/* NEM constraints tutorial + catalog. Tokens first: light on :root, dark under prefers-color-scheme (guarded) and again under [data-theme=dark] so the toggle wins both ways. Plain hex rather than light-dark() so older Android WebViews still render. */
@import url('https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:ital,wght@0,400;0,500;0,600;1,400&family=IBM+Plex+Mono:wght@400;500&family=Source+Serif+4:ital,opsz,wght@0,8..60,400;0,8..60,600;1,8..60,400&display=swap');

:root {
  color-scheme: light;
  --ground: #f4f7f6;
  --surface: #ffffff;
  --surface-2: #eaf0ee;
  --ink: #17221f;
  --ink-2: #4f615d;
  --ink-3: #7d8d89;
  --line: #d6e0dd;
  --accent: #0e7268;
  --accent-ink: #0b5b53;
  --accent-soft: #d8f0ec;
  --alert: #b0405a;
  --alert-soft: #f7e3e8;
  --ok: #2f7a3d;
  --ok-soft: #e1f2e3;
  --code-bg: #eef3f2;
  --s1: #0e7268;
  --s2: #2a78d6;
  --s3: #4a3aa7;
  --s4: #c2588a;
  --grid: #e4ebe9;
  --on-accent: #ffffff;
  --shadow: rgba(20, 40, 36, 0.12);
  /* chart series (validated order, no warm hues by owner rule) */
  --font-ui: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-body: "Source Serif 4", Georgia, "Times New Roman", serif;
  --font-mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  --measure: 68ch;
  --rail: 17rem;
  --radius: 6px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --ground: #0f1514;
    --surface: #161e1d;
    --surface-2: #1e2927;
    --ink: #e4ecea;
    --ink-2: #9fb1ac;
    --ink-3: #6f807c;
    --line: #2b3937;
    --accent: #37d1bd;
    --accent-ink: #7fe6d8;
    --accent-soft: #14403b;
    --alert: #e68ca2;
    --alert-soft: #402028;
    --ok: #7fce8c;
    --ok-soft: #1d3a24;
    --code-bg: #0b1110;
    --s1: #37d1bd;
    --s2: #3987e5;
    --s3: #9085e9;
    --s4: #d55181;
    --grid: #24302e;
    --on-accent: #0f1514;
    --shadow: rgba(0, 0, 0, 0.5);
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --ground: #0f1514;
  --surface: #161e1d;
  --surface-2: #1e2927;
  --ink: #e4ecea;
  --ink-2: #9fb1ac;
  --ink-3: #6f807c;
  --line: #2b3937;
  --accent: #37d1bd;
  --accent-ink: #7fe6d8;
  --accent-soft: #14403b;
  --alert: #e68ca2;
  --alert-soft: #402028;
  --ok: #7fce8c;
  --ok-soft: #1d3a24;
  --code-bg: #0b1110;
  --s1: #37d1bd;
  --s2: #3987e5;
  --s3: #9085e9;
  --s4: #d55181;
  --grid: #24302e;
  --on-accent: #0f1514;
  --shadow: rgba(0, 0, 0, 0.5);
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--ground); color: var(--ink);
  font-family: var(--font-body); font-size: 1.0625rem; line-height: 1.6;
  font-variant-numeric: tabular-nums;
}
a { color: var(--accent-ink); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { color: var(--accent); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
h1, h2, h3, h4 { font-family: var(--font-ui); line-height: 1.2; text-wrap: balance; margin: 0; color: var(--ink); }
h1 { font-size: clamp(1.7rem, 1.2rem + 1.8vw, 2.4rem); font-weight: 600; letter-spacing: -0.01em; }
h2 { font-size: 1.45rem; font-weight: 600; margin-top: 2.6rem; padding-top: 1.2rem; border-top: 1px solid var(--line); }
h3 { font-size: 1.12rem; font-weight: 600; margin-top: 1.8rem; }
p, ul, ol { margin: 0.9rem 0; max-width: var(--measure); }
li { margin: 0.3rem 0; }
strong { font-weight: 600; }
code, kbd, pre, .mono { font-family: var(--font-mono); font-size: 0.88em; }
code { background: var(--code-bg); padding: 0.08em 0.35em; border-radius: 4px; color: var(--ink); }
pre { background: var(--code-bg); border: 1px solid var(--line); border-radius: var(--radius); padding: 0.9rem 1rem; overflow-x: auto; line-height: 1.5; max-width: 100%; }
pre code { background: none; padding: 0; font-size: 0.85rem; }
hr { border: 0; border-top: 1px solid var(--line); margin: 2rem 0; }
small, .small { font-size: 0.86rem; color: var(--ink-2); font-family: var(--font-ui); }
.eyebrow { font-family: var(--font-ui); font-size: 0.74rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--accent-ink); font-weight: 600; }
.lede { font-size: 1.18rem; color: var(--ink-2); line-height: 1.5; }
.muted { color: var(--ink-2); }

