@font-face {
  font-family: "Saira Condensed";
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url("fonts/saira-condensed-600.woff2") format("woff2");
}
@font-face {
  font-family: "Saira Condensed";
  font-style: normal;
  font-weight: 700;
  font-display: swap;
  src: url("fonts/saira-condensed-700.woff2") format("woff2");
}
@font-face {
  font-family: "Inter";
  font-style: normal;
  font-weight: 100 900;
  font-display: swap;
  src: url("fonts/inter-var.woff2") format("woff2");
}

:root {
  --paper: #f2efe4;
  --panel: #fbf9f1;
  --panel-2: #e9e5d6;
  --ink: #101614;
  --ink-soft: #4a544f;
  --line: #d3cfbf;
  --line-strong: #b9b5a4;
  --accent: #b9570f;
  --accent-ink: #7a3506;
  --accent-wash: #f4e3cf;
  --fig-amber: #b9570f;
  --fig-red: #a63b2a;
  --fig-blue: #4d7f88;
  --jade: #6f8279;
  --navy: #283a4e;
  --table-head: #283a4e;
  --table-head-ink: #f2efe4;
  --shadow: 0 1px 0 rgba(16, 22, 20, .04);
  --wrap: 1180px;
  --font-body: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  --font-display: "Saira Condensed", "Inter", "Arial Narrow", Arial, sans-serif;
}

[data-theme="dark"] {
  --paper: #0b0e0d;
  --panel: #131917;
  --panel-2: #1a2220;
  --ink: #e9e7d9;
  --ink-soft: #a6b1aa;
  --line: #2b3531;
  --line-strong: #3d4a44;
  --accent: #dd6b1c;
  --accent-ink: #f0a25f;
  --accent-wash: #241a12;
  --fig-amber: #dd6b1c;
  --fig-red: #d9685a;
  --fig-blue: #7fb3ba;
  --jade: #9aada0;
  --navy: #2c4058;
  --table-head: #1f2d3d;
  --table-head-ink: #e9e7d9;
  --shadow: 0 1px 0 rgba(0, 0, 0, .35);
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  background-color: var(--paper);
  background-image:
    linear-gradient(rgba(111, 130, 121, .055) 1px, transparent 1px),
    linear-gradient(90deg, rgba(111, 130, 121, .055) 1px, transparent 1px),
    radial-gradient(1100px 600px at 82% -10%, rgba(185, 87, 15, .09), transparent 62%),
    radial-gradient(900px 520px at -10% 8%, rgba(40, 58, 78, .10), transparent 60%);
  background-size: 32px 32px, 32px 32px, auto, auto;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16.5px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
[data-theme="dark"] body {
  background-image:
    linear-gradient(rgba(154, 173, 160, .055) 1px, transparent 1px),
    linear-gradient(90deg, rgba(154, 173, 160, .055) 1px, transparent 1px),
    radial-gradient(1100px 600px at 82% -10%, rgba(221, 107, 28, .10), transparent 62%),
    radial-gradient(900px 520px at -10% 8%, rgba(44, 64, 88, .28), transparent 60%);
}

img, svg { max-width: 100%; }
a { color: var(--accent-ink); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }
strong { font-weight: 600; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 200;
  padding: .65rem 1rem;
  background: var(--panel);
  color: var(--ink);
  border: 1px solid var(--accent);
}
.skip-link:focus { left: 1rem; top: 1rem; }

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* ---------- header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: color-mix(in srgb, var(--paper) 90%, transparent);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}
.site-header::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent) 18%, var(--accent) 34%, transparent 60%);
  opacity: .55;
}
.header-inner {
  display: flex;
  align-items: center;
  gap: 1.1rem;
  min-height: 66px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: .65rem;
  color: var(--ink);
  text-decoration: none;
  flex-shrink: 0;
}
.brand-mark {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  border: 1px solid var(--accent);
  color: var(--accent-ink);
  background: linear-gradient(135deg, var(--accent-wash), transparent 70%);
  clip-path: polygon(0 0, 76% 0, 100% 24%, 100% 100%, 0 100%);
}
.brand-mark svg { width: 21px; height: 21px; }
.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.08rem;
  letter-spacing: .035em;
  text-transform: uppercase;
}
.brand-sub { font-size: .68rem; letter-spacing: .07em; color: var(--ink-soft); text-transform: uppercase; }

