:root {
  --bg: #0b0d12;
  --panel: #161922;
  --panel2: #1d2230;
  --panel3: #11141b;
  --fg: #e8ecf1;
  --muted: #8a93a3;
  --accent: #ffb454;
  --accent2: #5fb3ff;
  --accent3: #b48cff;
  --border: #262d3b;
  --border2: #353d4d;
}
* {
  box-sizing: border-box;
}
html,
body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--bg);
  color: var(--fg);
  font-family: 'Inter', system-ui, sans-serif;
  font-size: 14px;
}
#app {
  display: flex;
  flex-direction: column;
  height: 100%;
}
header {
  padding: 10px 18px;
  border-bottom: 1px solid var(--border);
  background: linear-gradient(180deg, var(--panel) 0%, #13161f 100%);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}
header h1 {
  margin: 0;
  font-size: 18px;
  letter-spacing: 0.3px;
  background: linear-gradient(90deg, var(--accent) 0%, var(--accent3) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.subtitle {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 12px;
}
.subtitle kbd {
  background: var(--panel2);
  padding: 1px 6px;
  border-radius: 3px;
  border: 1px solid var(--border);
  font-size: 12px;
  font-family: ui-monospace, 'JetBrains Mono', monospace;
}
main {
  display: flex;
  flex: 1;
  overflow: hidden;
}
#canvas-wrap {
  flex: 1;
  position: relative;
  background: radial-gradient(ellipse at center, #11141c 0%, #07090d 100%);
  overflow: hidden;
}
#lattice {
  width: 100%;
  height: 100%;
  display: block;
  cursor: crosshair;
}
#hint {
  position: absolute;
  bottom: 8px;
  left: 8px;
  color: var(--muted);
  font-size: 12px;
  background: rgba(10, 12, 18, 0.7);
  padding: 5px 10px;
  border-radius: 4px;
  pointer-events: none;
  border: 1px solid var(--border);
  backdrop-filter: blur(4px);
}
#panel {
  width: 420px;
  overflow-y: auto;
  background: var(--panel);
  border-left: 1px solid var(--border);
  padding: 14px;
}
#panel::-webkit-scrollbar {
  width: 10px;
}
#panel::-webkit-scrollbar-track {
  background: var(--panel);
}
#panel::-webkit-scrollbar-thumb {
  background: var(--border2);
  border-radius: 5px;
}
#panel::-webkit-scrollbar-thumb:hover {
  background: #4a5466;
}
details.section-group {
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 14px;
  background: var(--panel2);
  overflow: hidden;
}
details.section-group > summary {
  padding: 8px 12px;
  color: var(--accent);
  font-weight: 600;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 1px;
  background: var(--panel3);
  border-bottom: 1px solid var(--border);
  cursor: pointer;
  user-select: none;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 8px;
}
details.section-group > summary::-webkit-details-marker {
  display: none;
}
details.section-group > summary::before {
  content: '▶';
  font-size: 9px;
  color: var(--muted);
  transition: transform 0.15s;
  display: inline-block;
}
details.section-group[open] > summary::before {
  transform: rotate(90deg);
}
details.section-group > summary:hover {
  color: #ffc777;
}
details.section-group:not([open]) > summary {
  border-bottom: none;
}
.section-body {
  padding: 12px;
}
label {
  display: block;
  font-size: 13px;
  margin: 8px 0;
  color: var(--fg);
}
input[type='number'],
select {
  background: var(--panel);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 5px 8px;
  margin-left: 6px;
  font-family: inherit;
  font-size: 13px;
  transition: border-color 0.15s;
}
input[type='text'] {
  background: var(--panel);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 5px 8px;
  margin-left: 6px;
  font-family: ui-monospace, 'JetBrains Mono', monospace;
  font-size: 12px;
  transition: border-color 0.15s;
}
input[type='text']:focus {
  outline: none;
  border-color: var(--accent2);
}
input[type='number']:focus,
select:focus {
