Active Indicator Glide

<nav aria-label="Main" class="nuda-sb2-active-glide" style="--active: 1">
  <span class="nuda-sb2-active-glide__indicator" aria-hidden="true"></span>
  <ul class="nuda-sb2-active-glide__list">
    <li>
      <button type="button" class="nuda-sb2-active-glide__btn" aria-label="Home" data-index="0">
        <svg viewBox="0 0 24 24" fill="none" stroke="currentColor"
             stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
          <path d="M3 11l9-8 9 8v10a2 2 0 01-2 2h-4v-7H9v7H5a2 2 0 01-2-2V11z" />
        </svg>
      </button>
    </li>
    <!-- More items with data-index="1", "2" … -->
  </ul>
</nav>

const rail = document.querySelector('.nuda-sb2-active-glide');

rail.querySelectorAll('.nuda-sb2-active-glide__btn').forEach((btn) => {
  btn.addEventListener('click', () => {
    rail.style.setProperty('--active', btn.dataset.index);
    rail.querySelectorAll('.nuda-sb2-active-glide__btn').forEach((b) => {
      b.removeAttribute('aria-current');
    });
    btn.setAttribute('aria-current', 'page');
  });
});

.nuda-sb2-active-glide {
  position: relative;
  width: 56px;
  padding: 8px;
  background: rgba(255,255,255,.02);
  border: 1px solid rgba(255,255,255,.08);
  border-radius: 16px;
}

.nuda-sb2-active-glide__list {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
  z-index: 1;
}

.nuda-sb2-active-glide__btn {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: 0;
  border-radius: 10px;
  color: #a0a0a8;
  cursor: pointer;
  transition: color .25s;
}

.nuda-sb2-active-glide__btn svg {
  width: 18px;
  height: 18px;
}

.nuda-sb2-active-glide__btn:hover {
  color: #fafafa;
}

.nuda-sb2-active-glide__btn[aria-current="page"] {
  color: #0a0a0a;
}

.nuda-sb2-active-glide__btn:focus-visible {
  outline: 2px solid #e4ff54;
  outline-offset: 2px;
}

.nuda-sb2-active-glide__indicator {
  position: absolute;
  left: 8px;
  top: 8px;
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: #e4ff54;
  transform: translateY(calc(var(--active, 0) * 44px));
  transition: transform .45s cubic-bezier(.34,1.56,.64,1);
  box-shadow: 0 6px 16px -6px rgba(228,255,84,.5);
}

@media (prefers-reduced-motion:reduce) {
  .nuda-sb2-active-glide__indicator {
    transition: none;
  }
}