/* ---------- frame ---------- */
.frame { display: grid; grid-template-columns: var(--rail) minmax(0, 1fr); min-height: 100vh; }
.rail {
  position: sticky; top: 0; height: 100vh; overflow-y: auto; padding: 1.2rem 1rem 2rem;
  background: var(--surface); border-right: 1px solid var(--line); font-family: var(--font-ui);
}
.rail .brand { display: block; font-weight: 600; font-size: 1rem; color: var(--ink); text-decoration: none; letter-spacing: -0.01em; }
.rail .brand small { display: block; font-weight: 400; color: var(--ink-2); margin-top: 0.15rem; }
.rail nav { margin-top: 1.2rem; }
.rail .group { margin-top: 1.1rem; }
.rail .group > .eyebrow { display: block; margin-bottom: 0.4rem; }
.rail ol, .rail ul { list-style: none; margin: 0; padding: 0; max-width: none; }
.rail li { margin: 0; }
.rail li a {
  display: grid; grid-template-columns: 1.4rem 1fr auto; gap: 0.4rem; align-items: baseline;
  padding: 0.32rem 0.45rem; border-radius: var(--radius); text-decoration: none; color: var(--ink-2); font-size: 0.9rem; line-height: 1.3;
}
.rail li a:hover { background: var(--surface-2); color: var(--ink); }
.rail li a[aria-current="page"] { background: var(--accent-soft); color: var(--accent-ink); font-weight: 500; }
.rail .num { font-size: 0.78rem; color: var(--ink-3); font-variant-numeric: tabular-nums; }
.rail .dot { width: 0.55rem; height: 0.55rem; border-radius: 50%; border: 1.5px solid var(--line); align-self: center; }
.rail .dot.part { border-color: var(--accent); background: linear-gradient(90deg, var(--accent) 50%, transparent 50%); }
.rail .dot.done { border-color: var(--accent); background: var(--accent); }
.rail .foot { margin-top: 1.4rem; font-size: 0.8rem; color: var(--ink-3); }
.rail .foot button { font: inherit; color: var(--ink-2); background: none; border: 1px solid var(--line); border-radius: var(--radius); padding: 0.25rem 0.55rem; cursor: pointer; }
.rail .foot button:hover { border-color: var(--accent); color: var(--accent-ink); }

.topbar { display: none; }
main.page { padding: 2.2rem clamp(1.1rem, 4vw, 3.5rem) 5rem; max-width: 62rem; }
main.wide { max-width: none; }
.chapter-head { margin-bottom: 1.6rem; }
.chapter-head .eyebrow { display: block; margin-bottom: 0.5rem; }
.chapter-head .progress { margin-top: 0.8rem; }

/* ---------- reading components ---------- */
figure { margin: 1.6rem 0; max-width: 100%; }
figure.wide { max-width: none; }
figcaption { font-family: var(--font-ui); font-size: 0.86rem; color: var(--ink-2); margin-top: 0.5rem; max-width: var(--measure); }
figure.diagram pre { font-size: 0.82rem; line-height: 1.35; background: var(--surface); }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 1rem 1.2rem; }
.callout { border-left: 3px solid var(--accent); background: var(--surface); padding: 0.8rem 1.1rem; margin: 1.3rem 0; max-width: var(--measure); border-radius: 0 var(--radius) var(--radius) 0; }
.callout .eyebrow { display: block; margin-bottom: 0.3rem; }
.callout p:first-of-type { margin-top: 0.2rem; }
.callout.gotcha { border-left-color: var(--alert); }
.callout.gotcha .eyebrow { color: var(--alert); }
.callout.measured { border-left-color: var(--s2); }
.callout.measured .eyebrow { color: var(--s2); }
.stamp { font-family: var(--font-ui); font-size: 0.78rem; color: var(--ink-3); }
dl.defs { max-width: var(--measure); display: grid; grid-template-columns: max-content 1fr; gap: 0.35rem 1rem; margin: 1rem 0; }
dl.defs dt { font-family: var(--font-ui); font-weight: 600; font-size: 0.95rem; }
dl.defs dd { margin: 0; }

