on-off.css

body{
	margin: 0;
	padding: 0;
	background: #262626;
}

ul{
	position: absolute;
	top: 50%;
	left: 50%;
	transform: translate(-50%,50%);
	margin: 0;
	padding: 0;
	display: flex;
}

ul li{
	list-style: none;
	color: #484848;
	font-family: arial;
	font-size: 5em;
	letter-spacing: 15px;
	animation: ani 2.4s linear infinite;
}

@keyframes ani{
	0%{
		color: #484848;
		text-shadow: none;
	}
	90%{
		color: #484848;
		text-shadow: none;
	}
	100%{
		color: #FFA07A;
		text-shadow: 0 0 7px #FFA07A, 0 0 50px #FFA07A;
	}
}

ul li:nth-child(1){
	animation-delay: .2s;
}

ul li:nth-child(2){
	animation-delay: .4s;
}

ul li:nth-child(3){
	animation-delay: .8s;
}

ul li:nth-child(4){
	animation-delay: 1s;
}

ul li:nth-child(5){
	animation-delay: 1.2s;
}

ul li:nth-child(6){
	animation-delay: 1.4s;
}

ul li:nth-child(7){
	animation-delay: 1.8s;
}