:root {
  --bg: #f4f5f7;
  --surface: #ffffff;
  --text: #1d2228;
  --muted: #5f6b76;
  --border: #d9dee3;
  --accent: #2f6fdb;

  --sq-light: #dee3e6;
  --sq-dark: #8ca2ad;
  --sq-last: rgba(255, 214, 79, 0.45);
  --sq-selected: rgba(47, 111, 219, 0.35);

  --cls-best: #16a34a;
  --cls-good: #84cc16;
  --cls-inaccuracy: #eab308;
  --cls-mistake: #f97316;
  --cls-blunder: #dc2626;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #15181c;
    --surface: #1f242a;
    --text: #e6e9ec;
    --muted: #9aa5b0;
    --border: #333a42;
    --accent: #6b9cf0;
  }
}
:root[data-theme="dark"] {
  --bg: #15181c;
  --surface: #1f242a;
  --text: #e6e9ec;
  --muted: #9aa5b0;
  --border: #333a42;
  --accent: #6b9cf0;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 15px/1.45 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

.topbar { padding: 16px 24px 4px; }
.topbar h1 { margin: 0; font-size: 22px; }
.tagline { margin: 2px 0 0; color: var(--muted); }

.layout {
  display: flex;
  gap: 24px;
  padding: 16px 24px 32px;
  align-items: flex-start;
}

.board-area {
  display: flex;
  gap: 10px;
  flex: 0 1 auto;
  width: min(calc(100vh - 120px), calc(100vw - 420px));
  min-width: 320px;
}

.board-wrap { position: relative; flex: 1; aspect-ratio: 1; }
.board { display: block; width: 100%; height: 100%; touch-action: none; user-select: none; border-radius: 4px; }

.evalbar {
  position: relative;
  width: 22px;
  flex: none;
  background: #333;
  border-radius: 4px;
  overflow: hidden;
}
.evalbar-fill {
  position: absolute; left: 0; right: 0; bottom: 0;
  height: 50%;
  background: #f2f2f2;
  transition: height 0.3s ease;
}
.evalbar-label {
  position: absolute; left: 0; right: 0; bottom: 4px;
  font-size: 10px; text-align: center; color: #333; font-weight: 600;
}
.evalbar.black-ahead .evalbar-label { bottom: auto; top: 4px; color: #eee; }
.evalbar.flipped { transform: rotate(180deg); }
.evalbar.flipped .evalbar-label { transform: rotate(180deg); }

/* Board squares and marks */
.sq-light { fill: var(--sq-light); }
.sq-dark { fill: var(--sq-dark); }
.sq-last { fill: var(--sq-last); }
.sq-selected { fill: var(--sq-selected); }
.sq-check { fill: rgba(220, 38, 38, 0.55); filter: blur(6px); }
.coord { font-size: 15px; font-weight: 600; pointer-events: none; }
.coord-on-light { fill: var(--sq-dark); }
.coord-on-dark { fill: var(--sq-light); }

.piece { pointer-events: none; }
.ghost { opacity: 0.9; }

/* Piece rings */
.ring-track { fill: rgba(0, 0, 0, 0.18); }
.ring-none { fill: rgba(0, 0, 0, 0.1); }
.seg.cls-best { fill: var(--cls-best); }
.seg.cls-good { fill: var(--cls-good); }
.seg.cls-inaccuracy { fill: var(--cls-inaccuracy); }
.seg.cls-mistake { fill: var(--cls-mistake); }
.seg.cls-blunder { fill: var(--cls-blunder); }
.piece-ring { opacity: 0.92; }
.piece-ring.is-selected { opacity: 1; }
.best-star { fill: #facc15; stroke: #4a3700; stroke-width: 1.6; stroke-linejoin: round; }
/* A dark halo so stars and badges stand out from squares and rings. */
.best-star, .tactic-badge { filter: drop-shadow(0 0 1.2px rgba(0, 0, 0, 0.7)) drop-shadow(0 1px 2px rgba(0, 0, 0, 0.35)); }
.layer-overlay { pointer-events: none; }

