:root {
  --color-bg: #F2E5D3;
  --color-surface: #FFF4E4;
  --color-surface-soft: #F6BC8C;
  --color-primary: #0B3A35;
  --color-secondary: #6F927F;
  --color-accent: #E07D45;
  --color-accent-strong: #B0522A;
  --color-warning: #A96255;
  --color-border: rgba(11, 58, 53, 0.18);
  --shadow-soft: 0 12px 30px rgba(176, 82, 42, 0.14);
  --ink: var(--color-primary);
  --bark: var(--color-accent-strong);
  --sage: var(--color-secondary);
  --sand: var(--color-surface-soft);
  --cream: var(--color-bg);
  --paper: var(--color-bg);
  --white: var(--color-surface);
  --line: var(--color-border);
  --line-strong: rgba(11, 58, 53, 0.30);
  --text: var(--color-primary);
  --muted: rgba(11, 58, 53, 0.72);
  --accent: var(--color-accent);
  --accent-2: var(--color-secondary);
  --success: var(--color-secondary);
  --danger: var(--color-warning);
  --shadow: 0 18px 50px rgba(176, 82, 42, 0.16);
  --radius: 18px;
  --radius-sm: 12px;
  --mono: "Cascadia Code", "SFMono-Regular", Consolas, monospace;
  --sans: Inter, "Segoe UI", Arial, sans-serif;
  --serif: Georgia, "Times New Roman", serif;
}

* { box-sizing: border-box; }
html {
  scroll-behavior: smooth;
  overflow-x: hidden;
}
body {
  margin: 0;
  color: var(--text);
  font-family: var(--sans);
  line-height: 1.65;
  background:
    radial-gradient(circle at 16% 0%, rgba(246, 188, 140, 0.36), transparent 30rem),
    radial-gradient(circle at 92% 8%, rgba(111, 146, 127, 0.20), transparent 24rem),
    linear-gradient(180deg, var(--color-bg), var(--color-surface) 48%, var(--color-bg));
  overflow-x: hidden;
}

a { color: inherit; }
img, svg { max-width: 100%; }
button, input, select { font: inherit; }
button { -webkit-tap-highlight-color: transparent; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem clamp(1rem, 3vw, 2.2rem);
  background: rgba(242, 229, 211, 0.90);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  color: var(--ink);
  font-weight: 900;
  letter-spacing: -0.03em;
  text-decoration: none;
  white-space: nowrap;
}
.brand::before {
  content: "";
  width: 0.78rem;
  height: 0.78rem;
  border-radius: 999px;
  background: var(--color-accent);
  box-shadow: 0 0 0 5px rgba(224, 125, 69, 0.14);
}

.top-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.4rem;
}

.top-nav a,
.btn,
.tab-btn,
.choice {
  border: 1px solid var(--line);
  background: rgba(255, 244, 228, 0.78);
  color: var(--ink);
  border-radius: 999px;
  padding: 0.58rem 0.9rem;
  text-decoration: none;
  cursor: pointer;
  transition: transform 160ms ease, border-color 160ms ease, background 160ms ease, color 160ms ease, box-shadow 160ms ease;
}

.top-nav a:hover,
.btn:hover,
.tab-btn:hover,
.choice:hover,
.top-nav a:focus-visible,
.btn:focus-visible,
.tab-btn:focus-visible,
.choice:focus-visible {
  border-color: rgba(176, 82, 42, 0.48);
  background: var(--white);
  transform: translateY(-1px);
  box-shadow: var(--shadow-soft);
}

.tab-btn.active,
.btn.primary {
  color: var(--white);
  border-color: var(--color-accent-strong);
  background: var(--color-accent-strong);
}
.btn { display: inline-flex; align-items: center; justify-content: center; font-weight: 800; }
.ghost { background: transparent; }

.section {
  width: min(1180px, calc(100% - 2rem));
  margin: 0 auto;
  padding: clamp(2.4rem, 5vw, 4.2rem) 0;
}

.hero {
  min-height: 68vh;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 340px);
  align-items: center;
  gap: clamp(1.2rem, 3vw, 2.4rem);
}

