*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:"PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  color:#1a1a1a;
  background:#fff;
  line-height:1.75;
  -webkit-font-smoothing:antialiased;
  font-size:16px;
}
img{display:block;max-width:100%;height:auto}
a{color:#1565c0;text-decoration:none}
a:hover{text-decoration:underline}

.shell{width:min(1200px,calc(100% - 32px));margin:0 auto}

.site-top{
  padding:16px 0;
  border-bottom:1px solid #ececec;
  background:#fff;
  position:sticky;
  top:0;
  z-index:50;
}
.top-row{display:flex;align-items:center;justify-content:space-between;gap:16px}
.brand{display:flex;align-items:center;gap:10px;color:#111;font-weight:700;font-size:15px;text-decoration:none}
.brand:hover{text-decoration:none;color:#333}
.brand img{width:38px;border-radius:9px}
.menu-btn{display:none;border:1px solid #d0d0d0;background:#fff;padding:7px 12px;border-radius:8px;font-size:14px;cursor:pointer}
.top-nav{display:flex;gap:20px;flex-wrap:wrap}
.top-nav a{color:#555;font-size:13px;font-weight:600;text-decoration:none}
.top-nav a:hover{color:#111;text-decoration:none}
.mnav{display:none;flex-direction:column;padding:12px 0 4px;border-top:1px solid #f0f0f0;margin-top:12px}
.mnav.open{display:flex}
.mnav a{padding:10px 0;border-bottom:1px solid #f5f5f5;color:#444;font-size:14px;text-decoration:none}

.hero{padding:36px 0 24px;text-align:center}
.hero h1{font-size:clamp(26px,4.5vw,40px);line-height:1.28;margin:0 0 14px;color:#111;font-weight:800}
.hero-lead{max-width:720px;margin:0 auto;font-size:17px;color:#555;line-height:1.7}
.hero-meta{margin-top:12px;font-size:13px;color:#999}

/* Masonry gallery — Pinterest-style uneven grid */
.masonry-zone{padding:8px 0 48px;background:#fff}
.masonry-head{text-align:center;padding:0 0 28px}
.masonry-head h2{font-size:22px;margin:0 0 8px;color:#111;font-weight:700}
.masonry-head p{margin:0;color:#666;font-size:15px}

.masonry{
  column-count:3;
  column-gap:18px;
}
.masonry-item{
  break-inside:avoid;
  margin-bottom:18px;
  border:1px solid #e8e8e8;
  border-radius:14px;
  overflow:hidden;
  background:#fff;
  box-shadow:0 4px 18px rgba(0,0,0,.04);
  transition:transform .22s,box-shadow .22s;
}
.masonry-item:hover{
  transform:translateY(-3px);
  box-shadow:0 10px 28px rgba(0,0,0,.08);
}
.masonry-item img{width:100%;object-fit:cover;background:#f5f5f5}
.masonry-item.tall img{aspect-ratio:9/16}
.masonry-item.mid img{aspect-ratio:4/5}
.masonry-item.wide img{aspect-ratio:16/10}

.pin-body{padding:16px 18px}
.pin-body h3{margin:0 0 8px;font-size:16px;color:#111;line-height:1.35}
.pin-body p{margin:0;font-size:14px;color:#555;line-height:1.65}
.pin-body .tag{
  display:inline-block;margin-top:10px;padding:3px 10px;border-radius:999px;
  background:#f0f4ff;color:#1565c0;font-size:11px;font-weight:600;
}
.pin-body .step-num{
  display:inline-flex;align-items:center;justify-content:center;
  width:28px;height:28px;border-radius:50%;background:#111;color:#fff;
  font-size:13px;font-weight:700;margin-bottom:10px;
}

.pin-text{background:#fafafa}
.pin-accent{background:#f8fbff;border-color:#d6e4ff}
.pin-warn{background:#fffbf5;border-color:#ffe0b2}
.pin-link{display:flex;flex-direction:column;justify-content:center;min-height:120px;text-align:center}
.pin-link a{font-size:16px;font-weight:700;color:#1565c0;text-decoration:none}
.pin-link a:hover{text-decoration:underline}
.pin-link span{display:block;margin-top:6px;font-size:12px;color:#888}

.content{padding:20px 0 56px}
.content h2{font-size:24px;margin:44px 0 16px;color:#111;font-weight:700}
.content h3{font-size:18px;margin:28px 0 12px;color:#222}
.content p{margin:0 0 18px;color:#333;font-size:16px;line-height:1.8}
.content ul,.content ol{margin:0 0 18px;padding-left:22px;color:#333}
.content li{margin-bottom:8px;line-height:1.75}

.tip-box{margin:28px 0;padding:18px 20px;background:#f9f9f9;border-left:4px solid #1565c0;border-radius:0 8px 8px 0;font-size:15px;color:#444}
.tip-box strong{display:block;margin-bottom:6px;color:#111;font-size:14px}

.link-row{display:flex;flex-wrap:wrap;gap:12px;margin:28px 0}
.link-chip{
  display:inline-flex;align-items:center;gap:8px;
  padding:10px 16px;border:1px solid #e0e0e0;border-radius:8px;
  font-size:14px;color:#333;background:#fafafa;text-decoration:none;
}
.link-chip:hover{background:#f0f0f0;text-decoration:none;color:#111}

.faq{margin:40px 0 0;padding-top:32px;border-top:1px solid #ececec}
.faq h2{font-size:22px;margin-bottom:16px}
.faq details{border-bottom:1px solid #ececec;padding:14px 0}
.faq summary{cursor:pointer;font-weight:600;font-size:16px;color:#222;list-style:none}
.faq summary::-webkit-details-marker{display:none}
.faq p{margin:10px 0 0;font-size:15px;color:#555}

.prose{padding:40px 0 56px}
.prose h1{font-size:32px;line-height:1.25;margin:0 0 18px}
.prose h2{font-size:21px;margin:32px 0 12px;color:#222}
.prose p,.prose li{font-size:16px;color:#333;line-height:1.8}
.related{margin-top:36px;padding:20px;border:1px solid #e8e8e8;border-radius:10px;background:#fafafa}
.related h3{margin:0 0 12px;font-size:14px;color:#666;letter-spacing:.04em}
.related a{display:block;padding:4px 0;font-size:15px}

.site-foot{padding:36px 0 44px;border-top:1px solid #ececec;font-size:13px;color:#888}
.site-foot a{color:#666;margin-right:14px;text-decoration:none}
.site-foot a:hover{color:#333;text-decoration:none}
.site-foot p{margin:12px 0 0}

.err{min-height:55vh;display:grid;place-items:center;text-align:center;padding:48px 20px}
.err h1{font-size:52px;margin:0 0 12px;color:#ccc}
.err p{font-size:16px;color:#666}

@media(max-width:960px){
  .masonry{column-count:2}
}
@media(max-width:720px){
  .menu-btn{display:block}
  .top-nav{display:none}
  .hero{padding:28px 0 16px}
}
@media(max-width:540px){
  .masonry{column-count:1}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .masonry-item{transition:none}
}