1button {
2  display: flex;
3  align-items: center;
4  justify-content: center;
5  width: 100px;
6  position: relative;
7  cursor: pointer;
8  height: 100px;
9  border-radius: 100px;
10  border: none;
11  background: #333;
12  color: #e5e5e5;
13  font-weight: 600;
14  box-shadow: inset 20px 20px 39px #080a10,
15  inset -20px -20px 39px #1b263e;
16  font-size: 13px;
17}
18
19button::after {
20  content: '';
21  position: absolute;
22  z-index: -1;
23  left: -10px;
24  top: -10px;
25  border-radius: 50%;
26  width: calc(100% + 20px);
27  height: calc(100% + 20px);
28  background: linear-gradient(35deg, rgb(47, 190, 238), rgb(218, 57, 143), rgb(139, 255, 23));
29  filter: blur(10px);
30}
31
32button:hover::after {
33  animation: rotcirclegr 1s linear infinite;
34}
35
36@keyframes rotcirclegr {
37  to {
38    transform: rotate(360deg);
39  }
40}