/* ==========================================================================
   UBTree project page
   Palette: warm paper + spruce ink, amber marks the accepted path.
   ========================================================================== */

:root {
  color-scheme: light;
  --paper: #f5f2ea;
  --surface: #fffdf8;
  --surface-2: #efebe0;
  --ink: #18211d;
  --ink-2: #47514c;
  --muted: #7f857f;
  --line: #e2ddd0;
  --line-strong: #cdc6b5;

  --spruce: #0f6e50;          /* brand ink for UI */
  --spruce-soft: #dcebe3;
  --amber: #c9731f;           /* accepted path */
  --amber-soft: #f6e4cf;

  /* chart roles (validated) */
  --s-ours: #0f8a63;
  --s-2: #2a78d6;
  --s-3: #eb6834;
  --s-base: #c8c2b2;
  --s-base-strong: #a49d8b;
  --grid: #e8e3d7;
  --axis: #cdc6b5;

  --code-bg: #111a16;
  --code-ink: #d9e4dd;
  --code-dim: #7d9a8c;
  --code-key: #8fd6b4;
  --code-str: #f0c48a;

  --ph-ink: #9a5a12;
  --ph-bg: rgba(201, 115, 31, 0.07);
  --ph-line: rgba(201, 115, 31, 0.55);

  --shadow: 0 1px 0 rgba(24, 33, 29, 0.04), 0 8px 24px -12px rgba(24, 33, 29, 0.18);

  --f-display: var(--f-sans);
  --f-sans: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --f-mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;

  --w-prose: 720px;
  --w-wide: 1120px;
  --r: 10px;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --paper: #0e1311;
    --surface: #141b18;
    --surface-2: #1b2420;
    --ink: #e8ece6;
    --ink-2: #b4bdb6;
    --muted: #7e8882;
    --line: #26302b;
    --line-strong: #36423c;
    --spruce: #4cc79b;
    --spruce-soft: #173229;
    --amber: #eba35a;
    --amber-soft: #3a2a18;
    --s-ours: #22a079;
    --s-2: #3987e5;
    --s-3: #d95926;
    --s-base: #3f4a44;
    --s-base-strong: #5b6760;
    --grid: #222b27;
    --axis: #36423c;
    --code-bg: #0a0f0d;
    --ph-ink: #eba35a;
    --ph-bg: rgba(235, 163, 90, 0.06);
    --ph-line: rgba(235, 163, 90, 0.45);
    --shadow: 0 1px 0 rgba(0, 0, 0, 0.3), 0 8px 24px -12px rgba(0, 0, 0, 0.6);
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --paper: #0e1311;
  --surface: #141b18;
  --surface-2: #1b2420;
  --ink: #e8ece6;
  --ink-2: #b4bdb6;
  --muted: #7e8882;
  --line: #26302b;
  --line-strong: #36423c;
  --spruce: #4cc79b;
  --spruce-soft: #173229;
  --amber: #eba35a;
  --amber-soft: #3a2a18;
  --s-ours: #22a079;
  --s-2: #3987e5;
  --s-3: #d95926;
  --s-base: #3f4a44;
  --s-base-strong: #5b6760;
  --grid: #222b27;
  --axis: #36423c;
  --code-bg: #0a0f0d;
  --ph-ink: #eba35a;
  --ph-bg: rgba(235, 163, 90, 0.06);
  --ph-line: rgba(235, 163, 90, 0.45);
  --shadow: 0 1px 0 rgba(0, 0, 0, 0.3), 0 8px 24px -12px rgba(0, 0, 0, 0.6);
}

/* ---------- base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--f-sans);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img { max-width: 100%; display: block; }
a { color: var(--spruce); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }
strong { font-weight: 600; }
::selection { background: var(--amber-soft); }
code, kbd { font-family: var(--f-mono); font-size: 0.88em; }
:not(pre) > code {
  background: var(--surface-2); padding: 0.1em 0.38em; border-radius: 5px; border: 1px solid var(--line);
}
:focus-visible { outline: 2px solid var(--spruce); outline-offset: 2px; border-radius: 4px; }

.wrap { width: min(100% - 32px, var(--w-wide)); margin-inline: auto; }
.prose { width: min(100%, var(--w-prose)); }
.prose p { margin: 0 0 1.1em; }
.prose ul { padding-left: 1.2em; margin: 0 0 1.1em; }
.prose li { margin-bottom: 0.4em; }
.muted { color: var(--muted); }
.small { font-size: 0.86rem; }
.mono { font-family: var(--f-mono); }

