Flicker filter

<style>

@keyframes flicker {

  0% {

    opacity: 0.27861;

  }

  5% {

    opacity: 0.34769;

  }

  10% {

    opacity: 0.23604;

  }

  15% {

    opacity: 0.90626;

  }

  20% {

    opacity: 0.18128;

  }

  25% {

    opacity: 0.83891;

  }

  30% {

    opacity: 0.65583;

  }

  35% {

    opacity: 0.67807;

  }

  40% {

    opacity: 0.26559;

  }

  45% {

    opacity: 0.84693;

  }

  50% {

    opacity: 0.96019;

  }

  55% {

    opacity: 0.08594;

  }

  60% {

    opacity: 0.20313;

  }

  65% {

    opacity: 0.71988;

  }

  70% {

    opacity: 0.53455;

  }

  75% {

    opacity: 0.37288;

  }

  80% {

    opacity: 0.71428;

  }

  85% {

    opacity: 0.70419;

  }

  90% {

    opacity: 0.7003;

  }

  95% {

    opacity: 0.36108;

  }

  100% {

    opacity: 0.24387;

  }

}

body::after {

  content: " ";

  display: block;

  position: fixed;

  top: 0;

  left: 0;

  bottom: 0;

  right: 0;

  background: rgba(18, 16, 16, 0.1);

  opacity: 0;

  z-index: 2;

  pointer-events: none;

  animation: flicker 0.15s infinite;

}

</style>