.hero > div:first-child {
  border: 1px solid var(--line);
  border-radius: calc(var(--radius) + 8px);
  background: linear-gradient(135deg, rgba(255, 244, 228, 0.94), rgba(246, 188, 140, 0.42), rgba(111, 146, 127, 0.14));
  box-shadow: var(--shadow);
  padding: clamp(1.4rem, 4vw, 3.2rem);
  position: relative;
  overflow: hidden;
}
.hero > div:first-child::after {
  content: "";
  position: absolute;
  inset: auto -5rem -7rem auto;
  width: 19rem;
  height: 19rem;
  border-radius: 50%;
  background: rgba(111, 146, 127, 0.16);
  pointer-events: none;
}

.eyebrow {
  color: var(--bark);
  font-size: 0.75rem;
  font-weight: 900;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  margin: 0 0 0.55rem;
}

h1, h2, h3 { line-height: 1.12; margin: 0 0 0.85rem; }
h1 {
  font-family: var(--serif);
  font-weight: 700;
  letter-spacing: -0.055em;
  font-size: clamp(2.8rem, 7vw, 6.3rem);
  max-width: 920px;
}
h2 { font-size: clamp(1.55rem, 3vw, 2.55rem); letter-spacing: -0.035em; }
h3 { font-size: 1.05rem; letter-spacing: -0.015em; }
.lead {
  max-width: 780px;
  color: var(--muted);
  font-size: clamp(1rem, 1.5vw, 1.13rem);
}
.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin: 1rem 0 0;
  padding: 0;
  list-style: none;
}
.hero-meta li {
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255, 244, 228, 0.72);
  color: var(--bark);
  font-weight: 800;
  padding: 0.5rem 0.75rem;
}
.ar { color: var(--muted); }
.jump-row,
.control-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  margin-top: 1.1rem;
}
.control-row input,
.search-box {
  color: var(--ink);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.72rem 0.95rem;
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.75);
}
.control-row input { min-width: 180px; flex: 1; }
.control-row input:focus,
.search-box:focus { border-color: var(--color-accent-strong); outline: none; box-shadow: 0 0 0 4px rgba(224, 125, 69, 0.16); }

.progress-panel,
.chunk-card,
.lab-shell,
.code-card,
.practice-card,
.quiz-card,
.cheat-card,
.lecture-card,
.algorithm-card,
.method-card,
.image-card,
.result-card {
  background: rgba(255, 244, 228, 0.88);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
}

.progress-panel {
  display: grid;
  gap: 0.8rem;
  padding: 1rem;
  background: rgba(111, 146, 127, 0.13);
}
.progress-card {
  padding: 1.1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: rgba(255, 244, 228, 0.86);
}
.progress-card strong {
  display: block;
  color: var(--bark);
  font-family: var(--serif);
  font-size: 2.2rem;
  line-height: 1;
}
.progress-card span,
.muted { color: var(--muted); }

.section-heading { margin-bottom: 1.25rem; }
.section-heading h2 { max-width: 780px; }
.compact-section {
  padding-top: 0;
}
.section-jump-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 0.7rem;
}
.section-jump-grid a {
  min-height: 3.15rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: rgba(255, 244, 228, 0.88);
  color: var(--bark);
  font-weight: 900;
  text-align: center;
  text-decoration: none;
  padding: 0.8rem 0.9rem;
  box-shadow: var(--shadow-soft);
}
.section-jump-grid a:hover,
.section-jump-grid a:focus-visible {
  border-color: rgba(176, 82, 42, 0.48);
  background: var(--white);
}
.lecture-dashboard-grid,
.algorithm-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
}
.lecture-card {
  display: grid;
  gap: 0.45rem;
  padding: 1.15rem;
  text-decoration: none;
}
.lecture-card.featured {
  border-color: rgba(176, 82, 42, 0.36);
  background: linear-gradient(135deg, rgba(255, 244, 228, 0.94), rgba(246, 188, 140, 0.30));
}
.lecture-card-kicker {
  color: var(--bark);
  font-size: 0.75rem;
  font-weight: 900;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}
.lecture-card p { margin: 0; color: var(--muted); }
.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 0.35rem;
}
.tag-row span {
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--bark);
  background: rgba(255, 244, 228, 0.72);
  font-size: 0.82rem;
  font-weight: 800;
  padding: 0.34rem 0.58rem;
}
.chunk-list { display: grid; gap: 1rem; }
.chunk-card { scroll-margin-top: 5.8rem; overflow: hidden; }
.chunk-card summary {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 1.05rem 1.25rem;
  cursor: pointer;
  color: var(--ink);
  font-weight: 900;
  background: linear-gradient(90deg, rgba(246, 188, 140, 0.28), transparent);
}
.chunk-card summary::marker { color: var(--bark); }
.chunk-card summary small { color: var(--bark); font-weight: 800; }
.chunk-body { padding: 0 1.25rem 1.25rem; }

