Smooth Toggle

<!-- Smooth Toggle — iOS-style toggle switch
     Uses a hidden checkbox for native accessibility. -->
<label class="nuda-toggle" role="switch">
  <input class="nuda-toggle__input" type="checkbox" />
  <span class="nuda-toggle__track">
    <span class="nuda-toggle__thumb"></span>
  </span>
  <span class="nuda-toggle__label">Toggle</span>
</label>

/* ── Smooth Toggle ───────────────────────────────────────────
   Customize:
     --nuda-tg-w         : track width
     --nuda-tg-h         : track height
     --nuda-tg-bg-off    : track background (off)
     --nuda-tg-bg-on     : track background (on)
     --nuda-tg-thumb-clr : thumb color
     --nuda-tg-gap       : thumb padding from track edges
   ──────────────────────────────────────────────────────────── */
.nuda-toggle {
  --nuda-tg-w: 52px;
  --nuda-tg-h: 28px;
  --nuda-tg-bg-off: #d1d5db;
  --nuda-tg-bg-on: #6366f1;
  --nuda-tg-thumb-clr: #fff;
  --nuda-tg-gap: 3px;

  display: inline-flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  -webkit-user-select: none;
  user-select: none;
}

/* Visually-hidden native checkbox */
.nuda-toggle__input {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Track */
.nuda-toggle__track {
  position: relative;
  display: inline-block;
  width: var(--nuda-tg-w);
  height: var(--nuda-tg-h);
  background: var(--nuda-tg-bg-off);
  border-radius: 9999px;
  transition: background 0.3s ease;
}

/* Thumb */
.nuda-toggle__thumb {
  position: absolute;
  top: var(--nuda-tg-gap);
  left: var(--nuda-tg-gap);
  width: calc(var(--nuda-tg-h) - var(--nuda-tg-gap) * 2);
  height: calc(var(--nuda-tg-h) - var(--nuda-tg-gap) * 2);
  background: var(--nuda-tg-thumb-clr);
  border-radius: 50%;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
  transition: left 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* Checked state */
.nuda-toggle__input:checked + .nuda-toggle__track {
  background: var(--nuda-tg-bg-on);
}

.nuda-toggle__input:checked + .nuda-toggle__track .nuda-toggle__thumb {
  left: calc(var(--nuda-tg-w) - var(--nuda-tg-h) + var(--nuda-tg-gap));
}

/* Focus ring for keyboard users */
.nuda-toggle__input:focus-visible + .nuda-toggle__track {
  outline: 2px solid var(--nuda-tg-bg-on);
  outline-offset: 2px;
}

.nuda-toggle__label {
  font-size: 0.9rem;
  font-weight: 500;
}

/* ── Accessibility ──────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  .nuda-toggle__track,
  .nuda-toggle__thumb {
    transition: none;
  }
}