:root {
  color-scheme: dark;
  --bg: #102329;
  --panel: #193139;
  --ink: #eef0dc;
  --muted: #b6cbc6;
  --line: #365359;
  --accent: #d1e69a;
  --gold: #edc37e;
  --danger: #f5a698;

  /* Checkers board & token palette */
  --sq-light: #2a4a51;
  --sq-light-inner: #30535b;
  --sq-dark: #152d33;
  --sq-dark-hover: #1c3a42;
  --sq-last: rgba(237, 195, 126, 0.16);
  --sq-selected: rgba(209, 230, 154, 0.24);

  --cream-top: #fbf8ec;
  --cream-mid: #e9e0c4;
  --cream-edge: #b7ab86;
  --cream-ring: #93845c;

  --amber-top: #f7b963;
  --amber-mid: #df8428;
  --amber-edge: #8d480a;
  --amber-ring: #5a2b04;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: radial-gradient(ellipse at 20% 0, #21403d 0, transparent 60%), var(--bg);
  color: var(--ink);
  font: 16px/1.5 system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  overflow-x: hidden;
}

/* Status banner */
.status-banner {
  background: rgba(25, 49, 57, 0.88);
  border: 1px solid var(--line);
  border-left: 4px solid var(--accent);
  border-radius: 12px;
  padding: 12px 16px;
  margin: 12px 0 18px;
  font-weight: 600;
  color: var(--ink);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.status-banner.is-capture-state {
  border-left-color: var(--gold);
  background: rgba(58, 49, 32, 0.55);
}

.status-banner.is-gameover {
  border-left-color: var(--gold);
  background: rgba(35, 65, 55, 0.85);
}

/* Toolbar refinements */
.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  margin: 14px 0;
}

.toolbar label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--muted);
}

.toggle-control {
  background: #233f46;
  border: 1px solid #587478;
  border-radius: 9px;
  padding: 8px 13px;
  min-height: 44px;
  cursor: pointer;
  color: var(--ink) !important;
  user-select: none;
}

.toggle-control:hover {
  border-color: var(--accent);
  background: #304e50;
}

.toggle-control input[type="checkbox"] {
  width: 18px;
  height: 18px;
  min-height: 18px;
  margin: 0;
  padding: 0;
  accent-color: var(--accent);
  cursor: pointer;
}

/* Main two-column layout */
.checkers-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(270px, 0.85fr);
  gap: 20px;
  align-items: start;
}

.board-panel {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

/* Player scorecards bar */
.players-bar {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.player-card {
  display: flex;
  align-items: center;
  gap: 11px;
  padding: 10px 12px;
  border-radius: 12px;
  background: rgba(16, 35, 41, 0.65);
  border: 1.5px solid var(--line);
  transition: border-color 0.18s ease, background-color 0.18s ease, transform 0.18s ease;
}

.player-card.is-active {
  border-color: var(--accent);
  background: rgba(34, 65, 67, 0.78);
  box-shadow: 0 0 0 1px rgba(209, 230, 154, 0.25);
}

.player-card.is-winner {
  border-color: var(--gold);
  background: rgba(64, 56, 32, 0.65);
}

.player-token-preview {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  flex-shrink: 0;
  position: relative;
}

.player-token-preview.token-cream {
  background: radial-gradient(circle at 35% 30%, var(--cream-top), var(--cream-mid) 68%, var(--cream-edge) 100%);
  border: 2px solid var(--cream-ring);
  box-shadow: inset 0 0 0 4px rgba(147, 132, 92, 0.25), 0 2px 5px rgba(0, 0, 0, 0.45);
}

.player-token-preview.token-amber {
  background: radial-gradient(circle at 35% 30%, var(--amber-top), var(--amber-mid) 68%, var(--amber-edge) 100%);
  border: 2px solid var(--amber-ring);
  box-shadow: inset 0 0 0 4px rgba(90, 43, 4, 0.3), 0 2px 5px rgba(0, 0, 0, 0.45);
}

