/* Hallmark · docs · theme: Cobalt (shared tokens.css) · layout: side-rail · genre: docs
   knobs — rail: ~16rem fixed, grouped small-caps nav, sticky, own scroll
         — main: 68ch prose measure, wider allowance for code/tables
         — code: plain pre, hairline border, no chrome, filename figcaption (shared with landing)
         — heads: roman always, S2-style hanging sub under h1/h2
         — mobile <960px: rail collapses to a details/summary top bar, no horizontal scroll
   slop-test — tokens: pass (shared tokens.css only) · chrome: pass (no fake browser chrome)
             · honest: pass (no invented metrics) · responsive: pass (320–1280 checked) */

*, *::before, *::after { box-sizing: border-box; }
html { overflow-x: clip; scroll-behavior: smooth; }
body {
  margin: 0;
  overflow-x: clip;
  background: var(--color-paper);
  color: var(--color-ink-2);
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-style: normal; /* headings roman, always */
  color: var(--color-ink);
  letter-spacing: -0.02em;
  line-height: 1.18;
  margin: 0;
  overflow-wrap: anywhere;
  min-width: 0;
}
p { margin: 0; }
a { color: inherit; }
ul, ol { margin: 0; padding: 0; }
::selection { background: color-mix(in oklch, var(--color-accent) 18%, transparent); }

:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 3px;
  border-radius: 2px;
  transition: none; /* focus rings never animate */
}

/* docs-only :root extension, derived from existing Cobalt hues */
:root {
  --docs-rail-w: 16rem;
  --docs-measure: 68ch;
  --docs-bar-h: 60px;
}

code, .inline-code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--color-paper-2);
  border: 1px solid var(--color-rule);
  border-radius: 4px;
  padding: 0.1em 0.4em;
  white-space: nowrap;
}
pre code { border: 0; background: none; padding: 0; white-space: inherit; }

/* ---------- Shell: side-rail layout ---------- */
.shell {
  display: grid;
  grid-template-columns: var(--docs-rail-w) minmax(0, 1fr);
  min-height: 100vh;
  align-items: start;
}

/* ---------- Rail ---------- */
.rail {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  border-right: 1px solid var(--color-rule);
  padding: var(--space-lg) var(--space-lg) var(--space-2xl);
}
.rail__top {
  display: flex;
  flex-direction: column;
  gap: var(--space-2xs);
  padding-bottom: var(--space-md);
  margin-bottom: var(--space-md);
  border-bottom: 1px solid var(--color-rule);
}
.rail__brand {
  display: inline-flex;
  align-items: center;
  gap: 0.45em;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.02em;
  color: var(--color-ink);
  text-decoration: none;
}
.rail__brand::before {
  content: "";
  width: 0.55em;
  height: 0.55em;
  border-radius: 2px;
  background: var(--color-accent);
}
.rail__badge {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-accent-deep);
  background: color-mix(in oklch, var(--color-accent) 12%, var(--color-paper));
  border: 1px solid color-mix(in oklch, var(--color-accent) 30%, var(--color-rule));
  border-radius: var(--radius-ctrl);
  padding: 0.15em 0.5em;
  width: fit-content;
}
.rail__back {
  margin-top: var(--space-xs);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-neutral);
  text-decoration: none;
}
.rail__back:hover { color: var(--color-accent-deep); }

.rail__search {
  width: 100%;
  font: inherit;
  font-size: var(--text-sm);
  color: var(--color-ink);
  background: var(--color-paper);
  border: 1px solid var(--color-rule-strong);
  border-radius: var(--radius-ctrl);
  min-height: 36px;
  padding: var(--space-2xs) var(--space-sm);
  margin-bottom: var(--space-md);
}
.rail__search:focus-visible { outline: 2px solid var(--color-focus); outline-offset: 2px; }
.rail__empty { font-size: var(--text-sm); color: var(--color-neutral); }

.rail__group + .rail__group { margin-top: var(--space-lg); }
.rail__group h2 {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-neutral);
  margin-bottom: var(--space-xs);
}
.rail__group ul { display: flex; flex-direction: column; gap: 1px; list-style: none; }
.rail__group li { margin: 0; }
.rail__link {
  display: block;
  font-size: var(--text-sm);
  color: var(--color-ink-2);
  text-decoration: none;
  padding: 0.4em var(--space-sm);
  margin-inline: calc(var(--space-sm) * -1);
  border-radius: var(--radius-ctrl);
  transition: background-color var(--dur-short) var(--ease-out), color var(--dur-short) var(--ease-out);
}
.rail__link:hover { color: var(--color-ink); background: var(--color-paper-2); }
.rail__link.is-active { color: var(--color-accent-deep); font-weight: 600; background: color-mix(in oklch, var(--color-accent) 9%, transparent); }

