:root {
  --bg: #0f172a;
  --card: #1e293b;
  --line: #334155;
  --x-color: #38bdf8;
  --o-color: #fb7185;
  --accent: #a78bfa;
  --text: #e2e8f0;
  --text-dim: #94a3b8;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  background-image:
    radial-gradient(circle at 20% 20%, rgba(56, 189, 248, 0.12), transparent 40%),
    radial-gradient(circle at 80% 80%, rgba(251, 113, 133, 0.12), transparent 40%);
}

.game {
  width: 100%;
  max-width: 420px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 18px;
}

.title {
  font-size: 2rem;
  letter-spacing: 2px;
  text-transform: uppercase;
  font-weight: 800;
  background: linear-gradient(90deg, var(--x-color), var(--accent), var(--o-color));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.scoreboard {
  display: flex;
  gap: 12px;
  width: 100%;
}

.score {
  flex: 1;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 10px;
  text-align: center;
  font-size: 0.75rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.score .count {
  display: block;
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text);
  margin-top: 2px;
}

.mark {
  font-weight: 800;
  font-size: 1.1rem;
}

.mark.x-mark { color: var(--x-color); }
.mark.o-mark { color: var(--o-color); }

.status {
  font-size: 1rem;
  font-weight: 600;
  min-height: 1.5em;
  color: var(--text-dim);
}

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

.cell {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  font-size: clamp(2rem, 12vw, 4rem);
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: transform 0.1s ease, border-color 0.15s ease, background 0.15s ease;
  user-select: none;
}

.cell:hover:not(.taken):not(.winning) {
  border-color: var(--accent);
  background: #273349;
  transform: scale(1.02);
}

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

.cell.winning {
  background: rgba(167, 139, 250, 0.18);
  border-color: var(--accent);
  animation: pulse 1s infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.06); }
}

.new-game {
  background: linear-gradient(90deg, var(--x-color), var(--accent));
  border: none;
  color: #0f172a;
  font-weight: 700;
  font-size: 1rem;
  padding: 12px 28px;
  border-radius: 999px;
  cursor: pointer;
  transition: filter 0.15s ease, transform 0.1s ease;
}

.new-game:hover {
  filter: brightness(1.1);
}

.new-game:active {
  transform: scale(0.97);
}

.overlay {
  position: fixed;
  inset: 0;
  background: rgba(2, 6, 23, 0.7);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10;
}

.overlay.hidden {
  display: none;
}

.overlay-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 36px 48px;
  text-align: center;
  animation: pop 0.25s ease;
}

.overlay-card h2 {
  font-size: 1.8rem;
  margin-bottom: 8px;
}

.overlay-card p {
  color: var(--text-dim);
  margin-bottom: 20px;
}

@keyframes pop {
  from { transform: scale(0.8); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}