/* ============================================================================
   Interactive electrical background — presentation only.
   A single transparent, decorative canvas that sits BEHIND all page content
   (z-index:-1 keeps it above the body's engineering grid but under every
   block/positioned element, so no existing UI is covered or restyled).
   All drawing/idle logic lives in js/background.js.
   ============================================================================ */
.fx-bg {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  pointer-events: none; /* never blocks clicks, hover, or focus */
  display: block;
  /* No background of its own — the page grid must stay visible through it. */
  background: transparent;
  /* Isolate paint/layout without size containment (the fixed inset supplies
     the box; size containment would risk collapsing the canvas). */
  contain: layout paint style;
}