/* One thin arc travels for 24 seconds, followed by 8 seconds out of view.
   Two alternating copies start 16 seconds apart: the next enters at 2/3 travel.
   The idle interval keeps every new arc evenly spaced, with no short reset gap. */
.vault-shield-wave{fill:none;stroke:url(#vault-arc-light);transform-box:view-box;animation:vault-shield-descend 32s linear infinite}
.shield-edge{stroke-width:.95;stroke-linecap:round}
.outer-wave.wave-a{animation-delay:0s}
.outer-wave.wave-b{animation-delay:-16s}
@keyframes vault-shield-descend{
  0%{transform:translateY(0);opacity:0}
  3%{opacity:.62}
  66%{opacity:.62}
  75%,100%{transform:translateY(650px);opacity:0}
}
/* Four existing illuminated door edges, with subtly staggered downward scans. */
.vault-door-lights .vault-vertical-scan{stroke-width:2.4;stroke-dasharray:19 81;animation-duration:13s}
.pillar-left-outer{animation-delay:0s}
.pillar-left-inner{animation-delay:-3.2s}
.pillar-right-inner{animation-delay:-6.4s}
.pillar-right-outer{animation-delay:-9.6s}
@media(prefers-reduced-motion:reduce){.vault-shield-wave,.vault-door-lights{display:none}}