--mono);
  font-size: 13px;
  font-weight: 750;
  backdrop-filter: blur(12px);
}
.float-note.one { top: 90px; left: 0; transform: rotate(-5deg); }
.float-note.two { right: -10px; bottom: 88px; transform: rotate(4deg); }
.float-note .dot { display: inline-block; width: 8px; height: 8px; margin-right: 7px; border-radius: 50%; background: var(--green); }
.float-note.two .dot { background: var(--coral); }

.section { padding: 104px 0; }
.section-tight { padding: 76px 0; }
.section-band { border-block: 1px solid rgba(23,25,24,.08); background: rgba(255,253,248,.58); }
.section-dark { position: relative; overflow: hidden; background: var(--ink); color: #f7f5ef; }
.section-dark::after { content: "O(n log n)"; position: absolute; right: -30px; bottom: -64px; color: rgba(255,255,255,.035); font: 800 130px/1 var(--mono); }

.section-heading { display: grid; grid-template-columns: .72fr 1.28fr; gap: 54px; align-items: start; margin-bottom: 54px; }
.section-heading p { max-width: 660px; margin: 4px 0 0; color: var(--muted); font-size: 18px; }
.section-dark .section-heading p { color: rgba(255,255,255,.65); }

.method-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.method-card {
  min-height: 250px;
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: rgba(255,253,248,.74);
  box-shadow: 0 18px 45px rgba(54,51,42,.06);
}
.method-card:nth-child(1) { border-top: 5px solid var(--green); }
.method-card:nth-child(2) { border-top: 5px solid var(--yellow); }
.method-card:nth-child(3) { border-top: 5px solid var(--coral); }
.method-card:nth-child(4) { border-top: 5px solid var(--blue); }
.method-card .number { font: 800 12px/1 var(--mono); color: #717671; letter-spacing: .12em; }
.method-card h3 { margin-top: 36px; font-family: var(--mono); font-size: 22px; }
.method-card p { margin: 13px 0 0; color: var(--muted); font-size: 15px; }

.pattern-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.pattern-card {
  position: relative;
  min-height: 265px;
  padding: 26px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: var(--paper-white);
  text-decoration: none;
  transition: transform .22s ease, box-shadow .22s ease;
}
.pattern-card:hover { transform: translateY(-4px); box-shadow: 0 22px 52px rgba(48,46,39,.10); }
.pattern-card .complexity {
  position: absolute;
  right: -8px;
  bottom: -15px;
  color: rgba(23,25,24,.055);
  font: 800 64px/1 var(--mono);
  letter-spacing: -.09em;
}
.pattern-card .tag { color: #516f8c; font: 800 11px/1 var(--mono); letter-spacing: .11em; text-transform: uppercase; }
.pattern-card h3 { margin-top: 34px; font-family: var(--mono); }
.pattern-card p { color: var(--muted); }
.pattern-card .read { position: absolute; bottom: 24px; left: 26px; font: 800 12px/1 var(--mono); }

.showcase {
  display: grid;
  grid-template-columns: minmax(250px, .72fr) minmax(0, 1.28fr);
  gap: clamp(36px, 7vw, 92px);
  align-items: center;
}
.showcase-copy h2 { max-width: 600px; }
.showcase-copy p { max-width: 590px; color: rgba(255,255,255,.66); font-size: 18px; }
.screen-strip {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(210px, 1fr);
  gap: 16px;
  overflow-x: auto;
  padding: 24px 10px 34px;
  scroll-snap-type: x mandatory;
  scrollbar-color: rgba(255,255,255,.25) transparent;
}
.screen-card { margin: 0; scroll-snap-align: center; }
.screen-card img {
  width: 100%;
  height: auto;
  aspect-ratio: 990 / 2151;
  object-fit: contain;
  border-radius: 28px;
  box-shadow: 0 28px 50px rgba(0,0,0,.38);
}
.screen-card p { margin: 13px 0 0; color: rgba(255,255,255,.72); font: 700 12px/1.4 var(--mono); text-align: center; }

.curriculum-list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
.curriculum-item { padding: 21px; border: 1px solid var(--line); border-radius: 15px; background: rgba(255,255,255,.36); }
.curriculum-item strong { display: block; font-family: var(--mono); font-size: 15px; }
.curriculum-item span { display: block; margin-top: 6px; color: var(--muted); font-size: 14px; }

.quote-block {
  padding: 48px;
  border: 1px solid var(--line);
  border-radius: 26px;
  background: rgba(255,253,248,.78);
  box-shadow: var(--shadow);
}
.quote-block blockquote { margin: 0; font: 520 clamp(28px, 4vw, 48px)/1.25 var(--mono); letter-spacing: -.045em; }
.quote-block p { margin: 24px 0 0; color: var(--muted); }