/* mobile-only disclosure toggle, hidden on desktop */
.rail__mobile-toggle { display: none; }
.rail__toggle-wrap > summary { list-style: none; }
.rail__toggle-wrap > summary::-webkit-details-marker { display: none; }

/* ---------- Main column ---------- */
.main {
  min-width: 0;
  padding: var(--space-2xl) var(--page-gutter) var(--space-3xl);
}
.main__inner { max-width: 56rem; margin-inline: auto; }

.doc-hero { max-width: var(--docs-measure); margin-bottom: var(--space-3xl); }
.doc-hero h1 { font-size: var(--text-2xl); font-weight: 600; }
.doc-hero .sub {
  margin-top: var(--space-md);
  font-size: var(--text-md);
  line-height: 1.55;
  color: var(--color-ink-2);
}

section.doc-sec {
  padding-block: var(--space-2xl);
  border-top: 1px solid var(--color-rule);
  scroll-margin-top: var(--space-lg);
}
section.doc-sec:first-of-type { border-top: 0; padding-top: 0; }
.doc-sec h2 {
  font-size: var(--text-xl);
  font-weight: 600;
}
.doc-sec .pkg-name {
  font-family: var(--font-mono);
  font-size: 0.7em;
  font-weight: 500;
  color: var(--color-accent-deep);
  vertical-align: middle;
  margin-left: 0.5em;
  white-space: nowrap;
}
.doc-sec > p.lede {
  margin-top: var(--space-md);
  max-width: var(--docs-measure);
  font-size: var(--text-base);
  line-height: 1.65;
}
.doc-sec h3 {
  margin-top: var(--space-xl);
  font-size: var(--text-md);
  font-weight: 600;
}
.doc-sec p + p { margin-top: var(--space-md); }
.doc-sec p.lede + p.lede { margin-top: var(--space-sm); }

/* <yn-package-index> — the flat, anchorable package list the sidebar links into. */
.pkg-index {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(22rem, 1fr));
  gap: var(--space-md);
}
.pkg {
  padding: var(--space-md);
  border: 1px solid var(--color-rule);
  border-radius: var(--radius-ctrl);
  scroll-margin-top: var(--space-lg);
}
.pkg:target {
  border-color: var(--color-accent);
  background: color-mix(in srgb, var(--color-accent) 6%, transparent);
}
.pkg__name {
  margin: 0;
  font-size: var(--text-sm);
  font-weight: 600;
}
.pkg__name code { white-space: nowrap; }
.pkg__desc {
  margin-top: var(--space-xs);
  font-size: var(--text-sm);
  line-height: 1.55;
  color: var(--color-ink-2);
}
.pkg__link {
  display: inline-block;
  margin-top: var(--space-xs);
  font-size: var(--text-sm);
  font-weight: 500;
}
/* Usage examples inside index blocks: compact, scrollable when tall. */
.pkg pre.code {
  margin-top: var(--space-sm);
  font-size: 0.78rem;
  max-height: 18rem;
  overflow: auto;
}

.gh-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4em;
  margin-top: var(--space-md);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-ink-2);
  text-decoration: none;
  padding-block: 0.2em;
  background-image: linear-gradient(var(--color-accent), var(--color-accent));
  background-repeat: no-repeat;
  background-size: 0 1.5px;
  background-position: 0 100%;
  transition: background-size var(--dur-short) var(--ease-out), color var(--dur-short) var(--ease-out);
}
.gh-link:hover { color: var(--color-accent-deep); background-size: 100% 1.5px; }

/* ---------- Code figures — same treatment as the landing page ---------- */
.code-fig { margin: var(--space-lg) 0 0; min-width: 0; }
.code-fig figcaption {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-neutral);
  padding-bottom: var(--space-xs);
  border-bottom: 1px solid var(--color-rule);
  margin-bottom: var(--space-sm);
  display: flex;
  justify-content: space-between;
  gap: var(--space-md);
  align-items: center;
}
.code-fig figcaption .pkg { text-transform: none; letter-spacing: 0; color: var(--color-accent-deep); }
.code-fig__wrap { position: relative; }
pre.code {
  margin: 0;
  background: var(--color-graphite);
  border: 1px solid var(--color-graphite-rule);
  border-radius: var(--radius-code);
  box-shadow: 0 1px 2px var(--color-shadow);
  padding: var(--space-lg);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.83rem;
  line-height: 1.65;
  color: var(--color-code-ink);
  tab-size: 2;
}
pre.code code { font-family: inherit; }
.tk-d { color: var(--color-code-accent); }   /* decorators, keywords */
.tk-s { color: var(--color-code-str); }      /* strings, templates */
.tk-m { color: var(--color-code-muted); }    /* punctuation, comments */

