<button class="cp_button13">button</button>

.cp_button13 {
	position: relative;
	z-index: 1;
	display: inline-block;
	width: 160px;
	padding: 1em;
	line-height: 1.4;
	cursor: pointer;
	user-select: none;
	transition: transform 0.3s;
	color: #2e7d32;
	border: 0;
	background: #d4e157;
}
.cp_button13:before {
	position: absolute;
	z-index: -1;
	top: 100%;
	left: 5%;
	width: 90%;
	height: 10px;
	content: '';
	transition:transform 0.3s,opacity 0.3s;
	pointer-events: none;
	opacity: 0;
	background: -webkit-radial-gradient(center, ellipse, rgba(46,125,50, 0.35) 0%, rgba(46,125,50, 0) 80%);
	background: radial-gradient(ellipse at center, rgba(46,125,50, 0.35) 0%, rgba(46,125,50, 0) 80%);
}
.cp_button13:hover {
	-webkit-transform: translateY(-6px);
	        transform: translateY(-6px);
	-webkit-animation: button13 1.5s linear infinite alternate 0.3s;
	        animation: button13 1.5s linear infinite alternate 0.3s;
	color: #2e7d32;
}
.cp_button13:hover:before {
	-webkit-transform: translateY(6px);
	        transform: translateY(6px);
	-webkit-animation: button13_shadow 1.5s linear infinite alternate 0.3s;
	        animation: button13_shadow 1.5s linear infinite alternate 0.3s;
	opacity: 0.4;
}
.cp_button13:focus {
	color: #2e7d32;
}
@-webkit-keyframes button13 {
	50% {
		-webkit-transform: translateY(-3px);
		        transform: translateY(-3px);
	}
	100% {
		-webkit-transform: translateY(-6px);
		        transform: translateY(-6px);
	}
}
@keyframes button13 {
	50% {
		-webkit-transform: translateY(-3px);
		        transform: translateY(-3px);
	}
	100% {
		-webkit-transform: translateY(-6px);
		        transform: translateY(-6px);
	}
}
@-webkit-keyframes button13_shadow {
	0% {
		-webkit-transform: translateY(6px);
		        transform: translateY(6px);
		opacity: 0.4;
	}
	50% {
		-webkit-transform: translateY(3px);
		        transform: translateY(3px);
		opacity: 1;
	}
	100% {
		-webkit-transform: translateY(6px);
		        transform: translateY(6px);
		opacity: 0.4;
	}
}
@keyframes button13_shadow {
	0% {
		-webkit-transform: translateY(6px);
		        transform: translateY(6px);
		opacity: 0.4;
	}
	50% {
		-webkit-transform: translateY(3px);
		        transform: translateY(3px);
		opacity: 1;
	}
	100% {
		-webkit-transform: translateY(6px);
		        transform: translateY(6px);
		opacity: 0.4;
	}
}