/* Cogent Base — site styles.
   Tokens follow the brand foundations board. Mobile first; the desktop layout starts at 1100px.
   No inline styles anywhere, so the site runs under a strict Content-Security-Policy. */

/* ------------------------------------------------------------------ fonts (self-hosted, OFL) */
@font-face { font-family: 'Geist'; src: url('../fonts/Geist-Regular.woff2') format('woff2'); font-weight: 400; font-style: normal; font-display: swap; }
@font-face { font-family: 'Geist'; src: url('../fonts/Geist-Medium.woff2') format('woff2'); font-weight: 500; font-style: normal; font-display: swap; }
@font-face { font-family: 'Geist'; src: url('../fonts/Geist-SemiBold.woff2') format('woff2'); font-weight: 600; font-style: normal; font-display: swap; }
@font-face { font-family: 'Geist Mono'; src: url('../fonts/GeistMono-Regular.woff2') format('woff2'); font-weight: 400; font-style: normal; font-display: swap; }
@font-face { font-family: 'Geist Mono'; src: url('../fonts/GeistMono-Medium.woff2') format('woff2'); font-weight: 500; font-style: normal; font-display: swap; }

/* ------------------------------------------------------------------ tokens */
:root {
  --ink: #0F172A;           /* brackets: body text, dark sections */
  --blue: #2563EB;          /* wordmark: links, primary buttons, traces, supported, headline accent */
  --deep: #1E3A8A;          /* tick: hover and pressed, light surfaces only */
  --paper: #FFFFFF;
  --paper-2: #F8FAFC;
  --rule: #E2E8F0;
  --muted: #64748B;
  --amber: #B45309;         /* flagged items only */
  --grid-line: rgba(15, 23, 42, 0.06);
  --page-line: rgba(100, 116, 139, 0.32);
  --hl-fill: rgba(37, 99, 235, 0.12);
  --hl-weak-fill: rgba(100, 116, 139, 0.12);
  --sans: 'Geist', 'IBM Plex Sans', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --mono: 'Geist Mono', 'IBM Plex Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
  --max: 1200px;
  --pad: 16px;
  --cols: 4;
  --gutter: 16px;
  --c: var(--ink);
}
@media (min-width: 1100px) {
  :root { --cols: 12; --gutter: 24px; }
}

/* ------------------------------------------------------------------ base */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 16px; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 26px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: clip;
}
img { display: block; max-width: 100%; height: auto; }
h1, h2, h3, p, ol, ul, figure { margin: 0; }
ol, ul { padding: 0; list-style: none; }
a { color: var(--blue); }
a:hover { color: var(--deep); }
:focus-visible { outline: 2px solid var(--blue); outline-offset: 2px; }
::selection { background: var(--hl-fill); }

.skip {
  position: absolute; left: 16px; top: -100px; z-index: 10;
  padding: 10px 14px; background: var(--ink); color: var(--paper); border-radius: 2px;
  font-size: 15px; line-height: 20px; text-decoration: none;
}
.skip:focus { top: 16px; color: var(--paper); }

.wrap { position: relative; width: min(var(--max), 100% - 2 * var(--pad)); margin-inline: auto; }

/* status colour: blue = supported or clickable, amber = flagged (the only other colour is the headline accent) */
.is-supported { --c: var(--blue); }
.is-weak { --c: var(--muted); }
.is-flagged { --c: var(--amber); }

/* ------------------------------------------------------------------ type */
h1 {
  font-size: 48px; line-height: 46px; font-weight: 500; letter-spacing: -0.035em;
}
.h1-line { display: block; }
.h1-accent { color: var(--blue); }   /* "Verified." in the wordmark blue */
h2, .h2 {
  font-size: 34px; line-height: 38px; font-weight: 500; letter-spacing: -0.03em; text-wrap: balance;
}
.lead { font-size: 17px; line-height: 26px; text-wrap: pretty; }
.body { font-size: 17px; line-height: 26px; max-width: 560px; text-wrap: pretty; }
@media (min-width: 640px) {
  h1 { font-size: 60px; line-height: 60px; }
  h2, .h2 { font-size: 40px; line-height: 44px; }
}
@media (min-width: 1100px) {
  h1 { font-size: 72px; line-height: 72px; }
  h2, .h2 { font-size: 48px; line-height: 52px; max-width: 894px; }
  .lead { font-size: 18px; line-height: 28px; }
  .body { line-height: 27px; }
}

/* mono label in brackets: section labels and the eyebrow */
.label {
  display: inline-flex; align-items: stretch; gap: 8px;
  font: 500 11px/16px var(--mono); letter-spacing: 0.08em; text-transform: uppercase; color: var(--ink);
}
.label > span { display: flex; align-items: center; min-height: 20px; }
.label::before, .label::after { content: ""; width: 5px; flex: none; border: 1px solid currentColor; }
.label::before { border-right: 0; }
.label::after { border-left: 0; }