/* Selected-piece destinations */
.dest { pointer-events: none; }
.dest-track { fill: rgba(0, 0, 0, 0.22); }
.dest-disc { opacity: 0.35; }
.dest.cls-best .dest-arc, .dest.cls-best .dest-disc { fill: var(--cls-best); }
.dest.cls-good .dest-arc, .dest.cls-good .dest-disc { fill: var(--cls-good); }
.dest.cls-inaccuracy .dest-arc, .dest.cls-inaccuracy .dest-disc { fill: var(--cls-inaccuracy); }
.dest.cls-mistake .dest-arc, .dest.cls-mistake .dest-disc { fill: var(--cls-mistake); }
.dest.cls-blunder .dest-arc, .dest.cls-blunder .dest-disc { fill: var(--cls-blunder); }
.dest-pill { fill: rgba(20, 24, 28, 0.82); }
.dest-label { fill: #fff; font-size: 15px; font-weight: 600; }
.dest.is-hover .dest-pill { fill: var(--accent); }
.target-dot { fill: rgba(20, 24, 28, 0.3); pointer-events: none; }
.target-capture { fill: none; stroke: rgba(20, 24, 28, 0.3); stroke-width: 7; pointer-events: none; }

/* Promotion picker and game-over banner */
.promo, .banner {
  position: absolute;
  left: 50%; top: 50%;
  transform: translate(-50%, -50%);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.3);
  padding: 12px;
  z-index: 2;
}
.promo { display: flex; gap: 8px; }
.promo[hidden], .banner[hidden] { display: none; }
.promo button {
  width: 76px; padding: 4px; border-radius: 8px;
  border: 4px solid var(--border); background: var(--sq-light); cursor: pointer;
  display: flex; flex-direction: column; align-items: center; color: #222; font-weight: 600;
}
.promo button img { width: 60px; height: 60px; }
.banner { text-align: center; font-size: 18px; font-weight: 600; padding: 16px 24px; }
.banner button { margin-top: 10px; }

/* Side panel */
.panel {
  flex: 1 1 340px;
  max-width: 420px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 14px;
}
.card h2 { font-size: 14px; margin: 0 0 8px; color: var(--muted); font-weight: 600; text-transform: uppercase; letter-spacing: 0.04em; }
.status { font-weight: 600; min-height: 1.45em; }
.panel-head { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.menu-toggle { display: inline-flex; align-items: center; justify-content: center; padding: 6px; line-height: 0; }
.menu-toggle[aria-expanded="true"] { border-color: var(--accent); color: var(--accent); }
.settings-menu { box-shadow: 0 6px 18px rgba(0, 0, 0, 0.12); }
.row { display: flex; flex-direction: column; gap: 4px; margin-bottom: 10px; }
.row label { font-size: 13px; color: var(--muted); }
.row output { color: var(--text); font-weight: 600; margin-left: 4px; }
.check { display: flex; gap: 8px; align-items: center; font-size: 14px; margin: 4px 0; }
.engine-name { font-size: 12px; color: var(--muted); margin-top: 8px; }
.buttons { display: flex; gap: 8px; flex-wrap: wrap; }

select, input[type="text"], button {
  font: inherit;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 10px;
}
button { cursor: pointer; }
button:hover { border-color: var(--accent); }
button.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
button:disabled { opacity: 0.5; cursor: default; }
input[type="range"] { width: 100%; accent-color: var(--accent); }

.legend-items { display: flex; flex-wrap: wrap; gap: 6px 14px; font-size: 13px; }
.legend-items span { display: inline-flex; align-items: center; gap: 6px; }
.swatch { width: 12px; height: 12px; border-radius: 50%; display: inline-block; }
.hint { font-size: 12.5px; color: var(--muted); margin: 8px 0 0; }

.move-ratings { list-style: none; margin: 0; padding: 0; max-height: 260px; overflow-y: auto; }
.move-ratings li {
  display: grid;
  grid-template-columns: 14px 1fr auto auto;
  gap: 8px;
  align-items: center;
  padding: 3px 6px;
  border-radius: 6px;
  font-size: 14px;
  cursor: pointer;
}
.move-ratings li:hover, .move-ratings li.is-hover { background: var(--bg); }
.move-ratings .san { font-weight: 600; }
.move-ratings .star { color: #d4a500; }
.move-ratings .muted { color: var(--muted); font-size: 12px; }
.move-ratings .score { font-variant-numeric: tabular-nums; }
.move-ratings .win { color: var(--muted); font-size: 12px; font-variant-numeric: tabular-nums; min-width: 3.2em; text-align: right; }