/* ---------- 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 .2s;
}
.topbar.scrolled { border-bottom-color: var(--line); }
.topbar .wrap { display: flex; align-items: center; gap: 20px; height: 58px; }
.brand { display: inline-flex; align-items: center; gap: 9px; font-family: var(--f-display); font-weight: 600; font-size: 1.2rem; color: var(--ink); text-decoration: none; letter-spacing: -0.01em; }
.brand svg { width: 22px; height: 22px; flex-shrink: 0; }
.brand-lockup { display: flex; align-items: center; gap: 16px; flex-shrink: 0; }
.brand-lockup .brand { white-space: nowrap; }
.brand-partner { display: inline-flex; align-items: center; padding-left: 16px; border-left: 1px solid var(--line-strong); }
.brand-partner img { width: 164px; height: auto; }
:root[data-theme="dark"] .brand-partner img { filter: brightness(0) invert(1); }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .brand-partner img { filter: brightness(0) invert(1); } }
.nav { display: flex; gap: 4px; margin-left: auto; }
.nav a { color: var(--ink-2); text-decoration: none; font-size: 0.9rem; padding: 6px 10px; border-radius: 999px; }
.nav a:hover { color: var(--ink); background: var(--surface-2); }
.nav a.active { color: var(--spruce); background: var(--spruce-soft); }
.icon-btn {
  display: inline-grid; place-items: center; width: 36px; height: 36px; border-radius: 999px;
  border: 1px solid var(--line); background: var(--surface); color: var(--ink-2); cursor: pointer;
}
.icon-btn:hover { color: var(--ink); border-color: var(--line-strong); }
.icon-btn svg { width: 17px; height: 17px; }
@media (max-width: 1000px) { .nav { display: none; } .topbar .wrap { justify-content: space-between; } }
@media (max-width: 480px) {
  .topbar .wrap { gap: 12px; }
  .brand-lockup { gap: 10px; }
  .brand-partner { padding-left: 10px; }
  .brand-partner img { width: clamp(108px, 32vw, 132px); }
  .topbar .icon-btn { flex-shrink: 0; }
}

/* ---------- hero ---------- */
.hero { position: relative; padding: 56px 0 40px; overflow: hidden; }
.hero::before {
  /* faint lattice: candidate columns */
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background-image: radial-gradient(circle at 1px 1px, var(--line-strong) 1px, transparent 1.4px);
  background-size: 28px 28px;
  mask-image: radial-gradient(ellipse 70% 60% at 70% 30%, #000 10%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 70% 60% at 70% 30%, #000 10%, transparent 75%);
  opacity: .55;
}
.hero-grid { position: relative; display: grid; grid-template-columns: 1fr; gap: 40px; align-items: center; }
@media (min-width: 1000px) { .hero-grid { grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr); gap: 48px; } }

.title {
  font-family: var(--f-display); font-size: clamp(3.2rem, 8vw, 5.6rem);
  line-height: 1; letter-spacing: -0.03em; margin: 0 0 10px; font-weight: 700;
}
.title .u, .title .b { color: var(--spruce); }
.subtitle {
  font-family: var(--f-display); font-weight: 400; font-size: clamp(1.15rem, 2.1vw, 1.4rem); line-height: 1.4;
  color: var(--ink-2); margin: 0 0 22px; max-width: 30ch;
}
.subtitle em { font-style: normal; color: var(--ink); font-weight: 600; }
.authors { font-size: 0.97rem; line-height: 1.75; margin: 0 0 6px; }
.authors a { color: var(--ink); text-decoration: none; border-bottom: 1px solid var(--line-strong); }
.authors a:hover { border-color: var(--spruce); color: var(--spruce); }
.authors sup { font-size: 0.68em; color: var(--muted); margin-left: 1px; }
.affils { font-size: 0.86rem; color: var(--ink-2); margin: 0; }
.affils sup { color: var(--muted); }
.notes { font-size: 0.78rem; color: var(--muted); margin: 6px 0 22px; }

