:root {
  --bg: #f4efe2;
  --bg-accent: radial-gradient(circle at top left, rgba(183, 121, 255, 0.18), transparent 32%),
    radial-gradient(circle at bottom right, rgba(144, 94, 255, 0.12), transparent 28%);
  --panel: rgba(255, 250, 240, 0.78);
  --panel-solid: #f8f2e5;
  --card: rgba(255, 250, 240, 0.86);
  --card-strong: #fff8eb;
  --text: #151515;
  --muted: #6f6a62;
  --line: rgba(43, 39, 35, 0.22);
  --shadow: 6px 8px 0 rgba(30, 27, 24, 0.18);
  --accent: #a85bf9;
  --accent-strong: #8f3ff5;
  --accent-soft: rgba(168, 91, 249, 0.16);
  --success: #41a66c;
  --danger: #ef6d6d;
  --highlight: #ffd978;
  --font-heading: "Space Grotesk", sans-serif;
  --font-body: "Plus Jakarta Sans", sans-serif;
}

body.dark {
  --bg: #111111;
  --bg-accent: radial-gradient(circle at top left, rgba(168, 91, 249, 0.24), transparent 24%),
    radial-gradient(circle at bottom right, rgba(168, 91, 249, 0.14), transparent 22%);
  --panel: rgba(28, 28, 28, 0.88);
  --panel-solid: #171717;
  --card: rgba(31, 31, 31, 0.96);
  --card-strong: #232323;
  --text: #f5f1eb;
  --muted: #aca49a;
  --line: rgba(255, 252, 246, 0.12);
  --shadow: 6px 8px 0 rgba(0, 0, 0, 0.36);
  --accent: #ad5cff;
  --accent-strong: #bf82ff;
  --accent-soft: rgba(173, 92, 255, 0.18);
  --success: #5ccc88;
  --danger: #ff7f7f;
  --highlight: #f8bb38;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  background: var(--bg-accent), var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  transition: background 250ms ease, color 250ms ease;
}

button,
input,
select,
textarea {
  font: inherit;
}

button {
  cursor: pointer;
}

.app-shell {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  min-height: 100vh;
}

.sidebar {
  padding: 26px 18px;
  border-right: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.05);
  backdrop-filter: blur(12px);
}

.brand-block,
.theme-switch,
.sidebar-panel,
.panel,
.card,
.summary-box,
.algorithm-card,
.stat-card,
.visual-node,
.visual-edge,
.bar,
.array-cell,
.dp-cell,
.queen-cell,
.tree-node {
  border: 1.5px solid var(--line);
  border-radius: 28px;
  box-shadow: var(--shadow);
}

.brand-block {
  display: flex;
  gap: 14px;
  align-items: center;
  padding: 16px;
  background: var(--card);
}

.brand-mark {
  width: 64px;
  height: 64px;
  border-radius: 20px;
  display: block;
  object-fit: cover;
  flex-shrink: 0;
  background: transparent;
}

.eyebrow {
  margin: 0 0 4px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.75rem;
  color: var(--muted);
}

h1,
h2,
h3,
h4 {
  margin: 0;
  font-family: var(--font-heading);
}

h1 {
  font-size: 2rem;
}

h2 {
  max-width: 760px;
  font-size: clamp(2rem, 3.8vw, 3.6rem);
  line-height: 1.04;
}

h3 {
  font-size: 1.4rem;
}

h4 {
  font-size: 1.05rem;
}

.theme-switch,
.sidebar-panel {
  margin-top: 18px;
  padding: 16px;
  background: var(--card);
}

.theme-switch {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.theme-toggle {
  border: 0;
  background: transparent;
  padding: 0;
}

.theme-toggle__track {
  width: 64px;
  height: 34px;
  padding: 4px;
  display: block;
  border-radius: 999px;
  background: var(--card-strong);
  border: 1px solid var(--line);
}

.theme-toggle__thumb {
  width: 24px;
  height: 24px;
  display: block;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-strong));
  transition: transform 220ms ease;
}

body.dark .theme-toggle__thumb {
  transform: translateX(30px);
}

.category-nav {
  display: grid;
  gap: 10px;
}

.category-nav button,
.secondary-button,
.primary-button,
.icon-button {
  border: 1.5px solid var(--line);
  border-radius: 999px;
  transition: transform 180ms ease, background 180ms ease, color 180ms ease;
}

.category-nav button {
  padding: 12px 14px;
  background: var(--panel-solid);
  color: var(--text);
  text-align: left;
}

.category-nav button.active,
.category-nav button:hover,
.secondary-button:hover,
.primary-button:hover,
.icon-button:hover,
.algorithm-card:hover {
  transform: translateY(-2px);
}

.category-nav button.active {
  background: var(--accent-soft);
  color: var(--text);
}