.history {
  position: relative;
  font-size: 14px; line-height: 1.9;
  max-height: 260px; overflow-y: auto;
}
.history .num { color: var(--muted); margin-right: 3px; }
.history .ply {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 0 5px; border-radius: 5px; cursor: pointer;
}
.history .ply:hover { background: var(--bg); }
.history .ply.is-current { background: var(--accent); color: #fff; }
.history .ply.is-current .num { color: #fff; }
.history .ply.is-engine { font-style: italic; }
.history .variation {
  display: block; margin: 2px 0 2px 14px; padding-left: 8px;
  border-left: 2px solid var(--border);
  font-size: 13px; color: var(--muted);
}
.history .variation .ply.is-current { color: #fff; }
.history .variation.is-engine { border-left-color: #7c3aed; }
.history .sym { font-weight: 700; }
.history .sym.cls-inaccuracy { color: var(--cls-inaccuracy); }
.history .sym.cls-mistake { color: var(--cls-mistake); }
.history .sym.cls-blunder { color: var(--cls-blunder); }

.dot { width: 10px; height: 10px; border-radius: 50%; display: inline-block; flex: none; }
.dot.cls-best, .swatch.cls-best { background: var(--cls-best); }
.dot.cls-good, .swatch.cls-good { background: var(--cls-good); }
.dot.cls-inaccuracy, .swatch.cls-inaccuracy { background: var(--cls-inaccuracy); }
.dot.cls-mistake, .swatch.cls-mistake { background: var(--cls-mistake); }
.dot.cls-blunder, .swatch.cls-blunder { background: var(--cls-blunder); }
.dot.cls-none { background: var(--border); }

summary { cursor: pointer; font-size: 14px; color: var(--muted); }
.fen-row { display: flex; gap: 6px; margin-top: 8px; }
.voice-row { display: flex; gap: 6px; margin-top: 10px; }
.voice-row input { flex: 1; min-width: 0; font-size: 16px; } /* 16px stops iOS zooming on focus */
.mic { display: inline-flex; align-items: center; justify-content: center; padding: 6px 10px; }
.mic.listening { background: #d93b3b; border-color: #d93b3b; color: #fff; animation: mic-pulse 1.2s ease-in-out infinite; }
@keyframes mic-pulse { 50% { box-shadow: 0 0 0 5px rgba(217, 59, 59, 0.25); } }
@media (prefers-reduced-motion: reduce) { .mic.listening { animation: none; } }
.voice-feedback { font-size: 13px; margin-top: 6px; min-height: 1.3em; }
.voice-feedback:empty { min-height: 0; margin-top: 0; }
.voice-feedback button { padding: 2px 8px; margin: 2px 4px 0 0; font-size: 13px; }
.fen-row input { flex: 1; min-width: 0; font-size: 12px; }

@media (max-width: 860px) {
  .topbar { padding: 12px 16px 0; }
  .layout { flex-direction: column; padding: 12px 16px 24px; gap: 14px; }
  .board-area { width: 100%; min-width: 0; }
  .evalbar { width: 14px; }
  .panel { max-width: none; width: 100%; }
  .promo button { width: 60px; }
  .promo button img { width: 46px; height: 46px; }
}

/* Forced-tactic badges */
.tactic-badge circle { fill: #7c3aed; stroke: #fff; stroke-width: 2; }
.tactic-badge text { fill: #fff; font-size: 14px; font-weight: 700; }
.dest .tactic-badge { pointer-events: none; }

