body {
  font-family: Arial, sans-serif;
}

h1 {
  text-align: center;
}

form {
  width: 300px;
  margin: 0 auto;
}

input {
  display: block;
  width: 100%;
  margin-bottom: 10px;
}

button {
  width: 100%;
}

#gameBoard {
  display: grid;
  grid-template-columns: repeat(10, 30px);
  grid-gap: 2px;
  margin: 0 auto;
  width: 320px;
}

.cell {
  width: 30px;
  height: 30px;
  border: 1px solid #ddd;
  background-color: #eee;
  cursor: pointer;
}