<div class="full"></div>

.full {
  position:fixed;
  inset:-80px;
  z-index:969;
  display:flex;
  background:#fff;
  filter: blur(9px) contrast(90);
}
.full:before {
  content:"";
  flex:1;
  background:radial-gradient(farthest-side,#000 70%,#0000 72%) center/80px 80px space;
  -webkit-mask:linear-gradient(-45deg,#0009 40%,#000,#0008 60%) right/280% 100% no-repeat;
  animation:f 2s infinite linear alternate;
}

@keyframes f {
  100% {-webkit-mask-position:left}
}