:root {
  --bg: #05050f;
  --fg: #eaeaea;
  --muted: #bcbcbc;
  --accent: #ffd866;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: radial-gradient(1000px 600px at 50% 20%, #0b0b1f, var(--bg));
  color: var(--fg);
  font-family: 'Segoe UI', 'Microsoft JhengHei', system-ui, sans-serif;
}
.wrap {
  max-width: 860px;
  margin: 16px auto 40px;
  padding: 0 16px;
  text-align: center;
}
h1 { font-size: 22px; font-weight: 700; letter-spacing: .5px; margin: 8px 0 12px; }
canvas {
  background: #0a0a18;
  width: 100%;
  height: auto;
  box-shadow: 0 12px 30px rgba(0,0,0,.35);
  border: 1px solid #111;
  border-radius: 10px;
}
.help { color: var(--muted); font-size: 14px; margin-top: 10px; }