/* Arrows */
.arrow { pointer-events: none; opacity: 0.72; }
.arrow line { stroke-width: 11; stroke-linecap: round; }
.arrow.is-dashed line { stroke-dasharray: 14 10; stroke-linecap: butt; }
.arrow-good line { stroke: #7c3aed; } .arrow-good path { fill: #7c3aed; }
.arrow-bad line { stroke: #dc2626; } .arrow-bad path { fill: #dc2626; }
.arrow-neutral line { stroke: #475569; } .arrow-neutral path { fill: #475569; }
.arrow-move line { stroke: #0f766e; } .arrow-move path { fill: #0f766e; }
.arrow-book line { stroke: #2563eb; } .arrow-book path { fill: #2563eb; }
.arrow-book { opacity: 0.6; }
/* The move just played (and, under the mistake preventer, the only safe
   move), coloured by its rating; the last move is grey until rated. */
.arrow-last { opacity: 0.6; }
.arrow-last line { stroke: #64748b; } .arrow-last path { fill: #64748b; }
.arrow-only { opacity: 0.85; }
.arrow.cls-best line { stroke: var(--cls-best); } .arrow.cls-best path { fill: var(--cls-best); }
.arrow.cls-good line { stroke: var(--cls-good); } .arrow.cls-good path { fill: var(--cls-good); }
.arrow.cls-inaccuracy line { stroke: var(--cls-inaccuracy); } .arrow.cls-inaccuracy path { fill: var(--cls-inaccuracy); }
.arrow.cls-mistake line { stroke: var(--cls-mistake); } .arrow.cls-mistake path { fill: var(--cls-mistake); }
.arrow.cls-blunder line { stroke: var(--cls-blunder); } .arrow.cls-blunder path { fill: var(--cls-blunder); }

/* Explanation card */
.explain-head { display: flex; align-items: baseline; gap: 8px; flex-wrap: wrap; margin-bottom: 6px; }
.explain-head .san { font-size: 18px; font-weight: 700; }
.explain-head .cls { font-size: 13px; font-weight: 600; }
.explain-head .context { font-size: 12px; color: var(--muted); width: 100%; }
.reasons { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 4px; font-size: 14px; }
.reasons li { display: grid; grid-template-columns: 18px 1fr; gap: 4px; }
.reasons .mark { font-weight: 700; text-align: center; }
.reasons .tone-good .mark { color: var(--cls-best); }
.reasons .tone-bad .mark { color: var(--cls-blunder); }
.reasons .tone-neutral .mark { color: var(--muted); }
.reasons .tactic .mark { color: #7c3aed; }
.reasons .empty { color: var(--muted); font-style: italic; display: block; }
.comparison { margin: 8px 0 0; font-size: 14px; padding: 8px 10px; border-radius: 8px; background: var(--bg); }
.explain-actions { margin-top: 8px; display: flex; gap: 8px; }
.review + .review { margin-top: 12px; padding-top: 10px; border-top: 1px solid var(--border); }

/* Openings card */
.opening-name { font-weight: 700; }
.opening-eco { color: var(--muted); font-size: 12px; margin-left: 6px; }
.opening-idea { font-size: 13px; color: var(--muted); margin: 4px 0 8px; }
.book-moves { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 2px; }
.book-moves li { display: flex; gap: 8px; align-items: baseline; padding: 3px 6px; border-radius: 6px; cursor: pointer; font-size: 14px; }
.book-moves li:hover { background: var(--bg); }
.book-moves .san { font-weight: 700; min-width: 3.5em; color: #2563eb; }
.book-moves .names { color: var(--muted); font-size: 13px; }
.book-moves li.is-practice .san::after { content: ' ←'; }
.practice-note { font-size: 13px; margin: 6px 0 0; }
.legend-icon { display: inline-flex; width: 16px; height: 16px; border-radius: 50%; background: #7c3aed; color: #fff; font-size: 10px; font-weight: 700; align-items: center; justify-content: center; }
.move-ratings li.is-focus { box-shadow: inset 0 0 0 2px var(--accent); }
.reasons li.empty-row { display: block; }
.legend-icon svg { width: 13px; height: 13px; display: block; }
#tactic-legend { display: inline-flex; gap: 3px; vertical-align: middle; }
.tactic-badge.is-unsound circle { fill: #dc2626; }
.legend-icon.is-unsound { background: #dc2626; }
.tactic-badge, .legend-icon { --badge-bg: #7c3aed; }
.tactic-badge.is-unsound, .legend-icon.is-unsound { --badge-bg: #dc2626; }
.nav-caret { font-size: 22px; line-height: 1; padding: 3px 14px 6px; font-weight: 600; }
.nav-caret[hidden] { display: none; }