/* ===== Paper Library — shared styles (base palette shared with Class Notes) ===== */
:root {
  --bg: #ffffff;
  --surface: #ffffff;
  --ink: #14171b;
  --ink-soft: #4c5157;
  --line: #e3e7ea;

  --indigo: #4d7ea8;
  --indigo-dark: #375d7c;
  --violet: #7fb0c9;
  --teal: #5c9088;
  --coral: #cf9470;
  --amber: #d1ab68;
  --pink: #93b8cc;

  --dfs: #cf9470;
  --bfs: #5c9088;
  --ucs: #d1ab68;
  --ids: #6f93b0;

  --radius: 18px;
  --radius-sm: 10px;
  --shadow: 0 10px 26px -14px rgba(36, 39, 44, 0.16);
  --shadow-sm: 0 4px 12px -6px rgba(36, 39, 44, 0.1);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #15181c;
    --surface: #1d2126;
    --ink: #eef1f4;
    --ink-soft: #a9b1ba;
    --line: #2e343b;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 18px; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: 'Poppins', 'Inter', sans-serif;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

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

.site-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.9rem 1.5rem;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.site-nav .brand {
  font-family: 'Poppins', sans-serif;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--ink);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.site-nav .brand .dot { width: 10px; height: 10px; border-radius: 50%; background: var(--coral); display: inline-block; }

.site-nav nav { display: flex; gap: 1.25rem; font-weight: 600; font-size: 0.92rem; }
.site-nav nav a { color: var(--ink-soft); }
.site-nav nav a:hover { color: var(--indigo); text-decoration: none; }

.wrap { max-width: 1000px; margin: 0 auto; padding: 0 1.5rem; }

/* ---- hero ---- */
.hero {
  padding: 3.2rem 1.5rem 2.4rem;
  text-align: center;
  background:
    radial-gradient(60% 60% at 15% 0%, color-mix(in srgb, var(--violet) 8%, transparent), transparent 70%),
    radial-gradient(60% 60% at 90% 10%, color-mix(in srgb, var(--teal) 8%, transparent), transparent 70%);
}
.hero h1 { font-size: clamp(1.8rem, 4vw, 2.7rem); margin: 0 0 0.6rem; }
.hero p.lede { color: var(--ink-soft); max-width: 640px; margin: 0 auto 1.2rem; font-size: 1.05rem; }

.badges { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.5rem; margin-top: 1rem; }
.badge {
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 700;
  color: #fff;
}
.badge.dfs { background: var(--dfs); }
.badge.bfs { background: var(--bfs); }
.badge.ucs { background: var(--ucs); }
.badge.ids { background: var(--ids); }
.badge.dls { background: var(--pink); }
.badge.neutral { background: var(--indigo); }

/* ---- course cards (home page) ---- */
.grid-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
  padding: 2rem 0 3rem;
}
.card {
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--line);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.card .tag { font-size: 0.75rem; font-weight: 800; letter-spacing: 0.04em; text-transform: uppercase; color: var(--teal); }
.card h3 { margin: 0.4rem 0 0.5rem; font-size: 1.25rem; }
.card p { color: var(--ink-soft); margin: 0 0 1rem; font-size: 0.95rem; }
.card .go { font-weight: 700; font-size: 0.9rem; }
.card.soon { opacity: 0.6; }
.card.soon .go { color: var(--ink-soft); }

/* ---- sections ---- */
section.block { padding: 2.6rem 0; border-top: 1px solid var(--line); }
section.block:first-of-type { border-top: none; }

/* ---- algorithm sections: stronger, color-coded separation between DFS/BFS/UCS/DLS/IDS ---- */
section.algo-section { padding-top: 3.6rem; border-top: 4px solid var(--line); }
section.algo-section.dfs { border-top-color: var(--dfs); }
section.algo-section.bfs { border-top-color: var(--bfs); }
section.algo-section.ucs { border-top-color: var(--ucs); }
section.algo-section.dls { border-top-color: var(--pink); }
section.algo-section.ids { border-top-color: var(--ids); }
.eyebrow { color: var(--teal); font-weight: 800; letter-spacing: 0.06em; text-transform: uppercase; font-size: 0.78rem; margin: 0 0 0.4rem; }
h2.section-title { font-size: 1.7rem; margin: 0 0 0.6rem; }
.section-lede { color: var(--ink-soft); max-width: 700px; margin: 0 0 1.6rem; }

/* ---- in-page toc pills ---- */
.toc {
  position: sticky;
  top: 58px;
  z-index: 40;
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  padding: 0.8rem 1.5rem;
  background: color-mix(in srgb, var(--bg) 92%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
  margin-bottom: 0.5rem;
}
.toc a {
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--ink-soft);
  padding: 0.35rem 0.8rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--surface);
}
.toc a:hover { color: var(--indigo); text-decoration: none; border-color: var(--indigo); }

/* ---- concept bullet list ---- */
.concept-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 0.9rem; }
.concept-list li {
  position: relative; padding-left: 1.4rem; color: var(--ink-soft); line-height: 1.55;
}
.concept-list li::before {
  content: '';
  position: absolute; left: 0; top: 0.5em;
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--indigo);
}
.concept-list li b { color: var(--ink); }

/* ---- flip glossary cards ---- */
.flip-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 1rem; }
.flip-card { perspective: 1000px; height: 150px; cursor: pointer; }
.flip-inner {
  position: relative; width: 100%; height: 100%;
  transform-style: preserve-3d; transition: transform 0.5s cubic-bezier(.4,.2,.2,1);
}
.flip-card.flipped .flip-inner { transform: rotateY(180deg); }
.flip-face {
  position: absolute; inset: 0;
  backface-visibility: hidden;
  border-radius: var(--radius-sm);
  padding: 1rem;
  box-shadow: var(--shadow-sm);
}
.flip-front { background: linear-gradient(140deg, var(--indigo), var(--violet)); color: #fff; display: flex; flex-direction: column; justify-content: center; }
.flip-front .hint { font-size: 0.72rem; opacity: 0.85; margin-top: 0.4rem; }
.flip-front h4 { margin: 0; font-size: 1.05rem; }
.flip-back {
  background: var(--surface); border: 1px solid var(--line); transform: rotateY(180deg);
  font-size: 0.88rem; color: var(--ink-soft); overflow-y: auto;
}
.flip-back b { color: var(--ink); }

/* ---- tree explorer ---- */
.tree-panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  padding: 1rem;
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 1rem;
}
@media (max-width: 760px) { .tree-panel { grid-template-columns: 1fr; } }
.tree-panel svg { width: 100%; height: auto; }
.node circle, .node rect { stroke-width: 2.5; transition: all 0.25s ease; cursor: pointer; }
.node text { font-family: 'Poppins', sans-serif; font-weight: 700; font-size: 15px; fill: var(--ink); pointer-events: none; }
.node.goal circle, .node.goal rect { stroke-dasharray: 4 3; }
.edge { stroke: #b7bfc7; stroke-width: 2; }
.edge-label { font-size: 11px; fill: var(--ink-soft); font-weight: 700; }
.node-info {
  background: color-mix(in srgb, var(--indigo) 6%, var(--surface));
  border-radius: var(--radius-sm);
  border: 1px dashed var(--line);
  padding: 1rem;
  font-size: 0.92rem;
}
.node-info .placeholder { color: var(--ink-soft); }
.node-info dl { margin: 0; }
.node-info dt { font-weight: 700; color: var(--indigo); margin-top: 0.5rem; font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.03em; }
.node-info dd { margin: 0.15rem 0 0; }