table.data { border-collapse: collapse; width: 100%; font-family: var(--font-ui); font-size: 0.9rem; background: var(--surface); }
table.data th, table.data td { padding: 0.45rem 0.65rem; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
table.data th { font-weight: 600; font-size: 0.8rem; letter-spacing: 0.04em; text-transform: uppercase; color: var(--ink-2); background: var(--surface-2); }
table.data td.num, table.data th.num { text-align: right; font-variant-numeric: tabular-nums; }
table.data td.mono { font-family: var(--font-mono); font-size: 0.85rem; white-space: nowrap; }
.scroll { overflow-x: auto; max-width: 100%; border: 1px solid var(--line); border-radius: var(--radius); }
.scroll table.data { border: 0; }

.equation { font-family: var(--font-mono); background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 0.9rem 1.1rem; margin: 1.2rem 0; overflow-x: auto; font-size: 0.92rem; line-height: 1.7; max-width: 100%; }
.equation .op { color: var(--accent-ink); font-weight: 500; padding: 0 0.4em; }
.equation .lhs { color: var(--ink); }
.equation .rhs { color: var(--s2); }
.equation .neg { color: var(--alert); }
.pill { display: inline-block; font-family: var(--font-ui); font-size: 0.74rem; font-weight: 600; letter-spacing: 0.04em; padding: 0.12rem 0.5rem; border-radius: 999px; background: var(--surface-2); color: var(--ink-2); vertical-align: middle; }
.pill.accent { background: var(--accent-soft); color: var(--accent-ink); }
.pill.alert { background: var(--alert-soft); color: var(--alert); }
.pill.ok { background: var(--ok-soft); color: var(--ok); }

/* constraint-id token colouring (decoder + inline) */
.cid { font-family: var(--font-mono); white-space: nowrap; }
.cid .t-region { color: var(--accent-ink); font-weight: 500; }
.cid .t-cause { color: var(--s3); font-weight: 500; }
.cid .t-outage { color: var(--s2); }
.cid .t-unique { color: var(--ink-2); }
.cid .t-fcas { color: var(--s4); font-weight: 500; }

/* ---------- quiz ---------- */
.quiz { margin: 2.2rem 0; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); max-width: calc(var(--measure) + 4rem); }
.quiz > header { display: flex; align-items: center; justify-content: space-between; gap: 1rem; padding: 0.7rem 1.1rem; border-bottom: 1px solid var(--line); background: var(--surface-2); border-radius: var(--radius) var(--radius) 0 0; font-family: var(--font-ui); }
.quiz > header .eyebrow { margin: 0; }
.quiz > header .score { font-size: 0.82rem; color: var(--ink-2); }
.q { padding: 1rem 1.1rem 1.1rem; border-bottom: 1px solid var(--line); }
.q:last-child { border-bottom: 0; }
.q .prompt { font-family: var(--font-ui); font-weight: 500; margin: 0 0 0.6rem; max-width: none; }
.q .prompt .qn { color: var(--ink-3); font-weight: 400; margin-right: 0.4rem; }
.q .options { display: grid; gap: 0.4rem; margin: 0; padding: 0; list-style: none; max-width: none; }
.q .options li { margin: 0; }
.q .options label { display: grid; grid-template-columns: auto 1fr; gap: 0.6rem; align-items: start; padding: 0.5rem 0.7rem; border: 1px solid var(--line); border-radius: var(--radius); cursor: pointer; font-family: var(--font-ui); font-size: 0.95rem; line-height: 1.4; }
.q .options label:hover { border-color: var(--accent); }
.q .options input { margin-top: 0.3rem; accent-color: var(--accent); }
.q .options label.right { border-color: var(--ok); background: var(--ok-soft); }
.q .options label.wrong { border-color: var(--alert); background: var(--alert-soft); }
.q .inline { display: flex; gap: 0.6rem; align-items: center; flex-wrap: wrap; font-family: var(--font-ui); }
.q input[type="text"], .q input[type="number"] { font: inherit; font-family: var(--font-mono); font-size: 0.95rem; padding: 0.4rem 0.6rem; border: 1px solid var(--line); border-radius: var(--radius); background: var(--ground); color: var(--ink); min-width: 9rem; }
.q .actions { display: flex; gap: 0.6rem; align-items: center; margin-top: 0.7rem; font-family: var(--font-ui); }
.q button { font: inherit; font-family: var(--font-ui); font-weight: 500; font-size: 0.9rem; padding: 0.4rem 0.9rem; border-radius: var(--radius); border: 1px solid var(--accent); background: var(--accent); color: var(--on-accent); cursor: pointer; }
.q button:hover { filter: brightness(1.08); }
.q button.secondary { background: none; color: var(--accent-ink); }
.q .verdict { font-family: var(--font-ui); font-weight: 600; font-size: 0.9rem; }
.q .verdict.right { color: var(--ok); }
.q .verdict.wrong { color: var(--alert); }
.q .explain { margin: 0.7rem 0 0; padding: 0.7rem 0.9rem; background: var(--ground); border-radius: var(--radius); font-size: 0.97rem; max-width: none; }
.q .explain[hidden] { display: none; }
.q.answered .options label { cursor: default; }

