:root {
  --ink: #1a2332;
  --ink-soft: #2d3a4f;
  --paper: #faf6ee;
  --paper-warm: #f4ecd8;
  --paper-soft: #f8f2e2;
  --rule: #c9bfa8;
  --accent: #8b1e1e;
  --accent-soft: #b54848;
  --gold: #b8893d;
  --teal: #2d6a6a;
  --green: #4a7c3a;
  --grey: #7a7466;
  --grey-soft: #d4cdb8;
  --error: #a83232;
  --error-bg: #f3dede;
  --success: #2d6a3a;
  --success-bg: #dfeed8;
  --warn: #a87a1f;
  --warn-bg: #f5e7c4;
  --serif: 'Cormorant Garamond', Georgia, 'Times New Roman', serif;
  --sans: 'Inter Tight', system-ui, -apple-system, sans-serif;
  --mono: 'JetBrains Mono', Menlo, Consolas, monospace;
  --arabic: 'Amiri', 'Traditional Arabic', 'Times New Roman', serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--sans);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.65;
  font-size: 15px;
  min-height: 100vh;
}
::selection { background: var(--accent); color: var(--paper); }

.ar {
  font-family: var(--arabic);
  direction: rtl;
  unicode-bidi: isolate;
  font-size: 1.05em;
  color: var(--grey);
  font-weight: 400;
}

/* ============== Masthead ============== */
.masthead {
  border-bottom: 3px double var(--ink);
  padding: 32px 48px 28px;
  background: var(--paper-warm);
}
.masthead-inner {
  max-width: 1320px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  flex-wrap: wrap;
  gap: 20px;
}
.masthead-left .eyebrow {
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 6px;
}
.masthead-left h1 {
  font-family: var(--serif);
  font-size: 44px;
  font-weight: 600;
  line-height: 1.05;
  color: var(--ink);
  letter-spacing: -0.01em;
}
.masthead-left h1 em {
  font-style: italic;
  color: var(--accent);
  font-weight: 500;
}
.masthead-right {
  text-align: right;
  font-size: 12px;
  color: var(--grey);
  font-family: var(--serif);
  font-style: italic;
}
.masthead-right .vol {
  font-weight: 600; color: var(--ink); font-style: normal;
  font-family: var(--sans); letter-spacing: 0.1em;
  text-transform: uppercase; font-size: 11px;
}

/* ============== Top nav ============== */
.topnav {
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid var(--rule);
  padding: 10px 48px;
  backdrop-filter: blur(8px);
  background: rgba(250, 246, 238, 0.96);
}
.topnav-inner {
  max-width: 1320px;
  margin: 0 auto;
  display: flex;
  gap: 0;
  align-items: center;
  flex-wrap: wrap;
}
.nav-link {
  font-family: var(--sans);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  font-weight: 500;
  color: var(--ink-soft);
  text-decoration: none;
  padding: 6px 12px;
  border-right: 1px solid var(--rule);
  cursor: pointer;
  transition: color 0.15s;
}
.nav-link:first-child { padding-left: 0; }
.nav-link:last-child { border-right: none; }
.nav-link:hover { color: var(--accent); }
.nav-link.active { color: var(--accent); font-weight: 600; }

main {
  max-width: 1320px;
  margin: 0 auto;
  padding: 40px 48px 80px;
}

/* ============== Sections ============== */
.section {
  margin-bottom: 72px;
  scroll-margin-top: 80px;
}
.section-header {
  border-top: 2px solid var(--ink);
  padding-top: 14px;
  margin-bottom: 32px;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 20px;
  flex-wrap: wrap;
}
.section-header .num {
  font-family: var(--serif);
  font-size: 13px;
  letter-spacing: 0.2em;
  color: var(--accent);
  text-transform: uppercase;
  font-weight: 600;
}
.section-header h2 {
  font-family: var(--serif);
  font-size: 44px;
  font-weight: 500;
  line-height: 1;
  margin-top: 4px;
  letter-spacing: -0.01em;
}
.section-header .sublabel {
  font-family: var(--serif);
  font-style: italic;
  font-size: 16px;
  color: var(--grey);
}
.lede {
  font-family: var(--serif);
  font-size: 20px;
  line-height: 1.5;
  color: var(--ink-soft);
  max-width: 880px;
  margin-bottom: 36px;
  font-weight: 400;
}
.lede em { color: var(--accent); font-style: italic; }