.caption {
  margin-top: 14px;
  font: 400 11px/16px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted);
}
.cite { font: 500 11px/16px var(--mono); letter-spacing: 0.06em; color: var(--ink); white-space: nowrap; }

/* ------------------------------------------------------------------ buttons and links */
.btn {
  display: inline-flex; align-items: center; justify-content: center; flex: none;
  height: 44px; padding: 0 20px; border: 1px solid transparent; border-radius: 2px;
  font: 500 15px/20px var(--sans); text-decoration: none; white-space: nowrap; cursor: pointer;
}
.btn--primary { background: var(--blue); border-color: var(--blue); color: #FFFFFF; }
.btn--primary:hover { background: var(--deep); border-color: var(--deep); color: #FFFFFF; }
.btn--primary:active { background: var(--deep); border-color: var(--ink); }
.btn--secondary { background: transparent; border-color: var(--ink); color: var(--ink); }
.btn--secondary:hover { background: var(--paper-2); color: var(--ink); }
.btn--secondary:active { background: var(--rule); }
.btn[disabled] { background: var(--rule); border-color: var(--rule); color: var(--muted); cursor: progress; }
.link { color: var(--blue); text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 3px; }
.link:hover { color: var(--deep); }
.actions { display: flex; flex-wrap: wrap; gap: 12px; }

/* ------------------------------------------------------------------ nav */
.nav { position: relative; z-index: 2; background: var(--paper); border-bottom: 1px solid var(--rule); }
.nav__bar {
  display: grid; grid-template-columns: auto auto; grid-template-areas: "logo cta" "links links";
  align-items: center; justify-content: space-between; column-gap: 16px;
}
.nav__logo { grid-area: logo; display: block; padding: 23px 0; }
.nav__logo img { width: auto; height: 18px; }
.nav__cta { grid-area: cta; padding: 0 16px; }
.nav__links {
  grid-area: links; display: flex; gap: 24px; height: 44px; align-items: center;
  border-top: 1px solid var(--rule);
}
.nav__links a {
  display: inline-flex; align-items: center; height: 44px;
  font-size: 15px; line-height: 20px; color: var(--ink); text-decoration: none;
}
.nav__links a:hover { color: var(--blue); }
@media (min-width: 1100px) {
  .nav__bar { grid-template-columns: auto 1fr auto; grid-template-areas: "logo links cta"; column-gap: 32px; height: 72px; }
  .nav__logo { padding: 0; }
  .nav__logo img { height: 24px; }
  .nav__links { justify-content: flex-end; gap: 32px; height: auto; border-top: 0; }
  .nav__cta { padding: 0 20px; }
}

/* ------------------------------------------------------------------ hairline grid (engineering paper) */
.hero__wrap::before,
.section .wrap::before {
  content: ""; position: absolute; top: 0; left: 0; width: calc(100% + var(--gutter)); pointer-events: none;
  background-image: linear-gradient(to right,
    var(--grid-line) 0 1px,
    transparent 1px calc(100% - var(--gutter) - 1px),
    var(--grid-line) calc(100% - var(--gutter) - 1px) calc(100% - var(--gutter)),
    transparent calc(100% - var(--gutter)));
  background-size: calc(100% / var(--cols)) 100%;
}
.hero__wrap::before { bottom: 0; }
.section .wrap::before { height: 72px; }
@media (min-width: 1100px) {
  .section .wrap::before { height: 96px; }
}

/* ------------------------------------------------------------------ hero */
.hero__wrap { padding: 40px 0 64px; }
.hero__top { position: relative; display: flex; flex-direction: column; gap: 24px; }
.hero__title { display: flex; flex-direction: column; gap: 24px; }
.hero__intro { display: flex; flex-direction: column; gap: 24px; max-width: 560px; }
@media (min-width: 1100px) {
  .hero__wrap { padding: 88px 0 112px; }
  .hero__top { flex-direction: row; align-items: flex-end; gap: 24px; margin-bottom: 72px; }
  .hero__title { flex: 1 1 630px; max-width: 690px; gap: 32px; }
  .hero__intro { flex: 0 1 486px; margin-left: auto; gap: 32px; }
}

/* ------------------------------------------------------------------ statements in brackets */
.stmt {
  position: relative; width: fit-content; max-width: 100%;
  padding: 4px 14px; font-size: 15px; line-height: 22px; color: var(--ink); text-wrap: pretty;
}
.stmt::before, .stmt::after { content: ""; position: absolute; top: 0; bottom: 0; width: 6px; border: 1px solid var(--c); }
.stmt::before { left: 0; border-right: 0; }
.stmt::after { right: 0; border-left: 0; }

/* status chips: rectangular, mono, leading glyph so state never depends on colour alone */
.chip {
  display: inline-flex; align-items: center; gap: 6px; flex: none; height: 24px; padding: 0 8px;
  border: 1px solid var(--c); border-radius: 2px; background: var(--paper);
  font: 500 11px/16px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; color: var(--c); white-space: nowrap;
}
.chip::before { content: ""; width: 8px; height: 8px; flex: none; background: currentColor; }
.chip.is-weak { color: var(--ink); }
.chip.is-weak::before { background: linear-gradient(to right, currentColor 50%, transparent 50%); box-shadow: inset 0 0 0 1px currentColor; }
.chip.is-flagged::before { width: 9px; height: 10px; clip-path: polygon(0 0, 100% 5%, 80% 27.5%, 100% 50%, 11% 50%, 11% 100%, 0 100%); }