.faq-list { display: grid; gap: 10px; }
.faq-list details { border: 1px solid var(--line); border-radius: 15px; background: rgba(255,253,248,.68); }
.faq-list summary { padding: 19px 22px; cursor: pointer; font-weight: 800; list-style: none; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after { content: "+"; float: right; font: 800 20px/1 var(--mono); }
.faq-list details[open] summary::after { content: "−"; }
.faq-list details p { margin: 0; padding: 0 22px 21px; color: var(--muted); }

.cta-panel {
  position: relative;
  overflow: hidden;
  padding: clamp(42px, 7vw, 78px);
  border-radius: 32px;
  background: var(--blue);
  box-shadow: var(--shadow);
}
.cta-panel::after { content: "O(1)"; position: absolute; right: -18px; top: -42px; color: rgba(255,255,255,.18); font: 800 160px/1 var(--mono); }
.cta-panel h2 { position: relative; z-index: 1; max-width: 750px; font-family: var(--mono); }
.cta-panel p { position: relative; z-index: 1; max-width: 650px; font-size: 18px; }
.cta-panel .button, .cta-panel .app-store-badge { position: relative; z-index: 1; }

.home-cta {
  color: var(--paper-white);
  background: var(--ink);
  border: 1px solid rgba(255,255,255,.1);
  box-shadow: 0 30px 90px rgba(23,25,24,.22);
}
.home-cta::after { color: rgba(125,182,237,.12); }
.home-cta .eyebrow { color: var(--blue); }
.home-cta p { color: rgba(255,255,255,.72); }

.lesson-cta {
  color: var(--paper-white);
  background: var(--ink);
  border: 1px solid rgba(255,255,255,.1);
  box-shadow: 0 30px 90px rgba(23,25,24,.22);
}
.lesson-cta::after { color: rgba(125,182,237,.12); }
.lesson-cta .eyebrow { color: var(--blue); }
.lesson-cta p { color: rgba(255,255,255,.72); }

.site-footer { padding: 58px 0 42px; border-top: 1px solid var(--line); background: rgba(250,248,241,.86); }
.footer-grid { display: grid; grid-template-columns: 1.4fr repeat(2, 1fr); gap: 42px; }
.footer-grid h3 { margin-bottom: 13px; font: 800 12px/1 var(--mono); letter-spacing: .11em; text-transform: uppercase; }
.footer-grid a { display: block; width: fit-content; margin: 8px 0; color: var(--muted); text-decoration: none; font-size: 14px; }
.footer-grid a:hover { color: var(--ink); text-decoration: underline; }
.footer-brand p { max-width: 360px; color: var(--muted); font-size: 14px; }
.copyright { margin: 38px 0 0; padding-top: 22px; border-top: 1px solid var(--line); color: #777c78; font: 700 11px/1.5 var(--mono); }

/* Educational pages */
.breadcrumbs { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 26px; color: #707571; font: 700 12px/1.4 var(--mono); }
.breadcrumbs a { text-decoration: none; }
.breadcrumbs a:hover { text-decoration: underline; }
.breadcrumbs span + span::before { content: "/"; padding-right: 8px; color: #a4a8a5; }

.article-hero { position: relative; overflow: hidden; padding: 76px 0 66px; border-bottom: 1px solid var(--line); }
.article-hero::before { top: 15px; opacity: .72; }
.article-hero h1 { max-width: 930px; font-size: clamp(42px, 7vw, 78px); }
.article-hero .dek { max-width: 780px; margin: 24px 0 0; color: var(--muted); font-size: clamp(18px, 2.3vw, 22px); }
.article-meta { display: flex; flex-wrap: wrap; gap: 9px 18px; margin-top: 28px; color: #737874; font: 700 12px/1.5 var(--mono); }

.article-layout { display: grid; grid-template-columns: 220px minmax(0, 760px); justify-content: center; gap: 76px; padding: 74px 0 112px; }
.toc { position: sticky; top: 98px; align-self: start; }
.toc strong { display: block; margin-bottom: 14px; font: 800 11px/1 var(--mono); letter-spacing: .12em; text-transform: uppercase; }
.toc a { display: block; padding: 7px 0 7px 13px; border-left: 1px solid var(--line); color: var(--muted); text-decoration: none; font-size: 13px; }
.toc a:hover { border-color: var(--blue); color: var(--ink); }

