1.btn {
2  font-size: 17px;
3  background: transparent;
4  border: none;
5  padding: 1em 1.5em;
6  color: #f8f8f8;
7  text-transform: uppercase;
8  position: relative;
9  transition: .5s ease;
10  cursor: pointer;
11}
12
13.btn::before {
14  content: '';
15  position: absolute;
16  right: 0;
17  top: 0;
18  height: 2px;
19  width: 0;
20  background-color: #f8f8f8;
21  transition: .5s ease;
22}
23
24.btn:hover {
25  color: #181818;
26  transition-delay: .5s;
27}
28
29.btn:hover::before {
30  width: 100%;
31}
32
33.btn::after {
34  content: '';
35  position: absolute;
36  left: 0;
37  bottom: 0;
38  height: 0;
39  width: 100%;
40  background-color: #f8f8f8;
41  transition: .4s ease;
42  z-index: -1;
43}
44
45.btn:hover::after {
46  height: 100%;
47  transition-delay: 0.4s;
48}