.square {
  width: 100px;
  height: 100px;
  background: #eee;
  font-size: 800%;
  line-height:1em;
  text-align:center;

  /*-webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -o-user-select: none;
  user-select: none;*/
}

#ticktacktoe table, th, td {
  border: 1px solid black;
}