.toggle-row { display: flex; gap: 0.5rem; flex-wrap: wrap; margin-bottom: 0.9rem; }
.toggle-btn {
  border: 1px solid var(--line);
  background: var(--surface);
  padding: 0.4rem 0.8rem;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.82rem;
  cursor: pointer;
  color: var(--ink-soft);
}
.toggle-btn.active { background: var(--indigo); border-color: var(--indigo); color: #fff; }

/* ---- simulator ---- */
.sim-panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  padding: 1.4rem;
}
.sliders { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 1.2rem; margin-bottom: 1.4rem; }
.slider-group label { display: flex; justify-content: space-between; font-weight: 700; font-size: 0.88rem; margin-bottom: 0.4rem; }
.slider-group .val { color: var(--indigo); font-family: 'Poppins', sans-serif; }
input[type="range"] { width: 100%; accent-color: var(--indigo); }

.bars { display: grid; gap: 0.7rem; }
.bar-row { display: grid; grid-template-columns: 110px 1fr 130px; align-items: center; gap: 0.7rem; font-size: 0.85rem; }
.bar-row .label { font-weight: 800; }
.bar-track { background: var(--bg); border-radius: 999px; height: 16px; overflow: hidden; border: 1px solid var(--line); }
.bar-fill { height: 100%; border-radius: 999px; transition: width 0.35s ease; }
.bar-row .num { font-variant-numeric: tabular-nums; text-align: right; color: var(--ink-soft); }

/* ---- playground ---- */
.playground {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  padding: 1.4rem;
}
.pg-controls { display: flex; flex-wrap: wrap; gap: 0.6rem; align-items: center; margin-bottom: 1rem; }
.strategy-pick { display: flex; gap: 0.4rem; flex-wrap: wrap; }
.strat-btn {
  border: 2px solid var(--line);
  background: var(--surface);
  padding: 0.4rem 0.9rem;
  border-radius: 999px;
  font-weight: 800;
  font-size: 0.82rem;
  cursor: pointer;
}
.strat-btn[data-s="dfs"].active { background: var(--dfs); border-color: var(--dfs); color: #fff; }
.strat-btn[data-s="bfs"].active { background: var(--bfs); border-color: var(--bfs); color: #fff; }
.strat-btn[data-s="ucs"].active { background: var(--ucs); border-color: var(--ucs); color: #fff; }
.play-btns { display: flex; gap: 0.4rem; margin-left: auto; }
.icon-btn {
  border: none; background: var(--indigo); color: #fff; width: 38px; height: 38px;
  border-radius: 50%; cursor: pointer; font-size: 1rem; display: flex; align-items: center; justify-content: center;
}
.icon-btn:hover { background: var(--indigo-dark); }
.icon-btn:disabled { opacity: 0.4; cursor: not-allowed; }

.pg-grid { display: grid; grid-template-columns: 1.3fr 1fr; gap: 1.2rem; }
@media (max-width: 760px) { .pg-grid { grid-template-columns: 1fr; } }

.frontier-box { background: color-mix(in srgb, var(--indigo) 5%, var(--surface)); border: 1px dashed var(--line); border-radius: var(--radius-sm); padding: 0.9rem; margin-bottom: 0.8rem; }
.frontier-box h5 { margin: 0 0 0.5rem; font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.04em; color: var(--ink-soft); }
.chip-row { display: flex; flex-wrap: wrap; gap: 0.4rem; min-height: 32px; }
.chip {
  padding: 0.25rem 0.6rem;
  border-radius: 8px;
  font-weight: 700;
  font-size: 0.82rem;
  background: var(--surface);
  border: 1.5px solid var(--line);
}
.log-box { max-height: 190px; overflow-y: auto; font-size: 0.85rem; }
.log-box p { margin: 0.2rem 0; padding: 0.3rem 0.5rem; border-radius: 6px; }
.log-box p.current { background: color-mix(in srgb, var(--amber) 20%, transparent); font-weight: 700; }
.log-box p.win { background: color-mix(in srgb, var(--teal) 20%, transparent); font-weight: 800; }
.log-box p.iter { text-align: center; font-weight: 800; color: var(--ids); background: none; margin: 0.7rem 0 0.3rem; padding: 0; }
.ids-readout { display: inline-flex; align-items: center; gap: 0.5rem; background: color-mix(in srgb, var(--ids) 10%, var(--surface)); border: 1px solid var(--ids); border-radius: 999px; padding: 0.4rem 0.9rem; font-weight: 800; font-size: 0.88rem; color: var(--ids); margin-bottom: 0.8rem; }

.node.visited circle, .node.visited rect { fill: color-mix(in srgb, var(--indigo) 14%, var(--surface)); }
.node.current circle, .node.current rect { fill: var(--amber); }
.node.frontier circle, .node.frontier rect { fill: var(--surface); stroke: var(--indigo); }
.node.found circle, .node.found rect { fill: var(--teal); }
.node.fail circle, .node.fail rect { fill: color-mix(in srgb, var(--coral) 20%, var(--surface)); stroke: var(--coral); }

/* ---- summary table ---- */
.table-wrap { overflow-x: auto; border-radius: var(--radius); box-shadow: var(--shadow-sm); border: 1px solid var(--line); }
table.summary { width: 100%; border-collapse: collapse; background: var(--surface); font-size: 0.92rem; }
table.summary th, table.summary td { padding: 0.8rem 1rem; text-align: left; border-bottom: 1px solid var(--line); }
table.summary thead th { background: var(--indigo); color: #fff; font-family: 'Poppins', sans-serif; }
table.summary tbody tr:hover { background: color-mix(in srgb, var(--indigo) 5%, transparent); }
table.summary tr[data-s="dfs"] td:first-child { border-left: 4px solid var(--dfs); }
table.summary tr[data-s="bfs"] td:first-child { border-left: 4px solid var(--bfs); }
table.summary tr[data-s="ucs"] td:first-child { border-left: 4px solid var(--ucs); }
table.summary tr[data-s="dls"] td:first-child { border-left: 4px solid var(--pink); }
table.summary tr[data-s="ids"] td:first-child { border-left: 4px solid var(--ids); }

