:root {
  --bg: #fbfbf9;
  --surface: #ffffff;
  --text: #1d1f23;
  --muted: #5b6069;
  --border: #e2e2dc;
  --accent: #1f5fa8;
  --accent-soft: #e8f0fa;
  --code-bg: #f3f3ef;
  --plot-bg: #ffffff;
  --shadow: 0 1px 2px rgba(0, 0, 0, .05), 0 4px 16px rgba(0, 0, 0, .04);
  --serif: "Source Serif 4", Georgia, "Times New Roman", serif;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #15171a;
    --surface: #1c1f23;
    --text: #e6e6e3;
    --muted: #a0a5ad;
    --border: #2f333a;
    --accent: #7fb2ee;
    --accent-soft: #1f2b3a;
    --code-bg: #22262b;
    --plot-bg: #f4f4f1;
    --shadow: none;
  }
}

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

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
  overflow-x: hidden;
}

a { color: var(--accent); text-underline-offset: 2px; }

.wrap { max-width: 920px; margin: 0 auto; padding: 0 20px; }

/* Header */
header.hero { padding: 64px 0 32px; text-align: center; border-bottom: 1px solid var(--border); }
.hero h1 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(1.7rem, 4.6vw, 2.6rem);
  line-height: 1.2;
  margin: 0 0 8px;
  letter-spacing: -0.01em;
}
.hero .subtitle {
  font-family: var(--serif);
  font-size: clamp(1.05rem, 2.6vw, 1.35rem);
  color: var(--muted);
  margin: 0 0 28px;
}
.authors { font-size: 1.05rem; margin: 0 0 6px; }
.authors span { white-space: nowrap; }
.authors sup, .affils sup { color: var(--muted); font-size: .7em; }
.affils { color: var(--muted); font-size: .92rem; margin: 0 0 24px; }
.affils span { display: inline-block; margin: 0 8px; }

.buttons { display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 9px 18px;
  border-radius: 999px;
  background: var(--text);
  color: var(--bg);
  text-decoration: none;
  font-weight: 500;
  font-size: .95rem;
}
.btn.ghost { background: transparent; color: var(--text); border: 1px solid var(--border); }
.btn svg { width: 18px; height: 18px; fill: currentColor; }

/* Nav */
nav.toc {
  position: sticky; top: 0; z-index: 10;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
nav.toc .wrap { display: flex; gap: 4px 18px; overflow-x: auto; padding-top: 10px; padding-bottom: 10px; scrollbar-width: none; }
nav.toc .wrap::-webkit-scrollbar { display: none; }
nav.toc a { color: var(--muted); text-decoration: none; font-size: .9rem; white-space: nowrap; }
nav.toc a:hover { color: var(--text); }

/* Sections */
section { padding: 48px 0 8px; }
section h2 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.6rem;
  margin: 0 0 16px;
  scroll-margin-top: 60px;
}
section h3 { font-size: 1.05rem; margin: 28px 0 8px; }
p { margin: 0 0 14px; }
.lead { font-size: 1.08rem; }
.muted { color: var(--muted); }

.steps { padding-left: 1.3em; margin: 0 0 16px; }
.steps li { margin-bottom: 8px; }

figure.diagram {
  margin: 24px 0;
  padding: 20px 16px 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--shadow);
}
figure.diagram svg { width: 100%; height: auto; display: block; max-width: 640px; margin: 0 auto; }
figure.diagram figcaption { font-size: .88rem; color: var(--muted); margin-top: 10px; text-align: center; }
.diagram .node { fill: var(--accent-soft); stroke: var(--accent); stroke-width: 1.5; }
.diagram .label { fill: var(--text); font: 600 14px var(--sans); text-anchor: middle; dominant-baseline: middle; }
.diagram .small { fill: var(--muted); font: 12px var(--sans); text-anchor: middle; }
.diagram .stay { stroke: var(--muted); fill: none; stroke-width: 1.5; }
.diagram .grow { stroke: var(--accent); fill: none; stroke-width: 1.8; }
.diagram .reset { stroke: #c0533a; fill: none; stroke-width: 1.5; stroke-dasharray: 5 4; }
.diagram .legend { font: 12px var(--sans); fill: var(--muted); }