.subsection { margin-bottom: 44px; }
.subsection h3 {
  font-family: var(--serif);
  font-size: 28px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--ink);
  line-height: 1.15;
}
.subsection h3 .ar {
  margin-left: 12px;
  font-size: 20px;
}
.subsection h4 {
  font-family: var(--sans);
  font-size: 13px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 14px;
  margin-top: 28px;
}

p { margin-bottom: 16px; }
p:last-child { margin-bottom: 0; }
strong { font-weight: 700; }
em { font-style: italic; }

.term {
  border-bottom: 1.5px dotted var(--accent);
  cursor: help;
  position: relative;
  font-weight: 500;
}
.term:hover { color: var(--accent); }
.term-tooltip {
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  background: var(--ink);
  color: var(--paper);
  padding: 12px 14px;
  border-radius: 2px;
  font-size: 13px;
  font-weight: 400;
  font-family: var(--sans);
  width: 280px;
  line-height: 1.45;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.15s, visibility 0.15s;
  z-index: 50;
  pointer-events: none;
  box-shadow: 0 4px 18px rgba(26, 35, 50, 0.25);
}
.term-tooltip::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 6px solid transparent;
  border-top-color: var(--ink);
}
.term-tooltip .ar {
  display: block;
  margin-top: 6px;
  font-family: var(--arabic);
  direction: rtl;
  font-size: 14px;
  color: var(--gold);
}
.term:hover .term-tooltip { opacity: 1; visibility: visible; }

/* ============== Cards / panels ============== */
.card {
  background: var(--paper-warm);
  border: 1px solid var(--rule);
  padding: 22px 26px;
  margin-bottom: 20px;
  position: relative;
}
.card-label {
  position: absolute;
  top: -10px;
  left: 20px;
  background: var(--paper);
  padding: 0 10px;
  font-family: var(--sans);
  font-size: 10px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
}

/* Formulation grid */
.formulation-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
  margin-bottom: 32px;
}
.formulation-item {
  background: var(--paper-warm);
  border: 1px solid var(--rule);
  padding: 20px 22px;
  position: relative;
}
.formulation-item .num-tag {
  position: absolute;
  top: 14px;
  right: 18px;
  font-family: var(--serif);
  font-size: 30px;
  font-weight: 400;
  color: var(--rule);
  line-height: 1;
}
.formulation-item h5 {
  font-family: var(--serif);
  font-size: 20px;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 4px;
  padding-right: 28px;
}
.formulation-item .ar-label {
  font-family: var(--arabic);
  direction: rtl;
  color: var(--grey);
  font-size: 16px;
  margin-bottom: 10px;
}
.formulation-item p {
  font-size: 14px;
  line-height: 1.55;
  margin: 0;
  color: var(--ink-soft);
}

/* ============== SVG graph styles ============== */
.graph-stage {
  background: var(--paper);
  border: 1px solid var(--rule);
  padding: 18px;
  position: relative;
  margin-bottom: 16px;
}
.graph-stage svg { width: 100%; height: auto; display: block; }

.node-circle {
  fill: var(--paper-warm);
  stroke: var(--ink);
  stroke-width: 2;
  transition: fill 0.25s, stroke 0.25s;
}
.node-circle.start { fill: var(--ink); stroke: var(--ink); }
.node-circle.goal { fill: var(--green); stroke: var(--green); }
.node-circle.expanded { fill: var(--accent); stroke: var(--accent); }
.node-circle.fringe { fill: var(--warn-bg); stroke: var(--warn); stroke-dasharray: 4 2; }
.node-circle.current { fill: var(--gold); stroke: var(--ink); stroke-width: 3; }
.node-circle.on-path { fill: var(--gold); stroke: var(--accent); stroke-width: 3; }
.node-circle.visited { fill: var(--grey-soft); stroke: var(--grey); }

