:root {
  --bg: #0b0c10;
  --bg-elev: #14161c;
  --bg-elev-2: #1b1e26;
  --border: #262a33;
  --border-strong: #353a47;
  --text: #e4e6eb;
  --text-dim: #9aa0ac;
  --text-faint: #5e6371;
  --accent: #6b8eff;
  --accent-soft: #6b8eff22;
  --danger: #ef5a6f;
  --warn: #f0b35a;
  --good: #5dd39e;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  font-size: 14px;
  line-height: 1.45;
  -webkit-font-smoothing: antialiased;
}

body {
  display: flex;
  flex-direction: column;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 24px;
  border-bottom: 1px solid var(--border);
  background: linear-gradient(to bottom, #101218, var(--bg));
  flex-shrink: 0;
}

.title h1 {
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.title .sub {
  font-size: 12px;
  color: var(--text-dim);
  margin-top: 2px;
}

.status {
  font-size: 12px;
  color: var(--text-dim);
  font-family: 'JetBrains Mono', monospace;
}

main {
  flex: 1;
  display: grid;
  grid-template-columns: 340px 1fr;
  overflow: hidden;
}

.config-panel {
  padding: 16px 18px;
  border-right: 1px solid var(--border);
  overflow-y: auto;
  background: var(--bg);
}

.config-panel section {
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
}
.config-panel section:last-child { border-bottom: none; }

.config-panel h2 {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  margin-bottom: 10px;
}

.config-panel h3 {
  font-size: 10px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-faint);
  margin: 10px 0 6px;
}

.hint {
  font-size: 11px;
  color: var(--text-faint);
  margin-bottom: 8px;
}

/* Color palette */
.color-palette {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 6px;
}
.color-swatch {
  position: relative;
  height: 30px;
  border-radius: 6px;
  border: 2px solid transparent;
  cursor: pointer;
  padding: 0;
  font: inherit;
  transition: transform 0.08s, border-color 0.12s;
}
.color-swatch:hover { transform: translateY(-1px); }
.color-swatch.active {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--accent-soft);
}
.color-swatch .swatch-name {
  position: absolute;
  bottom: -16px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 9px;
  color: var(--text-faint);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  pointer-events: none;
}
.color-palette { margin-bottom: 18px; }

/* Buttons */
button { font: inherit; cursor: pointer; }

.ghost-btn {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 12px;
  transition: background .15s, border-color .15s;
}
.ghost-btn:hover {
  background: var(--bg-elev-2);
  border-color: var(--border-strong);
}

.primary-btn {
  background: var(--accent);
  color: white;
  border: 1px solid var(--accent);
  padding: 6px 12px;
  border-radius: 6px;
  font-size: 12px;
  font-weight: 500;
}
.primary-btn:hover { filter: brightness(1.1); }

.controls {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-top: 10px;
}

.row { display: flex; gap: 6px; }

/* Piece buttons */
.piece-buttons {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 4px;
}

.piece-btn {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 2px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
  transition: background .15s, border-color .15s, transform .1s;
  min-height: 50px;
}
.piece-btn:hover {
  background: var(--bg-elev-2);
  border-color: var(--accent);
  transform: translateY(-1px);
}
.piece-btn:active { transform: translateY(0); }
.piece-btn .glyph {
  font-size: 22px;
  line-height: 1;
  color: var(--text);
}
.piece-btn .glyph.code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: -0.04em;
}
.piece-btn .lbl {
  font-size: 9px;
  color: var(--text-faint);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

/* Sequence list */
.sequence-list {
  list-style: none;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px;
  min-height: 50px;
  max-height: 220px;
  overflow-y: auto;
  margin-bottom: 8px;
}
.sequence-list:empty::before {
  content: "Pick a color, then click pieces to build a sequence.";
  display: block;
  text-align: center;
  color: var(--text-faint);
  font-size: 11px;
  padding: 10px 4px;
}
.sequence-list li {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 4px 6px;
  background: var(--bg-elev-2);
  border-radius: 4px;
  margin-bottom: 3px;
  font-size: 12px;
}
.sequence-list li:last-child { margin-bottom: 0; }
.sequence-list li.current {
  outline: 1px solid var(--accent);
}
.sequence-list .idx {
  font-family: 'JetBrains Mono', monospace;
  font-size: 10px;
  color: var(--text-faint);
  width: 18px;
  text-align: right;
}
.sequence-list .glyph {
  font-size: 16px;
  width: 18px;
  text-align: center;
}
.sequence-list .glyph.code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  font-weight: 600;
}
.sequence-list .name {
  flex: 1;
  color: var(--text-dim);
}
.sequence-list .actions { display: flex; gap: 2px; }
.sequence-list .actions button {
  background: none;
  border: none;
  color: var(--text-faint);
  padding: 0 4px;
  font-size: 12px;
}
.sequence-list .actions button:hover { color: var(--text); }

