.kk-board {
  display: grid;
  gap: 0;
  margin: 0 auto;
  background: #1f2937;
  border: 3px solid #1f2937;
  border-radius: 8px;
  overflow: hidden;
  touch-action: manipulation;
}
.kk-cell {
  position: relative;
  aspect-ratio: 1 / 1;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: clamp(18px, 6vw, 26px);
  font-weight: 700;
  color: #222;
  cursor: pointer;
  user-select: none;
  border: 1px solid rgba(0,0,0,.25);
}
.kk-cell .lab {
  position: absolute;
  top: 2px; left: 3px;
  font-size: 10px;
  font-weight: 700;
  color: #b91c1c;
  line-height: 1;
}
.kk-cell.empty { color: #94a3b8; }
.kk-cell.wrong { background: #fee2e2 !important; }
.kk-cell.sel { outline: 3px solid #2563eb; outline-offset: -3px; z-index: 2; }