/* progress bar */
.progress { display: flex; align-items: center; gap: 0.7rem; font-family: var(--font-ui); font-size: 0.84rem; color: var(--ink-2); }
.progress .bar { flex: 0 0 9rem; height: 6px; border-radius: 3px; background: var(--surface-2); overflow: hidden; }
.progress .bar i { display: block; height: 100%; background: var(--accent); width: 0; transition: width 0.3s; }

/* prev / next */
.pager { display: flex; justify-content: space-between; gap: 1rem; margin-top: 3.5rem; padding-top: 1.2rem; border-top: 1px solid var(--line); font-family: var(--font-ui); }
.pager a { text-decoration: none; padding: 0.7rem 0.9rem; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); flex: 1; max-width: 48%; color: var(--ink); }
.pager a:hover { border-color: var(--accent); }
.pager a small { display: block; color: var(--ink-3); }
.pager a.next { text-align: right; margin-left: auto; }

/* course map on index */
.course { list-style: none; padding: 0; margin: 1.5rem 0; display: grid; gap: 0.6rem; max-width: none; }
.course li { margin: 0; }
.course a { display: grid; grid-template-columns: 2.4rem 1fr auto; gap: 0.8rem; align-items: center; padding: 0.8rem 1rem; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); text-decoration: none; color: var(--ink); font-family: var(--font-ui); }
.course a:hover { border-color: var(--accent); }
.course .num { font-size: 1.2rem; font-weight: 600; color: var(--accent-ink); font-variant-numeric: tabular-nums; }
.course .title { font-weight: 600; }
.course .blurb { display: block; font-weight: 400; color: var(--ink-2); font-size: 0.9rem; margin-top: 0.15rem; }
.course .state { font-size: 0.8rem; color: var(--ink-3); white-space: nowrap; }
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr)); gap: 0.8rem; margin: 1.2rem 0; }
.cards a.card { text-decoration: none; color: var(--ink); font-family: var(--font-ui); display: block; }
.cards a.card:hover { border-color: var(--accent); }
.cards a.card strong { display: block; margin-bottom: 0.25rem; }
.cards a.card span { color: var(--ink-2); font-size: 0.9rem; }

