/* QUASAR project page — design system
   Rose is reserved for QUASAR. Graphite = Standard QAT. Steel blue = gradients / saliency. Gold = optimum / full precision.
   Type scale: five sizes only (--fs-xs … --fs-xl). Components use the same values. */

:root {
  --paper: #f7f5f0;
  --paper-2: #efebe3;
  --card: #fdfdfd;
  --ink: #1d1f22;
  --ink-2: #44484f;
  --muted: #6b6f75;
  --faint: #9a9da3;
  --rule: #e2ddd3;
  --rule-2: #d3ccbf;
  --surface: #faf8f4;

  --rose: #d1495b;
  --rose-dark: #a13040;
  --graphite: #3d434c;
  --steel: #2e6f95;
  --gold: #c9a227;

  --serif: "Newsreader", "Iowan Old Style", "Palatino Linotype", Georgia, serif;
  --sans: "Inter", ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;

  /* type scale */
  --fs-xs: 12px;   /* labels: kickers, tags, axis titles, buttons */
  --fs-s: 13px;    /* captions, UI, tooltips */
  --fs-m: 17px;    /* body */
  --fs-l: 21px;    /* lead sentences, subtitle, h3 */
  --fs-xl: 34px;   /* section titles, big numbers */

  --col: 680px;
  --fig: 960px;
  --wide: 1200px;
  --gutter: 20px;
  --radius: 12px;

  --shadow: 0 1px 2px rgba(29, 31, 34, 0.04), 0 4px 18px rgba(29, 31, 34, 0.05);
  color-scheme: light;
}

@media (max-width: 600px) {
  :root { --gutter: 16px; --fs-l: 19px; --fs-xl: 28px; }
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #131416; --paper-2: #1b1d20; --ink: #ecebe7; --ink-2: #c5c4bf; --muted: #9b9a95; --faint: #6f6f6b;
    --rule: #2b2d31; --rule-2: #3a3d42; --surface: #1a1c1f;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 4px 18px rgba(0, 0, 0, 0.25);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --paper: #131416; --paper-2: #1b1d20; --ink: #ecebe7; --ink-2: #c5c4bf; --muted: #9b9a95; --faint: #6f6f6b;
  --rule: #2b2d31; --rule-2: #3a3d42; --surface: #1a1c1f;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 4px 18px rgba(0, 0, 0, 0.25);
  color-scheme: dark;
}

/* ---------- base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 72px; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: var(--fs-m);
  line-height: 1.6;
  font-optical-sizing: auto;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img, video, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration-color: color-mix(in srgb, var(--steel) 55%, transparent); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { text-decoration-color: var(--steel); }
::selection { background: color-mix(in srgb, var(--rose) 22%, transparent); }
:focus-visible { outline: 2px solid var(--steel); outline-offset: 2px; border-radius: 4px; }
.sr-only { position: absolute !important; width: 1px; height: 1px; margin: -1px; padding: 0; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0; }
.skip { position: absolute; left: 12px; top: -48px; z-index: 100; background: var(--ink); color: var(--paper); padding: 8px 12px; border-radius: 8px; font: 500 var(--fs-s) var(--sans); text-decoration: none; }
.skip:focus { top: 12px; }

.num { font-variant-numeric: tabular-nums lining-nums; }
sub, sup { font-size: var(--fs-xs); line-height: 0; }
.eq sup { font-size: var(--fs-s); }
.math { font-family: var(--serif); font-style: italic; text-transform: none; letter-spacing: 0; white-space: nowrap; }
.nw { white-space: nowrap; }

/* ---------- layout ---------- */
.col, .fig, .wide { width: min(100% - 2 * var(--gutter), var(--col)); margin-inline: auto; }
.fig { width: min(100% - 2 * var(--gutter), var(--fig)); }
.wide { width: min(100% - 2 * var(--gutter), var(--wide)); }
section.block { padding-block: clamp(56px, 9vw, 112px) 0; }
section.block:last-of-type { padding-bottom: clamp(56px, 9vw, 112px); }
.wide + .wide, .col + .col, .prose + .fig, .prose + .wide, .fig + .col, .wide + .col, .fig + .fig, .wide + .fig, .fig + .wide, .col + .fig, .col + .wide { margin-top: 32px; }