.main-nav {
  display: flex;
  flex-wrap: wrap;
  gap: .1rem;
  margin-left: auto;
}
.main-nav a {
  color: var(--ink-soft);
  text-decoration: none;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: .82rem;
  letter-spacing: .09em;
  text-transform: uppercase;
  padding: .45rem .55rem;
  border-bottom: 1px solid transparent;
}
.main-nav a:hover { color: var(--ink); border-bottom-color: var(--accent); }
.main-nav a[aria-current="page"] { color: var(--accent-ink); border-bottom-color: var(--accent); }

.header-actions { display: flex; gap: .35rem; }
.icon-btn {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--ink);
  cursor: pointer;
}
.icon-btn svg { width: 17px; height: 17px; }
.icon-btn:hover { border-color: var(--accent); color: var(--accent-ink); }
.menu-btn { display: none; }

/* ---------- hero ---------- */
.hero {
  position: relative;
  padding: 3.6rem 0 2.2rem;
  max-width: 860px;
}
.hero::before {
  content: "";
  position: absolute;
  inset: 1rem auto auto -1.25rem;
  width: 3px;
  height: 78px;
  background: var(--accent);
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  margin: 0 0 .9rem;
  color: var(--accent-ink);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: .78rem;
  letter-spacing: .16em;
  text-transform: uppercase;
}
.eyebrow::before {
  content: "";
  width: 7px;
  height: 7px;
  background: var(--accent);
  transform: rotate(45deg);
}
h1, h2, h3, h4 {
  font-family: var(--font-display);
  line-height: 1.12;
  letter-spacing: .005em;
  text-wrap: balance;
}
h1 {
  font-weight: 700;
  font-size: clamp(2.1rem, 4.6vw, 3.5rem);
  margin: 0 0 1rem;
}
h2 {
  font-weight: 700;
  font-size: clamp(1.42rem, 2.4vw, 1.85rem);
  margin: 0 0 .9rem;
}
h3 { font-weight: 600; font-size: 1.16rem; margin: 0 0 .4rem; }
.lede {
  font-size: 1.1rem;
  line-height: 1.68;
  color: var(--ink-soft);
  margin: 0 0 1.4rem;
  max-width: 72ch;
}

.hero-status {
  display: flex;
  flex-wrap: wrap;
  gap: .45rem;
  margin: 0 0 1.5rem;
}
.status-chip {
  display: inline-flex;
  align-items: baseline;
  gap: .35rem;
  padding: .25rem .65rem;
  border: 1px solid var(--line-strong);
  background: var(--panel);
  color: var(--ink-soft);
  font-size: .78rem;
  letter-spacing: .02em;
}
.status-chip strong { color: var(--ink); font-weight: 600; }

.btn-row { display: flex; flex-wrap: wrap; gap: .6rem; }
.btn {
  display: inline-block;
  padding: .58rem 1.05rem;
  border: 1px solid var(--accent);
  box-shadow: inset 0 0 0 2px var(--paper);
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: .92rem;
  letter-spacing: .07em;
  text-transform: uppercase;
}
.btn:hover { background: var(--accent-ink); border-color: var(--accent-ink); }
.btn--ghost {
  background: transparent;
  color: var(--accent-ink);
  box-shadow: inset 0 0 0 2px var(--panel);
}
.btn--ghost:hover { background: var(--accent-wash); color: var(--accent-ink); }

