html, body {
  height: 100%;
  min-height: 100%;
  margin: 0;
  padding: 0;
}

body {
  display: flex;
  align-items: center;
  justify-content: center;
}

.rainbow-glow {
  display: inline-block;
  padding: 2px;
  position: relative;
  border-radius: 25px;
}
.rainbow-glow:before {
  content: "";
  display: block;
  position: absolute;
  width: 200%;
  right: -50%;
  bottom: -50%;
  top: -50%;
  background-position: center center;
  background-image: conic-gradient(from 0 at 50% 50%, transparent 50%, #fff845, #1cc98c, #24cbde, #57a9f7, #bd52f9, #ebb347);
  animation: rainbowGlowRotate 4s linear infinite;
  filter: blur(150px);
}
.rainbow-glow .card {
  padding: 1px;
  position: relative;
  overflow: hidden;
  border-radius: 25px;
  box-shadow: inset 0 0 0 1px rgba(0, 0, 0, 0.15);
}
.rainbow-glow .card:before {
  content: "";
  display: block;
  position: absolute;
  width: 200%;
  right: -50%;
  bottom: -50%;
  top: -50%;
  background-position: center center;
  background-image: conic-gradient(from 0 at 50% 50%, transparent 50%, #fff845, #1cc98c, #24cbde, #57a9f7, #bd52f9, #ebb347);
  animation: rainbowRotate 4s linear infinite;
}
.rainbow-glow .content {
  padding: 100px;
  background: white;
  border-radius: 25px;
  position: relative;
  z-index: 1;
}

@keyframes rainbowRotate {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}
@keyframes rainbowGlowRotate {
  0% {
    transform: rotate(0deg) scale(0.3);
  }
  50% {
    transform: rotate(180deg) scale(0.3);
  }
  100% {
    transform: rotate(360deg) scale(0.3);
  }
}