.background-video {
  position: fixed;
  inset: -15% 0 0 0;
  z-index: var(--z-canvas);
  pointer-events: none;
  will-change: transform;
  overflow: hidden;
}

.background-video__video {
  width: 100%;
  height: 130%;
  object-fit: cover;
  filter: brightness(0.3);
}

.background-video__fallback {
  display: none;
  width: 100%;
  height: 130%;
  object-fit: cover;
  filter: brightness(0.3);
}

.background-video__overlay {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(to bottom, rgba(0,0,0,0.4) 0%, transparent 30%, transparent 70%, rgba(0,0,0,0.6) 100%),
    radial-gradient(ellipse at center, transparent 40%, rgba(0,0,0,0.5) 100%);
  pointer-events: none;
}

.background-video__grain {
  position: absolute;
  inset: 0;
  opacity: 0.05;
  pointer-events: none;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  background-repeat: repeat;
  background-size: 256px 256px;
  animation: grain 0.5s steps(4) infinite;
}

@keyframes grain {
  0%   { transform: translate(0, 0); }
  25%  { transform: translate(-2%, -3%); }
  50%  { transform: translate(3%, 1%); }
  75%  { transform: translate(-1%, 3%); }
  100% { transform: translate(2%, -2%); }
}

@media (max-width: 768px) {
  .background-video__video    { display: none; }
  .background-video__fallback { display: block; }
}