/* Node text: paint-order ensures a halo around the glyph */
.node-label {
  font-family: var(--sans);
  font-size: 14px;
  font-weight: 700;
  fill: var(--ink);
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
  user-select: none;
  paint-order: stroke fill;
  stroke: var(--paper);
  stroke-width: 3px;
  stroke-linejoin: round;
}
.node-label.on-dark {
  fill: var(--paper);
  stroke: var(--ink);
}

.edge-line {
  stroke: var(--ink-soft);
  stroke-width: 1.5;
  fill: none;
  transition: stroke 0.25s, stroke-width 0.25s;
}
.edge-line.on-path { stroke: var(--accent); stroke-width: 3.5; }
.edge-line.faded { stroke: var(--grey-soft); }
.edge-line.tree-edge { stroke: var(--accent); stroke-width: 2.5; }

/* Edge weight: filled paper-coloured pill with crisp typography */
.edge-weight-bg {
  fill: var(--paper);
  stroke: var(--rule);
  stroke-width: 0.8;
}
.edge-weight {
  font-family: var(--mono);
  font-size: 11.5px;
  font-weight: 700;
  fill: var(--accent);
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
  user-select: none;
}

.node-clickable { cursor: pointer; }
.node-clickable:hover .node-circle {
  stroke-width: 4;
  filter: drop-shadow(0 0 6px rgba(139, 30, 30, 0.4));
}

/* ============== Trace ============== */
.trace-wrapper {
  background: var(--paper-warm);
  border: 1px solid var(--rule);
  padding: 16px 18px;
  font-family: var(--mono);
  font-size: 13px;
  overflow-x: auto;
  max-height: 460px;
  overflow-y: auto;
}
.trace-wrapper h6 {
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 8px;
  font-weight: 600;
}
table.trace-table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--mono);
  font-size: 12px;
}
table.trace-table th {
  text-align: left;
  border-bottom: 2px solid var(--ink);
  padding: 8px 10px;
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-weight: 600;
  color: var(--ink);
  background: var(--paper-warm);
  position: sticky;
  top: 0;
}
table.trace-table td {
  padding: 6px 10px;
  border-bottom: 1px dotted var(--rule);
  vertical-align: top;
}
table.trace-table tr.current-step { background: var(--warn-bg); }
table.trace-table tr.goal-step { background: var(--success-bg); font-weight: 600; }
table.trace-table td.expanded-cell { color: var(--accent); font-weight: 700; }

/* ============== Controls ============== */
.controls {
  display: flex;
  gap: 8px;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 16px;
  padding: 14px 16px;
  background: var(--ink);
  color: var(--paper);
}
.controls button {
  font-family: var(--sans);
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  font-weight: 500;
  padding: 8px 14px;
  background: transparent;
  border: 1px solid var(--paper);
  color: var(--paper);
  cursor: pointer;
  transition: all 0.15s;
}
.controls button:hover:not(:disabled) {
  background: var(--paper);
  color: var(--ink);
}
.controls button:disabled { opacity: 0.4; cursor: not-allowed; }
.controls button.primary {
  background: var(--accent);
  border-color: var(--accent);
}
.controls button.primary:hover:not(:disabled) {
  background: var(--accent-soft);
  border-color: var(--accent-soft);
  color: var(--paper);
}
.controls .spacer { flex: 1; }
.controls .status {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--gold);
}
.controls select {
  font-family: var(--sans);
  font-size: 12px;
  padding: 7px 10px;
  background: transparent;
  color: var(--paper);
  border: 1px solid var(--paper);
}
.controls select option { background: var(--ink); }
.toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.toggle input { accent-color: var(--gold); }

