:root {
  --canvas: #FFFFFF;
  --ink: #0D1B2A;
  --text: #344757;
  --muted: #667481;
  --ember: #F24E2E;
  --action: #2457D6;
  --verified: #19704F;
  --mist: #F5F7F9;
  --line: #DCE2E7;
  --line-strong: #B6C0C8;
  --max: 1180px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--canvas);
  color: var(--ink);
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI",
    "Noto Sans JP", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  line-height: 1.75;
  overflow-wrap: anywhere;
}
a { color: inherit; }
img, svg { max-width: 100%; height: auto; }
button { font: inherit; }
code { font-family: ui-monospace, SFMono-Regular, Consolas, monospace; }
.skip-link { position: fixed; left: -9999px; top: 10px; z-index: 100; padding: 9px 13px; background: var(--ink); color: #fff; }
.skip-link:focus { left: 10px; }
.container { width: min(calc(100% - 40px), var(--max)); margin-inline: auto; }
.site-header { border-bottom: 1px solid var(--line); background: #fff; }
.header-inner { min-height: 70px; display: flex; align-items: center; justify-content: space-between; gap: 28px; }
.wordmark { display: inline-flex; align-items: baseline; gap: 6px; color: var(--ink); text-decoration: none; font-weight: 850; letter-spacing: -.035em; }
.wordmark-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--ember); transform: translateY(-7px); }
.wordmark small { display: block; margin-left: 8px; color: var(--muted); font-size: .66rem; font-weight: 600; letter-spacing: 0; }
.site-nav { display: flex; align-items: center; gap: 23px; }
.site-nav a { color: var(--text); font-size: .86rem; text-decoration: none; }
.site-nav a:hover, .site-nav a:focus { color: var(--action); text-decoration: underline; text-underline-offset: 5px; }
.menu-button { display: none; width: 42px; height: 42px; border: 1px solid var(--line); border-radius: 6px; background: #fff; }
main { min-height: 68vh; }

.hero { border-bottom: 1px solid var(--line); }
.hero-grid {
  min-height: 510px;
  display: grid;
  grid-template-columns: minmax(0, 1.34fr) minmax(330px, .66fr);
  gap: 72px;
  align-items: center;
  padding: 68px 0 56px;
}
.exp-id { display: flex; align-items: center; gap: 10px; color: var(--muted); font: 700 .72rem ui-monospace, SFMono-Regular, Consolas, monospace; letter-spacing: .12em; }
.exp-id::before { content: ""; width: 9px; height: 9px; border-radius: 50%; background: var(--ember); }
h1, h2, h3 { margin-top: 0; color: var(--ink); line-height: 1.28; letter-spacing: -.03em; }
h1 { max-width: 720px; margin: 18px 0 20px; font-size: clamp(2.55rem, 6vw, 4.75rem); }
h2 { margin-bottom: 14px; font-size: clamp(1.65rem, 3.4vw, 2.45rem); }
h3 { font-size: 1.15rem; }
.hero-copy { max-width: 720px; color: var(--text); font-size: 1.02rem; }
.hero-proof {
  position: relative;
  padding: 24px 0 0 28px;
  border-left: 1px solid var(--line-strong);
}
.hero-proof::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 0;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ember);
}
.proof-label { margin-bottom: 18px; color: var(--muted); font: 700 .68rem ui-monospace, monospace; letter-spacing: .1em; }
.proof-list { display: grid; gap: 0; border-top: 1px solid var(--line); }
.proof-row { display: grid; grid-template-columns: 105px 1fr; gap: 14px; padding: 14px 0; border-bottom: 1px solid var(--line); }
.proof-row strong { color: var(--ink); font-size: .83rem; }
.proof-row span { color: var(--muted); font-size: .82rem; }

.section { padding: 58px 0; }
.section + .section { border-top: 1px solid var(--line); }
.section-head { display: grid; grid-template-columns: 1fr minmax(260px, 430px); gap: 48px; align-items: end; margin-bottom: 26px; }
.section-label { display: flex; gap: 9px; align-items: center; margin-bottom: 8px; color: var(--muted); font: 700 .68rem ui-monospace, monospace; letter-spacing: .12em; }
.section-label::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--ember); }
.section-head p { margin: 0; color: var(--muted); font-size: .9rem; }