/* ---- quiz ---- */
.quiz-card {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow-sm); padding: 1.2rem 1.4rem; margin-bottom: 1rem;
}
.quiz-card p.q { font-weight: 700; margin: 0 0 0.8rem; }
.quiz-opts { display: grid; gap: 0.5rem; }
.quiz-opt {
  text-align: left; padding: 0.6rem 0.9rem; border-radius: var(--radius-sm);
  border: 1.5px solid var(--line); background: var(--bg); cursor: pointer; font-size: 0.92rem;
}
.quiz-opt:hover { border-color: var(--indigo); }
.quiz-opt.correct { background: color-mix(in srgb, var(--teal) 22%, var(--surface)); border-color: var(--teal); }
.quiz-opt.wrong { background: color-mix(in srgb, var(--coral) 18%, var(--surface)); border-color: var(--coral); }
.quiz-opt[disabled] { cursor: default; }
.quiz-score {
  position: sticky; bottom: 1rem; margin-top: 1.5rem; background: var(--indigo); color: #fff;
  padding: 1rem 1.4rem; border-radius: var(--radius); box-shadow: var(--shadow);
  display: flex; justify-content: space-between; align-items: center; font-weight: 700;
}

footer { text-align: center; color: var(--ink-soft); font-size: 0.85rem; padding: 2.5rem 1.5rem 3rem; }

/* ===== Lab 02 additions ===== */

/* ---- 8-puzzle heuristic calculator ---- */
.puzzle-panel {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow-sm); padding: 1.4rem;
}
.puzzle-row { display: flex; flex-wrap: wrap; gap: 2rem; align-items: flex-start; margin-bottom: 1.2rem; }
.puzzle-board { display: grid; grid-template-columns: repeat(3, 52px); grid-template-rows: repeat(3, 52px); gap: 6px; }
.puzzle-tile {
  display: flex; align-items: center; justify-content: center;
  background: var(--bg); border: 1.5px solid var(--line); border-radius: 8px;
  font-family: 'Poppins', sans-serif; font-weight: 700; font-size: 1.2rem;
  transition: background 0.25s ease, border-color 0.25s ease;
}
.puzzle-tile.blank { background: transparent; border-style: dashed; }
.puzzle-tile.hl-misplaced { background: color-mix(in srgb, var(--coral) 25%, var(--bg)); border-color: var(--coral); }
.puzzle-label { font-size: 0.78rem; font-weight: 800; text-transform: uppercase; letter-spacing: 0.04em; color: var(--ink-soft); margin: 0 0 0.5rem; }
.puzzle-table { width: 100%; border-collapse: collapse; font-size: 0.85rem; }
.puzzle-table th, .puzzle-table td { padding: 0.4rem 0.5rem; text-align: center; border-bottom: 1px solid var(--line); }
.puzzle-table th { color: var(--ink-soft); font-weight: 700; }
.puzzle-totals { display: flex; gap: 1rem; margin-top: 1rem; flex-wrap: wrap; }
.puzzle-total {
  flex: 1; min-width: 160px; background: color-mix(in srgb, var(--indigo) 6%, var(--surface));
  border: 1px dashed var(--line); border-radius: var(--radius-sm); padding: 0.8rem 1rem;
}
.puzzle-total .n { font-family: 'Poppins', sans-serif; font-size: 1.6rem; font-weight: 800; color: var(--indigo); }
.puzzle-total .l { font-size: 0.78rem; color: var(--ink-soft); text-transform: uppercase; letter-spacing: 0.03em; }

/* ---- admissibility / consistency check card ---- */
.check-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 0.8rem; margin: 1rem 0; }
.check-card {
  background: var(--surface); border: 1.5px solid var(--line); border-radius: var(--radius-sm);
  padding: 0.9rem; text-align: center; cursor: pointer;
}
.check-card .node-id { font-family: 'Poppins', sans-serif; font-weight: 800; font-size: 1.1rem; }
.check-card .ineq { font-size: 0.82rem; margin-top: 0.4rem; font-variant-numeric: tabular-nums; }
.check-card.pass { border-color: var(--bfs); background: color-mix(in srgb, var(--bfs) 10%, var(--surface)); }
.check-card.fail { border-color: var(--coral); background: color-mix(in srgb, var(--coral) 10%, var(--surface)); }
.check-card .verdict { font-size: 0.72rem; font-weight: 800; text-transform: uppercase; letter-spacing: 0.03em; margin-top: 0.3rem; }
.check-card.pass .verdict { color: var(--bfs); }
.check-card.fail .verdict { color: var(--coral); }

/* ---- simulated annealing widget ---- */
.sa-readout { display: flex; gap: 1rem; flex-wrap: wrap; margin: 1rem 0; }
.sa-readout .stat { background: color-mix(in srgb, var(--indigo) 6%, var(--surface)); border: 1px dashed var(--line); border-radius: var(--radius-sm); padding: 0.8rem 1.1rem; flex: 1; min-width: 140px; }
.sa-readout .stat .n { font-family: 'Poppins', sans-serif; font-size: 1.5rem; font-weight: 800; color: var(--indigo); }
.sa-readout .stat .l { font-size: 0.78rem; color: var(--ink-soft); text-transform: uppercase; letter-spacing: 0.03em; }
.sa-bar-track { background: var(--bg); border: 1px solid var(--line); border-radius: 999px; height: 22px; overflow: hidden; }
.sa-bar-fill { height: 100%; background: linear-gradient(90deg, var(--coral), var(--amber)); transition: width 0.3s ease; }

/* ---- beam width control ---- */
.beam-control { display: none; align-items: center; gap: 0.8rem; margin-top: 0.8rem; }
.beam-control.show { display: flex; }
.beam-control label { font-weight: 700; font-size: 0.85rem; }
.beam-control input[type="range"] { flex: 1; max-width: 220px; }
.beam-control .val { font-family: 'Poppins', sans-serif; font-weight: 800; color: var(--indigo); min-width: 1.5rem; }

/* ---- research paper cards ---- */
.paper-group { margin-bottom: 1.8rem; }
.paper-group h3 { font-size: 1.1rem; margin: 0 0 0.7rem; display: flex; align-items: center; gap: 0.5rem; }
.paper-card {
  background: var(--surface); border: 1px solid var(--line); border-left: 4px solid var(--indigo);
  border-radius: var(--radius-sm); box-shadow: var(--shadow-sm); padding: 1.1rem 1.3rem; margin-bottom: 0.9rem;
}
.paper-card h4 { margin: 0 0 0.2rem; font-size: 1.02rem; }
.paper-card .venue { font-size: 0.78rem; font-weight: 700; color: var(--ink-soft); margin-bottom: 0.6rem; }
.paper-card .venue a { color: inherit; }
.paper-card dl { margin: 0; display: grid; gap: 0.5rem; }
.paper-card dt { font-size: 0.72rem; font-weight: 800; text-transform: uppercase; letter-spacing: 0.03em; color: var(--indigo); }
.paper-card dd { margin: 0.1rem 0 0; font-size: 0.9rem; }
.paper-card .go { display: inline-block; margin-top: 0.7rem; font-weight: 700; font-size: 0.85rem; }

