:root {
  --bg: #0f172a;
  --card: #111827;
  --muted: #94a3b8;
  --accent: #22d3ee;
  --text: #e5e7eb;
  --danger: #ef4444;
}
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, "Helvetica Neue", Arial;
  background: radial-gradient(1200px 800px at 10% 10%, #0b1224, #0f172a);
  color: var(--text);
  display: grid;
  place-items: center;
}
.app {
  width: 100%;
  max-width: 520px;
  background: linear-gradient(180deg, #0f172a, #0d1726);
  border: 1px solid #1f2937;
  border-radius: 16px;
  padding: 20px;
  box-shadow: 0 30px 80px rgba(0,0,0,.4), inset 0 0 40px rgba(34,211,238,.06);
}
h1 { margin: 0 0 12px; }
.muted { color: var(--muted); margin: 0 0 12px; font-size: 14px; }
.controls {
  display: grid;
  grid-template-columns: 1fr 1.2fr 1fr;
  gap: 8px;
}
.controls input, .controls button, .bottom button {
  font: inherit;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid #1f2937;
  background: #0b1222;
  color: var(--text);
  outline: none;
}
.controls button, .bottom button {
  background: linear-gradient(180deg, #0b1222, #0c1a2c);
  cursor: pointer;
  transition: transform .08s ease, box-shadow .2s ease, border-color .2s ease;
}
.controls button:hover, .bottom button:hover {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(34,211,238,.12);
}
.status {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  margin: 12px 0;
  font-size: 14px;
  color: var(--muted);
}
.board {
  margin-top: 10px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
}
.board button {
  width: 100%;
  aspect-ratio: 1 / 1;
  border-radius: 12px;
  border: 1px solid #1f2937;
  background: #0b1222;
  color: var(--text);
  font-size: 42px;
  font-weight: 700;
  text-shadow: 0 2px 10px rgba(0,0,0,.4);
}
.board button:disabled { opacity: .65; cursor: not-allowed; }
.bottom { margin-top: 12px; display: flex; align-items: center; gap: 10px; }
.msg { color: var(--danger); }