/* ============================================================
   AI4AI Survey — project page styles
   Cool but sober: restrained motion, academic typography.
   ============================================================ */

:root {
  /* light theme */
  --bg: #fbfaf7;
  --bg-alt: #f2f1ec;
  --surface: #ffffff;
  --ink: #1c2028;
  --ink-soft: #404654;
  --muted: #6a7180;
  --line: #e2e0d8;
  --line-strong: #cfccc2;
  --accent: #2f4bc0;
  --accent-soft: rgba(47, 75, 192, 0.08);
  --accent-line: rgba(47, 75, 192, 0.35);
  --gold: #a07c2a;
  --code-bg: #f0eee8;
  --shadow: 0 1px 2px rgba(20, 24, 40, 0.05), 0 8px 28px rgba(20, 24, 40, 0.06);
  --shadow-lg: 0 2px 4px rgba(20, 24, 40, 0.06), 0 18px 48px rgba(20, 24, 40, 0.10);
  --hero-bg1: #0b1024;
  --hero-bg2: #131c3f;
  --serif: "Source Serif 4", "Source Serif Pro", Georgia, "Times New Roman", serif;
  --sans: "Inter", -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "Cascadia Code", Consolas, monospace;
}

[data-theme="dark"] {
  --bg: #0d1017;
  --bg-alt: #12161f;
  --surface: #161b26;
  --ink: #dfe3ea;
  --ink-soft: #b6bcc8;
  --muted: #8a91a0;
  --line: #262c3a;
  --line-strong: #363e50;
  --accent: #8b9dff;
  --accent-soft: rgba(139, 157, 255, 0.10);
  --accent-line: rgba(139, 157, 255, 0.4);
  --gold: #cfa54a;
  --code-bg: #1c2230;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.4), 0 8px 28px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 2px 4px rgba(0, 0, 0, 0.45), 0 18px 48px rgba(0, 0, 0, 0.45);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 17px;
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

::selection { background: var(--accent-soft); }

/* ---------------- reading progress bar ---------------- */
#progress-bar {
  position: fixed;
  top: 0; left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--accent), #7fd0c8);
  z-index: 1200;
  transition: width 0.08s linear;
}

/* ---------------- top nav ---------------- */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.65rem 1.5rem;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
  font-family: var(--sans);
  font-size: 0.85rem;
}

.site-nav .brand {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--ink);
  font-size: 0.92rem;
}
.site-nav .brand:hover { text-decoration: none; }

.brand-mark {
  width: 26px; height: 26px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--accent), #7fd0c8);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-family: var(--serif);
  font-style: italic;
  font-weight: 700;
  font-size: 0.8rem;
  box-shadow: var(--shadow);
}
[data-theme="dark"] .brand-mark { color: #0b1024; }

.site-nav .nav-links {
  display: flex;
  gap: 1.1rem;
  margin-left: auto;
  align-items: center;
}
.site-nav .nav-links a {
  color: var(--ink-soft);
  font-weight: 500;
  padding: 0.25rem 0;
  border-bottom: 2px solid transparent;
}
.site-nav .nav-links a:hover { color: var(--ink); text-decoration: none; }
.site-nav .nav-links a.active { color: var(--accent); border-bottom-color: var(--accent-line); }

.theme-toggle {
  border: 1px solid var(--line-strong);
  background: var(--surface);
  color: var(--ink-soft);
  width: 34px; height: 34px;
  border-radius: 10px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.25s ease, background 0.25s ease;
}
.theme-toggle:hover { transform: rotate(20deg) scale(1.06); }
.theme-toggle svg { width: 17px; height: 17px; }
[data-theme="dark"] .theme-toggle .icon-moon { display: none; }
:root:not([data-theme="dark"]) .theme-toggle .icon-sun { display: none; }

