.mj-board {
  display: grid;
  gap: 3px;
  background: #16263c;
  padding: 6px;
  border-radius: 10px;
  border: 3px solid #2b3f5c;
}
.mj-cell {
  width: min(9vw, 40px);
  height: min(9vw, 40px);
  display: flex; align-items: center; justify-content: center;
  font-size: min(5vw, 22px);
  background: #f7f9ff; border-radius: 6px; cursor: pointer;
  box-shadow: 0 1px 2px rgba(0,0,0,.3); user-select: none;
}
.mj-cell.empty { background: transparent; box-shadow: none; cursor: default; }
.mj-cell.sel { outline: 3px solid #ffd93d; outline-offset: -1px; background: #fff7d6; }