/* abstract page specimen: grey lines, one highlighted block */
.page {
  position: relative; display: block; flex: none; width: 39px; height: 51px; padding: 6px 6px 8px;
  border: 1px solid var(--rule); border-radius: 2px;
  background-color: var(--paper);
  background-image: linear-gradient(var(--paper), var(--paper)), repeating-linear-gradient(to bottom, var(--page-line) 0 2px, transparent 2px 5px);
  background-size: 100% 3px, auto;
  background-position: 0 var(--gap-y, 25px), 0 0;
  background-repeat: no-repeat, repeat;
  background-origin: content-box; background-clip: content-box;
  --hl-top: 14px; --hl-h: 9px;
}
.page::after {
  content: ""; position: absolute; left: 3px; right: 3px; top: var(--hl-top); height: var(--hl-h);
  background: var(--hl-fill); border: 1px solid var(--c); border-radius: 1px;
}
.page.is-weak::after { background: var(--hl-weak-fill); }
/* on narrow screens the trace runs down into the page and on to the highlighted block */
.page::before { content: ""; position: absolute; left: 18px; top: -1px; width: 1px; height: calc(var(--hl-top) + 1px); background: var(--c); }

.minipage {
  position: relative; display: block; flex: none; width: 16px; height: 20px; padding: 3px;
  border: 1px solid var(--rule); border-radius: 1px; background-color: var(--paper);
  background-image: repeating-linear-gradient(to bottom, var(--page-line) 0 1px, transparent 1px 3px);
  background-origin: content-box; background-clip: content-box;
  --c: var(--blue);
}
.minipage::after { content: ""; position: absolute; left: 1px; right: 1px; top: 7px; height: 5px; background: var(--hl-fill); border: 1px solid var(--c); }
.minipage.is-weak { --c: var(--muted); }
.minipage.is-weak::after { background: var(--hl-weak-fill); }

/* corner ticks, like crop marks on a drawing */
.trace__panel::before {
  content: ""; position: absolute; inset: -1px; pointer-events: none;
  background:
    linear-gradient(var(--ink), var(--ink)) 0 0 / 8px 1px no-repeat,
    linear-gradient(var(--ink), var(--ink)) 0 0 / 1px 8px no-repeat,
    linear-gradient(var(--ink), var(--ink)) 100% 0 / 8px 1px no-repeat,
    linear-gradient(var(--ink), var(--ink)) 100% 0 / 1px 8px no-repeat,
    linear-gradient(var(--ink), var(--ink)) 0 100% / 8px 1px no-repeat,
    linear-gradient(var(--ink), var(--ink)) 0 100% / 1px 8px no-repeat,
    linear-gradient(var(--ink), var(--ink)) 100% 100% / 8px 1px no-repeat,
    linear-gradient(var(--ink), var(--ink)) 100% 100% / 1px 8px no-repeat;
}

/* ------------------------------------------------------------------ the trace (hero specimen) */
.trace { margin-top: 40px; }
.trace__panel { position: relative; max-width: 640px; border: 1px solid var(--rule); border-radius: 4px; background: var(--paper); }
.trace__head {
  display: flex; align-items: center; gap: 24px; min-height: 44px; padding: 8px 16px;
  border-bottom: 1px solid var(--rule);
  font: 500 11px/16px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; color: var(--ink);
}
.trace__srchead { display: none; }
.trace__body { display: flex; flex-direction: column; gap: 28px; padding: 0 16px 20px; }

/* narrow screens: statement, line, page, top to bottom */
.trow, .tpair { display: grid; grid-template-columns: 39px minmax(0, 1fr); column-gap: 12px; align-items: center; }
.trow > .stmt, .tpair > .stmt { grid-column: 1 / -1; }
.trow__para { grid-column: 1 / -1; margin-bottom: 14px; font: 400 11px/16px var(--mono); letter-spacing: 0.06em; color: var(--muted); }
.tline { grid-column: 1; justify-self: center; display: block; width: 1px; height: 20px; background: var(--c); transform-origin: 50% 0; }
.page { grid-column: 1; }
.tsrc { grid-column: 2; display: flex; flex-wrap: wrap; align-items: center; gap: 6px 10px; }
.tsrc__note { flex-basis: 100%; font: 500 11px/16px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted); }
.tsrc__note.is-flagged { color: var(--amber); }
.trow--sel { margin: 0 -16px; padding: 16px; background: var(--paper-2); border-bottom: 1px solid var(--rule); }
.trow__detail { grid-column: 1 / -1; display: flex; flex-direction: column; gap: 14px; margin-top: 18px; }
.tpair { row-gap: 0; }
.tpair__s1 { grid-row: 1; }
.tpair__l1 { grid-row: 2; }
.tpair__p1, .tpair__c1 { grid-row: 3; }
.tpair__s2 { grid-row: 4; margin-top: 16px; }
.tpair__l2 { grid-row: 5; }
.tpair__p2, .tpair__c2 { grid-row: 6; }
.tline--short {
  width: 9px; height: 15px;
  background:
    linear-gradient(var(--c), var(--c)) 50% 0 / 1px 14px no-repeat,
    linear-gradient(var(--c), var(--c)) 50% 100% / 9px 1px no-repeat;
}
.trow--flag .tsrc { grid-column: 1 / -1; margin-top: 12px; }