.stat-card-grid {
  display: grid;
  gap: 10px;
}

.stat-card {
  padding: 14px;
  background: var(--panel-solid);
}

.stat-card span {
  display: block;
  color: var(--muted);
  margin-bottom: 8px;
}

.stat-card strong {
  font-size: 1.4rem;
}

.main-content {
  padding: 24px;
  max-width: 1560px;
  margin: 0 auto;
}

.panel-copy {
  max-width: 680px;
  color: var(--muted);
  line-height: 1.6;
}

.workspace-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.dashboard-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.dashboard-column,
.workspace-column {
  min-width: 0;
}

.panel {
  padding: 22px;
  background: var(--panel);
  backdrop-filter: blur(10px);
  min-width: 0;
}

.panel__header {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: start;
  margin-bottom: 18px;
}

.panel__header--stack {
  flex-direction: column;
}

.workspace-head {
  width: 100%;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
}

.search-field input,
.input-form input,
.input-form textarea,
.input-form select,
.speed-row select {
  width: 100%;
  padding: 12px 16px;
  border-radius: 18px;
  border: 1.5px solid var(--line);
  background: var(--card-strong);
  color: var(--text);
  outline: none;
}

.algorithm-grid {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(260px, 320px);
  gap: 14px;
  overflow-x: auto;
  overflow-y: hidden;
  padding: 4px 6px 10px 4px;
  align-items: stretch;
}

.algorithm-card {
  height: 100%;
  padding: 18px;
  background: var(--card);
  transition: transform 180ms ease, border-color 180ms ease, background 180ms ease;
}

.algorithm-card.active {
  background: var(--accent-soft);
  border-color: rgba(168, 91, 249, 0.42);
}

.algorithm-card__top {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 10px;
}

.algorithm-card p {
  margin: 0;
  color: var(--muted);
  line-height: 1.5;
}

.workspace-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.92fr) minmax(0, 1.4fr);
  grid-template-areas:
    "input visualization"
    "summary visualization"
    "insights visualization";
  gap: 18px;
  align-items: stretch;
}

.card,
.summary-box {
  padding: 18px;
  background: var(--card);
  min-width: 0;
}

.card--input {
  grid-area: input;
  min-height: 420px;
}

.card--summary {
  grid-area: summary;
  min-height: 320px;
}

.card--insights {
  grid-area: insights;
  min-height: 220px;
}

.card--visualization {
  grid-area: visualization;
  min-height: 900px;
}

.card__header {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
  margin-bottom: 14px;
}

.card__actions,
.playback-controls,
.speed-row {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
}

.primary-button,
.secondary-button,
.icon-button {
  padding: 10px 16px;
}

.primary-button {
  background: linear-gradient(135deg, var(--accent), var(--accent-strong));
  color: white;
}

.secondary-button,
.icon-button {
  background: var(--card-strong);
  color: var(--text);
}

.icon-button {
  min-width: 44px;
}

.input-form {
  display: grid;
  gap: 12px;
  align-content: start;
  min-height: 100%;
}

.detail-panel {
  overflow: hidden;
}

.field-group {
  display: grid;
  gap: 6px;
}

.field-group label {
  font-size: 0.92rem;
  color: var(--muted);
}

.field-group textarea,
.field-group input {
  font-size: 1.02rem;
}

.field-help {
  font-size: 0.82rem;
  color: var(--muted);
}

.visualization-panel {
  min-height: 700px;
  border-radius: 24px;
  border: 1px dashed var(--line);
  padding: 24px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.04), transparent);
  overflow: hidden;
}

.placeholder-panel {
  display: grid;
  place-items: center;
  color: var(--muted);
}

.insight-grid {
  display: grid;
  gap: 14px;
}

.insight-grid.compact {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.insight-box {
  padding: 16px 18px;
  border: 1.5px solid var(--line);
  border-radius: 22px;
  background: var(--card-strong);
  box-shadow: var(--shadow);
}

.insight-box__content {
  margin-top: 8px;
  font-size: 1.02rem;
  line-height: 1.6;
  color: var(--text);
}

.is-hidden {
  display: none;
}

.summary-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.summary-box__content {
  margin-top: 8px;
  color: var(--text);
  line-height: 1.6;
  font-size: 1.08rem;
  min-height: 80px;
}

#final-output.summary-box__content {
  font-size: 1.2rem;
  font-weight: 600;
}

.pill {
  padding: 8px 12px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--text);
  font-size: 0.9rem;
}

.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;
}

.visual-array {
  display: flex;
  gap: 10px;
  align-items: end;
  min-height: 540px;
}

.bar-group {
  flex: 1;
  min-width: 0;
  display: grid;
  gap: 8px;
  justify-items: center;
}

.bar {
  width: 100%;
  min-height: 18px;
  background: linear-gradient(180deg, var(--accent-strong), var(--accent));
  display: flex;
  align-items: start;
  justify-content: center;
  color: white;
  padding-top: 6px;
}

