body {
  font-family: Arial, sans-serif;
  text-align: center;
  background: #f4f4f9;
  margin: 0;
  padding: 20px;
}

h1 {
  margin-bottom: 10px;
}

.mode-select {
  margin: 10px;
}

.mode-select button {
  margin: 5px;
  padding: 10px 20px;
  font-size: 1rem;
  cursor: pointer;
}

#difficulty-container {
  margin: 10px;
}

#difficulty {
  padding: 5px 10px;
  border-radius: 6px;
  border: none;
  font-size: 1rem;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, 100px);
  grid-template-rows: repeat(3, 100px);
  gap: 5px;
  justify-content: center;
  margin: 20px auto;
}

.box {
  font-size: 2rem;
  font-weight: bold;
  background: white;
  border: 2px solid #333;
  cursor: pointer;
}

.box:disabled {
  cursor: not-allowed;
  background: #eaeaea;
}

.msg-container {
  margin: 20px;
}

.reset-btn, #new-btn {
  margin: 10px;
  padding: 10px 20px;
  cursor: pointer;
  font-size: 1rem;
  border-radius: 6px;
  border: none;
  background: #333;
  color: white;
}

.hide {
  display: none;
}