/* ---------- top bar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--paper) 86%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  -webkit-backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid transparent;
  transition: border-color .25s ease;
}
.topbar.scrolled { border-bottom-color: var(--rule); }
.topbar .inner { width: min(100% - 2 * var(--gutter), var(--wide)); margin-inline: auto; height: 56px; display: flex; align-items: center; justify-content: center; }
/* one link per section; when the bar is too narrow the links scroll sideways (no scrollbar, faded edges) */
.topnav { display: flex; gap: clamp(2px, 1.2vw, 18px); min-width: 0; max-width: 100%; overflow-x: auto; overscroll-behavior-x: contain; scrollbar-width: none; font: 500 var(--fs-s)/1 var(--sans); }
.topnav::-webkit-scrollbar { display: none; }
.topnav a { flex: none; white-space: nowrap; text-decoration: none; color: var(--ink-2); padding: 12px 6px; }
.topnav a:hover { color: var(--ink); }
.topnav.fade-r { -webkit-mask-image: linear-gradient(to right, #000 calc(100% - 28px), transparent); mask-image: linear-gradient(to right, #000 calc(100% - 28px), transparent); }
.topnav.fade-l { -webkit-mask-image: linear-gradient(to right, transparent, #000 28px); mask-image: linear-gradient(to right, transparent, #000 28px); }
.topnav.fade-l.fade-r { -webkit-mask-image: linear-gradient(to right, transparent, #000 28px, #000 calc(100% - 28px), transparent); mask-image: linear-gradient(to right, transparent, #000 28px, #000 calc(100% - 28px), transparent); }

/* ---------- hero ---------- */
.hero { padding-top: clamp(16px, 3vw, 40px); text-align: center; }
.hero h1 { margin: 0; font-family: var(--serif); font-weight: 500; line-height: 1.04; }
.hero h1 .name { display: block; font-size: var(--fs-xl); color: var(--rose); letter-spacing: 0.02em; }
.hero h1 .sub { display: block; margin: 10px auto 0; max-width: 820px; font-size: var(--fs-l); font-weight: 400; color: var(--ink); line-height: 1.25; text-wrap: balance; }
.authors { margin: 20px auto 0; font: 400 var(--fs-m)/1.6 var(--sans); color: var(--ink); max-width: 820px; }
.authors .a { white-space: nowrap; margin-inline: .5em; }
.authors a { color: inherit; text-decoration: underline; text-decoration-color: var(--rule-2); text-decoration-thickness: 1px; text-underline-offset: 4px; transition: text-decoration-color .15s ease; }
.authors a:hover { text-decoration-color: currentColor; }
.authors sup { font-size: var(--fs-xs); color: var(--muted); margin-left: 1px; }
.affils { margin-top: 2px; font: 400 var(--fs-s)/1.5 var(--sans); color: var(--muted); }
.affils span { margin-inline: .6em; white-space: nowrap; }
.links { margin: 24px auto 0; display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; }
.btn {
  max-width: 100%; overflow-wrap: anywhere; line-height: 1.25;
  display: inline-flex; align-items: center; gap: 8px; min-height: 40px; padding: 9px 15px;
  border: 1px solid var(--ink); border-radius: 999px; background: transparent; color: var(--ink);
  font: 500 var(--fs-xs)/1 var(--mono); letter-spacing: .08em; text-transform: uppercase; text-decoration: none;
  transition: background .18s ease, color .18s ease;
}
.btn:hover { background: var(--ink); color: var(--paper); }
.btn svg { width: 15px; height: 15px; flex: none; }
.hero-media { margin-top: clamp(40px, 5vw, 64px); }
.lede { margin: 40px auto 0; max-width: 720px; font-size: var(--fs-l); line-height: 1.4; color: var(--ink); text-wrap: balance; }