/* Mode cards */
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 16px; }
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px 22px;
  box-shadow: var(--shadow);
}
.card h3 { margin: 0 0 6px; font-family: var(--mono); font-size: .98rem; font-weight: 600; color: var(--accent); }
.card .tag { font-size: .78rem; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); margin-bottom: 10px; }
.card p:last-child { margin-bottom: 0; }

/* Code */
code { font-family: var(--mono); font-size: .88em; background: var(--code-bg); padding: 1px 5px; border-radius: 4px; }
pre {
  position: relative;
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px 18px;
  overflow-x: auto;
  font-size: .85rem;
  line-height: 1.55;
  margin: 0 0 18px;
}
pre code { background: none; padding: 0; font-size: inherit; }
.copy {
  position: absolute; top: 8px; right: 8px;
  font: 500 .75rem var(--sans);
  padding: 4px 10px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--muted);
  cursor: pointer;
}
.copy:hover { color: var(--text); }
.tok-c { color: #6a7380; font-style: italic; }
.tok-k { color: #a2367a; }
.tok-s { color: #2f7d4f; }
.tok-n { color: #b35c00; }
@media (prefers-color-scheme: dark) {
  .tok-c { color: #8a919c; }
  .tok-k { color: #e290c6; }
  .tok-s { color: #8fd2a5; }
  .tok-n { color: #f0b072; }
}

/* Gallery */
.picker { display: flex; flex-wrap: wrap; gap: 8px; margin: 8px 0 20px; }
.picker button {
  font: 500 .88rem var(--sans);
  padding: 7px 14px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
}
.picker button:hover { border-color: var(--accent); }
.picker button[aria-selected="true"] { background: var(--accent); border-color: var(--accent); color: var(--bg); }
.picker select { display: none; }

.rec-meta { font-size: .92rem; color: var(--muted); margin-bottom: 18px; }
.rec-meta code { font-size: .82rem; word-break: break-all; }

.plots { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.plot {
  margin: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow);
  display: flex; flex-direction: column;
}
.plot button.thumb {
  display: block; padding: 0; border: 0; margin: 0;
  background: var(--plot-bg);
  cursor: zoom-in;
  width: 100%;
  aspect-ratio: 4 / 3;
}
.plot img { width: 100%; height: 100%; object-fit: contain; display: block; }
.plot figcaption { padding: 12px 16px 16px; font-size: .88rem; border-top: 1px solid var(--border); }
.plot figcaption strong { display: block; font-size: .93rem; margin-bottom: 4px; }
.plot figcaption span { color: var(--muted); }

/* Lightbox */
.lightbox {
  position: fixed; inset: 0; z-index: 100;
  background: rgba(10, 12, 15, .92);
  display: none;
  align-items: center; justify-content: center;
  flex-direction: column;
  padding: 48px 12px 16px;
}
.lightbox.open { display: flex; }
.lightbox img { max-width: 100%; max-height: calc(100vh - 120px); object-fit: contain; background: #fff; border-radius: 6px; }
.lightbox .lb-cap { color: #ddd; font-size: .9rem; margin-top: 12px; text-align: center; max-width: 900px; }
.lightbox button {
  position: absolute;
  background: rgba(255, 255, 255, .1);
  border: 0; color: #fff;
  width: 44px; height: 44px; border-radius: 50%;
  font-size: 22px; line-height: 1; cursor: pointer;
}
.lightbox button:hover { background: rgba(255, 255, 255, .22); }
.lb-close { top: 10px; right: 12px; }
.lb-prev { left: 12px; top: 50%; transform: translateY(-50%); }
.lb-next { right: 12px; top: 50%; transform: translateY(-50%); }