/* ---------- charts ---------- */
.chart { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 0.8rem 0.8rem 0.4rem; position: relative; }
.chart svg { width: 100%; height: auto; display: block; font-family: var(--font-ui); }
.chart .axis text { fill: var(--ink-2); font-size: 11px; }
.chart .axis line, .chart .axis path { stroke: var(--grid); }
.chart .gridline { stroke: var(--grid); stroke-width: 1; }
.chart .label { fill: var(--ink-2); font-size: 11px; }
.chart .title { fill: var(--ink); font-size: 12px; font-weight: 600; }
.chart .legend { display: flex; gap: 1rem; flex-wrap: wrap; font-family: var(--font-ui); font-size: 0.8rem; color: var(--ink-2); padding: 0.3rem 0.2rem 0.2rem; }
.chart .legend i { display: inline-block; width: 0.7rem; height: 0.7rem; border-radius: 2px; margin-right: 0.35rem; vertical-align: -1px; }
.chart .tip { position: absolute; pointer-events: none; background: var(--ink); color: var(--ground); font-family: var(--font-ui); font-size: 0.78rem; padding: 0.35rem 0.55rem; border-radius: 4px; white-space: nowrap; transform: translate(-50%, calc(-100% - 10px)); opacity: 0; transition: opacity 0.1s; z-index: 2; }
.chart .tip.on { opacity: 1; }

/* ---------- catalog ---------- */
.catalog { display: grid; grid-template-columns: 19rem minmax(0, 1fr); gap: 1.5rem; align-items: start; }
.catalog .list { position: sticky; top: 1rem; max-height: calc(100vh - 2rem); overflow-y: auto; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); font-family: var(--font-ui); }
.catalog .list .search { position: sticky; top: 0; padding: 0.7rem; background: var(--surface); border-bottom: 1px solid var(--line); }
.search input { width: 100%; font: inherit; font-family: var(--font-ui); font-size: 0.92rem; padding: 0.45rem 0.6rem; border: 1px solid var(--line); border-radius: var(--radius); background: var(--ground); color: var(--ink); }
.catalog .list details { border-bottom: 1px solid var(--line); }
.catalog .list summary { cursor: pointer; padding: 0.45rem 0.7rem; font-size: 0.82rem; font-weight: 600; letter-spacing: 0.03em; color: var(--ink-2); list-style: none; display: flex; justify-content: space-between; }
.catalog .list summary::-webkit-details-marker { display: none; }
.catalog .list summary .count { font-weight: 400; color: var(--ink-3); }
.catalog .list ul { list-style: none; margin: 0; padding: 0 0 0.3rem; max-width: none; }
.catalog .list li { margin: 0; }
.catalog .list li a { display: block; padding: 0.22rem 0.7rem 0.22rem 1.2rem; font-family: var(--font-mono); font-size: 0.78rem; text-decoration: none; color: var(--ink); }
.catalog .list li a:hover { background: var(--surface-2); }
.catalog .list li a.current { background: var(--accent-soft); color: var(--accent-ink); }
.catalog .list li a .pkg { display: block; font-family: var(--font-ui); font-size: 0.7rem; color: var(--ink-3); }
.catalog .detail { min-width: 0; }
.detail h1 { font-family: var(--font-mono); font-size: 1.5rem; font-weight: 500; letter-spacing: 0; }
.detail .meta { display: flex; flex-wrap: wrap; gap: 0.5rem; margin: 0.6rem 0 1rem; font-family: var(--font-ui); }
.detail .desc { max-width: var(--measure); }
.annot { border: 1px solid var(--accent); border-radius: var(--radius); padding: 0.8rem 1rem; margin: 1.2rem 0; background: var(--surface); max-width: calc(var(--measure) + 4rem); }
.annot .eyebrow { display: block; margin-bottom: 0.4rem; }
.annot dl.defs { margin: 0.4rem 0; }
.cols th.pk, .cols td.pk { width: 2rem; text-align: center; color: var(--accent-ink); }
.related { display: flex; flex-wrap: wrap; gap: 0.4rem; margin: 0.6rem 0; }
.related a { font-family: var(--font-mono); font-size: 0.8rem; text-decoration: none; padding: 0.15rem 0.5rem; border: 1px solid var(--line); border-radius: 999px; color: var(--ink); background: var(--surface); }
.related a:hover { border-color: var(--accent); }
.filters { display: flex; flex-wrap: wrap; gap: 0.6rem; align-items: center; margin: 1rem 0; font-family: var(--font-ui); font-size: 0.9rem; }
.filters select { font: inherit; font-family: var(--font-ui); padding: 0.35rem 0.5rem; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); color: var(--ink); }
.filters .search { flex: 1 1 14rem; }
.hits { font-family: var(--font-ui); font-size: 0.85rem; color: var(--ink-2); }
mark { background: var(--accent-soft); color: inherit; padding: 0 0.1em; border-radius: 2px; }
.gloss-list { list-style: none; padding: 0; margin: 1rem 0; max-width: none; display: grid; gap: 0.5rem; }
.gloss-list li { margin: 0; padding: 0.7rem 0.9rem; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); }
.gloss-list li strong { font-family: var(--font-ui); }
.gloss-list li .links { margin-top: 0.3rem; font-family: var(--font-ui); font-size: 0.82rem; }
.az { display: flex; flex-wrap: wrap; gap: 0.2rem; font-family: var(--font-ui); font-size: 0.85rem; }
.az a { padding: 0.15rem 0.45rem; text-decoration: none; border-radius: 4px; }
.az a:hover { background: var(--surface-2); }