/* ============== Feedback ============== */
.feedback {
  padding: 14px 18px;
  margin-top: 12px;
  font-size: 14px;
  line-height: 1.6;
  border-left: 4px solid;
}
.feedback.success { background: var(--success-bg); border-color: var(--success); }
.feedback.error { background: var(--error-bg); border-color: var(--error); }
.feedback.warn { background: var(--warn-bg); border-color: var(--warn); }
.feedback.info { background: var(--paper-warm); border-color: var(--ink-soft); }

.feedback .what-happened {
  font-weight: 700;
  display: block;
  margin-bottom: 4px;
  font-family: var(--sans);
}
.feedback .why {
  font-family: var(--serif);
  font-style: italic;
  color: var(--ink-soft);
  font-size: 13.5px;
  display: block;
  margin-top: 4px;
}

/* ============== Properties panel ============== */
.props-detailed {
  background: var(--paper-warm);
  border: 1px solid var(--rule);
  padding: 22px 26px;
  margin-top: 18px;
}
.props-detailed h4 { margin-top: 0; margin-bottom: 16px; }
.props-detailed .prop-row {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 16px;
  padding: 12px 0;
  border-bottom: 1px dotted var(--rule);
}
.props-detailed .prop-row:last-child { border-bottom: none; }
.props-detailed .prop-label {
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--grey);
  font-weight: 600;
}
.props-detailed .prop-verdict {
  font-family: var(--serif);
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 4px;
}
.props-detailed .prop-verdict.yes { color: var(--success); }
.props-detailed .prop-verdict.no { color: var(--error); }
.props-detailed .prop-verdict.cond { color: var(--warn); }
.props-detailed .prop-reason {
  font-family: var(--sans);
  font-size: 13.5px;
  color: var(--ink-soft);
  line-height: 1.6;
}
.props-detailed .prop-formula {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--accent);
  font-weight: 600;
  margin-right: 8px;
}

/* ============== Tabs ============== */
.tabs {
  display: flex;
  gap: 0;
  border-bottom: 2px solid var(--ink);
  margin-bottom: 20px;
  flex-wrap: wrap;
}
.tab {
  font-family: var(--sans);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-weight: 500;
  padding: 10px 18px;
  background: transparent;
  border: none;
  cursor: pointer;
  color: var(--grey);
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  transition: all 0.15s;
}
.tab:hover { color: var(--ink); }
.tab.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
  font-weight: 600;
}
.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ============== Algorithm layout ============== */
.algo-stage {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 22px;
  align-items: start;
  margin-bottom: 24px;
}
@media (max-width: 980px) {
  .algo-stage { grid-template-columns: 1fr; }
  .masthead { padding: 24px 24px; }
  .topnav { padding: 10px 24px; }
  main { padding: 32px 24px 60px; }
  .section-header h2 { font-size: 32px; }
  .masthead-left h1 { font-size: 28px; }
}

.algo-desc {
  background: var(--paper-warm);
  border-left: 4px solid var(--accent);
  padding: 18px 22px;
  margin-bottom: 18px;
}
.algo-desc .name {
  font-family: var(--serif);
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 4px;
}
.algo-desc .ar-name {
  font-family: var(--arabic);
  direction: rtl;
  color: var(--grey);
  font-size: 17px;
  margin-bottom: 12px;
}
.algo-desc .idea {
  font-size: 14.5px;
  line-height: 1.6;
  margin-bottom: 10px;
}
.algo-desc .fringe-info {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--accent);
  font-weight: 600;
  letter-spacing: 0.02em;
}

/* ============== Pseudocode ============== */
.pseudo {
  background: var(--ink);
  color: var(--paper);
  padding: 18px 22px;
  font-family: var(--mono);
  font-size: 12.5px;
  line-height: 1.6;
  margin: 14px 0;
  border-left: 4px solid var(--gold);
  white-space: pre;
  overflow-x: auto;
}
.pseudo .kw { color: var(--gold); font-weight: 600; }
.pseudo .cm { color: var(--grey-soft); font-style: italic; }

