1button {
2  /* padding: 5px 10px; */
3  height: 50px;
4  width: 100px;
5  font-size: 20px;
6  position: relative;
7  border: navajowhite;
8  background-color: #222;
9  color: aliceblue;
10  z-index: 1;
11  overflow: hidden;
12  transition: all 0.3s;
13  box-shadow: 2px 2px 2px red;
14}
15
16button::before {
17  content: '';
18  height: 10px;
19  width: 30px;
20  position: absolute;
21  background-image: linear-gradient(45deg, salmon,red);
22  left: -10px;
23  top: 0;
24  z-index: -1;
25  transition: 0.3s ease-in-out;
26  border-radius: 5px;
27}
28
29button:hover::before {
30  height: 100px;
31  width: 100px;
32}
33
34button:hover {
35  border-radius: 5px;
36}
37