/* ---------------- landing: hero ---------------- */
.hero {
  position: relative;
  overflow: hidden;
  background:
    radial-gradient(1100px 600px at 78% -10%, rgba(94, 118, 255, 0.20), transparent 60%),
    radial-gradient(900px 520px at 8% 110%, rgba(72, 196, 182, 0.10), transparent 55%),
    linear-gradient(160deg, var(--hero-bg1), var(--hero-bg2));
  color: #e8ebf5;
  padding: 5.5rem 1.5rem 5rem;
}
#constellation {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0.55;
  pointer-events: none;
}
.hero-inner {
  position: relative;
  max-width: 980px;
  margin: 0 auto;
}
.hero .kicker {
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: #9fb0e8;
  margin: 0 0 1.2rem;
}
.hero h1 {
  font-family: var(--serif);
  font-weight: 700;
  font-size: clamp(2.4rem, 6vw, 4.1rem);
  line-height: 1.08;
  margin: 0 0 0.75rem;
  letter-spacing: -0.01em;
}
.hero h1 .grad {
  background: linear-gradient(92deg, #9db1ff 10%, #7fd0c8 90%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero .subtitle {
  font-family: var(--serif);
  font-style: italic;
  font-size: clamp(1.05rem, 2.4vw, 1.45rem);
  color: #b9c2dd;
  margin: 0 0 1.8rem;
}
.hero .byline {
  font-family: var(--sans);
  font-size: 0.95rem;
  color: #aab4d0;
  margin-bottom: 2.2rem;
}
.hero .byline strong { color: #e8ebf5; font-weight: 600; }

.hero-cta { display: flex; flex-wrap: wrap; gap: 0.9rem; align-items: center; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--sans);
  font-size: 0.9rem;
  font-weight: 600;
  padding: 0.72rem 1.35rem;
  border-radius: 10px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-2px); }
.btn-primary {
  background: linear-gradient(120deg, #4c63e8, #3ba7a0);
  color: #fff;
  box-shadow: 0 6px 22px rgba(66, 96, 220, 0.35);
}
.btn-primary:hover { box-shadow: 0 10px 30px rgba(66, 96, 220, 0.45); }
.btn-ghost {
  background: rgba(255, 255, 255, 0.06);
  border-color: rgba(255, 255, 255, 0.22);
  color: #dfe5f5;
}
.btn-ghost:hover { background: rgba(255, 255, 255, 0.12); }

.hero-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 2.4rem;
  font-family: var(--sans);
  font-size: 0.78rem;
  color: #9aa6c6;
}
.hero-stats .chip {
  padding: 0.32rem 0.8rem;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  background: rgba(255, 255, 255, 0.04);
  letter-spacing: 0.03em;
}

/* the self-referential loop motif */
.loop-motif {
  position: absolute;
  right: clamp(-40px, 4vw, 60px);
  top: 50%;
  transform: translateY(-50%);
  width: clamp(220px, 30vw, 380px);
  height: clamp(220px, 30vw, 380px);
  opacity: 0.9;
  pointer-events: none;
}
.loop-motif .ring { animation: loop-spin 26s linear infinite; transform-origin: 50% 50%; }
.loop-motif .ring-rev { animation: loop-spin 38s linear infinite reverse; transform-origin: 50% 50%; }
@keyframes loop-spin { to { transform: rotate(360deg); } }
.loop-label {
  font-family: var(--sans);
  font-size: 10px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  fill: #93a2cf;
}
@media (max-width: 860px) { .loop-motif { display: none; } }

/* ---------------- landing: generic section ---------------- */
.landing-section {
  max-width: 1020px;
  margin: 0 auto;
  padding: 4.2rem 1.5rem 0.5rem;
}
.landing-section h2.sec-title {
  font-family: var(--serif);
  font-size: 1.75rem;
  font-weight: 700;
  margin: 0 0 0.4rem;
  letter-spacing: -0.01em;
}
.landing-section .sec-lede {
  font-family: var(--sans);
  font-size: 0.95rem;
  color: var(--muted);
  margin: 0 0 2rem;
  max-width: 46rem;
}
.sec-rule {
  width: 52px; height: 3px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--accent), #7fd0c8);
  margin-bottom: 1.1rem;
}

/* abstract card */
.abstract-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 16px;
  box-shadow: var(--shadow);
  padding: 2.2rem 2.4rem;
  font-size: 0.98rem;
  line-height: 1.8;
  color: var(--ink-soft);
}
.abstract-card .abs-label {
  font-family: var(--sans);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--accent);
  display: block;
  margin-bottom: 0.9rem;
}
.abstract-card p { margin: 0 0 1rem; }
.abstract-card p:last-of-type { margin-bottom: 1.4rem; }
.abstract-more { font-family: var(--sans); font-size: 0.85rem; font-weight: 600; }

