/* Dihedral Interactive Explorer Styling */
:root {
  color-scheme: light;
  --background: #ffffff;
  --surface: #f8faf9;
  --surface-raised: #ffffff;
  --surface-dim: #f0f4f2;
  --text: #171a18;
  --text-dim: #454d4a;
  --muted: #59635f;
  --line: #d7deda;
  --line-light: #e8edea;
  --control-line: #87928d;
  --accent: #006f63;
  --accent-light: #e6f4f2;
  --accent-hover: #00564d;
  --accent-active: #003d36;
  --highlight: #d97706;
  --content: 1180px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08), 0 2px 4px rgba(0,0,0,0.04);
  --shadow-lg: 0 10px 24px rgba(0,0,0,0.10), 0 3px 6px rgba(0,0,0,0.05);
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  --font-math: "STIX Two Math", "Cambria Math", Georgia, serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-width: 320px;
  background: var(--background);
  color: var(--text);
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-color: var(--line);
  text-underline-offset: 0.22em;
  transition: text-decoration-color 0.15s ease, color 0.15s ease;
}
a:hover {
  text-decoration-color: var(--accent);
}

.site-header {
  border-bottom: 1px solid var(--line);
  background: var(--background);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
  background-color: rgba(255, 255, 255, 0.95);
}

.header-inner {
  width: min(calc(100% - 2rem), var(--content));
  min-height: 4rem;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.site-name {
  font-weight: 650;
  font-size: 1.05rem;
  text-decoration: none;
  color: var(--text);
  letter-spacing: -0.01em;
}
.site-name:hover { text-decoration: none; color: var(--accent); }

nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.45rem 1.1rem;
  font-size: 0.88rem;
}
nav a {
  color: var(--muted);
  text-decoration: none;
}
nav a:hover, nav a[aria-current="page"] {
  color: var(--text);
  font-weight: 550;
}

main.app-container {
  width: min(calc(100% - 2rem), var(--content));
  margin: 0 auto;
  padding: 2.5rem 0 5rem;
}

.hero-banner {
  margin-bottom: 2.5rem;
  border-bottom: 1px solid var(--line);
  padding-bottom: 2rem;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.2rem 0.65rem;
  background: var(--accent-light);
  color: var(--accent);
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}

.hero-title {
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 750;
  letter-spacing: -0.025em;
  line-height: 1.15;
  margin: 0 0 0.75rem;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--muted);
  max-width: 860px;
  margin: 0;
  line-height: 1.5;
}

/* Master Controls Bar */
.master-controls {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem;
  margin-bottom: 2rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1.25rem;
  box-shadow: var(--shadow-sm);
}

.control-group {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.control-label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.btn-pill-group {
  display: inline-flex;
  background: var(--surface-dim);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: 2px;
  gap: 2px;
  flex-wrap: wrap;
}

.btn-pill {
  border: none;
  background: transparent;
  padding: 0.4rem 0.85rem;
  font-size: 0.9rem;
  font-weight: 550;
  color: var(--text-dim);
  border-radius: calc(var(--radius-md) - 2px);
  cursor: pointer;
  transition: all 0.15s ease;
  font-family: inherit;
}
.btn-pill:hover {
  color: var(--text);
  background: rgba(255,255,255,0.6);
}
.btn-pill.active {
  background: var(--surface-raised);
  color: var(--accent);
  font-weight: 650;
  box-shadow: var(--shadow-sm);
}

.select-control {
  background: var(--surface-raised);
  border: 1px solid var(--line);
  padding: 0.4rem 0.8rem;
  border-radius: var(--radius-md);
  font-family: inherit;
  font-size: 0.9rem;
  color: var(--text);
  cursor: pointer;
}

/* Tabs Navigation */
.view-tabs-nav {
  display: flex;
  gap: 0.5rem;
  border-bottom: 2px solid var(--line-light);
  margin-bottom: 2rem;
  overflow-x: auto;
  padding-bottom: 2px;
}

