body {
  background-color: #263238;
  color: #eceff1;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
}

#game-container {
  text-align: center;
}

#info-frame {
  margin-bottom: 20px;
}

#game-guide {
  color: #b0bec5;
  margin-bottom: 15px;
  font-style: italic;
  min-height: 22px;
}

#score-label {
  font-size: 1.2em;
  font-weight: bold;
}

#status-label {
  font-size: 1em;
  margin-top: 10px;
  min-height: 20px;
}

#button-frame {
  display: grid;
  grid-template-columns: repeat(3, 0fr);
  gap: 10px;
  justify-content: center;
}

.cell {
  width: 100px;
  height: 100px;
  background-color: #455a64;
  border: none;
  font-size: 3em;
  font-weight: bold;
  color: #eceff1;
  cursor: pointer;
  transition: background-color 0.3s;
  display: flex;
  justify-content: center;
  align-items: center;
}

.cell:hover {
  background-color: #546e7a;
}

.cell:disabled {
  cursor: not-allowed;
  background-color: #37474f;
  color: #90a4ae;
}

.cell.X {
  color: #80cbc4;
}

.cell.O {
  color: #ffab91;
}

.cell.removal-highlight-x {
  background-color: #347870;
}

.cell.removal-highlight-o {
  background-color: #8f5a4b;
}