  outline: none;
  border-color: var(--accent2);
}
input[type='checkbox'] {
  accent-color: var(--accent);
  margin-right: 4px;
}
input[type='range'] {
  accent-color: var(--accent);
  vertical-align: middle;
  width: 140px;
  margin-left: 6px;
}
.rangeval {
  display: inline-block;
  min-width: 32px;
  font-family: ui-monospace, 'JetBrains Mono', monospace;
  font-size: 11px;
  color: var(--accent2);
  margin-left: 4px;
}
button {
  background: var(--accent);
  color: #1a1a1a;
  border: none;
  padding: 6px 14px;
  border-radius: 5px;
  cursor: pointer;
  font-weight: 600;
  font-size: 13px;
  margin-right: 6px;
  margin-top: 6px;
  transition:
    background 0.15s,
    transform 0.05s;
}
button:hover {
  background: #ffc777;
}
button:active {
  transform: translateY(1px);
}
#tile-info,
#walk-history {
  font-size: 12px;
}
#tile-info .section {
  margin: 10px 0 6px;
  padding-bottom: 4px;
  border-bottom: 1px dashed var(--border);
  color: var(--muted);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.8px;
}
#tile-info .kv {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 4px 8px;
  align-items: baseline;
  margin: 4px 0;
}
#tile-info .kv .k {
  color: var(--muted);
  font-size: 11px;
}
#tile-info .kv .v {
  font-family: ui-monospace, 'JetBrains Mono', 'Fira Code', monospace;
  font-size: 11.5px;
  color: var(--fg);
  word-break: break-word;
}
#tile-info code,
.alg {
  font-family: ui-monospace, 'JetBrains Mono', 'Fira Code', monospace;
  background: var(--panel3);
  color: var(--accent2);
  padding: 2px 6px;
  border-radius: 3px;
  font-size: 11px;
  border: 1px solid var(--border);
  display: inline-block;
}
.alg-block {
  font-family: ui-monospace, 'JetBrains Mono', 'Fira Code', monospace;
  background: var(--panel3);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 6px 8px;
  font-size: 11px;
  line-height: 1.6;
  color: var(--accent2);
}
.alg-block .axis {
  display: inline-block;
  width: 14px;
  color: var(--muted);
}
.alg-block .float {
  color: var(--muted);
  font-size: 10.5px;
  margin-top: 2px;
}
.vertex-row {
  display: grid;
  grid-template-columns: 36px 1fr;
  gap: 6px;
  align-items: center;
  margin: 4px 0;
  padding: 6px;
  background: var(--panel3);
  border: 1px solid var(--border);
  border-radius: 4px;
}
.neighbor-row {
  display: grid;
  grid-template-columns: 60px 1fr 90px;
  gap: 8px;
  align-items: center;
  padding: 5px 8px;
  margin: 3px 0;
  background: var(--panel3);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-family: ui-monospace, 'JetBrains Mono', monospace;
  font-size: 11px;
}
.neighbor-row.missing {
  opacity: 0.5;
  font-style: italic;
}
.neighbor-row .delta {
  color: var(--accent3);
  text-align: right;
}
#walk-history {
  list-style: none;
  padding-left: 0;
  max-height: 200px;
  overflow-y: auto;
  margin: 0;
}
#walk-history li {
  padding: 4px 6px;
  border-bottom: 1px dashed var(--border);
  font-family: ui-monospace, 'JetBrains Mono', monospace;
  font-size: 11px;
}
#walk-history li:last-child {
  background: rgba(255, 180, 84, 0.08);
  border-left: 2px solid var(--accent);
}
.pill {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 10px;
  background: var(--panel);
  border: 1px solid var(--border);
  font-size: 10.5px;
  margin-right: 4px;
  font-family: ui-monospace, monospace;
  color: var(--accent2);
  font-weight: 600;
}
.pill.edge {
  color: var(--accent);
}
.pill.sheet {
  color: var(--accent3);
}
p {
  margin: 4px 0;
  line-height: 1.5;
}
details.section-group p {
  font-size: 12px;
  color: var(--muted);
}
/* ── Doc tabs ─────────────────────────────────────────────────────────────── */
.doc-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  margin-bottom: 10px;