/* Footer */
footer { margin-top: 64px; padding: 28px 0 48px; border-top: 1px solid var(--border); font-size: .88rem; color: var(--muted); }
footer p { margin: 0 0 8px; }

@media (max-width: 720px) {
  body { font-size: 16px; }
  .wrap { padding: 0 16px; }
  header.hero { padding: 40px 0 24px; }
  .plots { grid-template-columns: 1fr; }
  .picker button { display: none; }
  .picker select {
    display: block; width: 100%;
    font: 500 1rem var(--sans);
    padding: 10px 12px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text);
  }
  .lb-prev, .lb-next { top: auto; bottom: 14px; transform: none; }
}

/* Get started steps */
.getting-started { list-style: none; counter-reset: step; padding: 0; margin: 20px 0 8px; }
.getting-started > li {
  counter-increment: step;
  position: relative;
  padding: 0 0 8px 52px;
  margin: 0 0 20px;
  min-width: 0;
}
.getting-started > li::before {
  content: counter(step);
  position: absolute; left: 0; top: 0;
  width: 34px; height: 34px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  background: var(--accent-soft); color: var(--accent);
  border: 1px solid var(--accent);
  font: 600 .95rem var(--sans);
}
.getting-started > li:not(:last-child)::after {
  content: "";
  position: absolute; left: 17px; top: 40px; bottom: 0;
  width: 1px; background: var(--border);
}
.getting-started h3 { margin: 4px 0 6px; }
.getting-started pre { margin-bottom: 10px; }
.see { font-size: .92rem; color: var(--muted); }

/* Mode decision helper */
.decide .q {
  font-weight: 600;
  margin: 0 0 14px;
  padding: 12px 16px;
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  border-radius: 0 8px 8px 0;
}
.decide .card .tag { margin-bottom: 6px; }
.decide .card h3 { margin-bottom: 10px; }
.also { margin: 16px 0 0; padding-left: 1.2em; }
.also li { margin-bottom: 6px; }

/* Parameters card */
.params dl { margin: 0 0 16px; }
.params dt { font-weight: 600; margin-top: 12px; }
.params dt:first-child { margin-top: 0; }
.params dt span { font-weight: 400; font-size: .82rem; color: var(--muted); margin-left: 6px; }
.params dd { margin: 2px 0 0; }
.table-wrap { overflow-x: auto; margin: 0 0 12px; }
.params table { border-collapse: collapse; width: 100%; font-size: .92rem; }
.params th, .params td { text-align: left; padding: 6px 10px; border-bottom: 1px solid var(--border); }
.params th { color: var(--muted); font-weight: 500; }

@media (max-width: 720px) {
  .getting-started > li { padding-left: 0; }
  .getting-started > li::before { position: static; display: inline-flex; margin-bottom: 6px; }
  .getting-started > li::after { display: none; }
  .getting-started h3 { display: inline-block; margin-left: 10px; vertical-align: middle; }
  .getting-started > li::before { vertical-align: middle; }
}

/* Data sources */
.rec-source { margin-top: 0.35rem; font-size: 0.9em; color: var(--muted, inherit); }
.refs { padding-left: 1.4rem; }
.refs li { margin-bottom: 0.5rem; overflow-wrap: anywhere; }

/* Hero call-to-action and citation */
.btn.accent { background: var(--accent); color: var(--bg); }
.btn:hover { filter: brightness(1.08); }
.btn.ghost:hover { border-color: var(--accent); filter: none; }
pre.oneline { padding-right: 76px; white-space: pre-wrap; overflow-wrap: anywhere; }
pre.oneline code { white-space: inherit; }
.cite-card {
  background: var(--accent-soft);
  border: 1px solid var(--accent);
  border-radius: 12px;
  padding: 20px 22px 8px;
}
.cite-card pre { background: var(--surface); padding-top: 44px; }
.copy.copy-bib {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--bg);
  font-weight: 600;
}
.copy.copy-bib:hover { color: var(--bg); filter: brightness(1.08); }
@media (max-width: 720px) {
  .cite-card { padding: 16px 14px 4px; }
}