/* ============== Comparison table ============== */
.compare-wrapper { overflow-x: auto; margin: 16px 0; }
table.compare-table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--sans);
  font-size: 13px;
  background: var(--paper-warm);
  min-width: 920px;
}
table.compare-table th, table.compare-table td {
  padding: 12px 14px;
  border: 1px solid var(--rule);
  text-align: left;
  vertical-align: top;
}
table.compare-table th {
  background: var(--ink);
  color: var(--paper);
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-weight: 600;
}
table.compare-table tr:hover td { background: var(--paper); }
table.compare-table td.algo {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 16px;
  color: var(--accent);
}
table.compare-table td .complexity { font-family: var(--mono); font-size: 12px; }

.yes-mark { color: var(--success); font-weight: 600; }
.no-mark { color: var(--error); font-weight: 600; }
.cond-mark { color: var(--warn); font-weight: 600; }

.romania-stage {
  background: var(--paper);
  border: 1px solid var(--rule);
  padding: 14px;
  margin-bottom: 16px;
}

.sld-table {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 4px 18px;
  font-family: var(--mono);
  font-size: 12px;
  background: var(--paper-warm);
  padding: 16px 20px;
  border: 1px solid var(--rule);
}
.sld-table .sld-row {
  display: flex;
  justify-content: space-between;
  padding: 3px 0;
  border-bottom: 1px dotted var(--rule);
}
.sld-table .sld-row .city { color: var(--ink); }
.sld-table .sld-row .dist { color: var(--accent); font-weight: 700; }

/* ============== Heuristic explorer overlay ============== */
.h-explorer-overlay { pointer-events: none; }
.h-explorer-overlay .h-path-edge {
  stroke: var(--gold);
  stroke-width: 5;
  fill: none;
  opacity: 0.9;
  stroke-linecap: round;
}
.h-explorer-overlay .h-dashed {
  stroke: var(--accent);
  stroke-width: 2.5;
  stroke-dasharray: 7 5;
  fill: none;
  opacity: 0.85;
}
.h-explorer-overlay .h-label-bg {
  fill: var(--paper);
  stroke: var(--accent);
  stroke-width: 1.2;
}
.h-explorer-overlay .h-label-text {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 700;
  fill: var(--accent);
}
.h-explorer-overlay .h-badge-bg {
  fill: var(--paper);
  stroke: var(--accent);
  stroke-width: 1.5;
}
.h-explorer-overlay .h-badge-name {
  font-family: var(--mono);
  font-size: 11.5px;
  font-weight: 700;
  fill: var(--ink);
}
.h-explorer-overlay .h-badge-gh {
  font-family: var(--mono);
  font-size: 11px;
  fill: var(--ink-soft);
}
.h-explorer-overlay .h-badge-f {
  font-family: var(--mono);
  font-size: 11.5px;
  font-weight: 700;
  fill: var(--accent);
}

.h-explorer-hint {
  font-family: var(--sans);
  font-size: 12px;
  color: var(--grey);
  font-style: italic;
  padding: 6px 12px;
  border-left: 3px solid var(--accent);
  background: var(--paper-warm);
  margin: 8px 0 14px;
}

/* ============== Maze pruning demo ============== */
.maze-comparison {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-top: 18px;
}
@media (max-width: 760px) {
  .maze-comparison { grid-template-columns: 1fr; }
}
.maze-panel { display: flex; flex-direction: column; }
.maze-panel h6 {
  font-family: var(--sans);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 8px;
}
.maze-stats {
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--ink-soft);
  padding: 10px 12px;
  background: var(--paper-warm);
  border: 1px solid var(--rule);
  margin-top: 10px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px 16px;
}
.maze-stats strong { color: var(--ink); font-weight: 700; }
.maze-wall {
  fill: var(--ink);
  stroke: var(--ink-soft);
  stroke-width: 1;
}
.maze-h-label {
  font-family: var(--mono);
  font-size: 10.5px;
  fill: var(--ink-soft);
  stroke: var(--paper);
  stroke-width: 2.5;
  paint-order: stroke fill;
  text-anchor: middle;
  pointer-events: none;
  user-select: none;
}
.maze-sg-label {
  font-family: var(--mono);
  font-size: 16px;
  font-weight: 700;
  fill: var(--paper);
  text-anchor: middle;
  pointer-events: none;
  user-select: none;
}