.view-tab-btn {
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  margin-bottom: -4px;
  padding: 0.75rem 1.25rem;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--muted);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  transition: all 0.15s ease;
  white-space: nowrap;
  font-family: inherit;
}
.view-tab-btn:hover {
  color: var(--text);
}
.view-tab-btn.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.tab-badge {
  font-size: 0.75rem;
  padding: 0.15rem 0.5rem;
  border-radius: 999px;
  background: var(--surface-dim);
  color: var(--muted);
}
.view-tab-btn.active .tab-badge {
  background: var(--accent-light);
  color: var(--accent);
}

/* Panel Layouts */
.tab-panel {
  display: none;
}
.tab-panel.active {
  display: block;
}

/* Interactive Studio Layout (Split View) */
.studio-grid {
  display: grid;
  grid-template-columns: minmax(360px, 480px) 1fr;
  gap: 2rem;
  align-items: start;
}
@media (max-width: 960px) {
  .studio-grid {
    grid-template-columns: 1fr;
  }
}

.canvas-card {
  background: var(--surface-raised);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.canvas-header {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}
.canvas-title {
  font-size: 1.05rem;
  font-weight: 650;
  margin: 0;
}
.canvas-subtitle {
  font-size: 0.82rem;
  color: var(--muted);
}

.main-stage {
  width: 100%;
  aspect-ratio: 1 / 1;
  max-width: 440px;
  border-radius: var(--radius-md);
  background: #faf9f6;
  border: 1px solid var(--line-light);
  position: relative;
  overflow: hidden;
}

.main-stage canvas {
  width: 100%;
  height: 100%;
  display: block;
}

.stage-overlay {
  position: absolute;
  bottom: 0.75rem;
  left: 0.75rem;
  right: 0.75rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  pointer-events: none;
}
.stage-overlay > * { pointer-events: auto; }

.stage-hint {
  font-size: 0.75rem;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(4px);
  padding: 0.25rem 0.6rem;
  border-radius: var(--radius-sm);
  color: var(--muted);
  border: 1px solid var(--line);
}

/* Group Action Keypad */
.action-keypad {
  width: 100%;
  margin-top: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.keypad-row-title {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 0.25rem;
}

.keypad-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.keypad-btn {
  flex: 1 0 auto;
  min-width: 42px;
  height: 36px;
  padding: 0 0.5rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s ease;
}
.keypad-btn:hover {
  background: var(--accent-light);
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-1px);
}
.keypad-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #ffffff;
}
.keypad-btn.reflection {
  color: #b45309;
}
.keypad-btn.reflection:hover {
  background: #fef3c7;
  border-color: #b45309;
}
.keypad-btn.reflection.active {
  background: #b45309;
  color: #ffffff;
}

/* Info Deck / Details Column */
.info-deck {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.deck-section {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
}

.deck-section h3 {
  margin: 0 0 1rem;
  font-size: 1.1rem;
  font-weight: 650;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Filter Controls */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: center;
  margin-bottom: 1.5rem;
  padding: 1rem 1.25rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
}

/* Subgroup Grid / Catalog View */
.subgroups-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
}

.subgroup-card {
  background: var(--surface-raised);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  transition: all 0.2s ease;
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  position: relative;
}
.subgroup-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.subgroup-card.selected {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--accent), var(--shadow-md);
  background: #fafdfc;
}

.subgroup-card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 0.75rem;
}

.subgroup-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin: 0;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.subgroup-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.badge {
  font-size: 0.72rem;
  font-weight: 650;
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}
.badge.normal {
  background: #dcfce7;
  color: #166534;
}
.badge.non-normal {
  background: #f1f5f9;
  color: #475569;
}
.badge.cyclic {
  background: #e0f2fe;
  color: #0369a1;
}
.badge.non-cyclic {
  background: #fef2f2;
  color: #991b1b;
}
.badge.colours {
  background: #fef3c7;
  color: #92400e;
}