.links { display: flex; flex-wrap: wrap; gap: 10px; }
.btn {
  display: inline-flex; align-items: center; gap: 8px; height: 40px; padding: 0 16px; border-radius: 999px;
  font-size: 0.9rem; font-weight: 500; text-decoration: none; border: 1px solid var(--line-strong);
  background: var(--surface); color: var(--ink); transition: transform .15s, border-color .15s, background .15s;
}
.btn:hover { transform: translateY(-1px); border-color: var(--ink-2); text-decoration: none; }
.btn svg { width: 17px; height: 17px; flex: none; }
.btn.primary { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.btn.primary:hover { background: var(--spruce); border-color: var(--spruce); }

/* ---------- tree widget ---------- */
.treecard {
  background: var(--surface); border: 1px solid var(--line); border-radius: 16px; box-shadow: var(--shadow);
  padding: 18px 18px 14px; position: relative;
}
.tc-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; margin-bottom: 4px; }
.tc-title { font-family: var(--f-mono); font-size: 0.74rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted); }
.seg { display: inline-flex; background: var(--surface-2); border-radius: 999px; padding: 3px; border: 1px solid var(--line); }
.seg button {
  font: inherit; font-size: 0.8rem; border: 0; background: transparent; color: var(--ink-2); padding: 5px 12px;
  border-radius: 999px; cursor: pointer; white-space: nowrap;
}
.seg button[aria-pressed="true"] { background: var(--surface); color: var(--ink); box-shadow: 0 1px 2px rgba(0,0,0,.12); }
.tc-svg { width: 100%; height: auto; display: block; margin: 6px 0 4px; overflow: visible; }
.tc-svg text { font-family: var(--f-sans); }
.tc-node rect { transition: fill .35s, stroke .35s, opacity .35s; }
.tc-node text { transition: fill .35s, opacity .35s; }
.tc-edge { transition: opacity .45s, stroke .35s, stroke-width .35s; fill: none; }
.tc-steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 6px; margin-top: 4px; }
.tc-step {
  font: inherit; text-align: left; border: 0; border-top: 2px solid var(--line); background: none; padding: 8px 2px 0;
  color: var(--muted); cursor: pointer; font-size: 0.78rem; line-height: 1.3;
}
.tc-step b { display: block; font-family: var(--f-mono); font-weight: 500; font-size: 0.7rem; letter-spacing: .05em; margin-bottom: 2px; }
.tc-step.on { border-top-color: var(--spruce); color: var(--ink); }
.tc-step.done { border-top-color: color-mix(in srgb, var(--spruce) 45%, var(--line)); }
.tc-readout {
  display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap;
  margin-top: 12px; padding-top: 12px; border-top: 1px dashed var(--line); font-size: 0.88rem; color: var(--ink-2); min-height: 44px;
}
.tc-readout .tau { font-family: var(--f-mono); font-size: 0.95rem; color: var(--ink); white-space: nowrap; }
.tc-readout .tau b { color: var(--amber); font-weight: 600; }
.tc-replay { font: inherit; font-size: 0.8rem; border: 1px solid var(--line); background: var(--surface); color: var(--ink-2); border-radius: 999px; padding: 4px 12px; cursor: pointer; }
.tc-replay:hover { color: var(--ink); border-color: var(--line-strong); }

/* ---------- stat strip ---------- */
.stats { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: 14px; overflow: hidden; margin-top: 44px; }
@media (min-width: 860px) { .stats { grid-template-columns: repeat(4, 1fr); } }
.stat { background: var(--surface); padding: 20px 20px 18px; }
.stat .v { font-family: var(--f-display); font-size: clamp(2rem, 4vw, 2.6rem); line-height: 1; letter-spacing: -0.02em; font-weight: 600; color: var(--ink); }
.stat .v small { font-size: 0.5em; color: var(--spruce); margin-left: 2px; font-weight: 500; }
.stat .k { font-size: 0.86rem; color: var(--ink); margin-top: 10px; font-weight: 500; }
.stat .d { font-size: 0.78rem; color: var(--muted); margin-top: 2px; line-height: 1.4; }

