:root {
  --bg: #f5f5f7;
  --card: #ffffff;
  --x: #2563eb;
  --o: #dc2626;
  --accent: #16a34a;
  --muted: #6b7280;
  --line: #e5e7eb;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: #111827;
  padding: 16px;
}

.card {
  background: var(--card);
  width: 100%;
  max-width: 420px;
  border-radius: 18px;
  padding: 24px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
  text-align: center;
}

h1 { margin: 0 0 16px; font-size: 1.6rem; }

.screen { display: flex; flex-direction: column; align-items: center; gap: 12px; }
.hidden { display: none !important; }

.big { font-size: 1.2rem; font-weight: 600; margin: 4px 0; }
.muted { color: var(--muted); }
.foot { margin-top: 20px; font-size: 0.8rem; }

.spinner {
  width: 36px; height: 36px;
  border: 4px solid var(--line);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.9s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.symbol-line { margin: 0; font-size: 1rem; }
.symbol { font-weight: 800; }
.symbol.X { color: var(--x); }
.symbol.O { color: var(--o); }

.turn-banner {
  margin: 6px 0 14px;
  font-weight: 600;
  padding: 8px 12px;
  border-radius: 10px;
  background: var(--line);
  color: var(--muted);
  width: 100%;
}
.turn-banner.your-turn { background: rgba(22, 163, 74, 0.12); color: var(--accent); }

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

.cell {
  border: none;
  background: var(--bg);
  border-radius: 12px;
  font-size: clamp(2rem, 14vw, 3.4rem);
  font-weight: 800;
  cursor: default;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  transition: background 0.12s, transform 0.05s;
  color: #111827;
}
.cell.X { color: var(--x); }
.cell.O { color: var(--o); }
.cell.playable { cursor: pointer; }
.cell.playable:hover { background: #e9eef6; }
.cell.playable:active { transform: scale(0.96); }
.cell.win { background: rgba(22, 163, 74, 0.25); }

.result { width: 100%; margin-top: 16px; display: flex; flex-direction: column; gap: 12px; }
.result-text { font-size: 1.3rem; font-weight: 700; margin: 0; }

.btn {
  border: none;
  background: var(--accent);
  color: #fff;
  font-size: 1rem;
  font-weight: 600;
  padding: 12px 18px;
  border-radius: 12px;
  cursor: pointer;
}
.btn:hover { filter: brightness(1.05); }
.btn:active { transform: scale(0.98); }