/* site search */
.sitesearch { position: relative; margin-top: 1rem; }
.sitesearch .results { position: absolute; left: 0; right: 0; top: 100%; z-index: 5; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: 0 8px 24px var(--shadow); max-height: 22rem; overflow-y: auto; font-family: var(--font-ui); font-size: 0.86rem; }
.sitesearch .results a { display: grid; grid-template-columns: 4.5rem 1fr; gap: 0.6rem; padding: 0.4rem 0.7rem; text-decoration: none; color: var(--ink); border-bottom: 1px solid var(--line); }
.sitesearch .results a:hover { background: var(--surface-2); }
.sitesearch .results .kind { font-size: 0.7rem; letter-spacing: 0.05em; text-transform: uppercase; color: var(--ink-3); align-self: center; }

/* ---------- responsive ---------- */
@media (max-width: 900px) {
  .frame { display: block; }
  .rail { position: fixed; inset: 0 auto 0 0; width: min(20rem, 85vw); transform: translateX(-100%); transition: transform 0.2s; z-index: 20; box-shadow: none; }
  .rail.open { transform: none; box-shadow: 0 0 40px rgba(0, 0, 0, 0.35); }
  .topbar { display: flex; align-items: center; justify-content: space-between; gap: 0.8rem; position: sticky; top: 0; z-index: 10; background: var(--surface); border-bottom: 1px solid var(--line); padding: 0.6rem 1rem; font-family: var(--font-ui); }
  .topbar button { font: inherit; background: none; border: 1px solid var(--line); border-radius: var(--radius); padding: 0.3rem 0.6rem; color: var(--ink); cursor: pointer; }
  .topbar .brand { font-weight: 600; text-decoration: none; color: var(--ink); font-size: 0.95rem; }
  main.page { padding: 1.4rem 1rem 4rem; }
  .catalog { grid-template-columns: 1fr; }
  .catalog .list { position: static; max-height: 40vh; }
  dl.defs { grid-template-columns: 1fr; gap: 0.1rem 0; }
  dl.defs dd { margin-bottom: 0.5rem; }
  .pager { flex-direction: column; }
  .pager a { max-width: none; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }
@media print { .rail, .topbar, .pager { display: none; } main.page { max-width: none; } }

/* site search input (index and catalog headers) */
.sitesearch > input { width: 100%; max-width: 40rem; font: inherit; font-family: var(--font-ui); font-size: 0.95rem; padding: 0.55rem 0.8rem; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); color: var(--ink); }
.sitesearch > input:focus { border-color: var(--accent); }

/* native app shell: keep content clear of the status bar and gesture areas */
html[data-native] .topbar { padding-top: calc(0.6rem + env(safe-area-inset-top)); }
html[data-native] .rail { padding-top: calc(1.2rem + env(safe-area-inset-top)); }
html[data-native] main.page { padding-bottom: calc(5rem + env(safe-area-inset-bottom)); }
@media (min-width: 901px) { html[data-native] main.page { padding-top: calc(2.2rem + env(safe-area-inset-top)); } }

/* filter rows on narrow screens: never wider than the viewport */
.filters label { display: inline-flex; align-items: center; gap: 0.4rem; max-width: 100%; min-width: 0; }
.filters select { max-width: 100%; min-width: 0; }
@media (max-width: 900px) { .filters label { width: 100%; } .filters select { flex: 1 1 auto; width: auto; } }