.feature-grid { display: grid; grid-template-columns: minmax(0, 1.52fr) minmax(300px, .48fr); gap: 22px; }
.feature {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(280px, .9fr);
  border-top: 4px solid var(--ink);
  border-bottom: 1px solid var(--line-strong);
}
.feature-copy { display: flex; flex-direction: column; min-height: 430px; padding: 30px 28px 26px 0; }
.meta { display: flex; flex-wrap: wrap; gap: 8px 14px; align-items: center; color: var(--muted); font-size: .76rem; }
.status { display: inline-flex; min-height: 24px; align-items: center; padding: 0 8px; border: 1px solid var(--line); font: 700 .66rem ui-monospace, monospace; letter-spacing: .04em; }
.status.verified { border-color: var(--verified); color: var(--verified); }
.status.progress { border-color: var(--action); color: var(--action); }
.status.unverified { color: var(--muted); }
.feature h2 { margin: 25px 0 14px; font-size: clamp(1.85rem, 4vw, 3rem); }
.feature p { color: var(--text); }
.feature-link { margin-top: auto; padding-top: 20px; color: var(--action); font-weight: 850; text-decoration: none; }
.feature-link:hover, .feature-link:focus { text-decoration: underline; }
.evidence-frame {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 28px;
  border-left: 1px solid var(--line);
  background: var(--mist);
  overflow: hidden;
}
.evidence-frame::before, .evidence-frame::after { content: ""; position: absolute; background: var(--line); }
.evidence-frame::before { left: 50%; top: 0; bottom: 0; width: 1px; }
.evidence-frame::after { left: 0; right: 0; top: 50%; height: 1px; }
.observation {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 8px;
}
.observation-title { margin-bottom: 12px; color: var(--ink); font-weight: 850; }
.node { padding: 9px 11px; border: 1px solid var(--line-strong); background: #fff; color: var(--ink); font: 700 .72rem ui-monospace, monospace; }
.node.child { margin-left: 20px; }
.node.protected { border-left: 4px solid var(--ember); }
.observation-note { position: relative; z-index: 1; margin: 15px 0 0; color: var(--muted); font-size: .74rem; }

.feed { border-top: 4px solid var(--ember); border-bottom: 1px solid var(--line-strong); }
.feed-title { margin: 0; padding: 16px 18px; border-bottom: 1px solid var(--line); font-size: .92rem; }
.feed-item { display: block; padding: 19px 18px; border-bottom: 1px solid var(--line); text-decoration: none; }
.feed-item:last-child { border-bottom: 0; }
.feed-item:hover, .feed-item:focus { background: var(--mist); }
.feed-item h3 { margin: 9px 0 7px; }
.feed-item p { margin: 0; color: var(--text); font-size: .84rem; }
.feed-item small { display: block; margin-top: 9px; color: var(--muted); }

.topic-grid { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line-strong); border-bottom: 1px solid var(--line-strong); }
.topic { min-height: 190px; padding: 24px; border-right: 1px solid var(--line); }
.topic:last-child { border-right: 0; }
.topic-no { color: var(--ember); font: 700 .68rem ui-monospace, monospace; letter-spacing: .08em; }
.topic h3 { margin: 22px 0 9px; font-size: 1.35rem; }
.topic p { margin: 0; color: var(--text); font-size: .88rem; }

.ledger { border-top: 1px solid var(--line-strong); }
.ledger-row { display: grid; grid-template-columns: 132px minmax(0,1fr) 120px 120px; gap: 18px; align-items: center; padding: 16px 0; border-bottom: 1px solid var(--line); }
.ledger-row.header { color: var(--muted); font: 700 .66rem ui-monospace, monospace; letter-spacing: .08em; }
.ledger-row a { color: var(--ink); font-weight: 800; text-decoration: none; }
.ledger-row a:hover, .ledger-row a:focus { color: var(--action); text-decoration: underline; }
.ledger-meta { color: var(--muted); font-size: .8rem; }

.method-grid { display: grid; grid-template-columns: .8fr 1.2fr; gap: 60px; }
.method-intro p { color: var(--text); }
.method-list { display: grid; grid-template-columns: repeat(2, 1fr); border-top: 1px solid var(--line); }
.method { min-height: 164px; padding: 22px 22px 22px 0; border-bottom: 1px solid var(--line); }
.method:nth-child(odd) { border-right: 1px solid var(--line); }
.method:nth-child(even) { padding-left: 22px; }
.method strong { display: block; margin-bottom: 7px; }
.method p { margin: 0; color: var(--text); font-size: .86rem; }

