*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:"PingFang SC","Microsoft YaHei",system-ui,sans-serif;color:#1c1c1c;background:#fff;line-height:1.75;-webkit-font-smoothing:antialiased}
img{display:block;max-width:100%;height:auto}
a{color:#2563eb;text-decoration:none}
a:hover{text-decoration:underline}
.shell{width:min(920px,calc(100% - 36px));margin:0 auto}
section{scroll-margin-top:72px}

.site-top{position:sticky;top:0;z-index:90;background:rgba(255,255,255,.97);backdrop-filter:blur(8px);border-bottom:1px solid #ececec}
.top-inner{display:flex;align-items:center;justify-content:space-between;min-height:60px;gap:14px}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;font-size:16px;color:#111}
.brand img{width:36px;height:36px;border-radius:10px}
.top-nav{display:flex;gap:18px}
.top-nav a{color:#666;font-size:14px;font-weight:500}
.top-nav a:hover{color:#111;text-decoration:none}
.menu-btn{display:none;border:1px solid #ddd;background:#fff;border-radius:8px;padding:7px 12px;cursor:pointer;font-size:14px}
.mobile-nav{display:none;flex-direction:column;padding:8px 18px 16px;border-top:1px solid #eee;background:#fff}
.mobile-nav.open{display:flex}
.mobile-nav a{padding:10px 0;border-bottom:1px solid #f4f4f4;color:#444;font-size:14px}

.ads-wrap{border-bottom:1px solid #f0f0f0;background:#fafafa}

.hero-mini{padding:32px 0 20px;text-align:center}
.hero-mini .eyebrow{display:inline-block;font-size:11px;font-weight:700;letter-spacing:.12em;color:#2563eb;margin-bottom:8px}
.hero-mini h1{font-size:clamp(24px,4vw,32px);margin:0 0 10px;line-height:1.3;color:#111;font-weight:800}
.hero-mini .lead{max-width:660px;margin:0 auto;font-size:15px;color:#555}

.acc-zone{padding:8px 0 48px}
.acc-zone-head{text-align:center;margin-bottom:28px}
.acc-zone-head h2{font-size:clamp(22px,4vw,30px);margin:0 0 8px;color:#111;font-weight:800}
.acc-zone-head p{margin:0;font-size:15px;color:#777}
.acc-stack{display:flex;flex-direction:column;gap:12px}
.acc-panel{border:1px solid #e5e5e5;border-radius:16px;background:#fff;overflow:hidden;transition:border-color .2s,box-shadow .2s}
.acc-panel[open]{border-color:#bfdbfe;box-shadow:0 8px 32px rgba(37,99,235,.08)}
.acc-panel summary{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:20px 22px;cursor:pointer;font-weight:600;font-size:16px;color:#111;list-style:none}
.acc-panel summary::-webkit-details-marker{display:none}
.acc-panel summary::after{content:"+";flex-shrink:0;width:28px;height:28px;border-radius:50%;background:#eff6ff;color:#2563eb;display:grid;place-items:center;font-size:18px;font-weight:400;transition:transform .2s,background .2s}
.acc-panel[open] summary::after{content:"−";background:#2563eb;color:#fff}
.acc-body{padding:0 22px 22px;border-top:1px solid #f3f3f3}
.acc-body p{margin:16px 0 0;font-size:15px;color:#555;line-height:1.8}
.acc-body ul,.acc-body ol{margin:12px 0 0;padding-left:20px;color:#555;font-size:14px}
.acc-body li{margin-bottom:6px}
.acc-body figure{margin:20px 0 0}
.acc-body figcaption{font-size:12px;color:#888;text-align:center;margin-top:6px}
.thumb-row{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:20px}
.thumb-row figure{margin:0;border-radius:12px;overflow:hidden;border:1px solid #eee}
.thumb-row figcaption{padding:8px;font-size:12px;color:#666;text-align:center;background:#fafafa}
.callout{margin-top:16px;padding:14px 16px;border-left:3px solid #2563eb;background:#f8fafc;border-radius:0 8px 8px 0;font-size:14px;color:#444}
.callout-warn{border-left-color:#f59e0b;background:#fffbeb}

.guide-links{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin:36px 0 48px}
.guide-links a{display:block;padding:18px 16px;border:1px solid #e8e8e8;border-radius:14px;font-size:14px;font-weight:600;color:#333;background:#fff;transition:border-color .2s}
.guide-links a:hover{border-color:#93c5fd;text-decoration:none}
.guide-links a span{display:block;font-size:12px;font-weight:400;color:#888;margin-top:6px}

.prose{max-width:720px;margin:0 auto;padding:40px 0 52px}
.prose h1{font-size:clamp(26px,3vw,34px);margin:0 0 18px;line-height:1.3}
.prose h2{font-size:20px;margin:28px 0 10px}
.prose p,.prose li{color:#444;font-size:15px}
.prose ul,.prose ol{padding-left:22px}
.prose .lead{font-size:16px;color:#555}

.site-foot{padding:36px 0 44px;background:#fafafa;border-top:1px solid #eee;font-size:13px;color:#888}
.site-foot a{color:#666;margin-right:14px}
.site-foot p{margin:10px 0 0}

.err-page{min-height:60vh;display:grid;place-items:center;text-align:center;padding:36px 20px}
.err-page h1{font-size:68px;margin:0;color:#ddd;font-weight:800}
.err-page p{font-size:16px;color:#666}

@media(max-width:720px){
  .guide-links,.thumb-row{grid-template-columns:1fr}
  .menu-btn{display:inline-flex}
  .top-nav{display:none}
  .acc-panel summary{font-size:15px;padding:16px 18px}
  .acc-body{padding:0 18px 18px}
}