.player-meta {
  min-width: 0;
  flex: 1;
}

.player-title-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 6px;
  margin-bottom: 3px;
}

.player-name {
  font-size: 14px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.turn-badge {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 2px 7px;
  border-radius: 999px;
  background: var(--accent);
  color: #13262b;
  flex-shrink: 0;
}

.turn-badge.badge-gold {
  background: var(--gold);
  color: #1f190b;
}

.player-counts {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 12px;
  font-size: 12.5px;
  color: var(--muted);
}

.player-counts strong {
  color: var(--ink);
}

/* Board frame & 8x8 Grid */
.board-frame {
  width: 100%;
  max-width: 540px;
  margin: 0 auto;
  padding: 8px;
  border-radius: 14px;
  background: linear-gradient(145deg, #13282e, #0d1d22);
  border: 2px solid #3c5d64;
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.42), inset 0 1px 0 rgba(255, 255, 255, 0.06);
}

.checkers-board {
  display: grid;
  grid-template-columns: repeat(8, minmax(0, 1fr));
  grid-template-rows: repeat(8, minmax(0, 1fr));
  aspect-ratio: 1 / 1;
  width: 100%;
  border: 2px solid #0b191d;
  border-radius: 8px;
  overflow: hidden;
  touch-action: manipulation;
  user-select: none;
}

/* Override shared.css button defaults inside the 8x8 grid */
.board-square {
  position: relative;
  width: 100%;
  height: 100%;
  aspect-ratio: 1 / 1;
  min-height: 0 !important;
  min-width: 0 !important;
  padding: 0 !important;
  margin: 0;
  border: none !important;
  border-radius: 0 !important;
  display: flex;
  align-items: center;
  justify-content: center;
  font: inherit;
  outline-offset: -3px !important;
}

.board-square.light-square {
  background: linear-gradient(135deg, var(--sq-light), var(--sq-light-inner));
  cursor: default;
}

.board-square.dark-square {
  background: var(--sq-dark);
  cursor: pointer;
  transition: background-color 0.14s ease;
}

.board-square.dark-square:hover:not(:disabled) {
  background: var(--sq-dark-hover);
}

/* Square coordinate & PDN number labels */
.sq-num {
  position: absolute;
  top: 3px;
  left: 4px;
  font-size: 10px;
  line-height: 1;
  color: rgba(182, 203, 198, 0.42);
  pointer-events: none;
  font-variant-numeric: tabular-nums;
}

.sq-coord {
  position: absolute;
  bottom: 2px;
  right: 4px;
  font-size: 9px;
  line-height: 1;
  color: rgba(182, 203, 198, 0.34);
  pointer-events: none;
}

/* Last move & selection highlights */
.board-square.is-last-from,
.board-square.is-last-to {
  background: linear-gradient(0deg, var(--sq-last), var(--sq-last)), var(--sq-dark);
}

.board-square.is-last-path::before {
  content: "";
  position: absolute;
  inset: 0;
  background: rgba(237, 195, 126, 0.1);
  pointer-events: none;
}

.board-square.is-selected {
  background: linear-gradient(0deg, var(--sq-selected), var(--sq-selected)), var(--sq-dark) !important;
  box-shadow: inset 0 0 0 2.5px var(--accent);
}

.board-square.is-capture-victim {
  box-shadow: inset 0 0 0 2.5px var(--danger);
  background: rgba(245, 166, 152, 0.16);
}

/* Destination indicators */
.dest-marker {
  width: 38%;
  height: 38%;
  border-radius: 50%;
  background: rgba(209, 230, 154, 0.85);
  border: 2px solid #13282e;
  box-shadow: 0 0 0 3px rgba(209, 230, 154, 0.32);
  pointer-events: none;
  transition: transform 0.14s ease;
}

.board-square.is-legal-dest:hover .dest-marker {
  transform: scale(1.18);
}

.board-square.is-capture-dest .dest-marker {
  width: 46%;
  height: 46%;
  background: var(--gold);
  box-shadow: 0 0 0 4px rgba(237, 195, 126, 0.38);
}

