.qa-dl{display:grid;grid-template-columns:280px 1fr;gap:0;min-height:calc(100vh - 72px)}
.qa-index{position:sticky;top:72px;height:calc(100vh - 72px);overflow:auto;padding:28px 18px;background:var(--navy-d);color:#fff}
.qa-index h2{font-size:13px;letter-spacing:.1em;text-transform:uppercase;opacity:.75;margin-bottom:16px;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Microsoft YaHei",sans-serif}
.qa-index a{display:block;padding:10px 12px;border-radius:8px;font-size:13px;font-weight:700;color:rgba(255,255,255,.82);margin-bottom:4px;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Microsoft YaHei",sans-serif}
.qa-index a:hover,.qa-index a.on{background:rgba(255,255,255,.12);color:#fff}
.qa-main{padding:36px 32px 64px;background:#fff}
.qa-main h1{font-size:clamp(26px,3.5vw,38px);margin:10px 0 12px}
.qa-main .lead{color:var(--muted);max-width:680px;margin-bottom:28px}
.dl-acc{margin-bottom:12px}
.dl-acc summary{display:flex;justify-content:space-between;align-items:center;gap:12px}
.dl-acc summary span.os{font-size:11px;padding:3px 8px;border-radius:4px;background:#eef2ff;color:var(--navy-d)}
.dl-body{padding:0 16px 18px}
.dl-body p{margin-bottom:12px}
.dl-body .btn{margin-right:8px;margin-bottom:8px}
.dl-visual{margin-top:28px;border-radius:12px;overflow:hidden;border:1px solid var(--line)}
.dl-visual img{width:100%;aspect-ratio:16/10;object-fit:cover}
@media(max-width:900px){.qa-dl{grid-template-columns:1fr}.qa-index{position:static;height:auto;display:flex;flex-wrap:wrap;gap:6px;padding:16px}.qa-index a{flex:1;min-width:140px;text-align:center}.qa-main{padding:24px 16px 48px}}