.mini-grid,
.code-grid,
.practice-grid,
.quiz-grid,
.cheat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 0.9rem;
}

.mini-card,
.exam-check,
.level-table div {
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: rgba(246, 188, 140, 0.28);
  padding: 0.9rem;
}
.exam-check {
  margin-top: 1rem;
  color: var(--bark);
  font-weight: 700;
}

.lab-shell { padding: clamp(0.75rem, 2vw, 1.1rem); }
.tab-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1rem;
}
.tab-panel { display: none; }
.tab-panel.active { display: block; }

.viz {
  min-height: 380px;
  width: 100%;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    linear-gradient(rgba(111, 146, 127, 0.11) 1px, transparent 1px),
    linear-gradient(90deg, rgba(111, 146, 127, 0.11) 1px, transparent 1px),
    var(--color-surface);
  background-size: 24px 24px;
}

.tree-link {
  fill: none;
  stroke: rgba(11, 58, 53, 0.42);
  stroke-width: 2.5;
}
.tree-node circle {
  fill: var(--cream);
  stroke: var(--bark);
  stroke-width: 2.5;
  filter: drop-shadow(0 5px 7px rgba(176, 82, 42, 0.14));
}
.tree-node text {
  fill: var(--ink);
  text-anchor: middle;
  font-family: var(--mono);
  font-weight: 900;
  font-size: 0.84rem;
  pointer-events: none;
}
.tree-node.active circle { fill: var(--sand); stroke: var(--ink); }
.tree-node.visited circle { fill: var(--sage); stroke: var(--ink); }

.level-table {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 0.75rem;
  margin-top: 0.85rem;
}
.level-table span { display: block; color: var(--muted); }

.array-row {
  display: flex;
  gap: 0.45rem;
  overflow-x: auto;
  padding: 0.85rem 0.1rem 0.2rem;
  scrollbar-width: thin;
}
.array-cell {
  min-width: 58px;
  min-height: 58px;
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--white);
  color: var(--ink);
  box-shadow: var(--shadow-soft);
}
.array-cell span,
.array-cell small { color: var(--muted); font-size: 0.74rem; }
.array-cell.selected { border-color: var(--color-accent-strong); box-shadow: inset 0 0 0 2px rgba(224, 125, 69, 0.14), var(--shadow-soft); }
.array-cell.active { background: var(--bark); color: var(--white); }
.array-cell.active small { color: var(--cream); }

.trace-log {
  max-height: 280px;
  overflow: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(246, 188, 140, 0.22);
  padding: 1rem 1rem 1rem 2.2rem;
}
.trace-log li::marker { color: var(--bark); font-weight: 900; }

.output-line { color: var(--bark); font-weight: 800; }
.code-card,
.practice-card,
.quiz-card,
.cheat-card,
.algorithm-card,
.method-card,
.image-card { padding: 1.05rem; }
.algorithm-card {
  overflow: hidden;
}
.algorithm-card ul,
.method-card ol {
  margin: 0.8rem 0 0;
  padding-left: 1.25rem;
}
.trap-card {
  border-color: rgba(169, 98, 85, 0.46);
  box-shadow: 0 0 0 4px rgba(169, 98, 85, 0.10), var(--shadow-soft);
}
.recognition-table {
  display: grid;
  gap: 0.55rem;
}
.recognition-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 1rem;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: rgba(255, 244, 228, 0.88);
  padding: 0.82rem 1rem;
}
.recognition-row strong {
  color: var(--bark);
  font-family: var(--mono);
}
.image-card {
  margin: 0;
  min-height: 180px;
  display: grid;
  place-items: center;
  color: var(--muted);
}
.image-card img {
  display: block;
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-sm);
}
.image-card figcaption {
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius-sm);
  padding: 2rem;
  text-align: center;
  width: 100%;
}
.big-o-viz {
  min-height: 260px;
  display: grid;
  align-content: start;
  gap: 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--color-surface);
  padding: 1rem;
  overflow: hidden;
}
.op-row,
.halving-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.op-row span,
.op-grid span,
.halving-row span,
.branch-tree span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.55rem;
  min-height: 2.55rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: rgba(246, 188, 140, 0.34);
  color: var(--ink);
  font-family: var(--mono);
  font-weight: 900;
}
.op-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(2.3rem, 1fr));
  gap: 0.45rem;
  max-width: 420px;
}
.halving-row span:not(:last-child)::after {
  content: ">";
  margin-left: 1rem;
  color: var(--bark);
}
.branch-tree {
  display: grid;
  justify-items: center;
  gap: 1rem;
  overflow-x: auto;
  padding-bottom: 0.25rem;
}
.branch-tree div {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
  min-width: max-content;
}
pre {
  overflow-x: auto;
  max-width: 100%;
  background: var(--ink);
  border: 1px solid rgba(11, 58, 53, 0.32);
  border-radius: var(--radius-sm);
  padding: 1rem;
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.07);
}
code { color: #f8efe6; font-family: var(--mono); font-size: 0.9rem; }

