/* Hallmark · genre: editorial · macrostructure: Map / Diagram · theme: Almanac-warm
 * nav: N9 edge-aligned minimal · footer: Ft4 dense colophon
 * Every colour and font below references a token from tokens.css. No inline values.
 */

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

html, body {
  overflow-x: clip;                 /* clip, never hidden — hidden kills position:sticky */
  margin: 0;
}

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

body {
  background: var(--color-paper);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: 380;
  line-height: 1.62;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

::selection { background: var(--color-accent-soft); color: var(--color-ink); }

:where(a):focus-visible,
:where(button):focus-visible,
:where(summary):focus-visible {
  outline: var(--rule-mid) solid var(--color-focus);
  outline-offset: 3px;
  border-radius: var(--radius-xs);
  /* never transitioned — the ring must appear instantly */
}

h1, h2, h3 {
  font-family: var(--font-display);
  font-style: normal;               /* roman only — italic headers are the tell */
  font-weight: 500;
  letter-spacing: -0.015em;
  line-height: 1.1;
  overflow-wrap: anywhere;
  min-width: 0;
  margin: 0;
}

p { margin: 0 0 var(--space-sm); max-width: var(--measure); }
p:last-child { margin-bottom: 0; }

a { color: var(--color-ink); text-decoration-color: var(--color-rule-strong); text-underline-offset: 0.22em; }
a { transition: text-decoration-color var(--dur-instant) var(--ease-out); }
a:hover { text-decoration-color: var(--color-accent); }

code, .mono { font-family: var(--font-mono); font-size: 0.88em; font-variant-ligatures: none; }
code { background: var(--color-paper-2); padding: 0.1em 0.34em; border-radius: var(--radius-xs); }
.tnum { font-variant-numeric: tabular-nums; }
.muted { color: var(--color-muted); }

.wrap { max-width: 78rem; margin-inline: auto; padding-inline: var(--page-gutter); }

/* ---------------------------------------------------------------- N9 nav --- */
.topbar {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-sm);
  padding-block: var(--space-md) var(--space-sm);
  flex-wrap: wrap;
}
.wordmark {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.02em;
  white-space: nowrap;
  text-decoration: none;
}
.wordmark b { font-weight: 600; }
.topbar__meta {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  color: var(--color-neutral);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  white-space: nowrap;
}

/* --------------------------------------------------------------- opening --- */
.lede { padding-block: var(--space-xl) var(--space-lg); }
.lede h1 {
  font-size: var(--text-display);
  max-width: 19ch;
  margin-bottom: var(--space-md);
}
.lede__sub {
  font-size: var(--text-lg);
  color: var(--color-muted);
  max-width: 56ch;
  line-height: 1.5;
}
.lede__body { margin-top: var(--space-lg); max-width: var(--measure); }

.orient {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-md);
}

/* --------------------------------------------------------- spec strip ------ */
.spec {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(9.5rem, 100%), 1fr));
  border-top: var(--rule-mid) solid var(--color-ink);
  border-bottom: var(--rule-hair) solid var(--color-rule);
  margin-block: var(--space-xl);
}
.spec div {
  padding: var(--space-sm) var(--space-sm) var(--space-sm) 0;
  border-right: var(--rule-hair) solid var(--color-rule);
}
.spec div:last-child { border-right: 0; }
.spec dt {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-neutral);
  margin-bottom: var(--space-3xs);
}
.spec dd {
  margin: 0;
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-variant-numeric: tabular-nums;
  line-height: 1.15;
}
.spec dd small { font-size: var(--text-xs); font-family: var(--font-body); color: var(--color-muted); display: block; letter-spacing: 0; }

