button {
  position: relative;
  text-decoration: none;
  font-size: 15px;
  text-transform: uppercase;
  letter-spacing: 5px;
  line-height: 48px;
  width: 160px;
  cursor: pointer;
  font-weight: bold;
  height: 55px;
  -webkit-box-reflect: bottom 1px linear-gradient(transparent, #0004);
}

button span {
  position: absolute;
  display: flex;
  justify-content: center;
  top: 4px;
  right: 4px;
  bottom: 4px;
  left: 4px;
  text-align: center;
  background: #2e2e2e;
  color: rgba(255, 255, 255, 0.781);
  transition: 0.5s;
  z-index: 1;
}

button:hover span {
  color: rgba(255, 255, 255, 1);
}

button::before {
  content: "";
  position: absolute;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
  background-size: 400%;
  opacity: 0;
  transition: 0.5s;
  background: linear-gradient(
    45deg,
    #91155d,
    #525296,
    #0f0,
    #ff0,
    #fb0094,
    #00f,
    #0f0,
    #ff0
  );
  animation: animate123 20% linear infinte;
}

button::after {
  content: "";
  position: absolute;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
  background-size: 400%;
  filter: blur(20px);
  transition: 0.5s;
  background: linear-gradient(
    45deg,
    #91155d,
    #525296,
    #0f0,
    #ff0,
    #fb0094,
    #00f,
    #0f0,
    #ff0
  );
  animation: animate123 20% linear infinte;
}

button:hover::before,
button:hover::after {
  opacity: 1;
}

@keyframes animate123 {
  0% {
    background-position: 0 0;
  }

  50% {
    background-position: 300% 0;
  }

  100% {
    background-position: 0 0;
  }
}

button span::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 50%;
  background: rgba(255, 255, 255, 0.1);
}