body {
  font-family: sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  margin-top: 50px;
  background: #f9f9f9;
}
h1 {
  margin-bottom: 20px;
}
#board {
  display: grid;
  grid-template-columns: repeat(3, 100px);
  grid-template-rows: repeat(3, 100px);
  gap: 5px;
}
.cell {
  width: 100px;
  height: 100px;
  background-color: white;
  border: 2px solid #444;
  font-size: 64px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}
.cell.taken {
  cursor: default;
}
#status {
  margin-top: 20px;
  font-size: 1.2em;
}
button {
  margin-top: 15px;
  padding: 8px 16px;
}