:root {
  --bg: #fbfbfa;
  --surface: #ffffff;
  --sunken: #f3f4f2;
  --text: #1d2422;
  --muted: #5c6764;
  --faint: #8a9491;
  --line: #e3e6e3;
  --accent: #006f75;
  --accent-strong: #00525a;
  --accent-soft: #e3f2f1;
  --link: #00636b;
  --code-bg: #f5f7f6;
  --code-line: #e2e7e5;
  --mark: #fff1b8;
  --shadow: 0 1px 2px rgb(16 24 22 / 0.05), 0 8px 24px rgb(16 24 22 / 0.06);
  /* code token colours, keyed by the colours used in the PDF */
  --k-kw: #1640b8;      /* HDFql keywords (blue)        */
  --k-type: #7b2fbf;    /* language types (purple)      */
  --k-op: #22336e;      /* operators (navy)             */
  --k-num: #b45309;     /* numbers / constants (orange) */
  --k-str: #6b7280;     /* strings (grey)               */
  --k-com: #2f7d32;     /* comments (green)             */
  --k-pre: #8a4b0f;     /* preprocessor (brown)         */
  --k-alt: #b4424d;     /* misc (rose)                  */
  --k-err: #c62828;
  --side-w: 400px;
  --top-h: 56px;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  --sans: Inter, ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #111615;
    --surface: #161c1b;
    --sunken: #1b2221;
    --text: #e4e9e7;
    --muted: #a3aeab;
    --faint: #75817e;
    --line: #29312f;
    --accent: #4fc3bf;
    --accent-strong: #7ad6d2;
    --accent-soft: #173130;
    --link: #6fd0cb;
    --code-bg: #0d1211;
    --code-line: #232b29;
    --mark: #5a4a12;
    --shadow: 0 1px 2px rgb(0 0 0 / 0.3), 0 8px 24px rgb(0 0 0 / 0.35);
    --k-kw: #82a8ff;
    --k-type: #c79bff;
    --k-op: #a9b8f0;
    --k-num: #f0a35e;
    --k-str: #a8b0b8;
    --k-com: #7fc786;
    --k-pre: #d9a66a;
    --k-alt: #f08f98;
    --k-err: #ff7b7b;
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --bg: #111615;
  --surface: #161c1b;
  --sunken: #1b2221;
  --text: #e4e9e7;
  --muted: #a3aeab;
  --faint: #75817e;
  --line: #29312f;
  --accent: #4fc3bf;
  --accent-strong: #7ad6d2;
  --accent-soft: #173130;
  --link: #6fd0cb;
  --code-bg: #0d1211;
  --code-line: #232b29;
  --mark: #5a4a12;
  --shadow: 0 1px 2px rgb(0 0 0 / 0.3), 0 8px 24px rgb(0 0 0 / 0.35);
  --k-kw: #82a8ff;
  --k-type: #c79bff;
  --k-op: #a9b8f0;
  --k-num: #f0a35e;
  --k-str: #a8b0b8;
  --k-com: #7fc786;
  --k-pre: #d9a66a;
  --k-alt: #f08f98;
  --k-err: #ff7b7b;
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-padding-top: calc(var(--top-h) + 16px); -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.65 var(--sans);
  overflow-x: hidden;
}
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 2px; }
code, kbd, pre { font-family: var(--mono); }
img { max-width: 100%; height: auto; }
[hidden] { display: none !important; }

.skip { position: absolute; left: -999px; top: 8px; background: var(--accent); color: #fff; padding: 8px 12px; border-radius: 6px; z-index: 100; }
.skip:focus { left: 8px; }