/* ---------- cards ---------- */
.card-group { padding: 2rem 0 .6rem; border-top: 1px solid var(--line); }
.card-group-head { display: flex; align-items: baseline; gap: .8rem; flex-wrap: wrap; }
.card-group h2 { margin: 0 0 .35rem; }
.card-group h2 .idx {
  color: var(--accent-ink);
  font-size: .72em;
  margin-right: .45rem;
  letter-spacing: .08em;
}
.group-note { margin: 0 0 1.15rem; color: var(--ink-soft); font-size: .93rem; max-width: 76ch; }
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(255px, 1fr));
  gap: .9rem;
}
.card {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: 1.15rem 1.15rem 1.05rem;
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--ink);
  text-decoration: none;
  clip-path: polygon(0 0, calc(100% - 11px) 0, 100% 11px, 100% 100%, 0 100%);
}
.card::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 34px;
  height: 2px;
  background: var(--accent);
  transition: width .18s ease;
}
.card:hover { border-color: var(--line-strong); }
.card:hover::before { width: 62%; }
.card h3 { margin: .1rem 0 .35rem; font-size: 1.12rem; }
.card p { margin: 0; color: var(--ink-soft); font-size: .89rem; line-height: 1.6; }
.card-tag {
  align-self: flex-start;
  margin-bottom: .55rem;
  color: var(--accent-ink);
  border: 1px solid var(--accent);
  padding: .08rem .4rem;
  font-family: var(--font-display);
  font-size: .68rem;
  font-weight: 600;
  letter-spacing: .1em;
  text-transform: uppercase;
}

/* ---------- article ---------- */
.breadcrumb { padding: 1.15rem 0 0; font-size: .79rem; color: var(--ink-soft); }
.breadcrumb ol { display: flex; flex-wrap: wrap; gap: .45rem; list-style: none; margin: 0; padding: 0; }
.breadcrumb li + li::before { content: "/"; margin-right: .45rem; color: var(--line-strong); }
.breadcrumb a { color: var(--ink-soft); text-decoration: none; }
.breadcrumb a:hover { color: var(--accent-ink); }

.doc {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 240px;
  gap: 3rem;
  align-items: start;
}
.doc-main { min-width: 0; }
.doc > .doc-main:only-child { grid-column: 1 / -1; }
.article-head { padding: 1.5rem 0 1.1rem; max-width: 800px; }
.meta-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .55rem;
  color: var(--ink-soft);
  font-size: .8rem;
  margin: 0;
}
.badge {
  padding: .1rem .45rem;
  border: 1px solid var(--line-strong);
  color: var(--ink-soft);
  font-family: var(--font-display);
  font-size: .7rem;
  letter-spacing: .08em;
  text-transform: uppercase;
}
.meta-dot { color: var(--line-strong); }

.keybox {
  position: relative;
  margin: 1.3rem 0 1.7rem;
  padding: 1.1rem 1.25rem 1.15rem;
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  background-color: var(--panel);
  background-image: repeating-linear-gradient(135deg, transparent 0 9px, rgba(111, 130, 121, .06) 9px 10px);
}
.keybox h2 {
  margin: 0 0 .7rem;
  font-family: var(--font-display);
  font-size: .8rem;
  font-weight: 600;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--accent-ink);
}
.keybox dl {
  display: grid;
  grid-template-columns: max-content minmax(0, 1fr);
  gap: .42rem 1.2rem;
  margin: 0;
  font-size: .92rem;
}
.keybox dt { color: var(--ink-soft); }
.keybox dd { margin: 0; font-weight: 500; }

.toc {
  position: sticky;
  top: 88px;
  margin-top: 1.5rem;
  padding: 1rem 0 0;
  border-top: 2px solid var(--accent);
  font-size: .84rem;
}
.toc p {
  margin: 0 0 .55rem;
  font-family: var(--font-display);
  font-size: .74rem;
  font-weight: 600;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--accent-ink);
}
.toc ol { list-style: none; margin: 0; padding: 0; }
.toc li { margin: .18rem 0; }
.toc a {
  display: block;
  padding: .16rem 0 .16rem .7rem;
  border-left: 1px solid var(--line);
  color: var(--ink-soft);
  text-decoration: none;
  line-height: 1.45;
}
.toc a:hover, .toc a.is-active { color: var(--accent-ink); border-left-color: var(--accent); }