/* ---------- sections ---------- */
section.block { padding: 72px 0 8px; }
.sec-head { display: grid; gap: 8px; margin-bottom: 26px; }
.sec-no { font-family: var(--f-mono); font-size: 0.76rem; color: var(--spruce); letter-spacing: .08em; text-transform: uppercase; display: flex; align-items: center; gap: 10px; }
.sec-no::after { content: ""; height: 1px; width: 56px; background: var(--line-strong); }
h2 {
  font-family: var(--f-display); font-weight: 600; font-size: clamp(1.9rem, 3.6vw, 2.6rem); line-height: 1.1;
  letter-spacing: -0.02em; margin: 0;
}
h3 { font-family: var(--f-display); font-weight: 600; font-size: 1.35rem; letter-spacing: -0.01em; margin: 40px 0 10px; }
h4 { font-size: 0.98rem; font-weight: 600; margin: 0 0 6px; }
.lede { font-size: 1.12rem; color: var(--ink-2); margin: 0; max-width: 62ch; }
.anchor { color: var(--line-strong); text-decoration: none; margin-left: 8px; font-size: 0.7em; opacity: 0; transition: opacity .15s; }
h2:hover .anchor, h3:hover .anchor { opacity: 1; }

/* ---------- placeholders ---------- */
.ph {
  border: 1.5px dashed var(--ph-line); background: var(--ph-bg); border-radius: var(--r); padding: 16px 18px; color: var(--ink-2);
  margin: 0 0 1.2em;
}
.ph-tag {
  display: inline-flex; align-items: center; gap: 8px; font-family: var(--f-mono); font-size: 0.7rem; letter-spacing: .06em; text-transform: uppercase;
  color: var(--ph-ink); margin-bottom: 6px;
}
.ph-tag::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: currentColor; }
.ph p { margin: 0 0 .5em; font-size: 0.93rem; }
.ph p:last-child { margin-bottom: 0; }
.ph ul { margin: .3em 0 0; padding-left: 1.2em; font-size: 0.9rem; }

/* ---------- video ---------- */
.video-grid { display: grid; gap: 24px; grid-template-columns: minmax(0, 1fr); }
.video-slot {
  aspect-ratio: 36 / 19; border-radius: 14px; overflow: hidden; background: #0c0c0c;
  border: 1px solid var(--line);
}
.video-slot video { width: 100%; height: 100%; object-fit: contain; display: block; }

/* ---------- quick start: tabs & code ---------- */
.tabs { display: flex; gap: 2px; border-bottom: 1px solid var(--line); margin-bottom: 0; overflow-x: auto; scrollbar-width: none; }
.tabs::-webkit-scrollbar { display: none; }
.tab {
  font: inherit; font-size: 0.9rem; background: none; border: 0; padding: 10px 14px; color: var(--ink-2); cursor: pointer;
  border-bottom: 2px solid transparent; margin-bottom: -1px; white-space: nowrap; display: inline-flex; align-items: center; gap: 8px;
}
.tab:hover { color: var(--ink); }
.tab[aria-selected="true"] { color: var(--ink); border-bottom-color: var(--spruce); font-weight: 500; }
.tab .pill { font-family: var(--f-mono); font-size: 0.68rem; padding: 1px 7px; border-radius: 999px; background: var(--surface-2); color: var(--muted); border: 1px solid var(--line); }
.tabpanel { padding-top: 20px; }
.tabpanel[hidden] { display: none; }
.step-row { display: grid; grid-template-columns: 28px 1fr; gap: 12px; margin-bottom: 18px; }
.step-n {
  width: 26px; height: 26px; border-radius: 50%; display: grid; place-items: center; font-family: var(--f-mono); font-size: 0.78rem;
  background: var(--spruce-soft); color: var(--spruce); margin-top: 2px;
}
.step-row > div { min-width: 0; }
.step-row h4 { margin-top: 3px; }
.step-row p { margin: 0 0 8px; font-size: 0.93rem; color: var(--ink-2); }

