Holographic Button

<button class="nuda-holo">
  <span>Activate</span>
</button>

/* Conic-gradient halo around the button. Works thanks to @property
   animating a custom angle. Falls back to a static halo where unsupported. */
@property --a {
  syntax: '<angle>';
  inherits: false;
  initial-value: 0deg;
}

.nuda-holo {
  position: relative;
  padding: 11px 24px;
  background: #0c0c10;
  color: #fafafa;
  border: 0;
  border-radius: 10px;
  cursor: pointer;
  overflow: hidden;
  isolation: isolate;
}

.nuda-holo::before {
  content: "";
  position: absolute;
  inset: -2px;
  background: conic-gradient(
    from var(--a, 0deg),
    #ff6dd4, #9d6dff, #62b6ff, #6ee7b7, #e4ff54, #ffb45e, #ff6dd4
  );
  border-radius: 12px;
  z-index: -1;
  animation: nuda-holo-spin 4s linear infinite;
}

.nuda-holo::after {
  content: "";
  position: absolute;
  inset: 1px;
  background: #0c0c10;
  border-radius: 9px;
  z-index: -1;
}

@keyframes nuda-holo-spin { to { --a: 360deg; } }