/* ---- deep-dive paper pages ---- */
.fail-badge {
  display: inline-flex; align-items: center; gap: 0.4rem;
  background: color-mix(in srgb, var(--coral) 12%, var(--surface)); border: 1px dashed var(--coral);
  border-radius: var(--radius-sm); padding: 0.5rem 0.8rem; font-size: 0.85rem; color: var(--ink-soft); margin-top: 0.8rem;
}
.fail-badge b { color: var(--coral); }
.caption-note { font-size: 0.82rem; color: var(--ink-soft); background: color-mix(in srgb, var(--amber) 10%, var(--surface)); border: 1px dashed var(--line); border-radius: var(--radius-sm); padding: 0.7rem 0.9rem; margin: 0.8rem 0; }

/* ---- definition box: for terms used right after (more prominent than a caption-note) ---- */
.definition-box {
  background: color-mix(in srgb, var(--indigo) 8%, var(--surface));
  border: 1.5px solid var(--indigo);
  border-left: 5px solid var(--indigo);
  border-radius: var(--radius-sm);
  padding: 1rem 1.2rem;
  margin: 1.2rem 0;
}
.definition-box .dbox-label {
  font-size: 0.72rem; font-weight: 800; text-transform: uppercase; letter-spacing: 0.05em;
  color: var(--indigo); margin-bottom: 0.4rem; display: flex; align-items: center; gap: 0.4rem;
}
.definition-box p { margin: 0; font-size: 0.98rem; color: var(--ink); line-height: 1.5; }
.stat-strip { display: flex; flex-wrap: wrap; gap: 0.8rem; margin: 1.2rem 0; }
.stat-strip .stat { flex: 1; min-width: 130px; background: color-mix(in srgb, var(--indigo) 6%, var(--surface)); border: 1px dashed var(--line); border-radius: var(--radius-sm); padding: 0.9rem 1rem; text-align: center; }
.stat-strip .stat .n { font-family: 'Poppins', sans-serif; font-size: 1.4rem; font-weight: 800; color: var(--indigo); display: block; }
.stat-strip .stat .l { font-size: 0.72rem; color: var(--ink-soft); text-transform: uppercase; letter-spacing: 0.03em; }
.funnel { display: grid; gap: 0.5rem; margin: 1rem 0; }
.funnel-row { display: grid; grid-template-columns: 170px 1fr 90px; align-items: center; gap: 0.7rem; font-size: 0.85rem; }
.funnel-row .label { font-weight: 700; }
.funnel-row .num { text-align: right; font-variant-numeric: tabular-nums; color: var(--ink-soft); }
.back-link { display: inline-block; margin-bottom: 1rem; font-weight: 700; font-size: 0.88rem; }

/* ---- per-algorithm stat card (Complete / Optimal / Time / Space) ---- */
.algo-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  margin: 1.2rem 0;
}
@media (max-width: 640px) {
  .algo-stats { grid-template-columns: repeat(2, 1fr); }
}
.algo-stats.dfs { border-top: 3px solid var(--dfs); }
.algo-stats.bfs { border-top: 3px solid var(--bfs); }
.algo-stats.ucs { border-top: 3px solid var(--ucs); }
.algo-stats.ids { border-top: 3px solid var(--ids); }
.algo-stats.dls { border-top: 3px solid var(--pink); }
.algo-stat { background: var(--surface); padding: 1rem 1.1rem; }
.algo-stat .label { font-size: 0.72rem; font-weight: 800; text-transform: uppercase; letter-spacing: 0.04em; color: var(--ink-soft); margin-bottom: 0.35rem; }
.algo-stat .value { font-family: 'Poppins', sans-serif; font-size: 1.05rem; font-weight: 700; color: var(--ink); }
.algo-stat .detail { font-size: 0.8rem; color: color-mix(in srgb, var(--ink) 65%, var(--ink-soft) 35%); margin-top: 0.35rem; line-height: 1.5; }

/* ---- static depth-limit diagram (DLS) ---- */
.dl-diagram { width: 100%; height: auto; }
.dl-diagram .lvl-line { stroke: #e3e7ea; stroke-width: 1; stroke-dasharray: 3 4; }
.dl-diagram .lvl-label { font-size: 12px; font-weight: 800; fill: var(--ink-soft); }
.dl-diagram .edge { stroke: #c9c1da; stroke-width: 2; }
.dl-diagram .edge.beyond { stroke: #d8d3e0; stroke-width: 1.5; stroke-dasharray: 3 3; }
.dl-diagram circle.node-circle { fill: #fff; stroke: var(--pink); stroke-width: 2.5; }
.dl-diagram circle.node-circle.beyond { stroke: #cfd3d6; stroke-dasharray: 3 3; fill: color-mix(in srgb, var(--ink-soft) 6%, #fff); }
.dl-diagram text.node-label { font-family: 'Poppins', sans-serif; font-weight: 700; font-size: 14px; fill: var(--ink); text-anchor: middle; }
.dl-diagram text.node-label.beyond { fill: var(--ink-soft); }
.dl-diagram .limit-line { stroke: var(--pink); stroke-width: 2.5; stroke-dasharray: 7 5; }
.dl-diagram .limit-label { font-family: 'Poppins', sans-serif; font-size: 13px; font-weight: 800; fill: var(--pink); }

/* ---- back-to-back comparison bars (e.g. IDS vs BFS) ---- */
.b2b-header { display: grid; grid-template-columns: 90px 1fr 3px 1fr 90px; gap: 0.6rem; margin-bottom: 0.5rem; }
.b2b-header .side-label { font-weight: 800; font-family: 'Poppins', sans-serif; font-size: 0.9rem; text-align: center; grid-column: span 1; }
.b2b-header .side-label.left { grid-column: 2; color: var(--ids); }
.b2b-header .side-label.right { grid-column: 4; color: var(--bfs); }
.b2b-chart { display: grid; grid-template-columns: 90px 1fr 3px 1fr 90px; align-items: center; gap: 0.6rem; }
.b2b-value { font-weight: 800; font-family: 'Poppins', sans-serif; font-size: 0.95rem; }
.b2b-value.left { text-align: right; }
.b2b-value.right { text-align: left; }
.b2b-track { height: 26px; background: var(--bg); border: 1px solid var(--line); border-radius: 6px; overflow: hidden; }
.b2b-track.left { display: flex; justify-content: flex-end; }
.b2b-track.right { display: flex; justify-content: flex-start; }
.b2b-fill { height: 100%; border-radius: 6px; }
.b2b-center { width: 3px; align-self: stretch; background: var(--ink-soft); border-radius: 2px; }

/* ===================================================================
   Paper Library — home page
   =================================================================== */

.hero .stats { display: flex; justify-content: center; gap: 2.2rem; margin-top: 1.6rem; flex-wrap: wrap; }
.hero .stats div { display: flex; flex-direction: column; align-items: center; }
.hero .stats .n { font-family: 'Poppins', sans-serif; font-weight: 700; font-size: 1.6rem; line-height: 1.1; }
.hero .stats .l { font-size: 0.78rem; color: var(--ink-soft); text-transform: uppercase; letter-spacing: 0.05em; font-weight: 700; }