.code-fig__wrap yn-copy {
  position: absolute;
  top: var(--space-sm);
  right: var(--space-sm);
}

.install-line {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  background: var(--color-graphite-2);
  border: 1px solid var(--color-graphite-rule);
  border-radius: var(--radius-code);
  padding: var(--space-md) var(--space-lg);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  min-width: 0;
  margin-top: var(--space-lg);
}
.install-line code { overflow-x: auto; white-space: nowrap; flex: 1; padding-block: var(--space-2xs); border: 0; background: none; }
.install-line .ps1 { color: var(--color-code-muted); user-select: none; }
.install-line .cmd { color: var(--color-code-str); }
.install-line .pkgname { color: var(--color-code-accent); }

.callout {
  margin-top: var(--space-lg);
  max-width: var(--docs-measure);
  font-size: var(--text-sm);
  color: var(--color-ink-2);
  background: var(--color-paper-2);
  border: 1px solid var(--color-rule);
  border-left: 3px solid var(--color-accent);
  border-radius: var(--radius-ctrl);
  padding: var(--space-md) var(--space-lg);
}
.callout b { color: var(--color-ink); font-weight: 600; }

/* ---------- naming convention list ---------- */
.conv-grid {
  margin-top: var(--space-lg);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-sm) var(--space-lg);
}
.conv-grid > div {
  border: 1px solid var(--color-rule);
  border-radius: var(--radius-ctrl);
  padding: var(--space-sm) var(--space-md);
}
.conv-grid code { display: block; margin-bottom: 0.3em; white-space: normal; }
.conv-grid span { font-size: var(--text-sm); color: var(--color-neutral); }

/* ---------- Footer ---------- */
.doc-foot {
  border-top: 1px solid var(--color-rule);
  margin-top: var(--space-2xl);
  padding-top: var(--space-lg);
  padding-bottom: max(var(--space-lg), env(safe-area-inset-bottom));
  font-size: var(--text-sm);
  color: var(--color-neutral);
  display: flex;
  flex-wrap: wrap;
  column-gap: var(--space-xs);
  row-gap: var(--space-2xs);
}
.doc-foot .brand { font-family: var(--font-display); font-weight: 600; color: var(--color-ink); }
.doc-foot a { color: var(--color-ink-2); text-decoration: none; white-space: nowrap; }
.doc-foot a:hover { color: var(--color-accent-deep); }

/* ---------- Responsive: rail collapses under 960px ---------- */
@media (max-width: 60rem) {
  .shell { display: block; }
  .rail {
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
    height: auto;
    max-height: none;
    width: auto;
    border-right: 0;
    border-bottom: 1px solid var(--color-rule);
    background: color-mix(in oklch, var(--color-paper) 92%, transparent);
    backdrop-filter: blur(12px);
    padding: 0;
    overflow-y: visible;
  }
  .rail__top {
    border-bottom: 0;
    margin-bottom: 0;
    padding: var(--space-sm) var(--page-gutter);
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    min-height: var(--docs-bar-h);
  }
  .rail__brand-group { display: flex; align-items: center; gap: var(--space-sm); }
  .rail__back { margin-top: 0; }
  .rail__desktop-nav { display: none; }
  .rail__mobile-toggle {
    display: inline-flex;
    align-items: center;
    gap: 0.4em;
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--color-ink);
    background: var(--color-paper-2);
    border: 1px solid var(--color-rule);
    border-radius: var(--radius-ctrl);
    min-height: 44px;
    padding: 0.4em 0.9em;
    cursor: pointer;
  }
  .rail__nav-body {
    max-height: min(70vh, 32rem);
    overflow-y: auto;
    padding: var(--space-md) var(--page-gutter) var(--space-lg);
    border-top: 1px solid var(--color-rule);
  }
  .rail__link { min-height: 44px; display: flex; align-items: center; }
  .main { padding-top: var(--space-xl); }
}
@media (max-width: 40rem) {
  .conv-grid { grid-template-columns: minmax(0, 1fr); }
  pre.code { padding: var(--space-md); font-size: 0.78rem; }
  .install-line { flex-wrap: wrap; }
  .doc-foot a { display: inline-flex; align-items: center; min-height: 44px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 150ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 150ms !important;
  }
}