.prose { min-width: 0; }
.prose > *:first-child { margin-top: 0; }
.prose h2 { margin: 70px 0 22px; font-size: clamp(32px, 4vw, 46px); scroll-margin-top: 105px; }
.prose h3 { margin: 40px 0 14px; scroll-margin-top: 105px; }
.prose p, .prose li { color: #4f5450; font-size: 17px; }
.prose p { margin: 0 0 22px; }
.prose .lesson-cta h2 { margin: 20px 0 16px; }
.prose .lesson-cta p { color: rgba(255,255,255,.72); }
.prose ul, .prose ol { padding-left: 24px; }
.prose li { margin: 9px 0; }
.prose strong { color: var(--ink); }
.prose code { padding: .15em .38em; border-radius: 5px; background: rgba(125,182,237,.13); color: #273d50; font-family: var(--mono); font-size: .89em; }
.prose pre { overflow-x: auto; margin: 26px 0; padding: 24px; border-radius: 17px; background: #1d211f; color: #f2f3ef; font: 14px/1.75 var(--mono); box-shadow: 0 18px 42px rgba(23,25,24,.13); }
.prose pre code { padding: 0; background: none; color: inherit; }

.lesson-note { margin: 30px 0; padding: 22px 24px; border: 1px solid rgba(125,182,237,.32); border-left: 5px solid var(--blue); border-radius: 13px; background: rgba(255,253,248,.72); }
.lesson-note strong { display: block; margin-bottom: 5px; font-family: var(--mono); }
.lesson-note p { margin: 0; font-size: 15px; }
.lesson-note.yellow { border-color: rgba(246,189,69,.34); border-left-color: var(--yellow); }
.lesson-note.green { border-color: rgba(118,196,135,.34); border-left-color: var(--green); }
.lesson-note.coral { border-color: rgba(245,141,123,.34); border-left-color: var(--coral); }

.compare-table { width: 100%; margin: 28px 0; border-collapse: collapse; border: 1px solid var(--line); background: rgba(255,253,248,.66); }
.compare-table th, .compare-table td { padding: 14px 16px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
.compare-table th { background: rgba(125,182,237,.10); font: 800 12px/1.3 var(--mono); }
.compare-table td { color: var(--muted); font-size: 15px; }

.signal-grid, .lesson-card-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; margin: 28px 0; }
.signal, .lesson-card { padding: 20px; border: 1px solid var(--line); border-radius: 15px; background: rgba(255,253,248,.7); }
.signal strong, .lesson-card strong { display: block; margin-bottom: 7px; font-family: var(--mono); }
.signal p, .lesson-card p { margin: 0; font-size: 15px; }
.lesson-card { display: block; min-height: 175px; text-decoration: none; }
.lesson-card:hover { border-color: rgba(23,25,24,.35); }
.lesson-card .arrow { display: block; margin-top: 20px; color: var(--ink); font: 800 12px/1 var(--mono); }

.demo {
  margin: 32px 0;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: rgba(255,253,248,.82);
  box-shadow: 0 18px 45px rgba(48,46,39,.07);
}
.demo-label { color: #69706b; font: 800 11px/1 var(--mono); letter-spacing: .12em; text-transform: uppercase; }
.array-visual { display: grid; grid-template-columns: repeat(6, minmax(42px, 1fr)); gap: 7px; margin: 24px 0 18px; }
.array-cell { position: relative; padding: 14px 5px; border: 1px solid var(--line); border-radius: 10px; background: white; text-align: center; font: 800 16px/1 var(--mono); transition: background .2s ease, transform .2s ease; }
.array-cell.is-left { background: rgba(118,196,135,.25); transform: translateY(-4px); }
.array-cell.is-right { background: rgba(245,141,123,.22); transform: translateY(-4px); }
.array-cell.is-mid { background: rgba(246,189,69,.25); transform: translateY(-4px); }
.array-cell::after { position: absolute; left: 50%; top: calc(100% + 6px); transform: translateX(-50%); font: 800 9px/1 var(--mono); }
.array-cell.is-left::after { content: "LEFT"; color: #397849; }
.array-cell.is-right::after { content: "RIGHT"; color: #9c4c3d; }
.array-cell.is-mid::after { content: "MID"; color: #85610f; }
.demo-output { min-height: 54px; margin-top: 26px; color: var(--muted); }
.demo-controls { display: none; gap: 9px; margin-top: 16px; }
.js .demo-controls { display: flex; }
.demo-controls button { padding: 10px 14px; border: 1px solid var(--ink); border-radius: 10px; background: var(--ink); color: white; cursor: pointer; font-weight: 800; }
.demo-controls button.secondary { background: transparent; color: var(--ink); }
.js .demo-fallback { display: none; }