#sequence-count {
  font-family: 'JetBrains Mono', monospace;
  font-size: 10px;
  font-weight: 400;
  margin-left: 4px;
}
.muted { color: var(--text-faint); }

/* Fields */
.field {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin-bottom: 8px;
  font-size: 12px;
  color: var(--text-dim);
}
.field.inline {
  flex-direction: row;
  align-items: center;
  gap: 6px;
}
.field em {
  font-style: normal;
  color: var(--text);
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  margin-left: 4px;
}
.field input[type="range"] { width: 100%; accent-color: var(--accent); }
.field input[type="number"],
.field select.select {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text);
  padding: 4px 6px;
  font: inherit;
  width: 100%;
}
.field select.select { appearance: none; cursor: pointer; }
.field select.select:focus { border-color: var(--accent); outline: none; }

/* Board */
.board-view {
  display: flex;
  flex-direction: column;
  padding: 16px;
  background: var(--bg);
  overflow: hidden;
}

.board-wrapper {
  flex: 1;
  background: var(--bg-elev);
  border-radius: 8px;
  border: 1px solid var(--border);
  overflow: hidden;
  position: relative;
}

#board {
  width: 100%;
  height: 100%;
  display: block;
  touch-action: none;
  user-select: none;
}

.cell {
  fill: #181b22;
  stroke: #20232b;
  stroke-width: 0.4;
  pointer-events: none;
}
.cell.center { fill: #232732; }

.cell-num {
  font-family: 'JetBrains Mono', monospace;
  font-size: 5px;
  fill: #4a4f5c;
  text-anchor: end;
  dominant-baseline: hanging;
  pointer-events: none;
}

#board.hide-numbers .cell-num { display: none; }

.piece-glyph {
  text-anchor: middle;
  dominant-baseline: central;
  font-weight: 600;
  pointer-events: none;
}
.piece-glyph.standard { font-size: 18px; }
.piece-glyph.code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: -0.04em;
}

#board.mode-fill .piece-glyph { display: none; }
#board.mode-fill .cell-num { fill: rgba(0,0,0,0.5); }

.piece-just-placed { animation: pop .3s cubic-bezier(.34,1.56,.64,1); transform-origin: center; transform-box: fill-box; }
@keyframes pop {
  0% { opacity: 0; transform: scale(0.2); }
  60% { transform: scale(1.25); }
  100% { opacity: 1; transform: scale(1); }
}

.legend {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 10px 4px 0;
  font-size: 11px;
  color: var(--text-dim);
  font-family: 'JetBrains Mono', monospace;
  flex-shrink: 0;
  flex-wrap: wrap;
}
.legend .stat { display: flex; align-items: center; gap: 6px; }
.legend .stat .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  border: 1px solid rgba(255,255,255,0.15);
}

/* Piece tooltip */
.piece-tooltip {
  position: fixed;
  z-index: 100;
  background: #0f1117;
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  padding: 8px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.5);
  pointer-events: none;
}
.piece-tooltip[hidden] { display: none; }
.piece-tooltip .tooltip-board {
  width: 140px;
  height: 140px;
  display: block;
}
.piece-tooltip .tooltip-name {
  font-size: 11px;
  color: var(--text);
  margin-top: 6px;
  text-align: center;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.tooltip-cell { fill: #181b22; stroke: #262a33; stroke-width: 0.3; }
.tooltip-cell.center { fill: #2a2f3b; }
.tooltip-cell.attacked { fill: #6b8eff55; }
.tooltip-piece {
  text-anchor: middle;
  dominant-baseline: central;
  fill: #e4e6eb;
  font-weight: 700;
}