.code {
  position: relative; background: var(--code-bg); color: var(--code-ink); border-radius: var(--r); border: 1px solid rgba(255,255,255,.06);
  margin: 0; overflow: hidden;
}
.code .code-bar {
  display: flex; align-items: center; justify-content: space-between; padding: 7px 10px 7px 14px; border-bottom: 1px solid rgba(255,255,255,.07);
  font-family: var(--f-mono); font-size: 0.72rem; color: var(--code-dim);
}
.code.tall pre { max-height: 420px; }
.code pre { margin: 0; padding: 14px 16px; overflow-x: auto; font-family: var(--f-mono); font-size: 0.82rem; line-height: 1.6; tab-size: 2; }
.code .c-dim { color: var(--code-dim); }
.code .c-key { color: var(--code-key); }
.code .c-str { color: var(--code-str); }
.copy {
  font: inherit; font-size: 0.72rem; background: rgba(255,255,255,.06); color: var(--code-ink); border: 1px solid rgba(255,255,255,.1);
  border-radius: 6px; padding: 3px 9px; cursor: pointer;
}
.copy:hover { background: rgba(255,255,255,.12); }
.copy.ok { color: var(--code-key); border-color: rgba(143,214,180,.4); }
.callout {
  display: flex; gap: 12px; align-items: flex-start; border: 1px solid var(--line); background: var(--surface); border-radius: var(--r);
  padding: 12px 14px; font-size: 0.88rem; color: var(--ink-2); margin: 0 0 18px;
}
.callout svg { width: 18px; height: 18px; flex: none; color: var(--spruce); margin-top: 2px; }

/* ---------- method ---------- */
.figure { margin: 8px 0 0; }
.figure .frame { background: #fff; border: 1px solid var(--line); border-radius: 14px; padding: 14px; overflow: hidden; }
:root[data-theme="dark"] .figure .frame { background: #f4f2ec; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .figure .frame { background: #f4f2ec; } }
.figure .frame img { width: 100%; height: auto; cursor: zoom-in; }
figcaption { font-size: 0.86rem; color: var(--muted); margin-top: 10px; max-width: 88ch; }
figcaption b { color: var(--ink-2); font-weight: 600; }

.stages { display: grid; gap: 14px; grid-template-columns: 1fr; margin-top: 30px; counter-reset: st; }
@media (min-width: 860px) { .stages { grid-template-columns: repeat(3, 1fr); } }
.stage {
  background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 18px 18px 16px; position: relative;
}
.stage .st-k { font-family: var(--f-mono); font-size: 0.72rem; color: var(--muted); letter-spacing: .06em; text-transform: uppercase; }
.stage h4 { font-family: var(--f-display); font-size: 1.2rem; font-weight: 600; margin: 6px 0 8px; }
.stage p { font-size: 0.92rem; color: var(--ink-2); margin: 0 0 10px; }
.stage .par {
  display: inline-flex; align-items: center; gap: 6px; font-family: var(--f-mono); font-size: 0.7rem; padding: 2px 8px; border-radius: 999px;
  background: var(--spruce-soft); color: var(--spruce);
}
.stage .par.seq { background: var(--surface-2); color: var(--ink-2); }
.stage .glyph { position: absolute; top: 16px; right: 16px; width: 54px; height: 32px; color: var(--spruce); opacity: .9; }

.mathbox {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--r); padding: 14px 18px; margin: 12px 0 18px;
  overflow-x: auto; overflow-y: hidden;
}
.mathbox .katex-display { margin: 0.3em 0; }
.mathbox math[display="block"] { margin: 0.4em 0; font-size: 1.15em; }
.mathbox .mlabel { font-family: var(--f-mono); font-size: 0.7rem; color: var(--muted); letter-spacing: .05em; text-transform: uppercase; }
.two-col { display: grid; gap: 22px; grid-template-columns: 1fr; }
@media (min-width: 960px) { .two-col { grid-template-columns: 1fr 1fr; gap: 32px; } }
.two-col > div { min-width: 0; }

.compare { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin: 14px 0 6px; }
.compare > div { border: 1px solid var(--line); border-radius: 12px; padding: 14px; background: var(--surface); font-size: 0.88rem; color: var(--ink-2); }
.compare h4 { font-size: 0.86rem; }
.compare .bad { color: var(--muted); }
.compare .good { border-color: color-mix(in srgb, var(--spruce) 45%, var(--line)); background: color-mix(in srgb, var(--spruce-soft) 45%, var(--surface)); }
.bars-mini { display: grid; gap: 6px; margin-top: 10px; }
.bars-mini div { display: grid; grid-template-columns: 52px 1fr 36px; align-items: center; gap: 8px; font-family: var(--f-mono); font-size: 0.74rem; }
.bars-mini i { display: block; height: 8px; border-radius: 0 4px 4px 0; background: var(--s-base); }
.compare .good .bars-mini i { background: var(--s-ours); }

/* ---------- results / charts ---------- */
.controls { display: flex; flex-wrap: wrap; gap: 10px 18px; align-items: center; margin: 4px 0 16px; }
.ctl-label { font-family: var(--f-mono); font-size: 0.7rem; color: var(--muted); text-transform: uppercase; letter-spacing: .06em; margin-right: 4px; }
.ctl { display: inline-flex; align-items: center; gap: 6px; }