/* ============== 8-puzzle ============== */
.puzzle-board {
  display: inline-grid;
  grid-template-columns: repeat(3, 64px);
  grid-template-rows: repeat(3, 64px);
  gap: 3px;
  background: var(--ink);
  padding: 3px;
  border: 2px solid var(--ink);
}
.puzzle-tile {
  background: var(--paper-warm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--serif);
  font-size: 30px;
  font-weight: 600;
  color: var(--ink);
  position: relative;
  cursor: pointer;
  transition: background 0.15s;
}
.puzzle-tile:hover { background: var(--gold); }
.puzzle-tile.empty { background: var(--ink-soft); cursor: default; }
.puzzle-tile.empty:hover { background: var(--ink-soft); }
.puzzle-tile.misplaced { background: var(--error-bg); }
.puzzle-tile .manh-badge {
  position: absolute;
  bottom: 3px;
  right: 5px;
  font-family: var(--mono);
  font-size: 10px;
  color: var(--accent);
  font-weight: 700;
}
.puzzle-row {
  display: flex;
  gap: 28px;
  align-items: flex-start;
  flex-wrap: wrap;
  margin-bottom: 16px;
}
.puzzle-col h6 {
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 10px;
}

/* ============== Quiz ============== */
.quiz-prompt {
  background: var(--ink);
  color: var(--paper);
  padding: 16px 20px;
  margin-top: 12px;
  font-family: var(--sans);
}
.quiz-prompt .question {
  font-family: var(--serif);
  font-size: 17px;
  margin-bottom: 10px;
  font-style: italic;
}
.quiz-prompt .hint {
  font-size: 12px;
  color: var(--gold);
  font-style: italic;
}
button.quiz-opt {
  font-family: var(--mono);
  padding: 7px 14px;
  background: var(--paper);
  color: var(--ink);
  border: 1px solid var(--paper);
  cursor: pointer;
  font-size: 13px;
  font-weight: 600;
}
button.quiz-opt:hover { background: var(--gold); }

/* ============== Footer ============== */
footer {
  border-top: 3px double var(--ink);
  padding: 36px 48px;
  background: var(--paper-warm);
  margin-top: 60px;
  font-family: var(--serif);
  font-size: 14px;
  font-style: italic;
  color: var(--grey);
}
footer .footer-inner {
  max-width: 1320px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
}
footer .refs {
  font-family: var(--sans);
  font-style: normal;
  font-size: 12px;
  color: var(--ink-soft);
  max-width: 620px;
  line-height: 1.6;
}
footer .refs strong {
  display: block;
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 8px;
  font-weight: 600;
}

/* ============== Callouts (NO pseudo-element ornaments) ============== */
.callout {
  background: var(--paper-warm);
  border: 1px solid var(--rule);
  border-left: 4px solid var(--gold);
  padding: 18px 22px;
  margin: 18px 0;
  font-family: var(--serif);
  font-size: 16.5px;
  font-style: italic;
  line-height: 1.55;
}
.callout .marker {
  font-family: var(--sans);
  font-weight: 700;
  font-style: normal;
  color: var(--accent);
  letter-spacing: 0.02em;
  font-size: 11.5px;
  margin-right: 10px;
  display: inline-block;
  padding: 2px 8px;
  background: var(--paper);
  border: 1px solid var(--accent);
  border-radius: 2px;
  vertical-align: middle;
}
.callout.tip { border-left-color: var(--teal); }
.callout.tip .marker { color: var(--teal); border-color: var(--teal); }
.callout.warn { border-left-color: var(--warn); background: var(--warn-bg); }
.callout.warn .marker { color: var(--warn); border-color: var(--warn); }

ul.tight, ol.tight { margin: 10px 0 16px 24px; }
ul.tight li, ol.tight li { margin-bottom: 6px; font-size: 14.5px; }