/* contribution cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 1.1rem;
}
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 1.5rem 1.4rem 1.4rem;
  box-shadow: var(--shadow);
  transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
  position: relative;
  overflow: hidden;
}
.card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), #7fd0c8);
  opacity: 0;
  transition: opacity 0.25s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: var(--accent-line); }
.card:hover::before { opacity: 1; }
.card .card-num {
  font-family: var(--sans);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  color: var(--accent);
  text-transform: uppercase;
}
.card h3 {
  font-family: var(--serif);
  font-size: 1.08rem;
  margin: 0.5rem 0 0.45rem;
  font-weight: 700;
}
.card p {
  font-size: 0.86rem;
  color: var(--muted);
  margin: 0;
  line-height: 1.65;
  font-family: var(--sans);
}

/* lineage timeline (landing) */
.timeline {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 0;
  position: relative;
  margin-top: 1rem;
}
.timeline::before {
  content: "";
  position: absolute;
  top: 13px;
  left: 3%;
  right: 3%;
  height: 2px;
  background: linear-gradient(90deg, #9aa1ad, var(--accent), #7fd0c8);
  opacity: 0.5;
}
.tl-item { position: relative; padding: 0 0.6rem; }
.tl-dot {
  width: 12px; height: 12px;
  border-radius: 50%;
  margin: 8px auto 0.9rem;
  background: var(--surface);
  border: 3px solid var(--accent);
  box-shadow: 0 0 0 4px var(--accent-soft);
  position: relative;
  z-index: 1;
}
.tl-item:nth-child(2) .tl-dot { border-color: #4a6cd4; }
.tl-item:nth-child(3) .tl-dot { border-color: #3f9e6e; }
.tl-item:nth-child(4) .tl-dot { border-color: #c78332; }
.tl-item:nth-child(5) .tl-dot { border-color: #8a5cc9; }
.tl-item:nth-child(6) .tl-dot { border-color: #c95c6e; }
.tl-item strong {
  display: block;
  font-family: var(--sans);
  font-size: 0.8rem;
  font-weight: 700;
  text-align: center;
  letter-spacing: 0.01em;
}
.tl-item span {
  display: block;
  font-family: var(--sans);
  font-size: 0.72rem;
  text-align: center;
  color: var(--muted);
  margin-top: 0.25rem;
  line-height: 1.45;
}
@media (max-width: 800px) {
  .timeline { grid-template-columns: repeat(2, 1fr); gap: 1.4rem; }
  .timeline::before { display: none; }
}
/* parallel research strands (no sequential connector) */
.timeline.strands { grid-template-columns: repeat(3, 1fr); gap: 1.7rem 1.2rem; }
.timeline.strands::before { display: none; }
.timeline.strands .tl-dot { margin-top: 0; }
@media (max-width: 800px) {
  .timeline.strands { grid-template-columns: repeat(2, 1fr); }
}

/* paper map (section list) */
.sec-list { list-style: none; margin: 0; padding: 0; counter-reset: secmap; }
.sec-list li {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  padding: 0.85rem 0.4rem;
  border-bottom: 1px solid var(--line);
  transition: background 0.2s ease, padding-left 0.2s ease;
}
.sec-list li:hover { background: var(--accent-soft); padding-left: 0.8rem; }
.sec-list .sec-no {
  font-family: var(--sans);
  font-weight: 700;
  font-size: 0.8rem;
  color: var(--accent);
  min-width: 1.6rem;
}
.sec-list .sec-name {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.02rem;
  color: var(--ink);
}
.sec-list .sec-desc {
  font-family: var(--sans);
  font-size: 0.8rem;
  color: var(--muted);
  margin-left: auto;
  text-align: right;
  max-width: 40%;
}
.sec-list a:hover { text-decoration: none; }
@media (max-width: 720px) { .sec-list .sec-desc { display: none; } }

/* bibtex */
.bib-box {
  position: relative;
  background: var(--code-bg);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 1.4rem 1.6rem;
  font-family: var(--mono);
  font-size: 0.82rem;
  line-height: 1.7;
  overflow-x: auto;
  color: var(--ink-soft);
}
.bib-copy {
  position: absolute;
  top: 0.8rem; right: 0.8rem;
  font-family: var(--sans);
  font-size: 0.72rem;
  font-weight: 600;
  padding: 0.35rem 0.75rem;
  border-radius: 8px;
  border: 1px solid var(--line-strong);
  background: var(--surface);
  color: var(--ink-soft);
  cursor: pointer;
  transition: all 0.2s ease;
}
.bib-copy:hover { color: var(--accent); border-color: var(--accent-line); }