.bar.active,
.array-cell.active,
.dp-cell.active,
.tree-node.active,
.queen-cell.active {
  outline: 3px solid var(--highlight);
  outline-offset: 2px;
}

.bar.done,
.array-cell.found,
.visual-edge.selected,
.dp-cell.filled,
.queen-cell.queen,
.tree-node.merged {
  background: linear-gradient(180deg, var(--success), #2e7a4c);
}

.bar.pivot,
.array-cell.mid,
.tree-node.leaf {
  background: linear-gradient(180deg, #ffb259, #ee8a24);
}

.bar.compare,
.array-cell.compare,
.visual-edge.considering,
.dp-cell.considering {
  background: linear-gradient(180deg, var(--highlight), #d39a1c);
  color: #1b1b1b;
}

.bar-labels,
.array-cells {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(44px, 1fr));
  gap: 10px;
}

.array-cell {
  min-height: 88px;
  display: grid;
  place-items: center;
  background: var(--card-strong);
  font-weight: 600;
  font-size: 1.05rem;
}

.visual-table,
.dp-table {
  display: grid;
  gap: 8px;
}

.table-row,
.dp-row {
  display: grid;
  gap: 8px;
}

.table-cell,
.dp-cell {
  min-height: 74px;
  border-radius: 18px;
  border: 1px solid var(--line);
  background: var(--card-strong);
  padding: 10px 8px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 4px;
  text-align: center;
  overflow: hidden;
}

.table-cell small,
.dp-cell small,
.tree-node small {
  color: var(--muted);
}

.dp-cell strong {
  display: block;
  font-size: 0.98rem;
  line-height: 1.05;
  max-width: 100%;
  word-break: break-word;
}

.dp-cell small {
  display: block;
  font-size: 0.68rem;
  line-height: 1;
  max-width: 100%;
  word-break: break-word;
}

.graph-layout {
  display: grid;
  gap: 12px;
  min-height: 620px;
  position: relative;
  height: 100%;
}

.graph-canvas {
  position: relative;
  min-height: 620px;
  height: 100%;
}

.graph-svg {
  width: 100%;
  height: 100%;
  min-height: 620px;
  overflow: visible;
}

.tree-svg {
  width: 100%;
  min-height: 260px;
  max-height: 420px;
}

.graph-line {
  stroke-linecap: round;
}

.graph-weight {
  font-family: var(--font-heading);
  font-weight: 700;
}

.graph-node-circle {
  fill: var(--card-strong);
  stroke: var(--line);
  stroke-width: 0.45;
}

.graph-node-circle.visited {
  fill: #43b36f;
}

.graph-node-circle.active {
  fill: #f4c24a;
}

.graph-node-label {
  fill: var(--text);
  font-family: var(--font-heading);
  font-weight: 700;
  dominant-baseline: middle;
  text-anchor: middle;
}

.tree-wrap {
  display: grid;
  gap: 16px;
}

.tree-level {
  display: flex;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}

.tree-node {
  min-width: 110px;
  min-height: 88px;
  padding: 14px 18px;
  background: var(--card-strong);
  display: grid;
  place-items: center;
  text-align: center;
}

.board {
  display: grid;
  gap: 0;
  width: min(100%, 760px);
  aspect-ratio: 1;
  margin: 0 auto;
  overflow: hidden;
  border-radius: 24px;
  border: 1.5px solid var(--line);
}

.queen-cell {
  display: grid;
  place-items: center;
  font-size: clamp(1.15rem, 2vw, 2rem);
}

.queen-cell.light {
  background: rgba(255, 255, 255, 0.35);
}

.queen-cell.dark {
  background: rgba(168, 91, 249, 0.18);
}

.queen-cell.attack {
  background: rgba(239, 109, 109, 0.28);
}

.footer-note {
  margin-top: 12px;
  color: var(--muted);
  font-size: 0.88rem;
}

@media (max-width: 1180px) {
  .summary-grid {
    grid-template-columns: 1fr;
  }

  .workspace-grid {
    grid-template-columns: 1fr;
    grid-template-areas:
      "input"
      "visualization"
      "summary"
      "insights";
  }
}

@media (max-width: 960px) {
  .app-shell {
    grid-template-columns: 1fr;
  }

  .sidebar {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .workspace-head {
    flex-direction: column;
  }
}

@media (max-width: 640px) {
  .main-content,
  .sidebar {
    padding: 16px;
  }

  .panel,
  .card,
  .summary-box,
  .algorithm-card,
  .sidebar-panel,
  .theme-switch,
  .brand-block {
    border-radius: 22px;
  }

  .card__header,
  .panel__header {
    flex-direction: column;
    align-items: start;
  }

  .algorithm-grid {
    grid-auto-columns: minmax(220px, 84vw);
  }

  .bar-labels,
  .array-cells {
    grid-template-columns: repeat(auto-fit, minmax(38px, 1fr));
  }
}