:root {
  --bg: #111827;
  --panel: #1f2937;
  --text: #f9fafb;
  --muted: #9ca3af;
  --line: #374151;
  --x: #38bdf8;
  --o: #f472b6;
  --glow-x: #7dd3fc;
  --glow-o: #f9a8d4;
  --win: #fbbf24;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: Georgia, "Times New Roman", serif;
  color: var(--text);
  background:
    radial-gradient(circle at 20% 0%, rgba(56, 189, 248, 0.15), transparent 40%),
    radial-gradient(circle at 80% 10%, rgba(244, 114, 182, 0.12), transparent 35%),
    linear-gradient(180deg, #0b1220, #111827);
}

.hidden {
  display: none !important;
}

.header {
  text-align: center;
  padding: 1.5rem 1rem 0.5rem;
}

.header h1 {
  margin: 0.35rem 0;
}

.header p {
  margin: 0;
  color: var(--muted);
}

.back {
  color: var(--muted);
  text-decoration: none;
  font-family: system-ui, sans-serif;
  font-size: 0.9rem;
}

.back:hover {
  color: var(--text);
}

.panel {
  max-width: 420px;
  margin: 0 auto;
  padding: 1.5rem 1rem 2.5rem;
  text-align: center;
}

.panel h2 {
  margin: 0 0 1.2rem;
}

.field {
  display: grid;
  gap: 0.35rem;
  text-align: left;
  margin: 0 auto 1rem;
  max-width: 280px;
  font-family: system-ui, sans-serif;
  font-size: 0.9rem;
  color: var(--muted);
}

.field select {
  padding: 0.55rem 0.7rem;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--text);
}

.primary,
.reset {
  font-family: system-ui, sans-serif;
  border: none;
  border-radius: 8px;
  padding: 0.7rem 1.2rem;
  cursor: pointer;
  color: #0f172a;
  background: var(--x);
}

.primary:hover,
.reset:hover {
  filter: brightness(1.06);
}

.reset {
  margin-top: 1.25rem;
  background: #64748b;
  color: #fff;
}

.status {
  font-family: system-ui, sans-serif;
  font-size: 1.1rem;
  font-weight: 600;
  min-height: 1.5rem;
  margin: 0 0 1rem;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  gap: 10px;
  width: min(320px, 90vw);
  height: min(320px, 90vw);
  margin: 0 auto;
}

.cell {
  width: 100%;
  height: 100%;
  min-width: 0;
  min-height: 0;
  padding: 0;
  margin: 0;
  border: none;
  border-radius: 12px;
  background: var(--panel);
  box-shadow: inset 0 0 0 2px var(--line);
  cursor: pointer;
  font-family: system-ui, sans-serif;
  font-size: clamp(2rem, 8vw, 3rem);
  font-weight: 800;
  line-height: 1;
  color: var(--text);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.12s ease, background 0.12s ease;
}

.cell:hover:not(:disabled) {
  transform: scale(1.03);
  background: #273549;
}

.cell:disabled {
  cursor: default;
}

.cell.mark-X {
  color: var(--x);
  text-shadow: 0 0 12px var(--glow-x);
}

.cell.mark-O {
  color: var(--o);
  text-shadow: 0 0 12px var(--glow-o);
}

body[data-skin="neon"] .board {
  box-shadow: 0 0 24px rgba(34, 211, 238, 0.25), 0 0 40px rgba(232, 121, 249, 0.15);
}

body[data-skin="royal"] .board {
  box-shadow: 0 0 24px rgba(167, 139, 250, 0.3), 0 0 36px rgba(251, 191, 36, 0.18);
}

body[data-skin="shadow"] {
  background:
    radial-gradient(circle at 50% 0%, rgba(239, 68, 68, 0.18), transparent 40%),
    linear-gradient(180deg, #020617, #111827);
}

body[data-skin="wood"] {
  background:
    radial-gradient(circle at 30% 0%, rgba(245, 158, 11, 0.2), transparent 45%),
    linear-gradient(180deg, #1c1006, #111827);
}

.cell.win {
  background: rgba(251, 191, 36, 0.2);
  box-shadow: inset 0 0 0 2px var(--win);
}

.cell.selected {
  box-shadow: inset 0 0 0 3px #fbbf24;
  background: #3f3a1f;
}

.cell.target {
  box-shadow: inset 0 0 0 2px #86efac;
}