table {
  border-collapse: collapse;
  margin: auto;
}

td {
  border: 1px solid black;
}

td td {
  height: 26px;
  width: 26px;
  text-align: center;
}

.start {
  background-color: #ccc;
  color: #000;
  font-weight: bold;
}

.solved {
  background-color: #fff;
  color: #c30;
  font-weight: bold;
}

.possibilities {
  vertical-align: top;
  text-align: left;
  color: #999;
  background-color: #f8f8f8;
  font-size: 0.53em;
  line-height: 1em;
}

.error {
  background-color: #c30;
}

fieldset {
  margin-bottom: 15px;
}