html, body {
  margin: 0;
  height: 100%;
  background: #0b0f1a;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  color: #e8eefc;
  overflow: hidden;
}

canvas { display: block; }

.hud {
  position: fixed;
  top: 10px;
  left: 10px;
  display: flex;
  gap: 14px;
  z-index: 2;
  background: rgba(0,0,0,0.35);
  padding: 8px 10px;
  border-radius: 10px;
  backdrop-filter: blur(6px);
}

.overlay {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  z-index: 3;
  background: rgba(0,0,0,0.55);
}

.card {
  width: min(520px, 92vw);
  background: rgba(15,20,35,0.95);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 16px;
  padding: 18px 18px 14px;
  box-shadow: 0 12px 40px rgba(0,0,0,0.5);
}

button {
  width: 100%;
  padding: 12px 14px;
  border-radius: 12px;
  border: 0;
  font-weight: 700;
  cursor: pointer;
}