.page-index-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; margin-top: 42px; }
.page-index-card { min-height: 240px; padding: 26px; border: 1px solid var(--line); border-radius: 20px; background: rgba(255,253,248,.74); text-decoration: none; }
.page-index-card:hover { box-shadow: 0 20px 44px rgba(48,46,39,.08); transform: translateY(-2px); }
.page-index-card .kicker { color: #5b7790; font: 800 11px/1 var(--mono); letter-spacing: .12em; text-transform: uppercase; }
.page-index-card h2 { margin-top: 28px; font: 720 28px/1.12 var(--mono); }
.page-index-card p { color: var(--muted); }

/* Existing public policy and support pages: visual refresh only. */
body.legacy-page {
  --legacy-accent: var(--blue);
  --legacy-background-accent: var(--legacy-accent);
  position: relative;
  min-height: 100vh;
  padding: clamp(30px, 6vw, 64px) 20px 80px;
  color: var(--ink);
  font-family: var(--sans);
  background-color: var(--paper);
  background-image:
    radial-gradient(circle at 1px 1px, var(--dot) 1.2px, transparent 1.3px),
    radial-gradient(circle at 14% 5%, color-mix(in srgb, var(--legacy-background-accent) 15%, transparent), transparent 28%),
    linear-gradient(180deg, rgba(255,255,255,.6), rgba(241,236,223,.38));
  background-size: 22px 22px, 100% 100%, 100% 100%;
}
body.legacy-privacy { --legacy-accent: var(--green); --legacy-background-accent: var(--yellow); }
body.legacy-terms { --legacy-accent: var(--yellow); }
body.legacy-contact { --legacy-accent: var(--blue); }
body.legacy-accessibility { --legacy-accent: var(--coral); }
body.legacy-support { --legacy-accent: var(--blue); }

.legacy-page .wrap { width: min(100%, 880px); margin: 0 auto; }
.legacy-page .toplink {
  display: inline-flex;
  align-items: center;
  min-height: 42px;
  margin-bottom: 18px;
  padding: 9px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--ink);
  background: rgba(255,253,248,.72);
  box-shadow: 0 10px 28px rgba(45,43,36,.05);
  font: 800 13px/1 var(--mono);
  text-decoration: none;
}
.legacy-page .toplink:hover { color: var(--ink); border-color: color-mix(in srgb, var(--legacy-accent) 62%, var(--line)); }
.legacy-page .toplink:focus-visible { outline: 3px solid var(--blue); outline-offset: 3px; }
.legacy-page .panel {
  position: relative;
  overflow: hidden;
  padding: clamp(30px, 6vw, 64px);
  border: 1px solid var(--line);
  border-radius: 30px;
  background: rgba(255,253,248,.9);
  box-shadow: var(--shadow);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}
.legacy-page .panel::before {
  content: "";
  position: absolute;
  inset: 0 0 auto;
  height: 7px;
  background: linear-gradient(90deg, var(--legacy-accent) 0 72%, var(--yellow) 72% 86%, var(--coral) 86% 100%);
}
.legacy-page .panel::after {
  content: "";
  position: absolute;
  z-index: -1;
  top: 30px;
  right: 28px;
  width: 96px;
  height: 96px;
  border-radius: 50%;
  opacity: .5;
  background-image: radial-gradient(circle, var(--legacy-accent) 1.3px, transparent 1.5px);
  background-size: 11px 11px;
}
.legacy-page h1 {
  max-width: 760px;
  margin: 0 0 10px;
  font: 760 clamp(38px, 7vw, 66px)/1.02 var(--mono);
  letter-spacing: -.055em;
  text-wrap: balance;
}
.legacy-page .updated {
  margin-bottom: 34px;
  color: var(--muted);
  font: 800 12px/1.5 var(--mono);
  letter-spacing: .04em;
  text-transform: uppercase;
}
.legacy-page h2 {
  margin: 34px 0 10px;
  padding-left: 13px;
  border-left: 4px solid var(--legacy-accent);
  font: 800 18px/1.35 var(--mono);
  letter-spacing: -.02em;
}
.legacy-page p, .legacy-page li { color: #303431; font-size: 16px; line-height: 1.78; }
.legacy-page ul { margin-top: 10px; padding-left: 24px; }
.legacy-page li + li { margin-top: 5px; }
.legacy-page li::marker { color: var(--legacy-accent); }
.legacy-page .panel a { color: var(--ink); text-decoration-color: var(--legacy-accent); text-decoration-thickness: 2px; text-underline-offset: 3px; }
.legacy-page .panel a:hover { text-decoration-thickness: 3px; }
.legacy-page .panel a:focus-visible { outline: 3px solid var(--blue); outline-offset: 3px; border-radius: 2px; }