/* ---------------- paper page layout ---------------- */
.paper-layout {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 3rem;
  max-width: 1180px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 6rem;
}
@media (max-width: 960px) {
  .paper-layout { grid-template-columns: 1fr; }
  .toc { position: static !important; max-height: none !important; display: none; }
  .toc.toc-open { display: block; }
}

.toc {
  position: sticky;
  top: 76px;
  align-self: start;
  max-height: calc(100vh - 100px);
  overflow-y: auto;
  font-family: var(--sans);
  font-size: 0.8rem;
  border-right: 1px solid var(--line);
  padding-right: 1.2rem;
}
.toc-title {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.9rem;
}
.toc-list { list-style: none; margin: 0; padding: 0; }
.toc-list li a {
  display: flex;
  gap: 0.55rem;
  padding: 0.3rem 0.5rem;
  border-radius: 7px;
  color: var(--ink-soft);
  line-height: 1.45;
  transition: background 0.15s ease, color 0.15s ease;
}
.toc-list li a:hover { background: var(--accent-soft); text-decoration: none; }
.toc-list li.toc-active > a { background: var(--accent-soft); color: var(--accent); font-weight: 600; }
.toc-num { color: var(--muted); min-width: 1.9rem; font-variant-numeric: tabular-nums; }
.toc-list li.toc-active .toc-num { color: var(--accent); }
.toc-h3 a { padding-left: 1.6rem; font-size: 0.76rem; color: var(--muted); }

.paper-main { max-width: 46rem; }

/* article header */
.paper-header { margin-bottom: 2.6rem; border-bottom: 1px solid var(--line); padding-bottom: 2rem; }
.paper-header .kicker {
  font-family: var(--sans);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 0.9rem;
}
.paper-header h1 {
  font-family: var(--serif);
  font-size: clamp(1.9rem, 4.5vw, 2.7rem);
  line-height: 1.15;
  margin: 0 0 0.5rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}
.paper-header .subtitle {
  font-family: var(--serif);
  font-style: italic;
  font-size: 1.15rem;
  color: var(--ink-soft);
  margin: 0 0 1.2rem;
}
.paper-header .byline {
  font-family: var(--sans);
  font-size: 0.9rem;
  color: var(--muted);
}
.paper-header .byline strong { color: var(--ink); font-weight: 600; }
.paper-header .byline a { color: var(--muted); font-family: var(--mono); font-size: 0.8rem; }

.epigraph {
  font-family: var(--serif);
  font-style: italic;
  font-size: 0.95rem;
  color: var(--ink-soft);
  text-align: center;
  max-width: 34rem;
  margin: 1.6rem auto 0;
  padding: 1.1rem 1.5rem;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  line-height: 1.7;
}

.paper-abstract {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 1.8rem 2rem;
  margin: 2.2rem 0 3rem;
  box-shadow: var(--shadow);
}
.paper-abstract .abs-label {
  font-family: var(--sans);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--accent);
  display: block;
  margin-bottom: 0.8rem;
}
.paper-abstract p { margin: 0; font-size: 0.95rem; color: var(--ink-soft); }

/* article body */
.paper-body p { margin: 0 0 1.15rem; text-align: justify; hyphens: auto; }
.paper-body h2.sec {
  font-family: var(--serif);
  font-size: 1.5rem;
  font-weight: 700;
  margin: 3rem 0 1.1rem;
  line-height: 1.3;
  scroll-margin-top: 80px;
}
.paper-body h3.subsec {
  font-family: var(--serif);
  font-size: 1.15rem;
  font-weight: 700;
  margin: 2.2rem 0 0.9rem;
  line-height: 1.35;
  scroll-margin-top: 80px;
}
.secnum {
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  margin-right: 0.65rem;
  font-weight: 600;
}
.runin-head { color: var(--ink); font-weight: 700; }

.citation { color: var(--ink-soft); }
.cite, .xref {
  color: var(--accent);
  text-decoration: none;
  text-decoration-color: var(--accent-line);
  text-underline-offset: 3px;
}
.cite:hover, .xref:hover { text-decoration: underline; }
.citation .cite:not(:first-child)::before { content: ""; }

code {
  font-family: var(--mono);
  font-size: 0.85em;
  background: var(--code-bg);
  padding: 0.12em 0.4em;
  border-radius: 5px;
}

