/* Pairwise — shared stylesheet */

:root {
  --paper: #e9ecec;
  --paper-raised: #f5f7f6;
  --ink: #101416;
  --ink-soft: #4c5658;
  --rule: #c8d0cf;
  --rule-soft: #dbe1e0;
  --accent: #14524a;
  --accent-soft: rgba(20, 82, 74, 0.12);

  --font-display: "Bricolage Grotesque", "Helvetica Neue", Arial, sans-serif;
  --font-text: "Newsreader", Georgia, "Times New Roman", serif;
  --font-util: "IBM Plex Mono", "SFMono-Regular", Consolas, monospace;

  --shell: 1140px;
  --gutter: clamp(1.25rem, 5vw, 3.5rem);
  --band: clamp(3.5rem, 8vw, 6.5rem);
}

*,
*::before,
*::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-text);
  font-size: clamp(1.0625rem, 0.4vw + 1rem, 1.1875rem);
  line-height: 1.65;
  font-synthesis-weight: none;
}

/* ---------- typography ---------- */

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 650;
  letter-spacing: -0.02em;
  line-height: 1.08;
  margin: 0 0 0.6em;
  text-wrap: balance;
}

h1 { font-size: clamp(2.25rem, 5.2vw, 3.75rem); }
h2 { font-size: clamp(1.6rem, 3vw, 2.15rem); }
h3 { font-size: clamp(1.15rem, 1.6vw, 1.35rem); letter-spacing: -0.01em; }

p { margin: 0 0 1.1em; }
p:last-child { margin-bottom: 0; }

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}
a:hover { text-decoration-thickness: 2px; }

strong { font-weight: 600; }

.eyebrow {
  font-family: var(--font-util);
  font-size: 0.6875rem;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 1.1rem;
  display: block;
}

.lede {
  font-size: clamp(1.1875rem, 1vw + 1rem, 1.4375rem);
  line-height: 1.5;
  color: var(--ink);
}

.fine {
  font-family: var(--font-util);
  font-size: 0.75rem;
  line-height: 1.6;
  letter-spacing: 0.01em;
  color: var(--ink-soft);
}

.measure { max-width: 62ch; }

/* ---------- layout ---------- */

.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.band { padding-block: var(--band); }
.band-tight { padding-block: calc(var(--band) * 0.62); }
.band + .band { padding-top: 0; }

.rule-top { border-top: 1px solid var(--rule); padding-top: calc(var(--band) * 0.62); }

.skip {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--ink);
  color: var(--paper);
  padding: 0.75rem 1.25rem;
  font-family: var(--font-util);
  font-size: 0.8rem;
  z-index: 50;
}
.skip:focus { left: 0; }

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

/* ---------- masthead ---------- */

.masthead {
  border-bottom: 1px solid var(--rule);
  background: var(--paper);
}

.masthead-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-block: 1.15rem;
}

.wordmark {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.3rem;
  letter-spacing: -0.03em;
  color: var(--ink);
  text-decoration: none;
}
.wordmark:hover { color: var(--accent); }

.wordmark svg { display: block; }

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(0.9rem, 2.4vw, 1.9rem);
  font-family: var(--font-util);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.nav a {
  color: var(--ink-soft);
  text-decoration: none;
  padding-block: 0.2rem;
  border-bottom: 1px solid transparent;
}
.nav a:hover,
.nav a[aria-current="page"] {
  color: var(--ink);
  border-bottom-color: var(--accent);
}

/* ---------- hero ---------- */

.hero {
  display: grid;
  gap: clamp(2.5rem, 5vw, 4rem);
  grid-template-columns: 1fr;
  align-items: start;
}

@media (min-width: 900px) {
  .hero { grid-template-columns: 1.05fr 0.95fr; }
}

.hero-note {
  margin-top: 2rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--rule);
}

/* ---------- signature: pairwise matrix ---------- */

.matrix-figure {
  margin: 0;
  background: var(--paper-raised);
  border: 1px solid var(--rule);
  padding: clamp(1.1rem, 3vw, 1.9rem);
}

.matrix-figure svg { width: 100%; height: auto; display: block; }

.matrix-caption {
  margin-top: 1.1rem;
  padding-top: 0.9rem;
  border-top: 1px solid var(--rule-soft);
}

.mx-label {
  font-family: var(--font-util);
  font-size: 8.5px;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  fill: var(--ink-soft);
}
.mx-index {
  font-family: var(--font-util);
  font-size: 9px;
  fill: var(--accent);
}
.mx-grid { stroke: var(--rule); stroke-width: 1; fill: none; }
.mx-cell { fill: var(--accent); }
.mx-dot { fill: var(--accent); opacity: 0.42; }

/* ---------- library list ---------- */

.list { border-top: 1px solid var(--rule); }

.entry {
  display: grid;
  gap: 0.35rem 2rem;
  grid-template-columns: 1fr;
  padding-block: clamp(1.5rem, 3vw, 2.1rem);
  border-bottom: 1px solid var(--rule);
}

@media (min-width: 760px) {
  .entry { grid-template-columns: 13rem 1fr; }
}

.entry-field {
  font-family: var(--font-util);
  font-size: 0.6875rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-soft);
  padding-top: 0.45rem;
}

.entry h3 { margin-bottom: 0.35rem; }
.entry h3 a { color: var(--ink); text-decoration: none; }
.entry h3 a:hover { color: var(--accent); text-decoration: underline; }
.entry p { color: var(--ink-soft); max-width: 58ch; }

.entry-meta { margin-top: 0.75rem; }

/* ---------- principles ---------- */

.principles {
  display: grid;
  gap: 0;
  grid-template-columns: 1fr;
  border-top: 1px solid var(--rule);
}