.choice-list { display: grid; gap: 0.45rem; margin: 0.75rem 0; }
.choice { width: 100%; text-align: left; border-radius: var(--radius-sm); }
.quiz-card.correct { border-color: rgba(111, 146, 127, 0.62); box-shadow: 0 0 0 4px rgba(111, 146, 127, 0.12); }
.quiz-card.wrong { border-color: rgba(169, 98, 85, 0.62); box-shadow: 0 0 0 4px rgba(169, 98, 85, 0.12); }
.answer { color: var(--bark); font-weight: 800; }

.search-box {
  width: 100%;
  margin-bottom: 1rem;
  border-radius: var(--radius-sm);
}
.search-results { display: grid; gap: 0.7rem; }
.result-card {
  display: grid;
  gap: 0.25rem;
  padding: 0.95rem;
  text-decoration: none;
}
.result-card span { color: var(--muted); }

:focus-visible {
  outline: 3px solid rgba(224, 125, 69, 0.50);
  outline-offset: 3px;
}

::selection { background: var(--bark); color: var(--white); }

.sorting-card {
  border-color: rgba(11, 58, 53, 0.30);
  background: linear-gradient(135deg, rgba(255, 244, 228, 0.96), rgba(111, 146, 127, 0.18));
}

.sorting-overview-grid,
.sorting-cheat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1rem;
}

.sorting-overview-card {
  display: grid;
  gap: 0.35rem;
  padding: 1.05rem;
  text-decoration: none;
  align-content: start;
}

.sorting-overview-card h3,
.sorting-overview-card p {
  margin-bottom: 0;
}

.exam-focus-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 0.75rem;
  align-items: center;
  border: 1px solid rgba(176, 82, 42, 0.26);
  border-radius: var(--radius-sm);
  background: rgba(246, 188, 140, 0.26);
  color: var(--ink);
  margin-bottom: 1rem;
  padding: 0.85rem 1rem;
}

.exam-focus-strip strong {
  color: var(--bark);
}

.sort-card-facts {
  display: grid;
  gap: 0.58rem;
  margin: 0.35rem 0 0;
}

.sort-card-facts div {
  border-top: 1px solid var(--line);
  padding-top: 0.55rem;
}

.sort-card-facts dt {
  color: var(--bark);
  font-size: 0.73rem;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.sort-card-facts dd {
  color: var(--muted);
  margin: 0.12rem 0 0;
}

.sorting-lab {
  overflow: hidden;
}

.sorting-trace-panel {
  display: grid;
  gap: 1rem;
}

.sort-trace-card,
.sorting-overview-card,
.sort-example-block {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 244, 228, 0.90);
  box-shadow: var(--shadow-soft);
}

.sort-trace-card {
  padding: clamp(1rem, 2vw, 1.35rem);
}

.sort-example-block {
  margin-top: 1rem;
  padding: 1rem;
}

.sort-example-block h4 {
  margin: 0 0 0.75rem;
  color: var(--bark);
  font-size: 0.98rem;
}

.trace-table-wrap {
  overflow-x: auto;
  max-width: 100%;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--white);
  -webkit-overflow-scrolling: touch;
}

.trace-table {
  width: 100%;
  min-width: 680px;
  border-collapse: collapse;
}

.trace-table th,
.trace-table td {
  border-bottom: 1px solid var(--line);
  padding: 0.72rem 0.75rem;
  text-align: left;
  vertical-align: middle;
}

.trace-table th {
  color: var(--bark);
  background: rgba(111, 146, 127, 0.18);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.trace-table tr:last-child td {
  border-bottom: 0;
}

