.btn-fill {
  position: relative;
  overflow: hidden;
  display: inline-block;
}

.btn-fill .fill {
  position: absolute;
  inset: 0;
  background: var(--btn-fill-color, currentColor);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.35s ease;
}

.btn-fill:hover .fill,
.btn-fill:focus-visible .fill {
  transform: scaleX(1);
}

.btn-fill .label {
  position: relative;
  z-index: 1;
}