@media (min-width: 820px) {
  .principles { grid-template-columns: 1fr 1fr; }
  .principle:nth-child(odd) { border-right: 1px solid var(--rule); padding-right: 2.5rem; }
  .principle:nth-child(even) { padding-left: 2.5rem; }
}

.principle {
  padding-block: 2rem;
  border-bottom: 1px solid var(--rule);
}
.principle h3 { margin-bottom: 0.5rem; }
.principle p { color: var(--ink-soft); }

/* ---------- inverted block ---------- */

.inverted {
  background: var(--ink);
  color: var(--paper);
}
.inverted h2 { color: var(--paper); }
.inverted .eyebrow { color: #7fb3a8; }
.inverted a { color: #9ecfc4; }
.inverted .fine { color: #96a3a4; }

.negations {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
  grid-template-columns: 1fr;
  border-top: 1px solid rgba(233, 236, 236, 0.22);
}

@media (min-width: 760px) {
  .negations { grid-template-columns: 1fr 1fr; column-gap: 3rem; }
}

.negations li {
  padding-block: 1.05rem;
  border-bottom: 1px solid rgba(233, 236, 236, 0.22);
  display: flex;
  gap: 0.85rem;
  align-items: baseline;
  line-height: 1.5;
}

.negations li::before {
  content: "";
  flex: 0 0 auto;
  width: 9px;
  height: 9px;
  background: #7fb3a8;
  transform: translateY(-1px);
}

/* ---------- faq ---------- */

.faq { border-top: 1px solid var(--rule); }

.faq details {
  border-bottom: 1px solid var(--rule);
  padding-block: 1.25rem;
}

.faq summary {
  cursor: pointer;
  list-style: none;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.0625rem;
  letter-spacing: -0.01em;
  display: flex;
  justify-content: space-between;
  gap: 1.5rem;
  align-items: baseline;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  font-family: var(--font-util);
  color: var(--accent);
  flex: 0 0 auto;
}
.faq details[open] summary::after { content: "\2013"; }
.faq details p {
  margin-top: 0.9rem;
  color: var(--ink-soft);
  max-width: 62ch;
}

/* ---------- support / contact ---------- */

.support {
  background: var(--paper-raised);
  border: 1px solid var(--rule);
  padding: clamp(1.6rem, 4vw, 2.75rem);
  display: grid;
  gap: 1.5rem;
  grid-template-columns: 1fr;
}

@media (min-width: 820px) {
  .support { grid-template-columns: 1fr 1fr; gap: 3rem; }
}

.mail {
  font-family: var(--font-display);
  font-size: clamp(1.15rem, 2.6vw, 1.65rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  word-break: break-word;
}

/* ---------- prose (legal + articles) ---------- */

.prose { max-width: 68ch; }
.prose h2 { margin-top: 2.6rem; }
.prose h3 { margin-top: 2rem; }
.prose h2:first-of-type { margin-top: 2rem; }
.prose ul, .prose ol { padding-left: 1.15rem; margin: 0 0 1.2em; }
.prose li { margin-bottom: 0.55em; }
.prose blockquote {
  margin: 1.8rem 0;
  padding: 0.2rem 0 0.2rem 1.4rem;
  border-left: 3px solid var(--accent);
  color: var(--ink-soft);
}

.page-head { border-bottom: 1px solid var(--rule); }

.sources {
  list-style: none;
  padding: 0;
  margin: 0;
  font-family: var(--font-util);
  font-size: 0.8125rem;
  line-height: 1.65;
}
.sources li {
  padding-block: 0.85rem;
  border-bottom: 1px solid var(--rule-soft);
  color: var(--ink-soft);
}
.sources li:first-child { border-top: 1px solid var(--rule-soft); }

.callout {
  border: 1px solid var(--rule);
  border-left: 3px solid var(--accent);
  background: var(--paper-raised);
  padding: 1.4rem 1.6rem;
  margin: 2.2rem 0;
}
.callout p { color: var(--ink-soft); }
.callout h3 { margin-bottom: 0.5rem; }

/* ---------- article furniture ---------- */

.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem 1.6rem;
  margin-top: 1.6rem;
  padding-top: 1.1rem;
  border-top: 1px solid var(--rule);
}

.next-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 2.5rem;
  justify-content: space-between;
  border-top: 1px solid var(--rule);
  padding-top: 1.5rem;
}

/* ---------- footer ---------- */

.colophon {
  border-top: 1px solid var(--rule);
  padding-block: 2.5rem 3.5rem;
}

.colophon-inner {
  display: grid;
  gap: 1.75rem;
  grid-template-columns: 1fr;
}

@media (min-width: 760px) {
  .colophon-inner { grid-template-columns: 1fr auto; align-items: start; }
}

.footlinks {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem 1.5rem;
  font-family: var(--font-util);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin: 0;
  padding: 0;
  list-style: none;
}
.footlinks a { color: var(--ink-soft); text-decoration: none; }
.footlinks a:hover { color: var(--accent); text-decoration: underline; }

/* ---------- 404 ---------- */

.notfound { min-height: 52vh; display: flex; align-items: center; }

/* ---------- motion ---------- */

@keyframes rise {
  from { opacity: 0; transform: translateY(14px); }
  to { opacity: 1; transform: none; }
}
@keyframes cellin {
  from { opacity: 0; transform: scale(0.4); }
  to { opacity: 1; transform: none; }
}

.rise { animation: rise 0.7s cubic-bezier(0.2, 0.7, 0.3, 1) both; }
.rise-2 { animation-delay: 0.09s; }
.rise-3 { animation-delay: 0.18s; }

.mx-cell, .mx-dot {
  transform-box: fill-box;
  transform-origin: center;
  animation: cellin 0.45s ease-out both;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-delay: 0ms !important;
    transition-duration: 0.001ms !important;
  }
}