/**
 * Accordion - canonical Marbl UI Items §14 pattern.
 * Extracted from ui-items/preview.html inline styles on 
 * so both the library preview and any consumer (e.g. legal pages) pull
 * from a single source of truth.
 *
 * Usage:
 *   <div class="accordion">
 *     <div class="accordion__item">
 *       <button class="accordion__trigger" aria-expanded="false">
 *         <span>Question</span>
 *         <svg class="accordion__icon" viewBox="0 0 24 24" fill="none"
 *              stroke="currentColor" stroke-width="2" aria-hidden="true">
 *           <polyline points="6 9 12 15 18 9"/>
 *         </svg>
 *       </button>
 *       <div class="accordion__body">
 *         <div class="accordion__body-inner">
 *           <div class="accordion__content">Answer content.</div>
 *         </div>
 *       </div>
 *     </div>
 *     ...
 *   </div>
 *
 * JS: toggle `.is-open` on both the trigger AND its sibling .accordion__body.
 * One item open at a time (pattern: close all siblings, then open clicked).
 *
 * Depends on: core/marbl-v2.css tokens (--radius, --text-base, --text-sm,
 * --marbl-charcoal-light, --marbl-ember, --font-body).
 */

.accordion {
  display: flex;
  flex-direction: column;
  border-radius: var(--radius, 10px);
  overflow: hidden;
}

.accordion__item {
  background: var(--marbl-charcoal-light, #1d1a1b);
  border-bottom: 1px solid var(--marbl-white-06, rgba(255, 255, 255, 0.06));
}

.accordion__item:last-child {
  border-bottom: none;
}

.accordion__trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 18px 24px;
  background: transparent;
  border: none;
  color: var(--marbl-white-90, rgba(255, 255, 255, 0.9));
  font-family: var(--font-body, 'Inter', sans-serif);
  font-size: var(--text-base, 15px);
  font-weight: 500;
  cursor: pointer;
  text-align: left;
  transition: color 0.2s ease;
}

.accordion__trigger:hover { color: #fff; }
.accordion__trigger.is-open { color: var(--marbl-ember, #F35226); }

.accordion__trigger:focus-visible {
  outline: 2px solid var(--marbl-ember, #F35226);
  outline-offset: -2px;
}

.accordion__icon {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  opacity: 0.5;
  transition: transform 0.5s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.3s ease;
}

.accordion__trigger.is-open .accordion__icon {
  transform: rotate(180deg);
  opacity: 1;
}

/* Height animation via CSS grid — smooth, GPU-compositable, no max-height jank. */
.accordion__body {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}

.accordion__body.is-open { grid-template-rows: 1fr; }

.accordion__body-inner { overflow: hidden; }

.accordion__content {
  padding: 0 24px 20px;
  font-size: var(--text-sm, 13px);
  color: rgba(255, 255, 255, 0.45);
  line-height: 1.7;
}

/* Reduced motion — snap open/close, no transition. */
@media (prefers-reduced-motion: reduce) {
  .accordion__body,
  .accordion__icon {
    transition: none;
  }
}