.muted { color: var(--grey); font-size: 13px; font-style: italic; }

.eq {
  font-family: var(--mono);
  background: var(--paper-warm);
  padding: 12px 18px;
  border-left: 3px solid var(--gold);
  margin: 14px 0;
  font-size: 14px;
}
.eq.centered { text-align: center; }

.legend-row {
  display: flex;
  gap: 18px;
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 0.06em;
  margin: 8px 0 16px;
  flex-wrap: wrap;
  color: var(--grey);
  padding: 10px 14px;
  background: var(--paper-warm);
  border: 1px solid var(--rule);
}
.legend-row .item { display: flex; align-items: center; gap: 6px; }
.legend-row .swatch {
  width: 14px;
  height: 14px;
  border: 1.5px solid var(--ink);
  display: inline-block;
}
.legend-row .swatch.start { background: var(--ink); }
.legend-row .swatch.goal { background: var(--green); border-color: var(--green); }
.legend-row .swatch.exp { background: var(--accent); border-color: var(--accent); }
.legend-row .swatch.fringe { background: var(--warn-bg); border-color: var(--warn); border-style: dashed; }
.legend-row .swatch.cur { background: var(--gold); }

.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 22px;
  margin: 16px 0;
}
@media (max-width: 800px) { .two-col { grid-template-columns: 1fr; } }

/* ============== Tree-vs-Graph side-by-side ============== */
.tree-vs-graph {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
  margin: 20px 0;
}
@media (max-width: 1000px) { .tree-vs-graph { grid-template-columns: 1fr; } }

.tvg-panel {
  background: var(--paper-warm);
  border: 1px solid var(--rule);
  padding: 18px;
}
.tvg-panel h5 {
  font-family: var(--serif);
  font-size: 22px;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 4px;
}
.tvg-panel .ar-sub {
  font-family: var(--arabic);
  direction: rtl;
  color: var(--grey);
  font-size: 15px;
  margin-bottom: 12px;
}
.tvg-panel p {
  font-size: 13.5px;
  line-height: 1.55;
  margin-bottom: 12px;
}
.tvg-panel svg {
  background: var(--paper);
  border: 1px solid var(--rule);
  width: 100%;
  height: auto;
  margin: 10px 0;
}

/* Local search specific */
.landscape-stage {
  background: var(--paper);
  border: 1px solid var(--rule);
  padding: 14px;
}
.landscape-stage svg { width: 100%; height: auto; display: block; }
.landscape-curve {
  fill: none;
  stroke: var(--ink-soft);
  stroke-width: 2;
}
.landscape-marker { fill: var(--accent); stroke: var(--paper); stroke-width: 2; }
.landscape-best { fill: var(--green); stroke: var(--paper); stroke-width: 2; }

/* Genetic algorithm board */
.genome-row {
  display: flex;
  gap: 3px;
  margin-bottom: 4px;
  font-family: var(--mono);
}
.genome-cell {
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--rule);
  background: var(--paper-warm);
  font-size: 12px;
  font-weight: 600;
}
.genome-cell.queen { background: var(--accent); color: var(--paper); }

/* Beam display */
.beam-state {
  display: inline-block;
  padding: 6px 10px;
  background: var(--paper-warm);
  border: 1px solid var(--rule);
  margin: 3px;
  font-family: var(--mono);
  font-size: 12px;
}
.beam-state.kept { border-color: var(--accent); border-width: 2px; }
.beam-state.dropped { opacity: 0.4; text-decoration: line-through; }

/* Buildup boxes */
.buildup {
  border: 1px solid var(--rule);
  padding: 24px 28px;
  margin: 24px 0;
  background: var(--paper);
}
.buildup .question {
  font-family: var(--serif);
  font-size: 17px;
  font-style: italic;
  color: var(--accent);
  margin-bottom: 8px;
}
.buildup .answer {
  font-size: 14.5px;
  line-height: 1.6;
}