body {
  padding: 50px;
  font: 14px "Lucida Grande", Helvetica, Arial, sans-serif;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

a {
  color: #00B7FF;
}

.row {
  clear: both;
}

.cell {
  height: 25px;
  width: 25px;
  float: left;
  cursor: pointer;
}
body {
  padding: 50px;
  font: 14px "Lucida Grande", Helvetica, Arial, sans-serif;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

a {
  color: #00B7FF;
}

.row {
  clear: both;
}

.cell {
  height: 25px;
  width: 25px;
  float: left;
  cursor: pointer;
}

.emptyCell {
  cursor: default;
}
Add emptyCell class to CSS
Add emptyCell class to CSS