.sort-array-row {
  display: flex;
  flex-wrap: nowrap;
  gap: 0.32rem;
  min-width: max-content;
}

.sort-cell {
  min-width: 2.35rem;
  min-height: 2.1rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  border-radius: 0.58rem;
  background: rgba(255, 244, 228, 0.86);
  color: var(--ink);
  font-family: var(--mono);
  font-weight: 900;
}

.sort-check-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 0.8rem;
  margin-top: 1rem;
}

.merge-levels {
  display: grid;
  gap: 0.58rem;
}

.merge-level {
  display: grid;
  grid-template-columns: minmax(7rem, 9rem) 1fr;
  gap: 0.75rem;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: rgba(246, 188, 140, 0.24);
  padding: 0.78rem 0.85rem;
}

.merge-level strong {
  color: var(--bark);
}

.merge-level span {
  font-family: var(--mono);
  font-weight: 800;
  overflow-wrap: anywhere;
}

.shift-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 0.8rem;
}

.shift-strip span {
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(246, 188, 140, 0.34);
  color: var(--bark);
  font-family: var(--mono);
  font-size: 0.82rem;
  font-weight: 900;
  padding: 0.38rem 0.62rem;
}

.sorting-image-card {
  margin-top: 1rem;
}

.sorting-image-card img {
  border: 1px solid var(--line);
  box-shadow: var(--shadow-soft);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.sorting-d3-section {
  padding-top: 0;
}

.sorting-visualizer-panel {
  display: grid;
  gap: 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 244, 228, 0.92);
  box-shadow: var(--shadow-soft);
  padding: clamp(1rem, 2.4vw, 1.4rem);
}

.sorting-controls {
  display: grid;
  grid-template-columns: minmax(180px, 0.85fr) minmax(260px, 1.35fr);
  gap: 0.85rem;
  align-items: end;
}

.sorting-controls label {
  display: grid;
  gap: 0.35rem;
  color: var(--bark);
  font-size: 0.82rem;
  font-weight: 900;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.sorting-controls select,
.sorting-controls input {
  width: 100%;
  min-height: 2.7rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--white);
  color: var(--ink);
  font: 800 0.95rem var(--mono);
  padding: 0.64rem 0.75rem;
}

.sorting-controls select:focus,
.sorting-controls input:focus {
  border-color: var(--bark);
  outline: none;
  box-shadow: 0 0 0 4px rgba(224, 125, 69, 0.16);
}

.sorting-control-buttons {
  grid-column: 1 / -1;
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.sorting-trace-status {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: rgba(246, 188, 140, 0.24);
  padding: 0.78rem 0.85rem;
}

.sorting-trace-status strong {
  color: var(--bark);
  font-family: var(--mono);
}

.sorting-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.trace-pill {
  display: inline-flex;
  align-items: center;
  min-height: 1.8rem;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: var(--white);
  color: var(--ink);
  font-size: 0.78rem;
  font-weight: 900;
  padding: 0.28rem 0.58rem;
}

.trace-pill.compare { background: rgba(246, 188, 140, 0.42); border-color: rgba(224, 125, 69, 0.55); color: var(--color-accent-strong); }
.trace-pill.swap { background: rgba(169, 98, 85, 0.16); border-color: rgba(169, 98, 85, 0.48); color: var(--color-warning); }
.trace-pill.sorted { background: rgba(111, 146, 127, 0.18); border-color: rgba(111, 146, 127, 0.58); color: var(--color-primary); }
.trace-pill.pivot { background: rgba(224, 125, 69, 0.16); border-color: rgba(176, 82, 42, 0.48); color: var(--color-accent-strong); }

.sorting-step-explanation {
  border-left: 5px solid var(--bark);
  border-radius: var(--radius-sm);
  background: rgba(246, 188, 140, 0.24);
  padding: 0.95rem 1rem;
}

.sorting-step-explanation strong {
  display: block;
  color: var(--bark);
  margin-bottom: 0.25rem;
}

.sorting-step-explanation p {
  margin: 0;
}

.sorting-svg-wrap {
  width: 100%;
  min-height: 290px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(255, 244, 228, 0.98), rgba(246, 188, 140, 0.22));
}

.sorting-svg-wrap svg {
  display: block;
  width: 100%;
  height: auto;
}

.sort-d3-group {
  fill: rgba(246, 188, 140, 0.18);
  stroke: rgba(176, 82, 42, 0.24);
  stroke-width: 1;
}