.chain-step-marker {
  position: absolute;
  width: 44%;
  height: 44%;
  border-radius: 50%;
  border: 2px dashed var(--gold);
  background: rgba(237, 195, 126, 0.22);
  color: var(--gold);
  font-size: 11px;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none;
}

/* Checkers Piece Token (Pure CSS + Inline SVG Crown) */
.piece {
  width: 78%;
  height: 78%;
  border-radius: 50%;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none;
  transition: transform 0.16s cubic-bezier(0.2, 0.9, 0.3, 1.1), box-shadow 0.16s ease;
  animation: pieceAppear 0.16s ease-out;
}

.piece::after {
  content: "";
  position: absolute;
  inset: 14%;
  border-radius: 50%;
  pointer-events: none;
}

/* Player 1: Cream Token */
.piece.player-1 {
  background: radial-gradient(circle at 32% 28%, var(--cream-top) 0%, var(--cream-mid) 66%, var(--cream-edge) 100%);
  border: 2.5px solid var(--cream-ring);
  box-shadow:
    0 4px 0 #7b6c48,
    0 5px 9px rgba(0, 0, 0, 0.55),
    inset 0 2px 3px rgba(255, 255, 255, 0.75);
}

.piece.player-1::after {
  border: 1.5px solid rgba(130, 114, 72, 0.42);
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.16);
}

/* Player 2: Amber Token */
.piece.player-2 {
  background: radial-gradient(circle at 32% 28%, var(--amber-top) 0%, var(--amber-mid) 66%, var(--amber-edge) 100%);
  border: 2.5px solid var(--amber-ring);
  box-shadow:
    0 4px 0 #4d2403,
    0 5px 9px rgba(0, 0, 0, 0.6),
    inset 0 2px 3px rgba(255, 232, 185, 0.55);
}

.piece.player-2::after {
  border: 1.5px solid rgba(77, 36, 3, 0.48);
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.25);
}

/* King styling (double stacked rim + crown SVG) */
.piece.is-king.player-1 {
  box-shadow:
    0 3px 0 #7b6c48,
    0 6px 0 #5b4e30,
    0 7px 11px rgba(0, 0, 0, 0.62),
    inset 0 0 0 2px rgba(212, 162, 56, 0.55);
}

.piece.is-king.player-2 {
  box-shadow:
    0 3px 0 #5b2b04,
    0 6px 0 #371801,
    0 7px 11px rgba(0, 0, 0, 0.65),
    inset 0 0 0 2px rgba(255, 224, 150, 0.55);
}

.king-crown {
  width: 54%;
  height: 54%;
  z-index: 2;
  filter: drop-shadow(0 1px 1px rgba(0, 0, 0, 0.35));
}

.piece.player-1 .king-crown {
  fill: #9e6710;
  stroke: #5c3904;
  stroke-width: 1.2px;
}

.piece.player-2 .king-crown {
  fill: #fff3d1;
  stroke: #5e2c04;
  stroke-width: 1.2px;
}

/* Movable, mandatory-capture, and selected piece states */
.board-square.is-movable .piece {
  box-shadow:
    0 4px 0 rgba(0, 0, 0, 0.45),
    0 0 0 2.5px rgba(209, 230, 154, 0.65),
    0 5px 10px rgba(0, 0, 0, 0.5);
}

.board-square.must-capture .piece {
  box-shadow:
    0 4px 0 rgba(0, 0, 0, 0.45),
    0 0 0 3px var(--gold),
    0 0 12px rgba(237, 195, 126, 0.65);
  animation: pulseCapture 1.4s infinite ease-in-out;
}

.board-square.is-selected .piece {
  transform: translateY(-3px) scale(1.06);
  box-shadow:
    0 6px 0 rgba(0, 0, 0, 0.4),
    0 0 0 3px var(--accent),
    0 8px 14px rgba(0, 0, 0, 0.6);
}

