/* Side Latch — Mullion Pane Editorial
   Frost pane field, dusk indigo ink, copper latch accents.
   Window sash lead lines + corner brackets. Distinct from tractor-feed,
   parchment, sage bars, waveform, drafting board, NCR, thermal, etc. */

:root {
  color-scheme: light;
  --pane: #EEF2F7;
  --pane-deep: #E2E8F0;
  --ink: #1B2433;
  --muted: #6B7585;
  --latch: #B87333;
  --latch-soft: #D4A574;
  --lead: rgba(27, 36, 51, 0.12);
  --glass: rgba(255, 255, 255, 0.55);
  --display: "Fraunces", "Iowan Old Style", Georgia, serif;
  --text: "Figtree", "Segoe UI", sans-serif;
  --shell: 68rem;
  --gutter: clamp(1.15rem, 4vw, 2.75rem);
  --mullion: 1px;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  background:
    linear-gradient(180deg, var(--pane) 0%, var(--pane-deep) 100%);
  color: var(--ink);
  font-family: var(--text);
  font-size: clamp(1.05rem, 1rem + 0.2vw, 1.14rem);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

.skip {
  position: absolute; left: -9999px; top: 0;
  background: var(--ink); color: #fff; padding: 0.6rem 1rem; z-index: 50;
}
.skip:focus { left: var(--gutter); }

.shell {
  width: min(100% - 2 * var(--gutter), var(--shell));
  margin-inline: auto;
}

/* —— Chrome —— */
.top {
  position: relative;
  z-index: 2;
  padding: 1.1rem 0 0.85rem;
  border-bottom: var(--mullion) solid var(--lead);
  background: var(--glass);
  backdrop-filter: blur(8px);
}
.top__row {
  display: flex; flex-wrap: wrap; align-items: baseline;
  justify-content: space-between; gap: 0.5rem 1.5rem;
  margin-bottom: 0.85rem;
}
.brand {
  font-family: var(--display);
  font-weight: 700;
  font-size: 1.35rem;
  letter-spacing: -0.02em;
  color: var(--ink);
  text-decoration: none;
  display: inline-flex; align-items: center; gap: 0.55rem;
}
.brand__mark {
  width: 1.15rem; height: 1.15rem;
  border: 1.5px solid var(--latch);
  background:
    linear-gradient(var(--latch) 0 0) center / 100% 1.5px no-repeat,
    linear-gradient(var(--latch) 0 0) center / 1.5px 100% no-repeat;
  flex-shrink: 0;
}
.top__meta {
  font-size: 0.78rem;
  color: var(--muted);
  letter-spacing: 0.04em;
}
.nav {
  display: flex; flex-wrap: wrap; gap: 0.35rem 1.4rem;
  font-weight: 600; font-size: 0.92rem;
}
.nav a {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  padding-bottom: 0.15rem;
}
.nav a:hover, .nav a[aria-current] {
  color: var(--ink);
  border-bottom-color: var(--latch);
}

/* —— Hero: mullion pane —— */
.hero {
  position: relative;
  isolation: isolate;
  padding: clamp(3.2rem, 8vw, 5.5rem) 0 clamp(2.8rem, 6vw, 4.2rem);
  overflow: hidden;
}
.hero__pane {
  position: absolute; inset: 0; z-index: -1;
  background:
    linear-gradient(var(--lead), var(--lead)) center / 100% var(--mullion) no-repeat,
    linear-gradient(var(--lead), var(--lead)) center / var(--mullion) 100% no-repeat,
    repeating-linear-gradient(
      90deg,
      transparent 0,
      transparent calc(25% - 0.5px),
      var(--lead) calc(25% - 0.5px),
      var(--lead) calc(25% + 0.5px)
    ),
    repeating-linear-gradient(
      0deg,
      transparent 0,
      transparent calc(33.33% - 0.5px),
      var(--lead) calc(33.33% - 0.5px),
      var(--lead) calc(33.33% + 0.5px)
    ),
    radial-gradient(ellipse 80% 60% at 50% 0%, #fff 0%, transparent 70%),
    var(--pane);
  animation: pane-breathe 12s ease-in-out infinite alternate;
}
@keyframes pane-breathe {
  from { opacity: 0.92; }
  to { opacity: 1; }
}
.hero__bracket {
  position: absolute; width: 1.6rem; height: 1.6rem;
  border-color: var(--latch); border-style: solid; z-index: 0;
  animation: latch-settle 0.9s ease-out both;
}
.hero__bracket--tl { top: 1.2rem; left: var(--gutter); border-width: 2px 0 0 2px; }
.hero__bracket--tr { top: 1.2rem; right: var(--gutter); border-width: 2px 2px 0 0; }
.hero__bracket--bl { bottom: 1.2rem; left: var(--gutter); border-width: 0 0 2px 2px; }
.hero__bracket--br { bottom: 1.2rem; right: var(--gutter); border-width: 0 2px 2px 0; }
@keyframes latch-settle {
  from { opacity: 0; transform: scale(0.85); }
  to { opacity: 1; transform: scale(1); }
}
.hero__content { position: relative; max-width: 40rem; }
.hero__brand {
  font-family: var(--display);
  font-weight: 700;
  font-size: clamp(2.6rem, 7vw, 4.4rem);
  letter-spacing: -0.03em;
  line-height: 1.05;
  margin: 0 0 1rem;
  color: var(--ink);
}
.hero h1 {
  font-family: var(--display);
  font-weight: 600;
  font-size: clamp(1.2rem, 2.5vw, 1.55rem);
  letter-spacing: -0.015em;
  line-height: 1.35;
  margin: 0 0 1rem;
  color: var(--ink);
}
.hero__stand {
  margin: 0;
  color: var(--muted);
  max-width: 34rem;
  font-size: 1.02rem;
}