.sort-d3-bar {
  fill: var(--sage);
  stroke: rgba(11, 58, 53, 0.35);
  stroke-width: 1.5;
}

.sort-d3-bar.compare { fill: var(--color-surface-soft); }
.sort-d3-bar.swap { fill: var(--color-warning); }
.sort-d3-bar.sorted { fill: var(--color-secondary); }
.sort-d3-bar.pivot { fill: var(--color-accent-strong); }

.sort-d3-value,
.sort-d3-index {
  text-anchor: middle;
  font-family: var(--mono);
  font-weight: 900;
  fill: var(--ink);
}

.sort-d3-value {
  font-size: 0.82rem;
}

.sort-d3-index {
  fill: var(--muted);
  font-size: 0.72rem;
}

.sorting-trace-table table {
  width: 100%;
  min-width: 780px;
  border-collapse: collapse;
}

.sorting-trace-table th,
.sorting-trace-table td {
  border-bottom: 1px solid var(--line);
  padding: 0.7rem 0.75rem;
  text-align: left;
  vertical-align: top;
}

.sorting-trace-table th {
  color: var(--bark);
  background: rgba(111, 146, 127, 0.18);
  font-size: 0.76rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.sorting-trace-table tr {
  cursor: pointer;
}

.sorting-trace-table tr.active td {
  background: rgba(246, 188, 140, 0.34);
  box-shadow: inset 4px 0 0 var(--bark);
}

.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  z-index: 100;
  padding: 0.75rem 1.25rem;
  background: var(--color-accent-strong);
  color: var(--white);
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  font-weight: 800;
  text-decoration: none;
  transition: top 160ms ease;
}
.skip-link:focus {
  top: 0;
}

.top-nav a.active {
  color: var(--white);
  border-color: var(--color-accent-strong);
  background: var(--color-accent-strong);
}

.back-to-top {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 30;
  width: 2.8rem;
  height: 2.8rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255, 244, 228, 0.92);
  color: var(--bark);
  font-size: 1.3rem;
  font-weight: 900;
  cursor: pointer;
  box-shadow: var(--shadow-soft);
  backdrop-filter: blur(12px);
  transition: transform 160ms ease, opacity 160ms ease, background 160ms ease;
  display: flex;
  align-items: center;
  justify-content: center;
}
.back-to-top:hover {
  background: var(--color-accent-strong);
  color: var(--white);
  transform: translateY(-2px);
}
.back-to-top[hidden] {
  display: none;
}

.site-footer {
  background: var(--color-primary);
  color: rgba(255, 244, 228, 0.85);
  margin-top: 2rem;
}

.footer-inner {
  width: min(1180px, calc(100% - 2rem));
  margin: 0 auto;
  padding: clamp(2.4rem, 5vw, 4.2rem) 0 clamp(1.2rem, 2vw, 2rem);
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(3, minmax(0, 1fr));
  gap: clamp(1.5rem, 3vw, 2.5rem);
  padding-bottom: clamp(1.5rem, 3vw, 2.5rem);
  border-bottom: 1px solid rgba(255, 244, 228, 0.15);
}

.footer-brand .brand {
  color: var(--color-surface);
  font-size: 1.2rem;
  margin-bottom: 0.75rem;
}

.footer-brand .brand::before {
  background: var(--color-accent);
}

.footer-brand p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.65;
  color: rgba(255, 244, 228, 0.65);
  max-width: 340px;
}

.footer-links h3 {
  color: var(--color-surface);
  font-size: 0.82rem;
  font-weight: 900;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin: 0 0 0.85rem;
}

.footer-links ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.5rem;
}

.footer-links a {
  color: rgba(255, 244, 228, 0.65);
  text-decoration: none;
  font-size: 0.92rem;
  transition: color 160ms ease;
}

.footer-links a:hover,
.footer-links a:focus-visible {
  color: var(--color-accent);
}

.footer-attribution {
  padding: 1.25rem 0 0;
  text-align: center;
}

.footer-attribution p {
  margin: 0;
  font-size: 0.88rem;
  color: rgba(255, 244, 228, 0.55);
}

.footer-attribution strong {
  color: var(--color-surface);
}

.footer-bottom {
  padding: 1rem 0 0;
  text-align: center;
}

.footer-bottom p {
  margin: 0;
  font-size: 0.82rem;
  color: rgba(255, 244, 228, 0.40);
}