/* ---- search + topic filter ---- */
.lib-controls {
  display: flex; flex-direction: column; gap: 0.9rem;
  padding: 1.1rem 0 0.4rem;
}
.lib-search {
  position: relative;
  max-width: 460px;
}
.lib-search input {
  width: 100%;
  font: inherit; font-size: 0.95rem;
  color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.6rem 1rem 0.6rem 2.4rem;
  outline: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
.lib-search input:focus { border-color: var(--indigo); box-shadow: 0 0 0 3px color-mix(in srgb, var(--indigo) 18%, transparent); }
.lib-search svg { position: absolute; left: 0.9rem; top: 50%; transform: translateY(-50%); width: 16px; height: 16px; color: var(--ink-soft); pointer-events: none; }

.topic-row { display: flex; flex-wrap: wrap; gap: 0.45rem; }
.topic-btn {
  font: inherit; font-size: 0.8rem; font-weight: 700;
  color: var(--ink-soft);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.32rem 0.8rem;
  cursor: pointer;
  transition: all 0.15s ease;
}
.topic-btn:hover { border-color: var(--indigo); color: var(--indigo); }
.topic-btn.active { background: var(--indigo); border-color: var(--indigo); color: #fff; }
.topic-btn .count { opacity: 0.65; font-weight: 600; margin-left: 0.25rem; }

.result-note { font-size: 0.85rem; color: var(--ink-soft); margin: 0; min-height: 1.3em; }

/* ---- paper cards ---- */
.paper-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: 1.25rem;
  padding: 1rem 0 2.5rem;
}
.lib-card {
  display: flex; flex-direction: column;
  background: var(--surface);
  border: 1px solid var(--line);
  border-top: 4px solid var(--accent, var(--indigo));
  border-radius: var(--radius);
  padding: 1.3rem 1.4rem 1.2rem;
  box-shadow: var(--shadow-sm);
  color: inherit;
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}
a.lib-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); text-decoration: none; }
.lib-card .venue {
  display: flex; justify-content: space-between; align-items: baseline; gap: 0.6rem;
  font-size: 0.74rem; font-weight: 800; letter-spacing: 0.05em; text-transform: uppercase;
  color: var(--accent, var(--teal));
}
.lib-card .venue .status { color: var(--ink-soft); font-weight: 700; letter-spacing: 0.03em; }
.lib-card h3 { margin: 0.45rem 0 0.15rem; font-size: 1.3rem; }
.lib-card .full-title { margin: 0 0 0.35rem; font-size: 0.88rem; font-weight: 600; color: var(--ink); line-height: 1.4; }
.lib-card .authors { margin: 0 0 0.75rem; font-size: 0.8rem; color: var(--ink-soft); }
.lib-card .hook { margin: 0 0 0.9rem; font-size: 0.92rem; color: var(--ink-soft); line-height: 1.55; }
.lib-card .interactive {
  display: flex; gap: 0.5rem; align-items: flex-start;
  margin: 0 0 1rem; padding: 0.55rem 0.7rem;
  font-size: 0.82rem; line-height: 1.45;
  background: color-mix(in srgb, var(--accent, var(--indigo)) 9%, transparent);
  border-radius: var(--radius-sm);
}
.lib-card .interactive .ic { flex: none; font-size: 0.9rem; line-height: 1.3; }
.lib-card .topics { display: flex; flex-wrap: wrap; gap: 0.35rem; margin-top: auto; padding-top: 0.2rem; }
.lib-card .topics span {
  font-size: 0.72rem; font-weight: 700;
  padding: 0.18rem 0.55rem; border-radius: 999px;
  border: 1px solid var(--line); color: var(--ink-soft);
}
.lib-card .go { margin-top: 0.9rem; font-weight: 700; font-size: 0.88rem; color: var(--indigo); }
.lib-card.soon { opacity: 0.62; box-shadow: none; }
.lib-card.soon .go { color: var(--ink-soft); }

.empty-state {
  grid-column: 1 / -1;
  text-align: center; color: var(--ink-soft);
  padding: 2.5rem 1rem;
  border: 1px dashed var(--line); border-radius: var(--radius);
}
.empty-state button { font: inherit; font-weight: 700; color: var(--indigo); background: none; border: 0; cursor: pointer; padding: 0; }

/* ---- "what's in a deep dive" strip ---- */
.anatomy {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 0.9rem;
  counter-reset: step;
}
.anatomy div {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 0.95rem 1rem 0.9rem;
}
.anatomy div::before {
  counter-increment: step;
  content: counter(step, decimal-leading-zero);
  display: block;
  font-family: 'Poppins', sans-serif; font-weight: 700; font-size: 0.8rem;
  color: var(--c, var(--indigo));
  margin-bottom: 0.2rem;
}
.anatomy b { display: block; font-size: 0.95rem; margin-bottom: 0.2rem; }
.anatomy span { font-size: 0.82rem; color: var(--ink-soft); line-height: 1.45; display: block; }

@media (max-width: 560px) {
  .wrap { padding: 0 1rem; }
  .site-nav { padding: 0.8rem 1rem; }
  .hero { padding: 2.4rem 1rem 1.8rem; }
  .hero .stats { gap: 1.4rem; }
  .paper-grid { grid-template-columns: 1fr; }
}

/* ===================================================================
   Paper pages
   =================================================================== */
.paper-links { font-size: 0.88rem; font-weight: 600; color: var(--ink-soft); margin: -0.4rem 0 0.4rem; }
.paper-links a { font-weight: 700; }

/* ---- charts (validated palette: see dataviz check — blue = validation/primary, orange = test/highlight) ---- */
:root { --viz-a: #3d7fc0; --viz-b: #d27228; --viz-neutral: #9aa3ab; --viz-grid: #eceff1; }
@media (prefers-color-scheme: dark) {
  :root { --viz-a: #5494d0; --viz-b: #d2742b; --viz-neutral: #6f7880; --viz-grid: #2a3036; }
}
svg.viz { width: 100%; height: auto; display: block; overflow: visible; font-family: 'Inter', sans-serif; }
svg.viz .grid { stroke: var(--viz-grid); stroke-width: 1; }
svg.viz .tick { font-size: 11px; fill: var(--ink-soft); }
svg.viz .row-label { font-size: 13px; font-weight: 600; fill: var(--ink); }
svg.viz .row-label.strong, svg.viz .val-label.strong { font-weight: 800; }
svg.viz .val-label { font-size: 12px; font-weight: 600; fill: var(--ink-soft); font-variant-numeric: tabular-nums; }
svg.viz .val-label.muted { font-style: italic; font-weight: 500; }
svg.viz .hit { fill: transparent; }
svg.viz .row:hover .hit, svg.viz .row:focus .hit { fill: color-mix(in srgb, var(--ink) 4%, transparent); }
svg.viz .row:focus { outline: none; }
svg.viz .connector { stroke: var(--viz-neutral); stroke-width: 2; }
svg.viz .lollipop { stroke: var(--viz-grid); stroke-width: 2; }
svg.viz .dot { stroke: var(--surface); stroke-width: 2; }
svg.viz .dot.val { fill: var(--viz-a); }
svg.viz .dot.test { fill: var(--viz-b); }
svg.viz .dot.neutral { fill: var(--viz-neutral); }
svg.viz .bar { fill: var(--viz-a); }
svg.viz .axis-line { stroke: var(--ink-soft); stroke-width: 1; }
svg.viz .zone { fill: color-mix(in srgb, var(--viz-b) 12%, transparent); }
svg.viz .zone-label { font-size: 12px; font-weight: 700; fill: var(--ink-soft); }
svg.viz .mark .stem { stroke: var(--viz-neutral); stroke-width: 1; }
svg.viz .mark .mark-label { font-size: 12px; font-weight: 700; fill: var(--ink); }
svg.viz .mark.muted .dot { fill: var(--viz-neutral); }
svg.viz .mark.val .dot { fill: var(--viz-a); }
svg.viz .mark.test .dot { fill: var(--viz-b); }
svg.viz .mark.thr .dot { fill: var(--ink); }
svg.viz .mark.thr .stem { stroke: var(--ink); stroke-width: 2; }

