Month Switcher Slide

<div class="nuda-monthslide">
  <button aria-label="Previous">‹</button>
  <div class="nuda-monthslide__viewport">
    <div class="nuda-monthslide__track">
      <span>April</span>
      <span>May</span>
      <span class="is-active">June</span>
      <span>July</span>
      <span>August</span>
    </div>
  </div>
  <button aria-label="Next">›</button>
</div>

const root  = document.querySelector('.nuda-monthslide');
const track = root.querySelector('.nuda-monthslide__track');
const items = root.querySelectorAll('.nuda-monthslide__track span');
const [prev, next] = root.querySelectorAll('button');

let index = [...items].findIndex(s => s.classList.contains('is-active'));
const SLOT = 90;

const update = () => {
  items.forEach(i => i.classList.remove('is-active'));
  items[index].classList.add('is-active');
  track.style.transform = `translateX(${-index * SLOT}px)`;
};

prev.onclick = () => { index = Math.max(0, index - 1); update(); };
next.onclick = () => { index = Math.min(items.length - 1, index + 1); update(); };

.nuda-monthslide {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px;
  background: rgba(255,255,255,.02);
  border: 1px solid rgba(255,255,255,.06);
  border-radius: 12px;
}

.nuda-monthslide button {
  background: rgba(255,255,255,.04);
  border: 1px solid rgba(255,255,255,.08);
  color: #fafafa;
  width: 24px;
  height: 28px;
  border-radius: 6px;
  cursor: pointer;
  transition: background .2s,transform .2s;
}

.nuda-monthslide button:hover {
  background: #e4ff54;
  color: #09090b;
  transform: translateY(-1px);
}

.nuda-monthslide__viewport {
  overflow: hidden;
  width: 90px;
}

.nuda-monthslide__track {
  display: flex;
  transform: translateX(-180px);
  transition: transform .55s cubic-bezier(.16,1,.3,1);
}

.nuda-monthslide__track span {
  flex-shrink: 0;
  width: 90px;
  text-align: center;
  color: #63636e;
  font-size: 12px;
  font-weight: 500;
  transition: color .35s;
}

.nuda-monthslide__track span.is-active {
  color: #e4ff54;
  font-weight: 700;
}