/* ---------- scrollbars ---------- */
:root { --sb-w: 10px; }
/* Code blocks, tables, search results (Chromium / Safari; Firefox keeps its native bar) */
::-webkit-scrollbar { width: var(--sb-w); height: var(--sb-w); }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
  background: color-mix(in srgb, var(--faint) 55%, transparent);
  border: 1px solid transparent; background-clip: padding-box; border-radius: 999px;
}
::-webkit-scrollbar-thumb:hover { background-color: var(--muted); }
::-webkit-scrollbar-corner { background: transparent; }
@supports not selector(::-webkit-scrollbar) {
  * { scrollbar-width: auto; scrollbar-color: color-mix(in srgb, var(--faint) 70%, transparent) transparent; }
}
/* Page and sidebar: custom-drawn bars (app.js) so the width works in every browser.
   html.fsb is set in <head> only for wide screens with a mouse or trackpad. */
html.fsb, html.fsb .sidebar { scrollbar-width: none; }
html.fsb::-webkit-scrollbar, html.fsb .sidebar::-webkit-scrollbar { display: none; }
html.fsb body { padding-right: var(--sb-w); }
html.fsb .sidebar { padding-right: calc(8px + var(--sb-w)); }
.fsb-track {
  position: fixed; width: var(--sb-w); z-index: 46;
  background: color-mix(in srgb, var(--sunken) 80%, transparent); border-left: 1px solid var(--line);
}
.fsb-track.page { top: 0; bottom: 0; right: 0; }
.fsb-track.side { top: var(--top-h); bottom: 0; left: calc(var(--side-w) - var(--sb-w) - 1px); }
.fsb-thumb {
  position: absolute; left: 1px; right: 1px; min-height: 40px; border-radius: 999px;
  background: color-mix(in srgb, var(--faint) 60%, transparent); cursor: grab;
}
.fsb-thumb:hover, .fsb-track.dragging .fsb-thumb { background: var(--muted); }
.fsb-track.dragging .fsb-thumb { cursor: grabbing; }
body.fsb-dragging { user-select: none; }

/* ---------- top bar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 50;
  height: var(--top-h);
  display: flex; align-items: center; gap: 12px;
  padding: 0 16px;
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--line);
}
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); font-weight: 700; letter-spacing: -0.01em; white-space: nowrap; }
.brand:hover { text-decoration: none; }
.brand em { font-style: normal; font-weight: 500; color: var(--muted); }
.ver { font: 500 12px/1 var(--mono); color: var(--accent); background: var(--accent-soft); padding: 4px 7px; border-radius: 999px; }
.search { position: relative; margin-left: auto; width: min(380px, 40vw); }
.search input {
  width: 100%; height: 36px; padding: 0 36px 0 12px;
  border: 1px solid var(--line); border-radius: 8px;
  background: var(--sunken); color: var(--text); font: inherit; font-size: 14px;
}
.search input:focus { outline: 2px solid var(--accent); outline-offset: -1px; background: var(--surface); }
.search kbd { position: absolute; right: 8px; top: 8px; font-size: 11px; color: var(--faint); border: 1px solid var(--line); border-radius: 4px; padding: 1px 6px; }
.results {
  position: absolute; right: 0; top: 42px; width: min(560px, calc(100vw - 32px));
  max-height: min(70vh, 560px); overflow: auto;
  background: var(--surface); border: 1px solid var(--line); border-radius: 10px; box-shadow: var(--shadow);
  padding: 6px;
}
.results a { display: block; padding: 8px 10px; border-radius: 7px; color: var(--text); }
.results a:hover, .results a.sel { background: var(--accent-soft); text-decoration: none; }
.results .r-t { font-weight: 600; font-size: 14px; }
.results .r-t .num { color: var(--accent); font: 500 12px var(--mono); margin-right: 8px; }
.results .r-x { display: block; font-size: 13px; color: var(--muted); margin-top: 2px; line-height: 1.45; }
.results mark { background: var(--mark); color: inherit; border-radius: 2px; }
.results .empty { padding: 12px; color: var(--muted); font-size: 14px; }

.theme, .menu {
  width: 36px; height: 36px; border-radius: 8px; border: 1px solid var(--line);
  background: var(--surface); color: var(--text); cursor: pointer; flex: none;
  display: grid; place-items: center;
}
.theme::before { content: ""; width: 16px; height: 16px; border-radius: 50%; box-shadow: inset -5px -3px 0 0 currentColor; }
:root[data-theme="dark"] .theme::before { box-shadow: none; background: currentColor; }
.menu { display: none; }
.menu span, .menu span::before, .menu span::after { display: block; width: 16px; height: 2px; background: currentColor; border-radius: 2px; position: relative; }
.menu span::before, .menu span::after { content: ""; position: absolute; left: 0; }
.menu span::before { top: -5px; }
.menu span::after { top: 5px; }