.req {
  display: flex; flex-wrap: wrap; align-items: center; gap: 4px 8px;
  font: 500 11px/16px var(--mono); letter-spacing: 0.06em; text-transform: uppercase;
}
.req__k { color: var(--muted); }
.req__v { color: var(--ink); }
.req__arrow, .req__met { color: var(--blue); }
.req__met { text-decoration: underline; text-underline-offset: 3px; }
.controls { display: flex; gap: 8px; }
.ctl {
  display: inline-flex; align-items: center; height: 32px; padding: 0 14px;
  border: 1px solid var(--ink); border-radius: 2px; font: 500 14px/20px var(--sans); color: var(--ink);
}
.ctl--primary { background: var(--blue); border-color: var(--blue); color: #FFFFFF; }

@media (min-width: 1100px) {
  .trace { margin-top: 0; }
  .trace__panel { max-width: none; }
  .trace__head { min-height: 48px; padding: 0 24px; }
  .trace__srchead { display: block; width: 376px; margin-left: auto; flex: none; font-weight: 400; color: var(--muted); }
  .trace__body { display: block; padding: 0 24px 12px; }
  .trace .stmt { font-size: 16px; line-height: 24px; }

  .trow { display: flex; flex-wrap: wrap; align-items: center; min-height: 96px; gap: 0; }
  .trow__para { width: 40px; flex: none; margin: 0; }
  .trow > .stmt { flex: none; white-space: nowrap; }
  .tline { flex: 1 1 auto; justify-self: stretch; min-width: 32px; width: auto; height: 1px; transform-origin: 0 50%; }
  .page { width: 60px; height: 78px; margin: 9px 0; padding: 8px 8px 10px; --hl-h: 12px;
    background-image: linear-gradient(var(--paper), var(--paper)), repeating-linear-gradient(to bottom, var(--page-line) 0 2px, transparent 2px 6px); }
  .page::before { content: none; }
  .page--a { top: 10px; --hl-top: 22px; --gap-y: 42px; }
  .page--b { --hl-top: 32px; --gap-y: 12px; }
  .page--c { top: -10px; --hl-top: 42px; --gap-y: 18px; }
  .tsrc { width: 300px; margin-left: 16px; flex: none; }
  .tsrc__note { flex-basis: 100%; }
  .trow--sel { margin: 0 -24px; padding: 2px 24px 24px; }
  .trow--sel .tsrc { align-self: center; }
  .trow__detail { flex-basis: 100%; margin-top: 0; padding-left: 40px; gap: 16px; }
  .trow--flag::before { content: ""; width: 40px; flex: none; }
  .tline--short {
    flex: 1 1 auto; min-width: 48px; height: 9px;
    background:
      linear-gradient(var(--c), var(--c)) 0 50% / 44% 1px no-repeat,
      linear-gradient(var(--c), var(--c)) 44% 50% / 1px 9px no-repeat;
  }
  .trow--flag .tsrc { margin: 0 0 0 76px; }

  .tpair { grid-template-columns: 40px auto auto minmax(32px, 1fr) 60px 16px 300px; grid-template-rows: 96px 96px; column-gap: 0; }
  .tpair > .stmt { white-space: nowrap; }
  .tpair > .tpair__s1 { grid-column: 2; grid-row: 1; }
  .tpair > .tpair__l1 { grid-column: 3 / 5; grid-row: 1; }
  .tpair > .tpair__p1 { grid-column: 5; grid-row: 1; }
  .tpair > .tpair__c1 { grid-column: 7; grid-row: 1; margin: 0; width: auto; }
  .tpair > .tpair__s2 { grid-column: 3; grid-row: 2; margin: 0; }
  .tpair > .tpair__l2 { grid-column: 4; grid-row: 2; }
  .tpair > .tpair__p2 { grid-column: 5; grid-row: 2; }
  .tpair > .tpair__c2 { grid-column: 7; grid-row: 2; margin: 0; width: auto; }
}