/* figures & diagrams */
.paper-figure, .paper-table {
  margin: 2.2rem 0;
  scroll-margin-top: 80px;
}
/* rasterized paper figures sit on a white plate so black-on-white
   vector art stays legible in dark mode too */
.fig-plate {
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 0.9rem;
  box-shadow: var(--shadow);
}
.fig-plate img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 6px;
}
sup.citation {
  font-size: 0.72em;
  line-height: 0;
  margin-left: 1px;
  font-family: var(--sans);
}
sup.citation .cite { font-weight: 600; }
.paper-figure figcaption, .paper-table figcaption {
  font-family: var(--sans);
  font-size: 0.8rem;
  color: var(--muted);
  line-height: 1.6;
  margin-top: 0.9rem;
  text-align: left;
}
.fig-label { font-weight: 700; color: var(--ink-soft); }

.diagram {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 1.6rem 1.4rem;
  box-shadow: var(--shadow);
}

/* flow diagrams (lineage, roadmap) */
.flow-diagram {
  display: flex;
  align-items: stretch;
  gap: 0.55rem;
  overflow-x: auto;
  padding-bottom: 0.3rem;
}
.era {
  flex: 1 0 128px;
  border-radius: 10px;
  padding: 0.75rem 0.7rem;
  text-align: center;
  border: 1px solid var(--line-strong);
  min-height: 92px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.3rem;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}
.era:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.era strong { font-family: var(--sans); font-size: 0.8rem; font-weight: 700; line-height: 1.3; }
.era span { font-family: var(--sans); font-size: 0.68rem; color: var(--muted); line-height: 1.4; }
.flow-arrow {
  flex: 0 0 26px;
  align-self: center;
  height: 2px;
  background: var(--line-strong);
  position: relative;
}
.flow-arrow::after {
  content: "";
  position: absolute;
  right: -1px; top: 50%;
  transform: translateY(-50%);
  border: 5px solid transparent;
  border-left: 7px solid var(--line-strong);
}

/* tints */
.tint-gray   { background: rgba(120, 128, 140, 0.10); }
.tint-blue   { background: rgba(59, 96, 210, 0.10); }
.tint-green  { background: rgba(46, 148, 90, 0.10); }
.tint-orange { background: rgba(210, 132, 45, 0.12); }
.tint-purple { background: rgba(140, 90, 200, 0.10); }
.tint-red    { background: rgba(205, 85, 100, 0.10); }
[data-theme="dark"] .tint-gray   { background: rgba(150, 158, 170, 0.12); }
[data-theme="dark"] .tint-blue   { background: rgba(110, 140, 255, 0.14); }
[data-theme="dark"] .tint-green  { background: rgba(90, 200, 140, 0.12); }
[data-theme="dark"] .tint-orange { background: rgba(255, 170, 90, 0.13); }
[data-theme="dark"] .tint-purple { background: rgba(180, 130, 250, 0.13); }
[data-theme="dark"] .tint-red    { background: rgba(250, 120, 140, 0.12); }

/* positioning diagram (svg) */
.position-diagram { padding: 1.2rem; }
.pos-svg { width: 100%; height: auto; display: block; }
.pos-svg .node { stroke: var(--line-strong); stroke-width: 1.2; rx: 10; }
.pos-svg .arrow-line { stroke: var(--ink-soft); stroke-width: 1.6; fill: none; }
.pos-svg .arrow-line.dashed { stroke-dasharray: 6 4; }
.pos-svg text { font-family: var(--sans); fill: var(--ink); }
.pos-svg .t-main { font-size: 13px; font-weight: 700; }
.pos-svg .t-sub { font-size: 11px; fill: var(--muted); }
.pos-svg .arrowhead { fill: var(--ink-soft); }
.pos-svg .tint-gray   { fill: rgba(120, 128, 140, 0.10); }
.pos-svg .tint-blue   { fill: rgba(59, 96, 210, 0.10); }
.pos-svg .tint-green  { fill: rgba(46, 148, 90, 0.10); }
.pos-svg .tint-orange { fill: rgba(210, 132, 45, 0.12); }
[data-theme="dark"] .pos-svg .tint-gray   { fill: rgba(150, 158, 170, 0.12); }
[data-theme="dark"] .pos-svg .tint-blue   { fill: rgba(110, 140, 255, 0.14); }
[data-theme="dark"] .pos-svg .tint-green  { fill: rgba(90, 200, 140, 0.12); }
[data-theme="dark"] .pos-svg .tint-orange { fill: rgba(255, 170, 90, 0.13); }
[data-theme="dark"] .pos-svg text { fill: var(--ink); }