/* —— Sections —— */
.block { padding: clamp(2.4rem, 5vw, 3.6rem) 0; }
.block--tint {
  background: color-mix(in srgb, var(--pane-deep) 70%, #fff);
  border-block: var(--mullion) solid var(--lead);
}
.block--latch {
  border-top: 3px solid var(--latch);
  background: #fff;
}
.eyebrow {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--latch);
  margin: 0 0 0.55rem;
}
h2 {
  font-family: var(--display);
  font-weight: 700;
  font-size: clamp(1.45rem, 3vw, 1.95rem);
  letter-spacing: -0.025em;
  margin: 0 0 1.1rem;
  line-height: 1.2;
}
.lede {
  display: grid;
  gap: 1rem;
  max-width: 42rem;
}
.lede p { margin: 0; color: var(--ink); }

.library { display: grid; gap: 0; }
.entry {
  display: grid;
  grid-template-columns: 5.5rem 1fr;
  gap: 1rem 1.4rem;
  padding: 1.35rem 0;
  border-bottom: var(--mullion) solid var(--lead);
}
.entry:first-child { border-top: var(--mullion) solid var(--lead); }
.entry__id {
  font-family: var(--display);
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--latch);
  margin: 0.2rem 0 0;
}
.entry h3 {
  font-family: var(--display);
  font-weight: 700;
  font-size: 1.12rem;
  letter-spacing: -0.02em;
  margin: 0 0 0.35rem;
  line-height: 1.25;
}
.entry h3 a { color: var(--ink); text-decoration: none; }
.entry h3 a:hover { color: var(--latch); }
.entry p { margin: 0; color: var(--muted); font-size: 0.98rem; }

.standards {
  list-style: none; padding: 0; margin: 0;
  display: grid; gap: 1rem; max-width: 44rem;
}
.standards li {
  padding-left: 1.1rem;
  border-left: 2px solid var(--latch-soft);
}
.standards strong { font-family: var(--display); }

.defs { margin: 0; max-width: 42rem; }
.defs dt {
  font-family: var(--display);
  font-weight: 700;
  margin-top: 1.15rem;
}
.defs dd { margin: 0.25rem 0 0; color: var(--muted); }

.flag {
  margin-top: 2rem;
  padding: 1.1rem 1.25rem;
  border: var(--mullion) solid var(--lead);
  border-left: 3px solid var(--latch);
  background: var(--pane);
  max-width: 44rem;
}
.flag p { margin: 0; font-size: 0.95rem; }

/* —— Article / prose —— */
.article__head {
  padding: clamp(2.2rem, 5vw, 3.2rem) 0 0.5rem;
  border-bottom: var(--mullion) solid var(--lead);
}
.article__meta {
  color: var(--muted);
  font-size: 0.92rem;
  margin: 0.75rem 0 0;
}
.article__meta b { color: var(--ink); }
.prose { max-width: 42rem; }
.prose h1 {
  font-family: var(--display);
  font-weight: 700;
  font-size: clamp(1.85rem, 4.5vw, 2.55rem);
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin: 0.2rem 0 0;
}
.prose h2 {
  margin-top: 2rem;
  font-size: 1.35rem;
}
.prose p, .prose li { color: var(--ink); }
.prose a { color: var(--latch); }
.prose ul { padding-left: 1.2rem; }
.backlink {
  display: inline-block;
  margin-top: 2rem;
  font-weight: 600;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 2px solid var(--latch);
}
.backlink:hover { color: var(--latch); }

.mail {
  font-family: var(--display);
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
}

/* —— 404 —— */
.void {
  padding: clamp(3rem, 8vw, 5rem) 0;
  min-height: 50vh;
}
.void h1 { color: var(--ink); }

/* —— Footer —— */
.foot {
  margin-top: 2rem;
  padding: 2rem 0 2.5rem;
  border-top: var(--mullion) solid var(--lead);
  background: #fff;
  font-size: 0.9rem;
}
.foot__nav {
  display: flex; flex-wrap: wrap; gap: 0.45rem 1.2rem;
  margin-bottom: 1rem;
}
.foot__nav a { color: var(--muted); text-decoration: none; }
.foot__nav a:hover { color: var(--latch); }
.colophon { color: var(--muted); margin: 0; font-size: 0.82rem; }

@media (max-width: 640px) {
  .entry { grid-template-columns: 1fr; gap: 0.25rem; }
  .hero__bracket { width: 1.1rem; height: 1.1rem; }
}