.prose { max-width: 800px; padding-bottom: 2.2rem; }
.prose > h2 {
  position: relative;
  margin: 2.6rem 0 1rem;
  padding-top: .55rem;
  border-top: 1px solid var(--line);
}
.prose > h2::before {
  content: "";
  position: absolute;
  left: 0;
  top: -.3rem;
  width: 8px;
  height: 8px;
  background: var(--accent);
  transform: rotate(45deg);
}
.prose h3 { margin: 1.7rem 0 .5rem; }
.prose p { margin: 0 0 1rem; }
.prose ul, .prose ol { padding-left: 1.25rem; margin: 0 0 1.1rem; }
.prose li { margin: .32rem 0; }
.prose li::marker { color: var(--accent); }
.prose strong { font-weight: 600; }
.prose blockquote {
  margin: 1.2rem 0;
  padding: .8rem 1.1rem;
  border-left: 2px solid var(--jade);
  background: var(--panel);
  color: var(--ink-soft);
}
.prose code {
  padding: .08rem .32rem;
  border: 1px solid var(--line);
  background: var(--panel-2);
  font-size: .86em;
}
.table-wrap { margin: 1.2rem 0 1.4rem; overflow-x: auto; border: 1px solid var(--line); }
.prose table {
  width: 100%;
  border-collapse: collapse;
  font-size: .88rem;
  line-height: 1.55;
  background: var(--panel);
}
.prose th, .prose td {
  padding: .55rem .7rem;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}
.prose thead th {
  background: var(--table-head);
  color: var(--table-head-ink);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: .76rem;
  letter-spacing: .08em;
  text-transform: uppercase;
  border-bottom: 1px solid var(--table-head);
}
.prose tbody tr:nth-child(even) td { background: color-mix(in srgb, var(--panel-2) 45%, transparent); }
.prose tbody tr:last-child td { border-bottom: 0; }
.prose td.num, .prose th.num { font-variant-numeric: tabular-nums; white-space: nowrap; }
.prose caption { caption-side: top; text-align: left; font-size: .8rem; color: var(--ink-soft); padding-bottom: .4rem; }

.callout {
  margin: 1.2rem 0;
  padding: .95rem 1.1rem;
  border: 1px solid var(--line);
  border-left: 3px solid var(--jade);
  background: var(--panel);
}
.callout p { margin: 0; }
.callout p + p { margin-top: .55rem; }
.callout--warn { border-left-color: var(--accent); background: var(--accent-wash); }
.callout--info { border-left-color: var(--navy); }
.callout-title {
  display: block;
  margin-bottom: .3rem;
  font-family: var(--font-display);
  font-size: .76rem;
  font-weight: 600;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--accent-ink);
}

.phase-list, .chain { display: grid; gap: .6rem; margin: 1.2rem 0; }
.phase {
  display: grid;
  grid-template-columns: 88px minmax(0, 1fr);
  gap: .9rem;
  padding: .8rem .95rem;
  border: 1px solid var(--line);
  background: var(--panel);
}
.phase b {
  font-family: var(--font-display);
  font-size: .8rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--accent-ink);
}
.phase p { margin: 0; font-size: .92rem; color: var(--ink-soft); }

.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: .6rem;
  margin: 1.2rem 0;
}
.stat {
  padding: .7rem .85rem;
  border: 1px solid var(--line);
  background: var(--panel);
}
.stat b {
  display: block;
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--accent-ink);
}
.stat span { font-size: .76rem; color: var(--ink-soft); letter-spacing: .03em; }

.tag-list { display: flex; flex-wrap: wrap; gap: .35rem; margin: .5rem 0 1.1rem; padding: 0; list-style: none; }
.tag-list li {
  border: 1px solid var(--line-strong);
  padding: .1rem .45rem;
  font-size: .76rem;
  color: var(--ink-soft);
}

.related {
  margin: 2rem 0 0;
  padding: 1.1rem 1.2rem;
  border: 1px solid var(--line);
  border-top: 2px solid var(--accent);
  background: var(--panel);
}
.related h2 { font-size: .95rem; letter-spacing: .1em; text-transform: uppercase; margin: 0 0 .6rem; }
.related ul { margin: 0; padding-left: 1.1rem; }
.related li { margin: .22rem 0; }

