:root {
  --bg: #0f1724;
  --accent: #60a5fa;
  --xcol: #ff6b6b;
  --ocol: #60ffa3;
  --muted: #9aa6b2;
}

body {
  margin: 0;
  font-family: 'Poppins', sans-serif;
  background: linear-gradient(180deg, #071024, #091426);
  color: white;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.container {
  background: rgba(255,255,255,0.05);
  padding: 20px;
  border-radius: 10px;
  text-align: center;
  box-shadow: 0 0 20px rgba(0,0,0,0.5);
  width: 90%;
  max-width: 400px;
}

h1 {
  color: var(--accent);
  margin-bottom: 15px;
}

.controls {
  display: flex;
  justify-content: space-between;
  margin-bottom: 15px;
  align-items: center;
}

.choice {
  display: flex;
  align-items: center;
  gap: 10px;
}

.choice-btn, .reset-btn {
  padding: 6px 12px;
  background: transparent;
  border: 1px solid var(--accent);
  color: white;
  border-radius: 6px;
  cursor: pointer;
  font-weight: 600;
}

.choice-btn.active {
  background: var(--accent);
  color: #0a1324;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  width: 100%;
  margin: 0 auto;
}

.cell {
  background: #1a243a;
  height: 100px;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 2.5rem;
  cursor: pointer;
  border-radius: 8px;
  transition: 0.2s;
}

.cell.x { color: var(--xcol); }
.cell.o { color: var(--ocol); }

.cell:hover {
  background: rgba(255,255,255,0.1);
}

.message {
  margin-top: 15px;
  color: var(--muted);
  font-weight: 600;
}

@media (max-width: 500px) {
  .cell { height: 80px; font-size: 2rem; }
}