  align-items: center;
}
.doc-tab {
  background: var(--panel3);
  color: var(--muted);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 4px 10px;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  margin: 0;
  transition:
    background 0.15s,
    color 0.15s;
}
.doc-tab:hover {
  background: var(--panel2);
  color: var(--fg);
}
.doc-tab.active {
  background: var(--accent);
  color: #1a1a1a;
  border-color: var(--accent);
}
.doc-tab.doc-maximize {
  margin-left: auto;
  font-size: 15px;
  padding: 2px 8px;
  color: var(--accent2);
  background: var(--panel3);
  border-color: var(--border2);
  line-height: 1;
}
.doc-tab.doc-maximize:hover {
  background: var(--panel2);
  color: var(--accent);
}
.doc-content {
  font-size: 13px;
  line-height: 1.7;
  color: var(--fg);
  max-height: 340px;
  overflow-y: auto;
  padding-right: 4px;
}
.doc-content h1,
.doc-content h2,
.doc-content h3 {
  color: var(--accent);
  margin-top: 1em;
}
.doc-content code {
  background: var(--panel3);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 1px 5px;
  font-size: 11.5px;
  color: var(--accent2);
}
.doc-content pre {
  background: var(--panel3);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 10px 12px;
  overflow-x: auto;
  font-size: 12px;
}
.doc-content a {
  color: var(--accent2);
}
.doc-content hr {
  border-color: var(--border);
}
/* ── Doc modal ─────────────────────────────────────────────────────────────── */
.doc-modal {
  position: fixed;
  inset: 0;
  z-index: 1000;
  background: rgba(7, 9, 13, 0.82);
  backdrop-filter: blur(6px);
  display: flex;
  align-items: center;
  justify-content: center;
  animation: docModalFadeIn 0.18s ease;
}
@keyframes docModalFadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}
.doc-modal-inner {
  background: var(--panel2);
  border: 1px solid var(--border2);
  border-radius: 10px;
  box-shadow: 0 8px 48px rgba(0, 0, 0, 0.7);
  width: 94vw;
  height: 90vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  animation: docModalSlideIn 0.18s ease;
}
@keyframes docModalSlideIn {
  from {
    transform: translateY(18px) scale(0.98);
    opacity: 0;
  }
  to {
    transform: translateY(0) scale(1);
    opacity: 1;
  }
}
.doc-modal-header {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 10px 14px;
  background: var(--panel3);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}
.doc-modal-tabs {
  display: flex;
  gap: 4px;
  flex: 1;
  flex-wrap: wrap;
}
.doc-modal-close {
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 3px 10px;
  font-size: 14px;
  cursor: pointer;
  margin: 0;
  line-height: 1.4;
  transition:
    background 0.12s,
    color 0.12s;
}
.doc-modal-close:hover {
  background: #3a1a1a;
  color: #f38ba8;
  border-color: #f38ba8;
}
.doc-modal-body {
  flex: 1;
  overflow-y: auto;
  padding: 24px 28px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--fg);
}
.doc-modal-body h1,
.doc-modal-body h2,
.doc-modal-body h3 {
  color: var(--accent);
  margin-top: 1.2em;
}
.doc-modal-body code {
  background: var(--panel3);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 1px 6px;
  font-size: 12.5px;
  color: var(--accent2);
}
.doc-modal-body pre {
  background: var(--panel3);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 12px 16px;
  overflow-x: auto;
  font-size: 13px;
}
.doc-modal-body a {
  color: var(--accent2);
}
.doc-modal-body hr {
  border-color: var(--border);
}
.doc-modal-body::-webkit-scrollbar {
  width: 10px;
}
.doc-modal-body::-webkit-scrollbar-track {
  background: var(--panel2);
}
.doc-modal-body::-webkit-scrollbar-thumb {
  background: var(--border2);
  border-radius: 5px;
}
.doc-modal-body::-webkit-scrollbar-thumb:hover {
  background: #4a5466;
}