:root {
  --pad-x: 4px;
  --pad-y: 18px;
  --circle-d: 28px;
  --radius: 9999px;

  --c-left: #0D00BC;
  --c-right:#00B9F5;
  --c-dot-bg:rgba 255, 255, 255, 255, 1;
  --c-dot-fg:#0D00BC;

  --dur: 0.8s;
  --ease: cubic-bezier(.25,.8,.25,1);
}

.btn-gradient {
  position: relative;
  border: 0;
  border-radius: var(--radius);
  cursor: pointer;
  color: #fff;
  font-weight: 400;
  font-size: 1.2rem;
  padding: var(--pad-y) var(--pad-x);
  min-width: 175px;
  isolation: isolate;
  overflow: hidden;
  background: transparent;
}

.btn-gradient::before,
.btn-gradient::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  transition: opacity var(--dur) var(--ease);
}
.btn-gradient::before {
  background: linear-gradient(to right, var(--c-left), var(--c-right));
  opacity: 1;
}
.btn-gradient::after {
  background: linear-gradient(to right, var(--c-right), var(--c-left));
  opacity: 0;
}
.btn-gradient:hover::before { opacity: 0; }
.btn-gradient:hover::after  { opacity: 1; }

.btn-gradient .label {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  z-index: 1;
  color: #fff;
}

.btn-gradient .dot {
  position: absolute;
  top: 50%;
  left: var(--pad-x);
  transform: translateY(-50%);
  width: var(--circle-d);
  height: var(--circle-d);
  border-radius: 50%;
  background: var(--c-dot-bg);
  display: grid;
  place-items: center;
  color: var(--c-dot-fg);
  font-weight: 900;
  font-size: 1.5rem;
  z-index: 2;
  transition: left var(--dur) var(--ease);
}
.btn-gradient:hover .dot {
  left: calc(100% - var(--pad-x) - var(--circle-d));
}

@media (prefers-reduced-motion: reduce) {
  .btn-gradient::before,
  .btn-gradient::after,
  .btn-gradient .dot { transition: none; }
}