.checkers-surface {
  display: flex;
  justify-content: center;
}

.checkers-board {
  display: grid;
  grid-template-columns: repeat(8, minmax(0, 1fr));
  width: min(100%, 28rem);
  aspect-ratio: 1;
  overflow: hidden;
  border-radius: 22px;
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-soft);
}

.square {
  position: relative;
  display: grid;
  place-items: center;
}

.square.light {
  background: #e8dcc2;
}

.square.dark {
  background: #5b3b2d;
}

.square.move-target::after,
.square.capture-target::after {
  content: "";
  width: 0.85rem;
  height: 0.85rem;
  border-radius: 999px;
  background: rgba(116, 215, 255, 0.72);
  box-shadow: 0 0 0 6px rgba(116, 215, 255, 0.14);
}

.square.capture-target::after {
  background: rgba(255, 207, 125, 0.82);
  box-shadow: 0 0 0 6px rgba(255, 207, 125, 0.16);
}

.piece {
  width: 72%;
  height: 72%;
  border-radius: 999px;
  border: none;
  display: grid;
  place-items: center;
  font-weight: 900;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.18s ease;
}

.piece.red {
  background: linear-gradient(180deg, #ff8b8b, #c65261);
  color: #fff8f6;
  box-shadow: inset 0 2px 6px rgba(255,255,255,0.18), 0 8px 18px rgba(0,0,0,0.24);
}

.piece.black {
  background: linear-gradient(180deg, #313b52, #171f2f);
  color: #eef3ff;
  box-shadow: inset 0 2px 6px rgba(255,255,255,0.1), 0 8px 18px rgba(0,0,0,0.24);
}

.piece.king::after {
  content: "K";
  font-size: 0.95rem;
}

.piece.selected {
  transform: translateY(-4px);
  box-shadow: 0 0 0 3px rgba(116, 215, 255, 0.28), 0 10px 22px rgba(0,0,0,0.3);
}

@media (max-width: 640px) {
  .checkers-board {
    width: min(100%, 22rem);
    border-radius: 18px;
  }

  .square.move-target::after,
  .square.capture-target::after {
    width: 0.7rem;
    height: 0.7rem;
  }
}