.btn-group-slider {
  position: relative;
}

.btn-group-slider .slider {
  left: var(--slider-left, 0);
  width: var(--slider-width, 0);
  position: absolute;
  top: 4px;
  bottom: 4px;
  background: var(--Orange, #FC6433);
  border-radius: 8px;
  transition: left .4s ease, width .4s ease;
}