<a href="#" class="cp_btn">button</a>

a.cp_btn {
	display: inline-block;
	position: relative;
	width: 160px;
	padding: 0.8em;
	text-align: center;
	border-top: 2px solid #FBC02D;
	border-bottom: 2px solid #FBC02D;
	text-decoration: none;
	font-weight: bold;
	color: #FBC02D;
}
a.cp_btn:before, a.cp_btn:after {
	content: '';
	position: absolute;
	top: -7px;
	width: 2px;
	height: calc(100% + 14px);
	background-color: #FBC02D;
	transition: .3s;
}
a.cp_btn:before {
	left: 7px;
}
a.cp_btn:after {
	right: 7px;
}
a.cp_btn:hover:before{
	top: 0px;
	left:0;
	height: 100%;
}
a.cp_btn:hover:after{
	top: 0px;
	right: 0;
	height: 100%;
}