body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background-color: #f9f9f9;
  color: #000;
  text-align: center;
  transition: background 0.3s, color 0.3s;
  padding: 20px;
}

/* DARK MODE STYLES */
body.dark-mode {
  background-color: #1e1e1e;
  color: #f0f0f0;
}

body.dark-mode .cell {
  background-color: #333;
  color: #f0f0f0;
  border-color: #888;
}

body.dark-mode .cell:hover {
  background-color: #444;
}

body.dark-mode #resetBtn,
body.dark-mode #modeToggle {
  background-color: #555;
  color: #f0f0f0;
}

/* Toggle Button */
#modeToggle {
  padding: 8px 20px;
  margin-bottom: 10px;
  font-size: 0.9rem;
  border: none;
  background-color: #007acc;
  color: white;
  border-radius: 5px;
  cursor: pointer;
}

#modeToggle:hover {
  background-color: #005f99;
}

/* Scoreboard */
.scoreboard {
  margin: 15px 0;
  font-size: 1.2rem;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 20px;
  color: #333;
}

.game-board {
  display: grid;
  grid-template-columns: repeat(3, 100px);
  gap: 10px;
  justify-content: center;
  margin: 20px auto;
}

.cell {
  width: 100px;
  height: 100px;
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
  font-size: 2.5rem;
  color: #333;
  font-weight: bold;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background 0.3s, transform 0.1s;
}

.cell:hover {
  background-color: #f0f8ff;
  transform: scale(1.05);
}

.cell.winning {
  background-color: #c0ffc0;
  color: #000;
  animation: blink 1s ease-in-out infinite;
}

@keyframes blink {
  50% {
    background-color: #90ee90;
  }
}

#status {
  font-size: 1.4rem;
  margin: 20px;
  color: #444;
}

#resetBtn {
  padding: 10px 25px;
  font-size: 1rem;
  border: none;
  border-radius: 5px;
  background-color: #007acc;
  color: white;
  cursor: pointer;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  transition: background 0.3s;
}

#resetBtn:hover {
  background-color: #005f99;
}

#startOverBtn {
  background-color: #d9534f;
  color: white;
  padding: 10px 20px;
  margin-left: 10px;
  border: none;
  border-radius: 5px;
  cursor: pointer;
}

#startOverBtn:hover {
  background-color: #c9302c;
}

body.dark-mode #startOverBtn {
  background-color: #aa3e3a;
}