/* ------------------------------------------------------------------ sections */
.section .wrap { padding: 24px 0 80px; border-top: 1px solid var(--ink); }
.section--alt { background: var(--paper-2); }
.section--first .wrap { border-top: 0; padding-top: 56px; }
.section__row { position: relative; display: flex; flex-direction: column; gap: 20px; }
.section__body { display: flex; flex-direction: column; gap: 20px; min-width: 0; }
@media (min-width: 1100px) {
  .section .wrap { padding: 32px 0 120px; }
  .section__row { flex-direction: row; gap: 24px; }
  .section__label { flex: 0 0 282px; align-self: flex-start; margin-top: 16px; }
  .section__body { flex: 1 1 560px; gap: 28px; }
}

/* ------------------------------------------------------------------ privacy notice (long-form legal text) */
.section__body.legal { gap: 16px; }
.legal > p, .legal > ul, .legal > h2 { max-width: 680px; }
.legal p, .legal li { font-size: 16px; line-height: 26px; text-wrap: pretty; }
.legal .lead { font-size: 17px; line-height: 26px; }
.legal h2 { margin-top: 24px; font-size: 22px; line-height: 28px; letter-spacing: -0.02em; }
.legal strong { font-weight: 600; }
.legal ul { display: flex; flex-direction: column; gap: 8px; }
.legal li { position: relative; padding-left: 22px; }
.legal li::before { content: ""; position: absolute; left: 4px; top: 13px; width: 8px; height: 1px; background: var(--ink); }
.legal__table { width: 100%; margin: 8px 0; border-collapse: collapse; font-size: 15px; line-height: 22px; }
.legal__table th, .legal__table td { padding: 14px 16px 14px 0; border-top: 1px solid var(--rule); text-align: left; vertical-align: top; }
.legal__table th:last-child, .legal__table td:last-child { padding-right: 0; }
.legal__table thead th {
  padding-top: 0; padding-bottom: 10px; border-top: 0;
  font: 500 11px/16px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted);
}
.legal__table tbody th { font-weight: 500; }
.legal__table tbody tr:last-child > * { border-bottom: 1px solid var(--rule); }
@media (max-width: 719px) {
  /* each row becomes a card: the information as its title, then labelled answers */
  .legal__table, .legal__table tbody, .legal__table tr, .legal__table th, .legal__table td { display: block; }
  .legal__table thead { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }
  .legal__table tr { padding: 16px 0; border-top: 1px solid var(--rule); }
  .legal__table tbody tr:last-child { border-bottom: 1px solid var(--rule); }
  .legal__table th, .legal__table td, .legal__table tbody tr:last-child > * { padding: 0; border: 0; }
  .legal__table tbody th { font-size: 16px; line-height: 24px; }
  .legal__table td { margin-top: 12px; }
  .legal__table td::before {
    content: attr(data-label); display: block; margin-bottom: 2px;
    font: 500 11px/16px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted);
  }
}
@media (min-width: 1100px) {
  .legal .lead { font-size: 18px; line-height: 28px; }
  .legal h2 { margin-top: 32px; font-size: 24px; line-height: 30px; }
}

/* ------------------------------------------------------------------ 02 how it works */
.steps { position: relative; margin-top: 36px; }
.step { position: relative; display: flex; flex-direction: column; align-items: flex-start; gap: 10px; padding: 0 0 36px 28px; }
.step::before { content: ""; position: absolute; left: 0; top: 0; bottom: 0; width: 1px; background: var(--ink); }
.step:last-child { padding-bottom: 0; }
.step:last-child::before { bottom: auto; height: 9px; }
.step::after { content: ""; position: absolute; left: 0; top: 8px; width: 16px; height: 1px; background: var(--ink); }
.step__n { font: 500 11px/16px var(--mono); letter-spacing: 0.06em; color: var(--ink); }
.step__t { font-size: 20px; line-height: 26px; font-weight: 500; letter-spacing: -0.01em; }
.step__d { font-size: 15px; line-height: 22px; text-wrap: pretty; }
@media (min-width: 1100px) {
  .steps {
    display: grid; grid-template-columns: repeat(auto-fit, minmax(min(200px, 100%), 1fr)); gap: 48px 24px;
    margin-top: 56px; border-top: 1px solid var(--ink);
  }
  .step, .step:last-child { gap: 14px; padding: 0; }
  .step::before, .step:last-child::before { top: 0; bottom: auto; height: 16px; }
  .step::after { content: none; }
  .step__n { height: 24px; padding: 6px 0 0 11px; }
  .step__t { font-size: 22px; line-height: 28px; }
}