/* ---------- layout ---------- */
.layout { display: grid; grid-template-columns: var(--side-w) minmax(0, 1fr); min-height: calc(100vh - var(--top-h)); }
.resizer {
  position: fixed; top: var(--top-h); bottom: 0; left: calc(var(--side-w) - 1px); width: 8px; z-index: 47;
  cursor: col-resize; touch-action: none;
}
.resizer::after {
  content: ""; position: absolute; top: 0; bottom: 0; left: 0; width: 1px; background: transparent; transition: background .15s, width .15s, left .15s;
}
.resizer:hover::after, .resizer:focus-visible::after, body.resizing .resizer::after { background: var(--accent); width: 3px; left: 0; }
.resizer:focus-visible { outline: none; }
body.resizing { cursor: col-resize; user-select: none; }
body.resizing .sidebar, body.resizing main { pointer-events: none; }
.sidebar {
  position: sticky; top: var(--top-h); height: calc(100vh - var(--top-h)); overflow-y: auto;
  border-right: 1px solid var(--line); background: var(--surface);
  padding: 16px 8px 40px; font-size: 14px; overscroll-behavior: contain;
}
.toc ul { list-style: none; margin: 0; padding: 0; }
.toc ul ul { padding-left: 14px; }
.toc li { position: relative; }
.toc a {
  display: flex; gap: 8px; padding: 4px 8px 4px 2px; border-radius: 6px; color: var(--muted); line-height: 1.35;
}
.toc a:hover { color: var(--text); background: var(--sunken); text-decoration: none; }
.toc .lvl1 > li > a { color: var(--text); font-weight: 600; }
.toc li.current > a { color: var(--accent-strong); background: var(--accent-soft); font-weight: 600; }
.toc .num { color: var(--faint); font: 500 12px/1.6 var(--mono); flex: none; }
.toc .lb { min-width: 0; overflow-wrap: anywhere; }
.toc li.current > a .num { color: var(--accent); }
.toc li { display: grid; grid-template-columns: 20px minmax(0, 1fr); }
.toc li > ul { grid-column: 1 / -1; }
.tw, .tw-sp { width: 20px; height: 26px; }
.tw { border: 0; background: none; color: var(--faint); cursor: pointer; padding: 0; display: grid; place-items: center; }
.tw::before { content: ""; width: 6px; height: 6px; border-right: 1.5px solid currentColor; border-bottom: 1.5px solid currentColor; transform: rotate(-45deg); transition: transform .15s; }
.tw[aria-expanded="true"]::before { transform: rotate(45deg); }
.tw:hover { color: var(--text); }

main { min-width: 0; }
.content { max-width: 1110px; margin: 0 auto; padding: 28px 40px 64px; }
.crumbs { font-size: 13px; color: var(--faint); display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 10px; }
.crumbs a { color: var(--muted); }
.content h1 { font-size: clamp(28px, 4vw, 38px); line-height: 1.15; letter-spacing: -0.02em; margin: 0 0 28px; overflow-wrap: anywhere; }
.content h1 .num { display: block; font: 600 14px/1.4 var(--mono); color: var(--accent); letter-spacing: 0; margin-bottom: 6px; }
.content h2 { font-size: 21px; letter-spacing: -0.01em; margin: 36px 0 10px; line-height: 1.3; position: relative; }
.content h3 { font-size: 13px; text-transform: uppercase; letter-spacing: 0.08em; color: var(--accent-strong); margin: 32px 0 8px; padding-top: 14px; border-top: 1px solid var(--line); position: relative; }
.content h2.term { font-size: 19px; }
.anchor { position: absolute; left: -22px; color: var(--faint); opacity: 0; padding-right: 6px; font-weight: 400; }
h2:hover .anchor, h3:hover .anchor { opacity: 1; text-decoration: none; }
.content p { margin: 0 0 14px; overflow-wrap: break-word; }
.content p.indent-1 { margin-left: 24px; }
.content p.indent-2 { margin-left: 48px; }
.content p.indent-3 { margin-left: 72px; }
.syntax-block { font-family: var(--mono); font-size: 14px; line-height: 1.75; background: var(--sunken); border-left: 3px solid var(--accent); padding: 12px 16px; border-radius: 0 8px 8px 0; margin: 0 0 18px; overflow-wrap: anywhere; }
.syntax-block p { margin: 0 0 8px !important; }
.syntax-block p:last-of-type { margin-bottom: 0 !important; }
.syntax-block p[class*="indent-"] { margin-left: 20px !important; }
.syntax-block p.indent-2.syntax, .syntax-block p.indent-3.syntax { margin-left: 40px !important; }
.syntax-block strong { color: var(--k-kw); }
.syntax-block em { color: var(--k-type); }
.content em { font-style: italic; }
.content ul { padding-left: 22px; margin: 0 0 14px; }
.content li { margin: 4px 0; }
.content li::marker { color: var(--accent); }
.content li > .code { margin-top: 8px; }
.content a.ext::after, .site-foot a.ext::after { content: "↗"; font-size: 0.75em; margin-left: 2px; color: var(--faint); }
.pdf-page { display: block; height: 0; }

