body {
  font-family: Arial, Sans-Serif;
  text-align: center;
}

#board {
  display: grid;
  grid-template-columns: repeat(3, 100px);
  grid-template-rows: repeat(3, 100px);
  justify-content: center;
  margin: 20px;
}

.cell {
  width: 100px;
  height: 100px;
  border:1px solid black;;
  font-size: 2.5em;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

.cell.taken {
  cursor: default;
  background-color: #f2f2f2;
}

#restart {
  padding: 10px 20px;
  cursor: pointer;
  border: 1px solid black;
  font-size: 1em;
}

#restart:hover {
  background-color: lightgrey;
}

#results {
  font-size: 1.3em;
  margin: 20px auto;
}