/* =========================================================
   Roiatek AI · bg3d.css
   Positioning for the 3D background canvas (js/bg3d.js).
   It sits between the page aurora (body::before, z-index -2) and the
   hero glow / blueprint grid (z-index -1, later in the DOM), behind all content.
   ========================================================= */
#bg3d {
  position: fixed;
  inset: 0;
  z-index: -1;
  display: block;
  width: 100%;
  height: 100%;
  pointer-events: none;   /* never blocks clicks, links, text selection or forms */
  contain: strict;        /* never affects page layout */
  opacity: 0;
  transition: opacity 1.8s ease;
}
#bg3d.is-ready { opacity: 0.92; }

@media print {
  #bg3d { display: none; }
}