/*
.block {
	position: relative;
    margin: 10px 0;
	width: 200px;
	height: 120px;
	background: linear-gradient(45deg, #000, #272727);
}

.block:before, .block:after {
	content: '';
	position: absolute;
	left: -2px;
	top: -2px;
	/*background: linear-gradient(45deg, blue, white, blue, white);*/
  background-size: 400%;
	width: calc(100% + 4px);	
	height: calc(100% + 4px);
	z-index: -1;
	animation: steam 20s linear infinite;
}

@keyframes steam {
	0% {
		background-position: 0 0;
	}
	50% {
		background-position: 400% 0;
	}
	100% {
		background-position: 0 0;
	}
}
*/

.block:after {
	/*filter: blur(50px);*/
}