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

a.cp_btn {
	position: relative;
	display: block;
	width: 160px;
	padding: 0.8em;
	text-align: center;
	border: 3px solid #9C27B0;
	text-decoration: none;
	outline: none;
	transition: all .4s;
}
a.cp_btn::before,
a.cp_btn::after {
	position: absolute;
	top: -3px;
	right: -3px;
	bottom: -3px;
	left: -3px;
	z-index: 2;
	content: '';
	transition: all .4s;
}
a.cp_btn::before {
	border-top: 3px solid #FF5722;
	border-bottom: 3px solid #FF5722;
	transform: scale(0, 1);
}
a.cp_btn::after {
	border-right: 3px solid #FF5722;
	border-left: 3px solid #FF5722;
	transform: scale(1, 0);
}
a.cp_btn:hover {
	color: #FF5722;
}
a.cp_btn:hover::after,
a.cp_btn:hover::before {
	transform: scale(1);
}