Expandable Card

<!-- Expandable Card — checkbox + :has() + grid-rows trick, zero JS -->
<div class="nuda-css-expand">
  <input class="nuda-css-expand__input" type="checkbox" id="nuda-css-ex-1" />
  <div class="nuda-css-expand__head">
    <span class="nuda-css-expand__title">Project Aurora</span>
    <span class="nuda-css-expand__sub">Realtime collaboration</span>
  </div>
  <div class="nuda-css-expand__more">
    <div class="nuda-css-expand__more-inner">
      <p class="nuda-css-expand__body">
        Expanded details appear here, animated with the
        grid-rows 0fr to 1fr trick. No JS.
      </p>
    </div>
  </div>
  <label class="nuda-css-expand__toggle" for="nuda-css-ex-1">
    <span class="nuda-css-expand__txt-more">Show more</span>
    <span class="nuda-css-expand__txt-less">Show less</span>
  </label>
</div>

/* Expandable Card
   A hidden checkbox + :has() toggles the expanded region.
   Height animates via the grid-template-rows 0fr -> 1fr trick
   (animating grid is allowed; no width/height/margin/padding
   transition). No JS. Customize: --nuda-css-ex-accent */

.nuda-css-expand {
  --nuda-css-ex-accent: #e4ff54;
  width: 100%;
  max-width: 420px;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 12px;
  overflow: hidden;
}

.nuda-css-expand__input {
  position: absolute;
  width: 1px; height: 1px;
  margin: -1px; overflow: hidden;
  clip: rect(0, 0, 0, 0); border: 0;
}

.nuda-css-expand__head {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 1rem;
}

.nuda-css-expand__title { font-size: 0.95rem; font-weight: 700; color: #fff; }
.nuda-css-expand__sub   { font-size: 0.8rem; color: #888; }

/* Collapsible region — grid-rows trick */
.nuda-css-expand__more {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 0.35s cubic-bezier(0.16, 1, 0.3, 1);
}

.nuda-css-expand__more-inner {
  overflow: hidden;
  min-height: 0;
}

.nuda-css-expand__body {
  padding: 0 1rem;
  font-size: 0.85rem;
  line-height: 1.5;
  color: #aaa;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.nuda-css-expand__toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  min-height: 44px;
  margin: 0.75rem 1rem 1rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: #09090b;
  background: var(--nuda-css-ex-accent);
  border-radius: 8px;
  cursor: pointer;
}

.nuda-css-expand__toggle .nuda-css-expand__txt-less { display: none; }

/* Expanded state via :has() */
.nuda-css-expand:has(.nuda-css-expand__input:checked) .nuda-css-expand__more {
  grid-template-rows: 1fr;
}

.nuda-css-expand:has(.nuda-css-expand__input:checked) .nuda-css-expand__body {
  opacity: 1;
  padding-bottom: 0.5rem;
}

.nuda-css-expand:has(.nuda-css-expand__input:checked) .nuda-css-expand__txt-more { display: none; }
.nuda-css-expand:has(.nuda-css-expand__input:checked) .nuda-css-expand__txt-less { display: inline; }

.nuda-css-expand__input:focus-visible + .nuda-css-expand__head .nuda-css-expand__title {
  outline: 2px solid var(--nuda-css-ex-accent);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  .nuda-css-expand__more,
  .nuda-css-expand__body { transition: none; }
}