/* ------------------------------------------------------------- sections ---- */
section { padding-block: var(--space-2xl); }
#map { padding-block: var(--space-2xl) var(--space-3xl); }   /* the map gets air */
#components { padding-block: var(--space-3xl) var(--space-2xl); }
#limits { padding-block: var(--space-xl) var(--space-2xl); } /* closes tighter */
section + section { border-top: var(--rule-hair) solid var(--color-rule); }
.section-head { margin-bottom: var(--space-lg); }
.section-head h2 { font-size: var(--text-3xl); max-width: 22ch; }
.section-head p { margin-top: var(--space-sm); color: var(--color-muted); max-width: 60ch; }

/* ------------------------------------------------------------ the map ------ */
.map {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  margin-block: var(--space-lg);
  max-width: 46rem;
}
.node {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  border: var(--rule-hair) solid var(--color-rule);
  background: var(--color-paper-2);
  border-radius: var(--radius-sm);
}
.node--io { background: var(--color-paper); border-style: dashed; }
.node--head { background: var(--color-paper-3); }
.node__name { font-weight: 550; }
.node__name span { display: block; font-weight: 380; font-size: var(--text-sm); color: var(--color-muted); }
.node__shape {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  color: var(--color-neutral);
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}
.flow {
  justify-self: start;
  margin-inline-start: var(--space-lg);
  width: var(--rule-mid);
  height: var(--space-md);
  background: var(--color-rule-strong);
}
.flow--tick { position: relative; }
.flow--tick::after {
  content: "";
  position: absolute;
  inset-block-end: 0;
  inset-inline-start: 50%;
  translate: -50% 0;
  border: 5px solid transparent;
  border-top-color: var(--color-rule-strong);
}

/* the repeated block: a bracketed group with a residual spine */
.stack {
  min-width: 0;
  position: relative;
  border: var(--rule-mid) solid var(--color-ink);
  border-radius: var(--radius-sm);
  padding: var(--space-md);
  display: grid;
  gap: var(--space-md);
  background: var(--color-paper);
}
.stack__label {
  position: absolute;
  inset-block-start: 0;
  inset-inline-start: var(--space-md);
  translate: 0 -50%;
  background: var(--color-paper);
  padding-inline: var(--space-2xs);
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-accent);
}
.residual {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: var(--space-sm);
  align-items: stretch;
}
.residual__spine {
  width: var(--rule-mid);
  background: var(--color-accent);
  margin-inline-start: var(--space-2xs);
  position: relative;
}
.residual__spine::after {
  content: "+";
  position: absolute;
  inset-block-end: -0.55em;
  inset-inline-start: 50%;
  translate: -50% 0;
  background: var(--color-paper);
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1;
  padding: 0.1em;
}
.residual__branch { display: grid; grid-template-columns: minmax(0, 1fr); gap: var(--space-2xs); min-width: 0; }
.leaf {
  padding: var(--space-2xs) var(--space-sm);
  border: var(--rule-hair) solid var(--color-rule);
  border-radius: var(--radius-xs);
  font-size: var(--text-sm);
  background: transparent;
  display: flex;
  justify-content: space-between;
  gap: var(--space-sm);
  flex-wrap: wrap;
}
.leaf b { font-weight: 550; }
.leaf .mono { color: var(--color-neutral); font-size: var(--text-2xs); }

.map-note {
  margin-top: var(--space-md);
  font-size: var(--text-sm);
  color: var(--color-muted);
  max-width: 60ch;
}

/* ------------------------------------------------------------- notes ------- */
/* grid-template-columns: minmax(0, 1fr) — a bare single track inherits the
   items' `min-width: auto`, so the long mono equation in .eq forced the whole
   column to its min-content width (~500px) and clipped on a phone. */
.notes {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-xl);
  max-width: var(--measure);
}
.note { min-width: 0; }
.note h3 {
  font-size: var(--text-xl);
  margin-bottom: var(--space-2xs);
  display: flex;
  align-items: baseline;
  gap: var(--space-2xs);
  flex-wrap: wrap;
}
.note h3 .file {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  color: var(--color-neutral);
  font-weight: 400;
  letter-spacing: 0;
}
.eq {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  background: var(--color-paper-2);
  border-inline-start: var(--rule-mid) solid var(--color-accent);
  padding: var(--space-xs) var(--space-sm);
  margin-block: var(--space-xs) var(--space-sm);
  overflow-x: auto;
  min-width: 0;
  border-radius: 0 var(--radius-xs) var(--radius-xs) 0;
}