/* ---------- cards / figures ---------- */
.viz {
  position: relative; margin: 0;
  background: var(--card); border: 1px solid var(--rule); border-radius: var(--radius); box-shadow: var(--shadow);
  overflow: hidden;
  color: #1d1f22;               /* figure content is always light */
  color-scheme: light;
}
.viz-head { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; padding: 16px 20px 0; flex-wrap: wrap; }
.viz-kicker { font: 500 var(--fs-xs)/1.3 var(--mono); letter-spacing: .1em; text-transform: uppercase; color: #6b6f75; }
.viz-kicker b { color: #1d1f22; font-weight: 600; }
.viz-body { padding: 10px 20px 18px; }
.viz video { width: 100%; height: auto; background: #fdfdfd; aspect-ratio: var(--ar, 16 / 9); object-fit: cover; }
figure.plate { margin: 0; }
figcaption {
  margin-top: 14px; padding-inline: 2px;
  font: 400 var(--fs-s)/1.55 var(--sans); color: var(--muted); text-wrap: pretty;
}
figcaption b { color: var(--ink); font-weight: 600; }
.hero figcaption { text-align: left; }
.tag { display: inline-block; font: 500 var(--fs-xs)/1 var(--mono); letter-spacing: .08em; text-transform: uppercase; padding: 4px 8px; border-radius: 999px; vertical-align: 1px; margin-right: 6px; background: rgba(29, 31, 34, .06); color: #4a4e55; }

.grid-2 { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; align-items: start; }
@media (max-width: 860px) { .grid-2 { grid-template-columns: minmax(0, 1fr); } }
/* Paired figures: cards share one height and captions start on one line. */
@media (min-width: 861px) {
  .grid-2:has(> figure.plate) { grid-template-rows: auto auto; row-gap: 0; }
  .grid-2 > figure.plate { display: grid; grid-row: span 2; grid-template-rows: subgrid; align-self: stretch; }
}

/* video play/pause chip */
.vplay {
  position: absolute; top: 12px; left: 12px; z-index: 2;
  width: 40px; height: 40px; border-radius: 999px; border: 1px solid rgba(29,31,34,.18);
  background: rgba(253,253,253,.92); color: #1d1f22; display: grid; place-items: center; cursor: pointer;
  opacity: 0; transition: opacity .2s ease;
}
.viz:hover .vplay, .vplay:focus-visible, .viz.paused .vplay { opacity: 1; }
.vplay svg { width: 16px; height: 16px; }
@media (hover: none) { .vplay { opacity: .85; } }
@media (max-width: 600px) { #hero-video { --ar: 4 / 5; } }

/* ---------- headings + prose ---------- */
.sec-head { margin-bottom: 24px; }
h2 { margin: 0; font: 500 var(--fs-xl)/1.1 var(--serif); letter-spacing: -0.015em; text-wrap: balance; }
h2 .n { margin-right: .3em; }
h3 { margin: 0 0 8px; font: 500 var(--fs-l)/1.25 var(--serif); }
.prose p { margin: 0 0 1em; text-wrap: pretty; }
.prose p:last-child { margin-bottom: 0; }
.prose .big { font-size: var(--fs-l); line-height: 1.42; }
.small { font: 400 var(--fs-s)/1.55 var(--sans); color: var(--muted); }

/* equation band */
.eq { padding: 22px 0; border-block: 1px solid var(--rule); text-align: center; }
.eq p { margin: 0 auto; max-width: 640px; font: 400 var(--fs-s)/1.55 var(--sans); color: var(--muted); text-wrap: balance; }
.eq p b { color: var(--ink); font-weight: 600; }
.eq .formulas { margin: 14px 0; display: flex; flex-wrap: wrap; justify-content: center; gap: 8px 44px; font: italic 400 var(--fs-l)/1.3 var(--serif); color: var(--ink); }
.eq .formulas .up { font-style: normal; }
.eq .frac { display: inline-flex; flex-direction: column; vertical-align: middle; font-style: normal; font-size: var(--fs-s); line-height: 1.05; text-align: center; margin: 0 2px; }
.eq .frac span + span { border-top: 1px solid currentColor; }
.eq .H { color: var(--steel); }

/* ---------- stat strip ---------- */
.stats { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); border-block: 1px solid var(--rule); }
.stat { padding: 26px 22px 24px; border-left: 1px solid var(--rule); display: flex; flex-direction: column; min-width: 0; }
.stat:first-child { border-left: 0; }
.stat .v { font: 500 var(--fs-xl)/1 var(--serif); color: var(--rose); font-variant-numeric: tabular-nums lining-nums; white-space: nowrap; }
.stat .v small { font-size: var(--fs-m); margin-left: 3px; }
.stat .l { margin: 12px 0 0; font: 400 var(--fs-s)/1.45 var(--sans); color: var(--ink-2); text-wrap: pretty; }
.stat .ctx { margin-top: auto; padding-top: 10px; display: flex; flex-wrap: wrap; row-gap: 2px; font: 500 var(--fs-xs)/1.35 var(--mono); letter-spacing: .08em; text-transform: uppercase; color: var(--muted); }
.stat .ctx span { white-space: nowrap; }
.stat .ctx span:not(:last-child)::after { content: "·"; margin: 0 .5em; }
@media (max-width: 900px) { .stats { grid-template-columns: repeat(2, minmax(0, 1fr)); } .stat:nth-child(3) { border-left: 0; } .stat:nth-child(n+3) { border-top: 1px solid var(--rule); } }
@media (max-width: 600px) { .stat { padding: 20px 14px; } .stat .ctx { flex-direction: column; } .stat .ctx span::after { content: none; } }