/* ------------------------------------------------------------------ 03 one chain */
.chain { margin-top: 28px; }
.chain__head { display: none; }
.chain__list { border-top: 1px solid var(--rule); }
.creq { padding: 20px 0 24px; border-bottom: 1px solid var(--rule); }
.creq__lead { display: flex; }
.creq__name {
  display: inline-flex; align-items: center; height: 32px; padding: 0 12px; flex: none;
  border: 1px solid var(--ink); border-radius: 2px; background: var(--paper);
  font: 500 11px/16px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; white-space: nowrap;
}
/* narrow screens: a tree — requirement, then its statements, then each statement's source */
.cstmts { margin-left: 16px; padding-left: 20px; }
.cst { position: relative; padding-top: 12px; --c: var(--blue); }
.cst::before { content: ""; position: absolute; left: -20px; top: 0; bottom: 0; width: 1px; background: var(--blue); transform-origin: 50% 0; }
.cst:last-child::before { bottom: auto; height: 27px; }
.cst::after { content: ""; position: absolute; left: -20px; top: 27px; width: 14px; height: 1px; background: var(--blue); transform-origin: 0 50%; }
.cst__lead .stmt { margin: 0; }
.csrc {
  position: relative; display: flex; flex-wrap: wrap; align-items: center; gap: 8px 10px;
  margin-left: 16px; padding: 12px 0 0 20px; min-height: 36px;
}
.csrc::before { content: ""; position: absolute; left: 0; top: 0; height: 24px; width: 1px; background: var(--c); transform-origin: 50% 0; }
.csrc::after { content: ""; position: absolute; left: 0; top: 24px; width: 14px; height: 1px; background: var(--c); transform-origin: 0 50%; }
.cst--weak { --c: var(--muted); }
.cst--broken .csrc, .creq__gap { padding-top: 30px; }
.cst--broken .csrc::before, .creq__gap::before {
  content: ""; position: absolute; left: -4px; top: 0; width: 9px; height: 15px;
  background:
    linear-gradient(var(--amber), var(--amber)) 50% 0 / 1px 14px no-repeat,
    linear-gradient(var(--amber), var(--amber)) 50% 100% / 9px 1px no-repeat;
}
.cst--broken .csrc::after { content: none; }
.creq__gap { position: relative; margin-left: 16px; padding-left: 20px; }
.creq__gap::before { left: -4px; }
.csrc__note { font: 500 11px/16px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; color: var(--amber); }

@media (min-width: 1100px) {
  .chain { margin-top: 56px; }
  .chain__scroll { overflow-x: auto; }
  .chain__head, .chain__list { min-width: 1200px; }
  .chain__head {
    display: grid; grid-template-columns: 408px 510px 282px; height: 32px; align-items: center;
    border-bottom: 1px solid var(--rule);
    font: 400 11px/16px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted);
  }
  .chain__list { border-top: 0; }
  .creq { display: grid; grid-template-columns: 408px 792px; padding: 0; border: 0; }
  .creq__lead { align-items: center; min-height: 72px; }
  .creq__lead::after { content: ""; flex: 1 1 auto; min-width: 24px; height: 1px; background: var(--blue); transform-origin: 0 50%; }
  .creq--multi .creq__lead { margin-right: 40px; }
  .cstmts { position: relative; margin: 0; padding: 0; }
  .creq--multi .cstmts::before { content: ""; position: absolute; left: -40px; top: 36px; bottom: 36px; width: 1px; background: var(--blue); transform-origin: 50% 50%; }
  .cst { display: grid; grid-template-columns: 510px 282px; align-items: center; height: 72px; padding: 0; }
  .cst::before, .cst:last-child::before { content: none; }
  .cst::after { content: none; }
  .creq--multi .cst::after { content: ""; position: absolute; left: -40px; top: 36px; width: 40px; height: 1px; background: var(--blue); }
  .cst__lead { display: flex; align-items: center; }
  .cst__lead .stmt { flex: 0 1 auto; max-width: 384px; }
  .cst__lead::after { content: ""; flex: 1 1 auto; min-width: 24px; height: 1px; background: var(--c); transform-origin: 0 50%; }
  .cst--broken .cst__lead::after {
    height: 9px;
    background:
      linear-gradient(var(--amber), var(--amber)) 0 50% / 44% 1px no-repeat,
      linear-gradient(var(--amber), var(--amber)) 44% 50% / 1px 9px no-repeat;
  }
  .csrc { margin: 0; padding: 0; min-height: 0; gap: 10px; }
  .csrc::before, .csrc::after, .cst--broken .csrc::before { content: none; }
  .cst--broken .csrc { padding: 0; }
  .creq--broken { grid-template-columns: 408px 510px 282px; }
  .creq--broken .creq__lead::after {
    height: 9px;
    background:
      linear-gradient(var(--amber), var(--amber)) 0 50% / 44% 1px no-repeat,
      linear-gradient(var(--amber), var(--amber)) 44% 50% / 1px 9px no-repeat;
  }
  .creq__gap { display: flex; align-items: center; margin: 0; padding: 0; }
  .creq__gap::before { content: none; }
  .chain .stmt { font-size: 15px; line-height: 22px; }
}

/* ------------------------------------------------------------------ 06 deployment */
.spec { border-top: 1px solid var(--rule); }
.spec li { padding: 20px 0; border-bottom: 1px solid var(--rule); }
.spec p { max-width: 560px; font-size: 17px; line-height: 26px; }
@media (min-width: 1100px) {
  .spec { margin-top: 4px; }
  .spec li { padding: 22px 0; }
  .spec p { line-height: 27px; }
}

