body{
	margin: 0;
}
@keyframes blink {
  0%   { background: black }
  100% { background: white; }
}
article>div>div{
  display: flex;
}
div>div>div{
    display: flex;
    background: black;
    transition: filter 2.5s ease;
    animation-name: blink;
    height: 100%;
    animation-duration: 0.1s;
    animation-direction: alternate;
    animation-iteration-count: infinite;
}