/* taxonomy diagram */
.taxonomy-diagram { position: relative; padding-bottom: 2.6rem; }
.taxonomy-diagram .grid4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.9rem;
}
@media (max-width: 760px) { .taxonomy-diagram .grid4 { grid-template-columns: repeat(2, 1fr); } }
.tax-head {
  font-family: var(--sans);
  font-size: 0.74rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 0.55rem;
  letter-spacing: 0.02em;
}
.tax-box {
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  padding: 0.85rem 0.8rem;
  font-family: var(--sans);
  font-size: 0.74rem;
  line-height: 1.75;
  min-height: 110px;
  text-align: left;
}
.tax-brace {
  margin: 1.1rem auto 0.4rem;
  width: 86%;
  height: 10px;
  border-bottom: 2px solid var(--line-strong);
  border-radius: 0 0 12px 12px;
  position: relative;
}
.tax-brace::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: -7px;
  transform: translateX(-50%);
  width: 2px;
  height: 8px;
  background: var(--line-strong);
}
.tax-note {
  font-family: var(--sans);
  font-size: 0.74rem;
  color: var(--muted);
  text-align: center;
  margin-top: 0.7rem;
}

/* tables */
.table-wrap {
  overflow-x: auto;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: var(--shadow);
}
table.thread-map {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--sans);
  font-size: 0.8rem;
}
table.thread-map th {
  text-align: left;
  font-weight: 700;
  padding: 0.85rem 1rem;
  border-bottom: 2px solid var(--line-strong);
  white-space: nowrap;
}
table.thread-map td {
  padding: 0.7rem 1rem;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
  color: var(--ink-soft);
  line-height: 1.55;
}
table.thread-map td:first-child { font-weight: 600; color: var(--ink); white-space: nowrap; }
table.thread-map tbody tr:last-child td { border-bottom: none; }
table.thread-map tbody tr { transition: background 0.15s ease; }
table.thread-map tbody tr:hover { background: var(--accent-soft); }

/* references */
.refs-heading { margin-top: 3.4rem; }
ol.references {
  list-style: none;
  margin: 1.4rem 0 0;
  padding: 0;
  counter-reset: refcounter;
  font-size: 0.84rem;
  font-family: var(--sans);
}
ol.references li {
  counter-increment: refcounter;
  display: flex;
  gap: 0.9rem;
  padding: 0.55rem 0.5rem;
  border-radius: 8px;
  line-height: 1.65;
  color: var(--ink-soft);
  scroll-margin-top: 90px;
}
ol.references li::before {
  content: "[" counter(refcounter) "]";
  min-width: 2.4rem;
  text-align: right;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  font-size: 0.78rem;
  padding-top: 0.1rem;
}
ol.references li:hover { background: var(--accent-soft); }
ol.references li:target { background: var(--accent-soft); box-shadow: inset 3px 0 0 var(--accent); }
.ref-text em { font-family: var(--serif); font-size: 1.04em; }
.ref-back {
  margin-left: auto;
  color: var(--muted);
  font-size: 0.8rem;
  align-self: center;
  opacity: 0;
  transition: opacity 0.15s ease;
  flex: 0 0 auto;
}
ol.references li:hover .ref-back { opacity: 1; }

/* ---------------- footer ---------------- */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 2.2rem 1.5rem;
  text-align: center;
  font-family: var(--sans);
  font-size: 0.8rem;
  color: var(--muted);
  background: var(--bg-alt);
}
.site-footer a { color: var(--muted); }
.site-footer .foot-mark {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.6rem;
  color: var(--ink-soft);
  font-weight: 600;
}

/* ---------------- reveal on scroll ---------------- */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .loop-motif .ring, .loop-motif .ring-rev { animation: none; }
  * { transition-duration: 0.01ms !important; }
}

/* misc */
.math-inline { white-space: nowrap; }
.katex { font-size: 1.02em; }