.chips { display: flex; flex-wrap: wrap; gap: 6px; margin: 0 0 14px; }
.chip {
  font: inherit; font-size: 0.8rem; padding: 4px 11px; border-radius: 999px; border: 1px solid var(--line); background: var(--surface);
  color: var(--ink-2); cursor: pointer; font-variant-numeric: tabular-nums;
}
.chip:hover { border-color: var(--line-strong); color: var(--ink); }
.chip[aria-pressed="true"] { background: var(--ink); color: var(--paper); border-color: var(--ink); }

.card { background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 18px 18px 14px; }
.card-head { display: flex; justify-content: space-between; align-items: baseline; gap: 12px; flex-wrap: wrap; margin-bottom: 8px; }
.card-title { font-weight: 600; font-size: 0.98rem; }
.card-sub { font-size: 0.8rem; color: var(--muted); }
.chart { width: 100%; position: relative; }
.chart svg { width: 100%; height: auto; display: block; overflow: visible; }
.chart text { font-family: var(--f-sans); fill: var(--ink-2); font-size: 12.5px; }
.chart .tick { fill: var(--muted); font-size: 11.5px; font-variant-numeric: tabular-nums; }
.chart .gridline { stroke: var(--grid); stroke-width: 1; }
.chart .baseline { stroke: var(--axis); stroke-width: 1; }
.chart .bar { transition: opacity .15s, fill .2s; }
.chart .hit:hover + .bar, .chart .bar.hover { opacity: .78; }
.chart .val { fill: var(--ink); font-size: 12px; font-weight: 500; font-variant-numeric: tabular-nums; }
.chart .val.ours { font-weight: 700; }
.chart .lbl { fill: var(--ink-2); font-size: 12.5px; }
.chart .lbl.ours { fill: var(--ink); font-weight: 600; }
.chart .lbl .sub { fill: var(--muted); font-size: 10.5px; }

.legend { display: flex; flex-wrap: wrap; gap: 6px 16px; font-size: 0.8rem; color: var(--ink-2); margin: 2px 0 8px; }
.legend span { display: inline-flex; align-items: center; gap: 7px; }
.legend i { display: inline-block; width: 18px; height: 0; border-top: 2px solid; }
.legend i.dash { border-top-style: dashed; }
.legend i.sq { width: 11px; height: 11px; border: 0; border-radius: 3px; }

.tooltip {
  position: fixed; z-index: 100; pointer-events: none; background: var(--surface); color: var(--ink); border: 1px solid var(--line-strong);
  border-radius: 8px; padding: 8px 10px; font-size: 0.78rem; box-shadow: var(--shadow); min-width: 140px; opacity: 0; transition: opacity .1s;
  font-variant-numeric: tabular-nums;
}
.tooltip.show { opacity: 1; }
.tooltip .tt-h { color: var(--muted); font-size: 0.72rem; margin-bottom: 4px; }
.tooltip .tt-r { display: grid; grid-template-columns: 14px auto 1fr; gap: 6px; align-items: center; }
.tooltip .tt-r i { width: 12px; border-top: 2px solid; }
.tooltip .tt-r b { font-weight: 600; }
.tooltip .tt-r span { color: var(--ink-2); }

.grid-2 { display: grid; gap: 16px; grid-template-columns: 1fr; }
@media (min-width: 900px) { .grid-2 { grid-template-columns: 1fr 1fr; } }
.grid-4 { display: grid; gap: 12px; grid-template-columns: 1fr; }
@media (min-width: 640px) { .grid-4 { grid-template-columns: 1fr 1fr; } }
@media (min-width: 1040px) { .grid-4 { grid-template-columns: repeat(4, 1fr); } }
.grid-4 .card { padding: 14px 14px 10px; }