/* Board footer & legend */
.board-footer {
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: center;
}

.capture-pill {
  background: rgba(237, 195, 126, 0.16);
  border: 1px solid var(--gold);
  color: var(--gold);
  font-size: 13px;
  font-weight: 600;
  padding: 5px 12px;
  border-radius: 999px;
  text-align: center;
}

.legend {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 14px;
  font-size: 12.5px;
  color: var(--muted);
}

.legend-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.legend-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
}

.legend-dot.dot-movable {
  border: 2px solid var(--accent);
  background: transparent;
}

.legend-dot.dot-dest {
  background: var(--accent);
}

.legend-dot.dot-capture {
  background: var(--gold);
}

/* Sidebar & Move History */
.sidebar-panel {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.sidebar-header h2 {
  margin: 0;
  font-size: 20px;
}

.move-counter {
  font-size: 12.5px;
  font-weight: 600;
  color: var(--gold);
  background: rgba(237, 195, 126, 0.12);
  border: 1px solid rgba(237, 195, 126, 0.35);
  padding: 3px 9px;
  border-radius: 999px;
}

.match-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}

.stat-box {
  background: rgba(16, 35, 41, 0.55);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 8px 10px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.stat-label {
  font-size: 11.5px;
  color: var(--muted);
}

.stat-box strong {
  font-size: 15px;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}

.history-empty {
  font-size: 14px;
  color: var(--muted);
  padding: 14px 12px;
  background: rgba(16, 35, 41, 0.4);
  border: 1px dashed var(--line);
  border-radius: 10px;
}

.history-list {
  list-style: none;
  margin: 0;
  padding: 0;
  max-height: 360px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.history-row {
  display: grid;
  grid-template-columns: 36px 1fr 1fr;
  gap: 6px;
  align-items: center;
  padding: 6px 10px;
  border-radius: 8px;
  background: rgba(16, 35, 41, 0.55);
  border: 1px solid rgba(54, 83, 89, 0.65);
  font-size: 13px;
  font-variant-numeric: tabular-nums;
}

.history-turn-num {
  color: var(--muted);
  font-weight: 600;
}

.history-ply {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  color: var(--ink);
}

.history-ply.is-capture {
  color: var(--gold);
  font-weight: 600;
}

.ply-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}

.ply-dot.p1 {
  background: var(--cream-mid);
  border: 1px solid var(--cream-ring);
}

.ply-dot.p2 {
  background: var(--amber-mid);
  border: 1px solid var(--amber-ring);
}

/* Rules help section */
.rules-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
  margin-top: 10px;
}

.rules-grid p {
  margin: 0 0 10px;
}

kbd {
  display: inline-block;
  padding: 1px 5px;
  font-size: 12px;
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  color: var(--ink);
  background: #233f46;
  border: 1px solid #587478;
  border-radius: 4px;
}

@keyframes pieceAppear {
  from {
    transform: scale(0.88);
  }
  to {
    transform: scale(1);
  }
}

@keyframes pulseCapture {
  0%, 100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.05);
  }
}

/* Responsive layout for tablets and 390px mobile screens */
@media (max-width: 900px) {
  .checkers-layout {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 650px) {
  .player-title-row { flex-wrap:wrap; }
  .player-name { white-space:normal; }
  .game-shell {
    padding: 14px 10px;
  }

  .panel {
    padding: 10px;
  }

  .board-frame {
    padding: 5px;
  }

  .players-bar {
    gap: 8px;
  }

  .player-card {
    padding: 8px 9px;
    gap: 8px;
  }

  .player-token-preview {
    width: 26px;
    height: 26px;
  }

  .player-name {
    font-size: 13px;
  }

  .player-counts {
    font-size: 11.5px;
    gap: 4px 8px;
  }

  .sq-num {
    font-size: 8.5px;
    top: 2px;
    left: 3px;
  }

  .sq-coord {
    display: none;
  }
}