#spipa-bg {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  z-index: -2;
  pointer-events: none;
  background: radial-gradient(#111, #000);
}
body { background: #000; }
.container, .topbar { position: relative; z-index: 1; }