/* tables */
.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); }
table.data { width: 100%; border-collapse: collapse; font-size: 0.82rem; font-variant-numeric: tabular-nums; }
table.data th, table.data td { padding: 7px 10px; text-align: right; white-space: nowrap; border-bottom: 1px solid var(--line); }
table.data th:first-child, table.data td:first-child { text-align: left; position: sticky; left: 0; background: var(--surface); z-index: 1; }
table.data thead th { font-weight: 500; color: var(--muted); font-size: 0.74rem; background: var(--surface-2); }
table.data thead th:first-child { background: var(--surface-2); }
table.data thead tr.grp th { color: var(--ink-2); font-family: var(--f-mono); letter-spacing: .05em; text-transform: uppercase; font-size: 0.68rem; text-align: center; }
table.data tbody tr:last-child td { border-bottom: 0; }
table.data tr.ours td { background: color-mix(in srgb, var(--spruce-soft) 55%, var(--surface)); font-weight: 600; color: var(--ink); }
table.data tr.ours td:first-child { background: color-mix(in srgb, var(--spruce-soft) 55%, var(--surface)); }
table.data tr.sep td { background: var(--surface-2); color: var(--muted); font-size: 0.72rem; font-family: var(--f-mono); text-align: left; letter-spacing: .04em; padding: 4px 10px; }
table.data td.best { color: var(--spruce); }
table.data tr.meanrow td { font-weight: 600; border-top: 1px solid var(--line-strong); }
table.data td .tau { color: var(--muted); font-weight: 400; }
table.data tr.ours td .tau { color: var(--ink-2); }
table.data .avgcol { border-left: 1px solid var(--line); }
details.more { margin-top: 14px; }
details.more summary { cursor: pointer; font-size: 0.88rem; color: var(--spruce); list-style: none; display: inline-flex; align-items: center; gap: 6px; }
details.more summary::-webkit-details-marker { display: none; }
details.more summary::before { content: "+"; font-family: var(--f-mono); width: 16px; height: 16px; display: inline-grid; place-items: center; border: 1px solid currentColor; border-radius: 4px; font-size: 0.8rem; line-height: 1; }
details.more[open] summary::before { content: "−"; }
details.more > div { margin-top: 12px; }

.takeaways { display: grid; gap: 10px; margin: 18px 0 0; padding: 0; list-style: none; }
.takeaways li { display: grid; grid-template-columns: 18px 1fr; gap: 10px; font-size: 0.93rem; color: var(--ink-2); }
.takeaways li::before { content: ""; width: 8px; height: 8px; margin-top: 8px; border-radius: 2px; background: var(--s-ours); transform: rotate(45deg); }

/* ---------- models ---------- */
.models { display: grid; gap: 16px; grid-template-columns: 1fr; }
@media (min-width: 860px) { .models { grid-template-columns: 1fr 1fr; } }
.model {
  background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 18px; display: grid; gap: 12px; text-decoration: none; color: inherit;
}
.model:hover { border-color: var(--line-strong); text-decoration: none; }
.model-top { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; }
.model-name { font-family: var(--f-mono); font-size: 0.92rem; color: var(--ink); word-break: break-all; }
.model-for { font-size: 0.82rem; color: var(--muted); margin-top: 2px; }
.badge { font-family: var(--f-mono); font-size: 0.68rem; padding: 2px 8px; border-radius: 999px; background: var(--spruce-soft); color: var(--spruce); white-space: nowrap; }
.kv { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
.kv div { background: var(--surface-2); border-radius: 8px; padding: 8px 10px; }
.kv b { display: block; font-size: 0.98rem; font-weight: 600; font-variant-numeric: tabular-nums; }
.kv span { font-size: 0.72rem; color: var(--muted); }

/* ---------- citation ---------- */
.bib .code pre { white-space: pre; }

/* ---------- footer ---------- */
footer { margin-top: 88px; border-top: 1px solid var(--line); padding: 34px 0 46px; font-size: 0.86rem; color: var(--muted); }
.foot { display: flex; flex-wrap: wrap; gap: 24px; justify-content: space-between; align-items: center; }
.foot img { height: 26px; width: auto; }
:root[data-theme="dark"] .foot img { filter: invert(1) hue-rotate(180deg) brightness(1.1); }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .foot img { filter: invert(1) hue-rotate(180deg) brightness(1.1); } }

/* ---------- lightbox ---------- */
.lightbox { position: fixed; inset: 0; z-index: 200; background: rgba(8, 12, 10, .86); display: none; place-items: center; padding: 24px; cursor: zoom-out; }
.lightbox.open { display: grid; }
.lightbox img { max-width: min(1600px, 100%); max-height: 100%; background: #fff; border-radius: 8px; padding: 10px; }

/* ---------- reveal ---------- */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
}