/* ---------- code ---------- */
.code { position: relative; margin: 12px 0 20px; border: 1px solid var(--code-line); border-radius: 10px; background: var(--code-bg); }
.code::before {
  content: attr(data-lang); position: absolute; left: 14px; top: 8px;
  font: 600 10.5px/1 var(--sans); letter-spacing: .08em; text-transform: uppercase; color: var(--faint);
}
.code[data-lang=""]::before { content: none; }
.code pre { margin: 0; padding: 30px 16px 14px; overflow-x: auto; font-size: 13.5px; line-height: 1.6; tab-size: 4;
  /* lines the PDF wrapped are re-joined; a line that is wider than the box wraps at the box edge instead of scrolling */
  white-space: pre-wrap; overflow-wrap: anywhere; }
.code .nw { white-space: nowrap; }
.code[data-lang=""] pre { padding-top: 14px; }
.copy {
  position: absolute; top: 6px; right: 6px; font: 500 12px/1 var(--sans); padding: 6px 9px; border-radius: 6px;
  border: 1px solid var(--code-line); background: var(--surface); color: var(--muted); cursor: pointer; opacity: 0; transition: opacity .15s;
}
.code:hover .copy, .copy:focus-visible { opacity: 1; }
.copy.done { color: var(--accent); }
@media (hover: none) { .copy { opacity: 1; } }
.c0000ff { color: var(--k-kw); }
.c8000ff { color: var(--k-type); }
.c000080 { color: var(--k-op); }
.cff8000 { color: var(--k-num); }
.c808080 { color: var(--k-str); }
.c008000, .c008040 { color: var(--k-com); font-style: italic; }
.c804000 { color: var(--k-pre); }
.cd26d6d { color: var(--k-alt); }
.cff0000 { color: var(--k-err); }
.cb { font-weight: 600; }

/* ---------- tables & figures ---------- */
.table-wrap { overflow-x: auto; margin: 14px 0 6px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); }
table { border-collapse: collapse; width: 100%; font-size: 14px; line-height: 1.45; }
th, td { padding: 8px 12px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
thead th { background: var(--sunken); font-weight: 600; font-size: 13px; color: var(--muted); position: sticky; top: 0; }
tbody th { background: var(--sunken); }
tbody tr:last-child td { border-bottom: 0; }
tbody tr:hover td { background: color-mix(in srgb, var(--accent-soft) 45%, transparent); }
td:first-child { font-weight: 500; }
.caption, figcaption { font-size: 13px; color: var(--muted); text-align: center; margin: 6px 0 22px !important; }
figure { margin: 18px 0; text-align: center; }
figure img { border-radius: 8px; background: #fff; padding: 8px; border: 1px solid var(--line); }

.footnotes { margin-top: 48px; padding-top: 8px; border-top: 1px solid var(--line); font-size: 14px; color: var(--muted); }
.footnotes h2 { font-size: 14px !important; text-transform: uppercase; letter-spacing: .08em; }
.footnotes li { margin: 6px 0; overflow-wrap: anywhere; }
.fnref a { font-size: 11px; padding: 0 2px; }
.back { margin-left: 4px; }

.subsections { margin-top: 36px; border: 1px solid var(--line); border-radius: 12px; padding: 6px 18px 12px; background: var(--surface); }
.subsections h2 { font-size: 13px !important; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); margin: 12px 0 6px !important; }
.subsections ul { list-style: none; padding: 0; margin: 0; columns: 2 260px; column-gap: 24px; }
.subsections li { break-inside: avoid; margin: 0; }
.subsections a { display: flex; gap: 10px; padding: 4px 0; }
.subsections .num { font: 500 12px/1.9 var(--mono); color: var(--faint); min-width: 44px; }

.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 48px; }
.pager a { border: 1px solid var(--line); border-radius: 10px; padding: 12px 16px; color: var(--text); font-weight: 600; font-size: 15px; background: var(--surface); }
.pager a:hover { border-color: var(--accent); text-decoration: none; }
.pager small { display: block; font-weight: 500; color: var(--faint); font-size: 12px; margin-bottom: 2px; }
.pager .next { text-align: right; grid-column: 2; }

