<div class="block glow"></div>

body {
  margin: 0;
  padding: 0;
  background-color: white;
}

.block {
  position: relative;
  margin: 10% auto 0;
  border-radius: 4px;
  width: 896px;
  height: 200px;
  background: linear-gradient(0deg, white, #fdfdfd);
  box-shadow: 0px 3px 1px -2px rgb(0 0 0 / 20%), 0px 2px 2px 0px rgb(0 0 0 / 14%), 0px 1px 5px 0px rgb(0 0 0 / 12%);
}

.glow::before, .glow::after {
  content: '';
  position: absolute;
  left: 0px;
  top: 0px;
  border-radius: 4px;
  background: linear-gradient(45deg, #e6fb04, #ff6600, #00ff66, #00ffff, #ff00ff, #ff0099, #6e0dd0, #ff3300, #099fff);
  background-size: 400%;
  width: calc(100% + 0px);
  height: calc(100% + 0px);
  z-index: -1;
  animation: animate 60s linear infinite;
}

@keyframes animate {
  0% {
    background-position: 0 0;
  }
  50% {
    background-position: 400% 0;
  }
  100% {
    background-position: 0 0;
  }
}

.glow::after {
  filter: blur(30px);
  opacity: .95
    
}