Halo ring

Halo ring: a CSS button. Copy the rules, or the prompt that rebuilds it.

gradient-border animated pillconicglowproperty

CSS

@property --a103 {
  syntax: "<angle>";
  inherits: false;
  initial-value: 0deg
}
.btn-103 {
  position: relative;
  font: 600 15px/1 system-ui,sans-serif;
  color: #fff;
  background: #111;
  border: 0;
  border-radius: 999px;
  padding: 14px 32px;
  cursor: pointer;
  isolation: isolate
}
.btn-103::before,.btn-103::after {
  content: "";
  position: absolute;
  inset: -2px;
  border-radius: inherit;
  background: conic-gradient(from var(--a103),#34d399,#3b82f6,#d946ef,#34d399);
  z-index: -2;
  animation: spin103 4s linear infinite
}
.btn-103::after {
  filter: blur(12px);
  opacity: .6;
  z-index: -3
}
.btn-103 span {
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: #111;
  z-index: -1
}
.btn-103:hover::after {
  opacity: 1
}
.btn-103:focus-visible {
  outline: 2px solid #3b82f6;
  outline-offset: 5px
}
.btn-103:active {
  transform: translateY(1px)
}
@keyframes spin103 {
  to {
    --a103: 360deg
  }
}
@media (prefers-reduced-motion: reduce) {
  .btn-103, .btn-103 * { animation: none; transition: none; }
}

HTML

<button class="btn-103"><span></span>Generate</button>

Prompt

A black pill button with a rotating conic border (#34d399, #3b82f6, #d946ef) plus a second copy of the same gradient blurred 12px behind it as a soft halo at 60% opacity, rising to 100% on hover. Border 2px, rotation 4s linear infinite via @property. White 15px semibold text, 14px by 32px padding. An empty inner span masks the interior. Active drops 1px, focus 2px blue outline offset 5px.

Halo ring

Same shelf