.site-foot { border-top: 1px solid var(--line); padding: 20px 16px; font-size: 13px; color: var(--faint); text-align: center; background: var(--surface); }
.site-foot p { margin: 0 auto; max-width: 860px; }

/* ---------- home ---------- */
.home-main { max-width: 1270px; margin: 0 auto; padding: 48px 24px 72px; }
.hero { display: flex; gap: 28px; align-items: flex-start; }
.hero img { flex: none; margin-top: 8px; }
.eyebrow { font: 600 12px/1 var(--mono); color: var(--accent); text-transform: uppercase; letter-spacing: .08em; margin: 0 0 12px; }
.hero > div { min-width: 0; flex: 1; }
.hero h1 { font-size: clamp(28px, 3.7vw, 44px); line-height: 1.08; letter-spacing: -0.03em; margin: 0 0 14px; }
@media (min-width: 900px) {
  /* title sized to span the text column on one line (column = page width − padding − logo − gap − scrollbar) */
  .hero h1 { white-space: nowrap; font-size: clamp(28px, calc((min(100vw, 1282px) - 190px) * 0.0505), 55px); }
  .hero .lede { max-width: none; }
}
.lede { font-size: 18px; color: var(--muted); max-width: 62ch; margin: 0 0 22px; }
.cta { display: flex; gap: 10px; flex-wrap: wrap; }
.btn { display: inline-block; background: var(--accent); color: #fff; padding: 10px 18px; border-radius: 8px; font-weight: 600; }
:root[data-theme="dark"] .btn { color: #062221; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .btn { color: #062221; } }
.btn:hover { background: var(--accent-strong); text-decoration: none; }
.btn.ghost { background: transparent; color: var(--accent-strong); border: 1px solid var(--line); }
.btn.ghost:hover { border-color: var(--accent); background: var(--accent-soft); }
.quick { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin: 60px 0 32px; font-size: 14px; }
.quick span { color: var(--faint); margin-right: 4px; }
.quick a { border: 1px solid var(--line); background: var(--surface); padding: 5px 11px; border-radius: 999px; color: var(--text); font-family: var(--mono); font-size: 13px; }
.quick a:hover { border-color: var(--accent); text-decoration: none; }
.cards { display: grid; grid-template-columns: minmax(0, 1fr); gap: 16px; }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 18px 20px; }
.card-h { display: flex; gap: 12px; align-items: baseline; font-size: 18px; font-weight: 700; color: var(--text); letter-spacing: -0.01em; }
.card-h:hover { color: var(--accent-strong); text-decoration: none; }
.card-h .num { font: 600 13px var(--mono); color: var(--accent); }
.card p { color: var(--muted); font-size: 14px; margin: 6px 0 10px; }
.card ul { list-style: none; padding: 0; margin: 0; font-size: 14px; border-top: 1px solid var(--line); padding-top: 8px; columns: 3 220px; column-gap: 24px; }
.card li { padding: 2px 0; break-inside: avoid; }
.card .more { color: var(--faint); font-size: 13px; }

/* ---------- responsive ---------- */
@media (max-width: 960px) {
  .resizer { display: none; }
  .menu { display: grid; }
  .layout { grid-template-columns: minmax(0, 1fr); }
  .sidebar {
    position: fixed; left: 0; top: var(--top-h); width: min(86vw, 340px); z-index: 40;
    transform: translateX(-100%); transition: transform .2s ease; box-shadow: var(--shadow);
  }
  body.nav-open .sidebar { transform: none; }
  body.nav-open::after { content: ""; position: fixed; inset: var(--top-h) 0 0 0; background: rgb(0 0 0 / .35); z-index: 30; }
  .content { padding: 22px 16px 48px; }
  .anchor { display: none; }
}
@media (max-width: 640px) {
  .brand em, .ver, .search kbd { display: none; }
  .search { width: auto; flex: 1; }
  .topbar { gap: 8px; padding: 0 12px; }
  .hero { flex-direction: column; gap: 12px; }
  .hero img { width: 64px; height: auto; }
  .home-main { padding: 28px 16px 56px; }
  .pager { grid-template-columns: minmax(0, 1fr); }
  .pager .next { grid-column: 1; }
  .content p.indent-2, .content p.indent-3 { margin-left: 24px; }
}
@media print {
  .topbar, .sidebar, .pager, .copy, .site-foot { display: none !important; }
  .layout { display: block; }
}