.subgroup-preview {
  width: 100%;
  aspect-ratio: 16 / 10;
  background: #faf9f6;
  border-radius: var(--radius-md);
  border: 1px solid var(--line-light);
  overflow: hidden;
  position: relative;
}
.subgroup-preview canvas {
  width: 100%;
  height: 100%;
  display: block;
}

.subgroup-details {
  font-size: 0.85rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  color: var(--text-dim);
}
.detail-row {
  display: flex;
  justify-content: space-between;
  border-bottom: 1px dashed var(--line-light);
  padding-bottom: 0.25rem;
}
.detail-row:last-child { border-bottom: none; }
.detail-label { font-weight: 500; color: var(--muted); }
.detail-value { font-weight: 600; font-family: var(--font-mono); }

/* Palette Swatches Bar */
.palette-swatches {
  display: flex;
  gap: 0.35rem;
  flex-wrap: wrap;
  margin: 0.5rem 0;
}
.swatch-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  background: var(--surface-dim);
  font-size: 0.78rem;
  font-weight: 600;
  border: 1px solid var(--line);
}
.swatch-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
}

/* Playback Controls */
.playback-bar {
  display: flex;
  align-items: center;
  gap: 1rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: 0.75rem 1.25rem;
  margin-top: 1rem;
  width: 100%;
}

.play-toggle-btn {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: var(--accent);
  color: #ffffff;
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background 0.15s ease, transform 0.1s ease;
  font-size: 1rem;
  flex-shrink: 0;
}
.play-toggle-btn:hover {
  background: var(--accent-hover);
  transform: scale(1.05);
}

.scrubber-slider {
  flex: 1;
  accent-color: var(--accent);
  cursor: pointer;
}

.phase-counter {
  font-family: var(--font-mono);
  font-size: 0.88rem;
  font-weight: 600;
  min-width: 65px;
  text-align: right;
}

/* Math Cards & Callouts */
.math-card {
  background: var(--surface-raised);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 1rem 1.25rem;
  margin: 1rem 0;
  font-size: 0.92rem;
}
.math-card.highlight {
  border-left-color: var(--highlight);
  background: #fffbeb;
}
.math-card-title {
  font-weight: 650;
  margin-bottom: 0.35rem;
  color: var(--text);
}

.mono { font-family: var(--font-mono); }
.sym { font-family: var(--font-math); font-style: italic; }

/* Table Wrappers */
.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  margin-top: 1rem;
  background: var(--surface-raised);
}

table.cayley-table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  text-align: center;
}
table.cayley-table th, table.cayley-table td {
  padding: 0.45rem 0.6rem;
  border: 1px solid var(--line-light);
  transition: background 0.1s ease;
}
table.cayley-table th {
  background: var(--surface-dim);
  font-weight: 700;
  color: var(--text);
}
table.cayley-table td:hover {
  background: var(--accent-light);
  cursor: pointer;
}

/* Permutation Matrix / Cycle Box */
.cycle-box {
  background: var(--surface-raised);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: 0.75rem 1rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

/* Theory Prose */
.theory-article {
  max-width: 860px;
  margin: 0 auto;
  font-size: 1.05rem;
  line-height: 1.65;
}
.theory-article h2 {
  font-size: 1.6rem;
  font-weight: 750;
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--line);
}
.theory-article h3 {
  font-size: 1.25rem;
  font-weight: 650;
  margin: 1.75rem 0 0.75rem;
}
.theory-article p { margin: 1rem 0; }

.site-footer {
  border-top: 1px solid var(--line);
  background: var(--surface);
  padding: 3rem 0;
  margin-top: 5rem;
  color: var(--muted);
  font-size: 0.9rem;
}
.footer-inner {
  width: min(calc(100% - 2rem), var(--content));
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
}