.subhead {
  font-size: var(--text-xl);
  margin-block: var(--space-lg) var(--space-sm);
}

/* A generated-text specimen — body face, so it reads as prose the model wrote,
   not as an equation. Shares the eq block's left rule so both read as quoted. */
.sample {
  font-size: var(--text-sm);
  background: var(--color-paper-2);
  border-inline-start: var(--rule-mid) solid var(--color-rule-strong);
  padding: var(--space-sm) var(--space-md);
  margin-block: var(--space-sm) var(--space-md);
  border-radius: 0 var(--radius-xs) var(--radius-xs) 0;
  color: var(--color-muted);
  max-width: var(--measure);
}

/* ------------------------------------------------------------- tables ------ */
.scroller { overflow-x: auto; margin-block: var(--space-md); }
table { border-collapse: collapse; width: 100%; min-width: 30rem; font-size: var(--text-sm); }
caption { text-align: left; color: var(--color-muted); font-size: var(--text-sm); margin-bottom: var(--space-2xs); }
th, td { text-align: left; padding: var(--space-2xs) var(--space-sm) var(--space-2xs) 0; border-bottom: var(--rule-hair) solid var(--color-rule); }
thead th { border-bottom: var(--rule-hair) solid var(--color-rule-strong); font-family: var(--font-mono); font-size: var(--text-2xs); text-transform: uppercase; letter-spacing: 0.08em; color: var(--color-neutral); font-weight: 500; }
tbody tr:last-child td { border-bottom: 0; }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; padding-right: 0; }
tr.is-final td { font-weight: 600; }

/* ------------------------------------------------------------- steps ------- */
.steps { counter-reset: step; display: grid; grid-template-columns: minmax(0, 1fr); gap: var(--space-md); max-width: var(--measure); margin: 0; padding: 0; list-style: none; }
.steps li { counter-increment: step; display: grid; grid-template-columns: 2.4rem minmax(0, 1fr); gap: var(--space-sm); min-width: 0; }
.steps li::before {
  content: counter(step, decimal-leading-zero);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-accent);
  padding-top: 0.25em;
  font-variant-numeric: tabular-nums;
}

/* ------------------------------------------------------------- callout ----- */
.limits { max-width: var(--measure); display: grid; grid-template-columns: minmax(0, 1fr); gap: var(--space-md); margin: 0; padding: 0; list-style: none; }
.limits li { padding-inline-start: var(--space-md); border-inline-start: var(--rule-hair) solid var(--color-rule-strong); }
.limits b { font-weight: 600; }

/* ------------------------------------------------------------- footer ------ */
.colophon {
  border-top: var(--rule-mid) solid var(--color-ink);
  margin-top: var(--space-2xl);
  padding-block: var(--space-lg) var(--space-2xl);
}
.colophon p {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  line-height: 1.85;
  color: var(--color-muted);
  max-width: 74ch;
}
.colophon a { color: var(--color-muted); }

/* ------------------------------------------------------- reduced motion ---- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ---------------------------------------------------------------- 640 ------ */
@media (max-width: 40rem) {
  .node { grid-template-columns: minmax(0, 1fr); gap: var(--space-3xs); }
  .node__shape { justify-self: start; }
  .spec div { border-right: 0; border-bottom: var(--rule-hair) solid var(--color-rule); }
  .spec div:last-child { border-bottom: 0; }
  .stack { padding: var(--space-sm); }
  .residual { gap: var(--space-2xs); }
  section { padding-block: var(--space-xl); }
}