.article-foot {
  margin-top: 1.4rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: .79rem;
}

/* ---------- footer ---------- */
.site-footer {
  margin-top: 3.2rem;
  border-top: 1px solid var(--line);
  background: var(--panel-2);
}
.footer-inner {
  display: flex;
  flex-wrap: wrap;
  gap: 2.2rem;
  justify-content: space-between;
  padding-top: 2.2rem;
  padding-bottom: 1.6rem;
}
.footer-brand { max-width: 340px; }
.footer-brand .brand-name { font-size: 1rem; }
.footer-note { color: var(--ink-soft); font-size: .8rem; margin: .5rem 0 0; }
.footer-cols { display: flex; flex-wrap: wrap; gap: 2.2rem; }
.footer-cols a {
  display: block;
  padding: .1rem 0;
  color: var(--ink-soft);
  text-decoration: none;
  font-size: .84rem;
}
.footer-cols a:hover { color: var(--accent-ink); }
.footer-head {
  margin: 0 0 .4rem;
  font-family: var(--font-display);
  font-size: .72rem;
  font-weight: 600;
  letter-spacing: .13em;
  text-transform: uppercase;
  color: var(--ink);
}
.footer-base {
  padding-top: 1rem;
  padding-bottom: 1.6rem;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: .76rem;
}
.footer-base p { margin: 0; }

/* ---------- 404 ---------- */
.error-page { padding: 4rem 0 5rem; max-width: 700px; }
.error-code {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(4rem, 14vw, 8rem);
  line-height: .9;
  color: var(--accent-ink);
  margin: 0;
}
.error-page h1 { margin-top: .5rem; }

/* ---------- inline figures ---------- */
.figure {
  margin: 1.7rem 0 0;
  padding: 1rem 1.1rem .8rem;
  border: 1px solid var(--line);
  background: var(--panel);
  box-shadow: var(--shadow);
}
.figure svg { display: block; width: 100%; height: auto; }
.figure figcaption {
  margin-top: .7rem;
  padding-top: .6rem;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: .8rem;
  line-height: 1.55;
}
.fig-k {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 12px;
  letter-spacing: .08em;
  text-transform: uppercase;
  fill: var(--ink-soft);
}
.fig-t {
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 600;
  fill: var(--ink);
}
.fig-s { font-family: var(--font-body); font-size: 11px; fill: var(--ink-soft); }
.fig-n {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
  fill: var(--ink);
}
.fig-rule { stroke: var(--line); stroke-width: 1; }

/* ---------- responsive ---------- */
@media (max-width: 1080px) {
  .doc { grid-template-columns: minmax(0, 1fr); gap: 0; }
  .toc { display: none; }
}
@media (max-width: 900px) {
  .menu-btn { display: grid; }
  .main-nav {
    display: none;
    position: absolute;
    left: 1rem;
    right: 1rem;
    top: calc(100% + .4rem);
    padding: .55rem;
    border: 1px solid var(--line);
    background: var(--panel);
    box-shadow: 0 18px 40px rgba(0, 0, 0, .18);
    flex-direction: column;
    margin-left: 0;
  }
  .main-nav.is-open { display: flex; }
  .main-nav a { padding: .55rem .6rem; border-bottom: 1px solid var(--line); }
  .main-nav a:last-child { border-bottom: 0; }
  .header-inner { position: relative; }
  .doc { grid-template-columns: minmax(0, 1fr); }
}
@media (max-width: 640px) {
  body { font-size: 16px; background-size: 26px 26px, 26px 26px, auto, auto; }
  .hero { padding-top: 2.6rem; }
  .hero::before { display: none; }
  .keybox dl { grid-template-columns: 1fr; gap: .1rem; }
  .keybox dd { margin-bottom: .55rem; }
  .phase { grid-template-columns: 1fr; gap: .25rem; }
  .footer-cols { gap: 1.4rem 2rem; }
  .brand-sub { display: none; }
  .prose { max-width: 100%; }
}
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; scroll-behavior: auto !important; }
}