.viz-legend { display: flex; gap: 1.1rem; font-size: 0.82rem; font-weight: 600; color: var(--ink-soft); margin-bottom: 0.6rem; }
.viz-legend .sw { display: inline-block; width: 10px; height: 10px; border-radius: 50%; margin-right: 0.4rem; vertical-align: -1px; }
.viz-legend .sw-val { background: var(--viz-a); }
.viz-legend .sw-test { background: var(--viz-b); }
.viz-table { margin-top: 0.8rem; font-size: 0.85rem; }
.viz-table summary { cursor: pointer; color: var(--ink-soft); font-weight: 700; }
.viz-table table { margin-top: 0.6rem; }
.viz-tip {
  position: fixed; z-index: 100; pointer-events: none; max-width: 260px;
  background: var(--surface); color: var(--ink); border: 1px solid var(--line);
  border-radius: 8px; box-shadow: var(--shadow); padding: 0.5rem 0.7rem; font-size: 0.8rem; line-height: 1.45;
}
.viz-tip .k { color: var(--ink-soft); display: inline-block; min-width: 72px; }

/* ===================================================================
   Paper: stylometric code detection
   =================================================================== */
.cd-stats .stat .n { font-size: 1.25rem; }
.cd-h3 { font-size: 1.15rem; margin: 1.8rem 0 0.5rem; }
.cd-h3:first-of-type { margin-top: 0.4rem; }

/* pipeline explorer */
.cd-pipe-wrap { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 1.4rem; align-items: start; }
@media (max-width: 760px) { .cd-pipe-wrap { grid-template-columns: 1fr; } }
.cd-pipe { display: flex; flex-direction: column; align-items: stretch; }
.cd-pipe .row { display: flex; justify-content: center; gap: 0.6rem; }
.cd-pipe .row.two .stage { flex: 1; min-width: 0; }
.cd-pipe .arrow { text-align: center; color: var(--ink-soft); line-height: 1.2; font-size: 0.9rem; }
.cd-pipe .stage {
  --c: var(--indigo);
  font: inherit; font-size: 0.85rem; font-weight: 700; color: var(--ink);
  min-width: 60%; padding: 0.55rem 0.8rem; cursor: pointer;
  background: color-mix(in srgb, var(--c) 10%, var(--surface));
  border: 1.5px solid color-mix(in srgb, var(--c) 45%, var(--surface));
  border-radius: 10px; transition: all 0.15s ease;
}
.cd-pipe .stage:hover { border-color: var(--c); }
.cd-pipe .stage.active { background: var(--c); border-color: var(--c); color: #fff; box-shadow: var(--shadow-sm); }
.cd-pipe .stage.io { --c: var(--ink-soft); }
.cd-pipe .stage.aux { --c: var(--teal); }
.cd-pipe .stage.parse { --c: var(--ids); }
.cd-pipe .stage.feat { --c: var(--amber); }
.cd-pipe .stage.ml { --c: var(--indigo); }
.cd-pipe .stage.logic { --c: var(--coral); }
.cd-stage-info {
  position: sticky; top: 130px;
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow-sm); padding: 1.2rem 1.3rem; font-size: 0.92rem;
}
.cd-stage-info h4 { margin: 0 0 0.4rem; font-size: 1.1rem; }
.cd-stage-info p { margin: 0 0 0.6rem; color: var(--ink-soft); }
.cd-stage-info dl { margin: 0; display: grid; gap: 0.1rem; }
.cd-stage-info dt { font-weight: 700; color: var(--indigo); margin-top: 0.45rem; font-size: 0.74rem; text-transform: uppercase; letter-spacing: 0.03em; }
.cd-stage-info dd { margin: 0; }

/* feature x-ray */
.cd-code, .cd-lines code { font-family: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace; }
.cd-code {
  width: 100%; min-height: 190px; resize: vertical; tab-size: 4;
  font-size: 0.8rem; line-height: 1.55; color: var(--ink);
  background: color-mix(in srgb, var(--ink) 3%, var(--surface));
  border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 0.8rem 0.9rem; outline: none;
}
.cd-code:focus { border-color: var(--indigo); }
.cd-xray { display: grid; grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr); gap: 1.2rem; margin-top: 1rem; }
@media (max-width: 760px) { .cd-xray { grid-template-columns: 1fr; } }
.cd-lines { max-height: 420px; overflow: auto; font-size: 0.76rem; }
.cd-lines .ln { display: grid; grid-template-columns: 72px 1fr; align-items: baseline; gap: 0.5rem; padding: 1px 4px; border-radius: 4px; }
.cd-lines .ln code { white-space: pre-wrap; overflow-wrap: anywhere; }
.cd-lines .tag { font-size: 0.64rem; font-weight: 800; text-transform: uppercase; letter-spacing: 0.04em; color: var(--ink-soft); text-align: right; }
.cd-lines .ln.comment { background: color-mix(in srgb, var(--viz-a) 11%, transparent); }
.cd-lines .ln.comment .tag { color: var(--viz-a); }
.cd-lines .ln.text, .cd-lines .ln.marker { background: color-mix(in srgb, var(--viz-b) 14%, transparent); }
.cd-lines .ln.text .tag, .cd-lines .ln.marker .tag { color: var(--viz-b); }
.cd-lines mark { background: color-mix(in srgb, var(--amber) 45%, transparent); color: inherit; border-radius: 3px; padding: 0 1px; }
.cd-lines .muted, .cd-verdict span, .cd-rule span { color: var(--ink-soft); }