/* ---------- pills (chart toggles) ---------- */
.pills { display: inline-flex; flex-wrap: wrap; gap: 4px; padding: 3px; border: 1px solid #e3e0da; border-radius: 999px; background: #f4f2ee; }
.pills button {
  appearance: none; border: 0; background: transparent; color: #44484f; cursor: pointer;
  font: 500 var(--fs-xs)/1 var(--sans); padding: 8px 12px; border-radius: 999px; min-height: 32px;
}
.pills button[aria-pressed="true"], .pills button[aria-checked="true"] { background: #1d1f22; color: #fdfdfd; }
.pills button:hover:not([aria-pressed="true"]):not([aria-checked="true"]) { background: #e8e5df; }
.controls { display: flex; flex-wrap: wrap; gap: 10px 14px; align-items: center; }
.controls .lab { font: 500 var(--fs-xs)/1 var(--mono); letter-spacing: .08em; text-transform: uppercase; color: #6b6f75; }

/* ---------- charts (shared SVG styling; figure content is light-only) ---------- */
.chart { position: relative; width: 100%; }
.chart svg { overflow: visible; font-family: var(--sans); }
.chart .axis line, .chart .axis path { stroke: #c9c6c0; shape-rendering: crispEdges; }
.chart .axis text { fill: #6b6f75; font-size: var(--fs-xs); font-variant-numeric: tabular-nums; }
.chart .grid line { stroke: #ecebe7; shape-rendering: crispEdges; }
.chart .axis-title { fill: #6b6f75; font: 500 var(--fs-xs) var(--mono); letter-spacing: .08em; text-transform: uppercase; }
.chart .end-label { font-size: var(--fs-xs); font-weight: 500; }
.chart .end-label.q { font-weight: 700; }
.vtip {
  position: absolute; z-index: 5; pointer-events: none; min-width: 120px; max-width: 280px;
  background: #fffdf9; border: 1px solid #e3ded4; border-radius: 8px; box-shadow: 0 6px 20px rgba(29,31,34,.10);
  padding: 8px 10px; font: 400 var(--fs-s)/1.45 var(--sans); color: #1d1f22; opacity: 0; transform: translateY(4px);
  transition: opacity .12s ease, transform .12s ease;
}
.vtip.on { opacity: 1; transform: none; }
.vtip .tt { font: 500 var(--fs-xs)/1.3 var(--mono); letter-spacing: .08em; text-transform: uppercase; color: #6b6f75; margin-bottom: 4px; }
.vtip .tt .math, .vtip .tt i { text-transform: none; letter-spacing: 0; }
.vtip .row { display: flex; justify-content: space-between; gap: 12px; }
.vtip .sw { display: inline-block; width: 9px; height: 9px; border-radius: 2px; margin-right: 6px; }

/* ---------- abstract ---------- */
details.abstract { border: 1px solid var(--rule); border-radius: var(--radius); background: var(--surface); }
details.abstract summary { list-style: none; cursor: pointer; display: flex; align-items: center; justify-content: space-between; padding: 16px 20px; font: 500 var(--fs-xs)/1 var(--mono); letter-spacing: .1em; text-transform: uppercase; color: var(--ink-2); }
details.abstract summary::-webkit-details-marker { display: none; }
details.abstract summary .pm { position: relative; flex: none; width: 24px; height: 24px; border-radius: 999px; border: 1px solid var(--rule-2); font-size: 0; transition: transform .2s ease; }
/* the + is a vector mask filling the circle, so it sits exactly in its centre (and turns into a centred x when open) */
details.abstract summary .pm::before { content: ""; position: absolute; inset: 0; background: currentColor;
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M12 7v10M7 12h10' stroke='%23000' stroke-width='1.5' stroke-linecap='round'/%3E%3C/svg%3E") center / 100% 100% no-repeat;
          mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M12 7v10M7 12h10' stroke='%23000' stroke-width='1.5' stroke-linecap='round'/%3E%3C/svg%3E") center / 100% 100% no-repeat; }
details.abstract[open] summary .pm { transform: rotate(45deg); }
details.abstract .body { padding: 0 20px 20px; color: var(--ink-2); }