/* ------------------------------------------------------------------ 07 team */
.team { display: flex; flex-direction: column; margin-top: 8px; }
.person { display: grid; grid-template-columns: 88px minmax(0, 1fr); grid-template-areas: "photo head" "bio bio"; align-items: center; column-gap: 20px; row-gap: 16px; padding: 24px 0; border-top: 1px solid var(--rule); }
.photo { grid-area: photo; position: relative; width: 88px; height: 110px; }
.photo img { width: 100%; height: 100%; object-fit: cover; background: var(--paper-2); }
/* printer's crop marks outside each corner */
.photo::before {
  content: ""; position: absolute; inset: -14px; pointer-events: none;
  background:
    linear-gradient(var(--ink), var(--ink)) 0 14px / 10px 1px no-repeat,
    linear-gradient(var(--ink), var(--ink)) 14px 0 / 1px 10px no-repeat,
    linear-gradient(var(--ink), var(--ink)) 100% 14px / 10px 1px no-repeat,
    linear-gradient(var(--ink), var(--ink)) calc(100% - 14px) 0 / 1px 10px no-repeat,
    linear-gradient(var(--ink), var(--ink)) 0 calc(100% - 14px) / 10px 1px no-repeat,
    linear-gradient(var(--ink), var(--ink)) 14px 100% / 1px 10px no-repeat,
    linear-gradient(var(--ink), var(--ink)) 100% calc(100% - 14px) / 10px 1px no-repeat,
    linear-gradient(var(--ink), var(--ink)) calc(100% - 14px) 100% / 1px 10px no-repeat;
}
.person__head { grid-area: head; display: flex; flex-direction: column; gap: 4px; min-width: 0; }
.person__name { font-size: 20px; line-height: 26px; font-weight: 500; letter-spacing: -0.01em; }
.person__role { font: 400 11px/16px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted); }
.person__bio { grid-area: bio; font-size: 15px; line-height: 22px; text-wrap: pretty; }
@media (min-width: 1100px) {
  .team { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(240px, 100%), 1fr)); gap: 40px 24px; margin-top: 12px; }
  .person { display: flex; flex-direction: column; align-items: flex-start; gap: 22px; padding: 14px 0 0; border-top: 0; }
  .photo { width: 200px; height: 250px; }
  .person__head { gap: 6px; }
  .person__name { font-size: 22px; line-height: 28px; }
  .person__bio { margin-top: -6px; }
}

/* ------------------------------------------------------------------ contact form */
.book { position: relative; }
.form { display: flex; flex-direction: column; gap: 28px; max-width: 894px; }
.form__grid { display: grid; grid-template-columns: minmax(0, 1fr); gap: 20px 24px; }
@media (min-width: 640px) {
  .form__grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
.field { display: flex; flex-direction: column; gap: 8px; min-width: 0; }
.field label { font: 500 11px/16px var(--mono); letter-spacing: 0.08em; text-transform: uppercase; color: var(--ink); }
.field input {
  width: 100%; height: 48px; padding: 0 14px; border: 1px solid var(--muted); border-radius: 2px;
  background: #FFFFFF; color: var(--ink); font: 400 17px/24px var(--sans);
}
.field input:focus { border-color: var(--blue); outline: 2px solid var(--blue); outline-offset: 2px; }
.field input[aria-invalid="true"] { border-color: var(--amber); }
.field__err {
  display: flex; align-items: center; gap: 6px; min-height: 16px;
  font: 500 11px/16px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; color: var(--amber);
}
.field__err::before { content: ""; width: 9px; height: 10px; flex: none; background: currentColor; clip-path: polygon(0 0, 100% 5%, 80% 27.5%, 100% 50%, 11% 50%, 11% 100%, 0 100%); }
.field__err[hidden] { display: none; }
.form__actions { display: flex; flex-wrap: wrap; align-items: center; gap: 16px 24px; }
.form__actions .btn { width: 100%; }
.form__actions .link { font-size: 15px; line-height: 20px; }
@media (min-width: 640px) {
  .form__actions .btn { width: auto; }
}
.form__status {
  display: flex; align-items: center; gap: 6px;
  font: 500 11px/16px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; color: var(--amber);
}
.form__status[hidden] { display: none; }
.hp { position: absolute; left: -10000px; width: 1px; height: 1px; overflow: hidden; }
.confirm:focus { outline: none; }
.confirm__text { padding: 10px 22px; font-size: 24px; line-height: 32px; --c: var(--ink); }
.confirm__text::before, .confirm__text::after { width: 8px; }
@media (min-width: 1100px) {
  .confirm__text { font-size: 32px; line-height: 40px; }
}
.confirm-note { font: 500 11px/16px var(--mono); letter-spacing: 0.06em; color: var(--amber); }