body.legacy-404 {
  background-color: var(--paper);
  background-image:
    radial-gradient(circle at 1px 1px, var(--dot) 1.2px, transparent 1.3px),
    radial-gradient(circle at 16% 18%, rgba(246,189,69,.16), transparent 22%),
    radial-gradient(circle at 84% 78%, rgba(125,182,237,.16), transparent 24%),
    linear-gradient(180deg, rgba(255,255,255,.58), rgba(241,236,223,.28));
  background-size: 22px 22px, 100% 100%, 100% 100%, 100% 100%;
}
.legacy-404 .panel {
  border-color: var(--line);
  border-radius: 30px;
  background: rgba(255,253,248,.92);
  box-shadow: var(--shadow);
}
.legacy-404 .code { font-weight: 800; letter-spacing: -.09em; }
.legacy-404 .button { border-radius: 12px; background: var(--ink); color: white; }
.legacy-404 .text-link { border-radius: 12px; background: rgba(255,255,255,.58); color: var(--muted); }

@media (max-width: 960px) {
  .site-nav { gap: 1px; }
  .site-nav a { padding-inline: 9px; }
  .hero-grid { grid-template-columns: 1fr; }
  .hero-copy { max-width: 800px; }
  .hero-visual { min-height: 610px; }
  .phone-shell { width: 340px; }
  .method-grid { grid-template-columns: repeat(2, 1fr); }
  .pattern-grid { grid-template-columns: repeat(2, 1fr); }
  .showcase { grid-template-columns: 1fr; }
  .article-layout { grid-template-columns: minmax(0, 760px); }
  .toc { display: none; }
}

@media (max-width: 760px) {
  .nav-wrap { width: min(calc(100% - 28px), var(--max)); }
  .nav-toggle { display: grid; place-items: center; }
  .site-nav {
    position: absolute;
    top: 66px;
    left: 14px;
    right: 14px;
    display: none;
    padding: 12px;
    border: 1px solid var(--line);
    border-radius: 17px;
    background: rgba(255,253,248,.98);
    box-shadow: var(--shadow);
  }
  .site-nav.is-open { display: grid; }
  .site-nav a { padding: 12px 13px; }
  .site-nav a.nav-store-badge { width: fit-content; padding: 4px; }
  .js .site-nav { display: none; }
  .js .site-nav.is-open { display: grid; }
  .no-js .nav-toggle { display: none; }
  .no-js .site-nav { display: grid; position: static; box-shadow: none; }
  .container, .narrow { width: min(calc(100% - 30px), var(--max)); }
  .hero { padding-top: 64px; }
  h1 { font-size: clamp(40px, 12vw, 64px); }
  .hero-visual { min-height: 560px; }
  .float-note.one { left: -2px; top: 72px; }
  .float-note.two { right: -1px; }
  .section { padding: 78px 0; }
  .section-heading { grid-template-columns: 1fr; gap: 18px; }
  .method-grid, .pattern-grid, .curriculum-list, .signal-grid, .lesson-card-grid, .page-index-grid { grid-template-columns: 1fr; }
  .method-card { min-height: 215px; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
  .quote-block { padding: 31px; }
  .article-layout { padding-top: 56px; }
  .article-hero { padding-top: 58px; }
  .compare-table { display: block; overflow-x: auto; }
  .legacy-page .panel::after { display: none; }
}

@media (max-width: 470px) {
  .brand span { display: none; }
  .hero-visual { min-height: 520px; }
  .phone-shell { width: min(310px, 86vw); border-radius: 48px; }
  .phone-shell img { border-radius: 39px; }
  .float-note { font-size: 11px; padding: 12px; }
  .trust-line span { display: block; }
  .trust-line span + span::before { display: none; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-brand { grid-column: auto; }
  .array-visual { grid-template-columns: repeat(3, 1fr); row-gap: 25px; }
}

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

@media print {
  .site-header, .site-footer, .toc, .cta-panel { display: none; }
  body { background: white; }
  .article-layout { display: block; padding: 24px 0; }
  .prose { width: 100%; }
  body.legacy-page { padding: 0; background: white; }
  .legacy-page .toplink { display: none; }
  .legacy-page .panel { padding: 0; border: 0; box-shadow: none; background: white; }
}