/* ---------- code + bibtex ---------- */
.code { position: relative; margin: 0; border-radius: var(--radius); background: #17191c; color: #e6e4de; font: 400 var(--fs-s)/1.65 var(--mono); overflow: hidden; border: 1px solid #26292d; }
.code + .code { margin-top: 20px; }
.code .bar { display: flex; align-items: center; justify-content: space-between; padding: 10px 14px; border-bottom: 1px solid #26292d; font: 500 var(--fs-xs)/1 var(--mono); letter-spacing: .08em; text-transform: uppercase; color: #8d9096; }
.code pre { margin: 0; padding: 16px 18px 18px; overflow-x: auto; tab-size: 4; white-space: pre; }
.code .k { color: #e58a96; } .code .s { color: #9fc7a1; } .code .c { color: #7f848c; font-style: italic; } .code .f { color: #8ec1e0; } .code .n { color: #e6c07b; } .code .hl { color: #ff8a9a; font-weight: 600; }
.copy {
  appearance: none; border: 1px solid #34383d; background: transparent; color: #c9c7c1; border-radius: 999px; cursor: pointer;
  font: 500 var(--fs-xs)/1 var(--mono); letter-spacing: .08em; text-transform: uppercase; padding: 7px 10px; min-height: 32px; min-width: 72px;
}
.copy:hover { background: #24272b; color: #fff; }
.copy.done { color: #9fc7a1; border-color: #3d5a40; }
@media (max-width: 600px) { .code { font-size: var(--fs-xs); } }

/* ---------- models ---------- */
.models { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 16px; }
.models-foot { margin: 14px 0 0; text-align: center; }
.models-foot + .models-foot { margin-top: 6px; }
.models-foot a { display: inline-block; padding: 8px 0; }

/* ---------- footer ---------- */
footer.site { margin-top: clamp(40px, 5vw, 64px); border-top: 1px solid var(--rule); padding: 32px 0 48px; font: 400 var(--fs-s)/1.6 var(--sans); color: var(--muted); }
footer.site .inner { width: min(100% - 2 * var(--gutter), var(--wide)); margin-inline: auto; display: flex; flex-wrap: wrap; gap: 12px 28px; justify-content: space-between; align-items: center; }
footer.site a { color: var(--ink-2); }
footer.site .links-f { display: flex; flex-wrap: wrap; gap: 6px 18px; }
footer.site .links-f a { display: inline-block; padding: 6px 0; }

/* ---------- reveal on scroll ---------- */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .7s ease, transform .7s cubic-bezier(.2,.7,.2,1); }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) { .reveal { opacity: 1; transform: none; transition: none; } }
.no-js .reveal { opacity: 1; transform: none; }
.no-js .copy, .no-js .chart { display: none; }

/* dark mode: neutral tag */
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .hero .tag, :root:not([data-theme="light"]) figcaption .tag { background: rgba(255, 255, 255, .08); color: #c5c4bf; } }
:root[data-theme="dark"] figcaption .tag { background: rgba(255, 255, 255, .08); color: #c5c4bf; }

/* print */
@media print {
  .reveal { opacity: 1 !important; transform: none !important; transition: none !important; }
  .topbar, .vplay, .copy, .skip, .links { display: none !important; }
  .viz, figure { break-inside: avoid; box-shadow: none; }
  body { background: #fff; }
}

/* appendix figure blocks */
.app-head { margin-top: 64px; }
.app-head h3 { padding-top: 20px; border-top: 1px solid var(--rule); }
.app-sub { margin-top: 40px; }
.app-sub h4 { margin: 0; font: 500 var(--fs-m)/1.3 var(--serif); color: var(--ink); }

.star { font-family: "STIX Two Math", "Cambria Math", "Apple Symbols", "Segoe UI Symbol", serif; font-style: normal; }
table.sr-only { display: block; }
@media (max-width: 600px) { .stat .ctx span { white-space: normal; } }