.cd-meter { margin-bottom: 0.85rem; }
.cd-meter .top { display: flex; justify-content: space-between; font-size: 0.85rem; font-weight: 700; }
.cd-meter .top b { font-family: 'Poppins', sans-serif; font-variant-numeric: tabular-nums; }
.cd-meter .track { position: relative; height: 10px; background: var(--bg); border: 1px solid var(--line); border-radius: 999px; margin: 0.3rem 0; overflow: visible; }
.cd-meter .fill { height: 100%; background: var(--viz-a); border-radius: 999px; transition: width 0.25s ease; }
.cd-meter .thr { position: absolute; top: -4px; bottom: -4px; width: 2px; background: var(--ink); z-index: 1; }
.cd-meter .detail { font-size: 0.76rem; color: var(--ink-soft); }
.cd-bucket { font-size: 0.8rem; color: var(--ink-soft); margin: 0.2rem 0 0; }

.cd-pill { display: inline-block; font-size: 0.68rem; font-weight: 800; padding: 0.08rem 0.45rem; border-radius: 999px; border: 1px solid var(--line); white-space: nowrap; }
.cd-pill.keep { color: var(--viz-a); border-color: color-mix(in srgb, var(--viz-a) 45%, transparent); }
.cd-pill.rule { color: var(--viz-b); border-color: color-mix(in srgb, var(--viz-b) 45%, transparent); }
.cd-pill.drop { color: var(--ink-soft); }
.cd-sub { font-size: 0.76rem; color: var(--ink-soft); }

.cd-rule { display: grid; grid-template-columns: 62px 1fr; gap: 0.5rem; font-size: 0.82rem; padding: 0.45rem 0; border-bottom: 1px solid var(--line); }
.cd-rule .st { font-weight: 800; font-size: 0.74rem; color: var(--ink-soft); padding-top: 0.1rem; }
.cd-rule.on .st { color: var(--viz-b); }
.cd-verdict { margin-top: 0.7rem; padding: 0.6rem 0.75rem; border-radius: var(--radius-sm); font-size: 0.82rem; line-height: 1.45; }
.cd-verdict.machine { background: color-mix(in srgb, var(--viz-b) 14%, var(--surface)); }
.cd-verdict.tree { background: color-mix(in srgb, var(--viz-a) 10%, var(--surface)); }
.cd-verdict b { display: block; font-size: 0.92rem; }
section.block[id] { scroll-margin-top: 110px; }
@media (max-width: 560px) {
  .site-nav .brand { white-space: nowrap; font-size: 1rem; }
  .site-nav nav { gap: 0.9rem; font-size: 0.85rem; white-space: nowrap; }
  .toc { top: 52px; flex-wrap: nowrap; overflow-x: auto; scrollbar-width: none; padding: 0.6rem 1rem; }
  .toc::-webkit-scrollbar { display: none; }
  .toc a { white-space: nowrap; flex: none; }
  section.block[id] { scroll-margin-top: 100px; }
}
@media (max-width: 560px) {
  .playground, .sim-panel { padding: 1rem 0.8rem; }
  .cd-lines .ln { grid-template-columns: 50px 1fr; gap: 0.35rem; }
  .cd-lines .tag { font-size: 0.56rem; }
}

/* shared chart bits used by several papers */
svg.viz .bar.hl { fill: var(--viz-b); }
svg.viz .bar.muted { fill: var(--viz-neutral); }
svg.viz .chance { stroke: var(--ink-soft); stroke-width: 1; stroke-dasharray: 3 3; }
svg.viz .ci { stroke: var(--ink); stroke-width: 1.5; }
svg.viz .series { fill: none; stroke-width: 2.5; stroke-linejoin: round; }
svg.viz .series.a { stroke: var(--viz-a); }
svg.viz .series.b { stroke: var(--viz-b); }
svg.viz .ref { stroke: var(--ink-soft); stroke-width: 1; stroke-dasharray: 4 3; }
svg.viz .ref-label { font-size: 11px; font-weight: 700; fill: var(--ink-soft); }
svg.viz .cur { stroke: var(--ink); stroke-width: 1.5; }
svg.viz .cross { fill: var(--surface); stroke: var(--ink); stroke-width: 1.5; }

/* ===================================================================
   Paper: CAP — open QA correctness
   =================================================================== */
.cap-fig1 { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow-sm); padding: 1.2rem 1.3rem; margin: 0 0 1.6rem; max-width: 760px; }
.cap-fig1 p { margin: 0 0 0.5rem; }
.cap-fig1 .k, .cap-ex .k { display: inline-block; min-width: 86px; font-size: 0.72rem; font-weight: 800; text-transform: uppercase; letter-spacing: 0.04em; color: var(--ink-soft); }
.cap-fig1 .g { font-weight: 700; }
.cap-fig1-rows { display: grid; grid-template-columns: 1fr 1fr; gap: 0.8rem; margin-top: 0.8rem; }
@media (max-width: 640px) { .cap-fig1-rows { grid-template-columns: 1fr; } }
.cap-fig1 .ans { border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 0.75rem 0.85rem; }
.cap-fig1 .ans .lab { font-size: 0.7rem; font-weight: 800; text-transform: uppercase; letter-spacing: 0.04em; padding: 0.1rem 0.5rem; border-radius: 999px; }
.cap-fig1 .ans.bad .lab { color: var(--viz-b); border: 1px solid color-mix(in srgb, var(--viz-b) 50%, transparent); }
.cap-fig1 .ans.good .lab { color: var(--teal); border: 1px solid color-mix(in srgb, var(--teal) 50%, transparent); }
.cap-fig1 .ans p { margin: 0.5rem 0 0.6rem; font-size: 0.95rem; }
.cap-fig1 dl { display: flex; gap: 0.5rem; margin: 0; flex-wrap: wrap; }
.cap-fig1 dl div { flex: 1; min-width: 70px; text-align: center; background: color-mix(in srgb, var(--ink) 4%, var(--surface)); border-radius: 8px; padding: 0.3rem 0.2rem; }
.cap-fig1 dl div.cap { background: color-mix(in srgb, var(--viz-a) 14%, var(--surface)); }
.cap-fig1 dt { font-size: 0.66rem; font-weight: 700; color: var(--ink-soft); text-transform: uppercase; letter-spacing: 0.03em; }
.cap-fig1 dd { margin: 0; font-family: 'Poppins', sans-serif; font-weight: 700; font-size: 1.05rem; }
.cap-fig1 .src { font-size: 0.75rem; color: var(--ink-soft); margin: 0.7rem 0 0; }