.disclosure { padding: 28px; border: 1px solid var(--line-strong); }
.disclosure p { color: var(--text); }
.text-link { color: var(--action); font-weight: 800; text-underline-offset: 4px; }

.site-footer { padding: 34px 0; border-top: 1px solid var(--line-strong); }
.footer-grid { display: grid; grid-template-columns: 1fr auto; gap: 28px; }
.footer-links { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 16px; }
.footer-links a { color: var(--muted); font-size: .82rem; }
.footer-small { margin: 5px 0; color: var(--muted); font-size: .76rem; }

/* Article */
.article-head { padding: 46px 0 34px; border-bottom: 1px solid var(--line); }
.breadcrumbs { display: flex; flex-wrap: wrap; gap: 7px; color: var(--muted); font-size: .76rem; }
.breadcrumbs a { color: var(--action); }
.article-head h1 { max-width: 950px; margin: 20px 0 15px; font-size: clamp(2.15rem, 5.4vw, 3.75rem); }
.article-deck { max-width: 850px; margin: 0; color: var(--text); font-size: 1rem; }
.article-meta { display: flex; flex-wrap: wrap; gap: 10px 18px; margin-top: 19px; color: var(--muted); font-size: .78rem; }
.article-shell { display: grid; grid-template-columns: minmax(0,1fr) 260px; gap: 58px; align-items: start; padding: 40px 0 78px; }
.article-body { min-width: 0; }
.article-body h2 { margin-top: 56px; padding-top: 8px; font-size: clamp(1.55rem,3vw,2.05rem); }
.article-body h3 { margin-top: 30px; }
.article-body p, .article-body li { color: var(--text); }
.article-body a { color: var(--action); }
.article-body code { padding: 2px 5px; border-radius: 3px; background: var(--mist); }
.article-body pre { overflow-x: auto; padding: 18px; border-left: 4px solid var(--ember); background: var(--mist); color: var(--ink); font-size: .82rem; }

.summary { display: grid; grid-template-columns: 1.25fr .75fr; border-top: 4px solid var(--ink); border-bottom: 1px solid var(--line-strong); }
.quick, .record { padding: 24px; }
.quick { padding-left: 0; border-right: 1px solid var(--line); }
.quick h2, .record h2 { margin: 0 0 13px; padding: 0; font-size: 1.18rem; }
.quick ul { margin: 0; }
.record { background: var(--mist); }
.record dl { display: grid; grid-template-columns: 84px 1fr; gap: 8px 10px; margin: 0; }
.record dt { color: var(--muted); font-size: .74rem; }
.record dd { margin: 0; color: var(--text); font-size: .82rem; }

.note { position: relative; margin: 24px 0; padding: 19px 21px 19px 26px; border-left: 1px solid var(--line-strong); }
.note::before { content: ""; position: absolute; left: -5px; top: 21px; width: 9px; height: 9px; border-radius: 50%; background: var(--ember); }
.note.warning::before { background: #C07817; }
.note strong { color: var(--ink); }

.steps { counter-reset: step; margin: 26px 0; }
.step { position: relative; margin-left: 17px; padding: 0 0 27px 53px; border-left: 1px solid var(--line-strong); }
.step:last-child { border-left-color: transparent; padding-bottom: 0; }
.step::before { counter-increment: step; content: counter(step); position: absolute; left: -18px; top: 0; width: 36px; height: 36px; display: grid; place-items: center; border: 1px solid var(--ember); border-radius: 50%; background: #fff; color: var(--ember); font-weight: 850; }
.step h3 { margin: 0 0 7px; }

.table-wrap { overflow-x: auto; }
table { width: 100%; min-width: 680px; border-collapse: collapse; }
th, td { padding: 13px 14px; border: 1px solid var(--line); text-align: left; vertical-align: top; }
th { background: var(--mist); }

.evidence-row { display: grid; grid-template-columns: 150px minmax(0,1fr); gap: 18px; padding: 16px 0; border-top: 1px solid var(--line); }
.evidence-row:last-child { border-bottom: 1px solid var(--line); }
.evidence-row strong { color: var(--ink); }
.evidence-row span { color: var(--text); }

