:root{
  --brand:#1677ff; --brand-d:#0958d9; --bg:#f5f6f8; --card:#fff;
  --text:#1f2329; --sub:#8a9099; --line:#e5e6eb; --warn-bg:#fff7e6;
  --warn-bd:#ffd591; --warn-tx:#874d00; --danger:#d4380d;
}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}
html,body{margin:0;padding:0}
body{
  font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",
    "Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  background:var(--bg);color:var(--text);line-height:1.7;
  -webkit-font-smoothing:antialiased;
}
.app{max-width:760px;margin:0 auto;min-height:100vh;display:flex;flex-direction:column}
.topbar{
  position:sticky;top:0;z-index:20;display:flex;align-items:center;justify-content:space-between;
  padding:10px 16px;background:rgba(255,255,255,.92);backdrop-filter:saturate(180%) blur(8px);
  border-bottom:1px solid var(--line);
}
.brand{display:flex;align-items:center;gap:8px}
.logo{width:30px;height:30px;border-radius:7px;object-fit:cover}
.app-name{font-weight:700;font-size:16px}
.lang select{
  appearance:none;-webkit-appearance:none;border:1px solid var(--line);background:#fff;
  border-radius:8px;padding:6px 28px 6px 10px;font-size:13px;color:var(--text);
  background-image:url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'><path d='M2 4l4 4 4-4' stroke='%238a9099' stroke-width='1.5' fill='none'/></svg>");
  background-repeat:no-repeat;background-position:right 8px center;cursor:pointer;
}
.main{flex:1;padding:18px 16px 40px}
.hero{text-align:center;padding:14px 4px 6px}
.hero h1{font-size:24px;margin:0 0 6px;font-weight:800}
.sub{color:var(--sub);font-size:14px;margin:0 0 18px}
.dl-btn{
  display:inline-flex;align-items:center;gap:10px;justify-content:center;
  background:linear-gradient(180deg,var(--brand),var(--brand-d));
  color:#fff;text-decoration:none;font-weight:700;font-size:17px;
  padding:15px 30px;border-radius:14px;box-shadow:0 6px 18px rgba(22,119,255,.35);
  transition:transform .08s ease,box-shadow .2s ease;min-width:220px;
}
.dl-btn:active{transform:translateY(1px) scale(.99)}
.dl-btn.disabled{background:#c9cdd4;box-shadow:none;pointer-events:none}
.dl-ico{font-size:20px;font-weight:800}
.dl-size{font-size:12px;opacity:.85;font-weight:500}
.dl-note{color:var(--sub);font-size:12px;margin-top:10px;min-height:16px}
.block{background:var(--card);border-radius:14px;padding:16px 16px 6px;margin-top:16px;
  box-shadow:0 1px 3px rgba(0,0,0,.05)}
.block h2{font-size:17px;margin:0 0 12px;font-weight:700}
.video-wrap{position:relative;width:100%;border-radius:12px;overflow:hidden;background:#000}
.video-wrap video{width:100%;height:auto;display:block;max-height:70vh}
.gallery{display:grid;grid-template-columns:repeat(auto-fill,minmax(140px,1fr));gap:10px}
.gallery figure{margin:0}
.gallery img{width:100%;border-radius:10px;display:block;object-fit:cover;aspect-ratio:9/16;
  background:#eef0f3;cursor:pointer}
.gallery figcaption{font-size:12px;color:var(--sub);margin-top:4px;text-align:center}
.warn{background:var(--warn-bg);border:1px solid var(--warn-bd);color:var(--warn-tx);
  border-radius:10px;padding:12px 14px;font-size:14px;margin-bottom:14px}
.steps{list-style:none;margin:0;padding:0}
.steps li{display:flex;gap:12px;margin-bottom:16px}
.steps .num{flex:0 0 28px;height:28px;border-radius:50%;background:var(--brand);color:#fff;
  display:flex;align-items:center;justify-content:center;font-weight:700;font-size:14px}
.steps .num.key{background:var(--danger)}
.steps .body b{display:block;margin-bottom:2px;font-size:15px}
.steps .body p{margin:0;color:#4e5969;font-size:14px}
.steps .body code{background:#f0f2f5;padding:1px 6px;border-radius:5px;font-size:13px}
.table-wrap{overflow-x:auto}
table{width:100%;border-collapse:collapse;font-size:13px}
th,td{border:1px solid var(--line);padding:8px 10px;text-align:left;vertical-align:top}
th{background:#f7f8fa;font-weight:700;white-space:nowrap}
.faq{font-size:14px}
.faq p{margin:0 0 12px}
.faq b{color:var(--danger)}
.foot{text-align:center;color:#a9aeb8;font-size:12px;padding:20px 16px 8px}
.lightbox{position:fixed;inset:0;background:rgba(0,0,0,.9);display:none;align-items:center;
  justify-content:center;z-index:50;padding:20px}
.lightbox img{max-width:100%;max-height:100%;border-radius:8px}
.lightbox.show{display:flex}
@media (max-width:420px){
  .hero h1{font-size:21px}
  .dl-btn{width:100%}
  .gallery{grid-template-columns:repeat(auto-fill,minmax(120px,1fr))}
}