/* taxonomy explorer */
.cap-tax { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr); gap: 1.4rem; align-items: start; }
@media (max-width: 760px) { .cap-tax { grid-template-columns: 1fr; } }
.cap-ladder { list-style: none; margin: 0; padding: 0; }
.cap-ladder li.rel { text-align: center; font-weight: 800; color: var(--ink-soft); line-height: 1; padding: 0.15rem 0; font-size: 0.95rem; }
.cap-rung {
  width: 100%; font: inherit; color: var(--ink); text-align: left; cursor: pointer;
  display: grid; grid-template-columns: 30px 1fr; grid-template-rows: auto auto; column-gap: 0.6rem;
  padding: 0.5rem 0.75rem; border-radius: 10px;
  background: var(--surface); border: 1.5px solid var(--line);
  border-left: 5px solid color-mix(in srgb, var(--viz-b) calc(var(--t) * 100%), var(--teal));
  transition: all 0.15s ease;
}
.cap-rung:hover { border-color: var(--indigo); border-left-color: color-mix(in srgb, var(--viz-b) calc(var(--t) * 100%), var(--teal)); }
.cap-rung.active { background: color-mix(in srgb, var(--indigo) 9%, var(--surface)); border-color: var(--indigo); border-left-color: color-mix(in srgb, var(--viz-b) calc(var(--t) * 100%), var(--teal)); box-shadow: var(--shadow-sm); }
.cap-rung .num { grid-row: 1 / 3; align-self: center; font-family: 'Poppins', sans-serif; font-weight: 800; font-size: 1rem; color: var(--ink-soft); text-align: center; }
.cap-rung .nm { font-weight: 800; font-size: 0.9rem; }
.cap-rung .df { font-size: 0.76rem; color: var(--ink-soft); line-height: 1.35; }
.cap-tax-info {
  position: sticky; top: 130px;
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow-sm); padding: 1.2rem 1.3rem; font-size: 0.9rem;
}
.cap-tax-info h4 { margin: 0 0 0.2rem; font-size: 1.2rem; }
.cap-tax-info .def { margin: 0 0 0.8rem; color: var(--ink-soft); }
.cap-tax-info dl { margin: 0.8rem 0 0; }
.cap-tax-info dt { font-weight: 700; color: var(--indigo); margin-top: 0.55rem; font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.03em; }
.cap-tax-info dd { margin: 0.1rem 0 0; }
.cap-ex { background: color-mix(in srgb, var(--ink) 3%, var(--surface)); border: 1px dashed var(--line); border-radius: var(--radius-sm); padding: 0.7rem 0.85rem; }
.cap-ex p { margin: 0 0 0.3rem; display: grid; grid-template-columns: 86px 1fr; }
.cap-ex .k { min-width: 0; padding-top: 0.15rem; }
.cap-ex .pred { font-weight: 700; }
.cap-ex .stmt { font-style: italic; color: var(--ink-soft); font-size: 0.86rem; }
.cap-ex .src { display: block; font-size: 0.72rem; color: var(--ink-soft); margin: 0.45rem 0 0; }

/* formula + calculator */
.cap-formula { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 0.9rem 1.1rem; margin: 0 0 1.2rem; font-size: 1rem; }
.cap-formula div { margin: 0.2rem 0; font-family: 'Poppins', sans-serif; font-weight: 600; }
.cap-formula .lhs { display: inline-block; min-width: 88px; }
.cap-formula .alp, .cap-formula .lam { color: var(--viz-b); }
.cap-formula p { margin: 0.45rem 0 0; font-size: 0.8rem; color: var(--ink-soft); }
.cap-ctl-label { font-size: 0.82rem; font-weight: 700; color: var(--ink-soft); }
.cap-dirs { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-bottom: 1.2rem; }
@media (max-width: 640px) { .cap-dirs { grid-template-columns: 1fr; } }
.cap-dir { border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 0.9rem 1rem; background: color-mix(in srgb, var(--ink) 2%, var(--surface)); }
.cap-dir h5 { margin: 0; font-size: 0.95rem; font-family: 'Poppins', sans-serif; }
.cap-dir .sub { margin: 0.15rem 0 0.6rem; font-size: 0.76rem; color: var(--ink-soft); }
.cap-dir .slider-group { margin-top: 0.5rem; }
.cap-dir .slider-group label { font-size: 0.8rem; margin-bottom: 0.15rem; }
.cap-stack { display: flex; height: 14px; border-radius: 999px; overflow: hidden; gap: 2px; background: var(--surface); }
.cap-stack i { display: block; height: 100%; transition: width 0.2s ease; }
.cap-stack .e { background: var(--viz-a); }
.cap-stack .n { background: var(--viz-neutral); }
.cap-stack .c { background: var(--viz-b); }
.cap-dir .contra { font-size: 0.8rem; margin: 0.4rem 0 0; }
.cap-dir .contra span { color: var(--ink-soft); }
.cap-dir .dval { margin: 0.5rem 0 0; font-size: 0.85rem; font-variant-numeric: tabular-nums; }
.cap-hyper { margin-bottom: 1rem; }
.cap-result { border-top: 1px solid var(--line); padding-top: 0.9rem; }
.cap-meter-big { height: 16px; border-radius: 999px; background: var(--bg); border: 1px solid var(--line); overflow: hidden; }
.cap-meter-big .fill { height: 100%; background: var(--viz-a); border-radius: 999px; transition: width 0.2s ease; }
.cap-eq { margin: 0.6rem 0 0; font-size: 0.95rem; font-variant-numeric: tabular-nums; }
.cap-eq b { font-family: 'Poppins', sans-serif; font-size: 1.2rem; }
.cap-best td { background: color-mix(in srgb, var(--viz-b) 9%, transparent); }

/* results */
.cap-measure-note { font-size: 0.82rem; color: var(--ink-soft); margin: 0 0 0.6rem; }
.cap-pairs { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0.9rem; }
@media (max-width: 760px) { .cap-pairs { grid-template-columns: 1fr; } }
.cap-pair { padding: 0.9rem 1rem 0.6rem; }
.cap-pair h5 { margin: 0 0 0.4rem; font-size: 0.85rem; font-family: 'Poppins', sans-serif; }
.cap-viol { margin: 0.6rem 0 0; font-size: 0.9rem; }
.cap-viol span { color: var(--ink-soft); font-size: 0.8rem; }
.viz-legend { flex-wrap: wrap; }
.viz-legend .sw-dash { display: inline-block; width: 14px; height: 0; border-top: 1.5px dashed var(--ink-soft); margin-right: 0.4rem; vertical-align: 3px; }
.viz-legend .sw-ring { display: inline-block; width: 8px; height: 8px; border-radius: 50%; border: 1.5px solid var(--ink); margin-right: 0.4rem; vertical-align: 0; }
.cap-fig1 p.q, .cap-fig1 p.g { display: grid; grid-template-columns: 86px 1fr; align-items: baseline; }
.cap-fig1 p.q .k, .cap-fig1 p.g .k { min-width: 0; }
.cap-tax-info { scroll-margin-top: 120px; }
.cap-ex .stmt .k { text-transform: none; font-size: 0.85rem; font-style: italic; }
.cap-key { display: flex; gap: 0.8rem; flex-wrap: wrap; font-size: 0.72rem; color: var(--ink-soft); margin: 0.35rem 0 0; }
.cap-key i { display: inline-block; width: 9px; height: 9px; border-radius: 2px; margin-right: 0.3rem; vertical-align: -1px; }
.cap-key .e { background: var(--viz-a); } .cap-key .n { background: var(--viz-neutral); } .cap-key .c { background: var(--viz-b); }