/* ------------------------------------------------------------------ footer */
.footer__wrap { display: flex; flex-direction: column; gap: 28px; padding: 40px 0 48px; border-top: 1px solid var(--ink); }
.footer__logo { align-self: flex-start; width: auto; height: 18px; }
.footer__line {
  display: flex; flex-wrap: wrap; align-items: center; gap: 8px 12px; padding-top: 20px; border-top: 1px solid var(--rule);
  font-size: 14px; line-height: 20px; color: var(--muted);
}
.footer__line a { color: var(--ink); text-decoration: underline; text-underline-offset: 3px; }
.footer__line a:hover { color: var(--blue); }
@media (min-width: 1100px) {
  .footer__wrap { padding: 48px 0 56px; }
  .footer__logo { height: 24px; }
}

/* ------------------------------------------------------------------ motion: one signature move, once per view.
   motion.js adds .motion to <html> unless reduced motion is requested, and .is-drawn when a specimen enters view.
   Without JavaScript, or with reduced motion, every specimen shows its end state. */
@keyframes cb-draw-x { from { transform: scaleX(0); } to { transform: scaleX(1); } }
@keyframes cb-draw-y { from { transform: scaleY(0); } to { transform: scaleY(1); } }
@keyframes cb-fade { from { opacity: 0; } to { opacity: 1; } }

.t-0 { --d: 0ms; } .t-100 { --d: 100ms; } .t-160 { --d: 160ms; } .t-200 { --d: 200ms; } .t-220 { --d: 220ms; }
.t-300 { --d: 300ms; } .t-350 { --d: 350ms; } .t-500 { --d: 500ms; } .t-650 { --d: 650ms; } .t-700 { --d: 700ms; }
.t-760 { --d: 760ms; } .t-840 { --d: 840ms; } .t-850 { --d: 850ms; } .t-860 { --d: 860ms; } .t-900 { --d: 900ms; }
.t-960 { --d: 960ms; } .t-1000 { --d: 1000ms; } .t-1050 { --d: 1050ms; } .t-1100 { --d: 1100ms; } .t-1200 { --d: 1200ms; }
.t-1360 { --d: 1360ms; } .t-1460 { --d: 1460ms; } .t-1500 { --d: 1500ms; }

/* before the specimen is in view */
.motion [data-trace]:not(.is-drawn) .tline,
.motion [data-trace]:not(.is-drawn) .tsrc,
.motion [data-trace]:not(.is-drawn) .page::after,
.motion [data-trace]:not(.is-drawn) .page::before,
.motion [data-trace]:not(.is-drawn) .csrc,
.motion [data-trace]:not(.is-drawn) .creq__gap,
.motion [data-trace]:not(.is-drawn) .creq__lead::after,
.motion [data-trace]:not(.is-drawn) .cst__lead::after,
.motion [data-trace]:not(.is-drawn) .cstmts::before,
.motion [data-trace]:not(.is-drawn) .cst::before,
.motion [data-trace]:not(.is-drawn) .cst::after { opacity: 0; }

/* the trace: line draws, highlight fades in, chip resolves */
.motion .is-drawn .tline { animation: cb-draw-y 450ms var(--ease) var(--d, 0ms) both; }
.motion .is-drawn .tline--short { animation-duration: 300ms; }
.motion .is-drawn .page::before { animation: cb-draw-y 200ms var(--ease) calc(var(--d, 0ms) - 150ms) both; }
.motion .is-drawn .page::after { animation: cb-fade 250ms var(--ease) var(--d, 0ms) both; }
.motion .is-drawn .tsrc { animation: cb-fade 200ms var(--ease) var(--d, 0ms) both; }
/* the chain, narrow screens: rails draw down, stubs across, then sources and flags resolve */
.motion .is-drawn .cst::before { animation: cb-draw-y 300ms var(--ease) calc(var(--d, 0ms) - 500ms) both; }
.motion .is-drawn .cst::after { animation: cb-draw-x 200ms var(--ease) calc(var(--d, 0ms) - 240ms) both; }
.motion .is-drawn .csrc,
.motion .is-drawn .creq__gap { animation: cb-fade 220ms var(--ease) var(--d, 0ms) both; }
@media (min-width: 1100px) {
  .motion .is-drawn .tline { animation-name: cb-draw-x; animation-duration: 600ms; }
  .motion .is-drawn .tline--short { animation-duration: 400ms; }
  /* the chain, wide screens: links draw left to right; broken links stop short and resolve to a flag */
  .motion .is-drawn .creq__lead::after { animation: cb-draw-x 600ms var(--ease) var(--d, 0ms) both; }
  .motion .is-drawn .creq--multi .creq__lead::after { animation-duration: 420ms; }
  .motion .is-drawn .creq--multi .cstmts::before { animation: cb-draw-y 260ms var(--ease) 520ms both; }
  .motion .is-drawn .creq--multi .cst::after { animation: cb-draw-x 220ms var(--ease) 740ms both; transform-origin: 0 50%; }
  .motion .is-drawn .cst__lead::after { animation: cb-draw-x 600ms var(--ease) var(--d, 0ms) both; }
  .motion .is-drawn .cst::before { animation: none; }
}

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

@media print {
  .nav, .skip, .form, .footer__line a { display: none; }
  .motion [data-trace] * { opacity: 1 !important; animation: none !important; }
}