body {
  background-color: #121212;
  color: #fff;
  font-family: Arial, sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
  margin: 0;
}

h1 {
  margin-bottom: 10px;
  color: #11d7d7;
  text-align: center;
}

.turn {
  margin-bottom: 20px;
  font-size: 1.5rem;
  color: #f0db4f;
  text-align: center;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, minmax(100px, 12vw));
  grid-template-rows: repeat(3, minmax(100px, 12vw));
  gap: 5px;
  justify-content: center;
}

.cell {
  background-color: #1e1e1e;
  border: 2px solid #333;
  font-size: 2.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: 0.3s;
}

.cell:hover {
  background-color: #2e2e2e;
}

.winner {
  background-color: #00cc77 !important;
  color: black;
  font-weight: bold;
}

.message {
  margin-top: 15px;
  font-size: 1.2rem;
  color: #00ffcc;
  text-align: center;
}

button {
  margin-top: 15px;
  padding: 10px 20px;
  background-color: #21abd1;
  border: none;
  color: black;
  font-weight: bold;
  cursor: pointer;
  border-radius: 5px;
  transition: 0.2s ease;
}

button:hover {
  background-color: #00cc77;
}

/* Phones → Fixed 250% size */
@media (max-width: 600px) {
  .board {
    grid-template-columns: repeat(3, 250px);
    grid-template-rows: repeat(3, 250px);
  }

  .cell {
    font-size: 6rem;
  }

  .turn,
  .message {
    font-size: 2rem;
  }

  button {
    font-size: 1.5rem;
    padding: 15px 30px;
  }
}