.fit-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.fit { padding: 21px; border-top: 3px solid var(--verified); background: var(--mist); }
.fit.no { border-top-color: #C07817; }
.fit h3 { margin-top: 0; }

.toc { position: sticky; top: 20px; padding: 17px; border-top: 3px solid var(--ember); background: var(--mist); }
.toc strong { color: var(--ink); }
.toc ol { margin-bottom: 0; padding-left: 18px; }
.toc a { color: var(--muted); font-size: .78rem; text-decoration: none; }
.toc a:hover, .toc a:focus { color: var(--action); text-decoration: underline; }
.source-list { font-size: .86rem; }
.change-log { display: grid; grid-template-columns: 120px 1fr; border-top: 1px solid var(--line); }
.change-log div { padding: 12px 0; border-bottom: 1px solid var(--line); }
.change-log .date { color: var(--muted); }

.next-story { margin-top: 48px; padding: 25px; border: 1px solid var(--line-strong); }
.next-story::before { content: ""; display: block; width: 9px; height: 9px; margin-bottom: 16px; border-radius: 50%; background: var(--ember); }
.next-story h2 { margin-bottom: 10px; }
.next-story p { color: var(--text); }

/* Legal */
.legal { max-width: 840px; padding: 48px 0 72px; }
.legal h1 { font-size: clamp(2.1rem,5vw,3.25rem); }
.legal h2 { margin-top: 40px; font-size: 1.42rem; }
.legal p, .legal li { color: var(--text); }
.not-found { min-height: 65vh; display: grid; place-items: center; }
.not-found-box { max-width: 670px; padding: 36px; border-top: 4px solid var(--ember); }
.not-found-code { margin: 0; color: var(--ember); font-size: 3rem; font-weight: 850; }

@media (max-width: 980px) {
  .feature-grid, .article-shell, .method-grid { grid-template-columns: 1fr; }
  .article-shell { gap: 24px; }
  .toc { position: static; order: -1; }
}
@media (max-width: 820px) {
  .hero-grid, .feature, .summary { grid-template-columns: 1fr; }
  .hero-grid { min-height: 0; gap: 36px; }
  .hero-proof { border-left: 0; border-top: 1px solid var(--line); padding: 25px 0 0; }
  .hero-proof::before { left: 0; top: -5px; }
  .feature-copy { min-height: 0; padding-right: 0; }
  .evidence-frame { border-left: 0; border-top: 1px solid var(--line); }
  .quick { padding-left: 24px; border-right: 0; border-bottom: 1px solid var(--line); }
  .topic-grid { grid-template-columns: 1fr; }
  .topic { border-right: 0; border-bottom: 1px solid var(--line); }
  .topic:last-child { border-bottom: 0; }
  .ledger-row { grid-template-columns: 115px 1fr 110px; }
  .ledger-scope { display: none; }
}
@media (max-width: 720px) {
  .container { width: min(calc(100% - 28px), var(--max)); }
  .site-nav { display: none; position: absolute; top: 70px; left: 14px; right: 14px; z-index: 50; padding: 16px; border: 1px solid var(--line); background: #fff; }
  .site-nav.is-open { display: grid; gap: 13px; }
  .site-header { position: relative; }
  .menu-button { display: inline-grid; place-items: center; }
  .section-head { grid-template-columns: 1fr; gap: 9px; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-links { justify-content: flex-start; }
  .method-list { grid-template-columns: 1fr; }
  .method, .method:nth-child(odd), .method:nth-child(even) { padding: 18px 0; border-right: 0; }
  .fit-grid { grid-template-columns: 1fr; }
}
@media (max-width: 520px) {
  h1 { font-size: 2.45rem; }
  .hero-grid { padding-top: 42px; }
  .feature-copy, .evidence-frame, .record { padding: 21px; }
  .feature-copy { padding-left: 0; }
  .ledger-row { grid-template-columns: 1fr auto; gap: 7px 13px; }
  .ledger-row.header { display: none; }
  .ledger-meta { grid-column: 1; }
  .ledger-row .status { grid-column: 2; grid-row: 1; }
  .evidence-row { grid-template-columns: 1fr; gap: 4px; }
  .change-log { grid-template-columns: 92px 1fr; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}