/* details/summary の見た目 */
.qa details{border:1px solid var(--line); border-radius:12px; background:#fff; padding:10px 12px}
.qa details+details{margin-top:10px}
.qa summary{cursor:pointer; font-weight:700; list-style:none}
.qa summary::-webkit-details-marker{display:none}
.qa summary::after{content:"＋"; float:right; color:#64748b}
.qa details[open] summary::after{content:"－"}