/* 梯子e家 etizi.mom — lightweight technical knowledge-base design system
   Plain CSS, no framework, mobile-first. */

:root{
  --bg:#f6f7f9;
  --surface:#ffffff;
  --surface-soft:#eef1f4;
  --border:#e1e5ea;
  --border-strong:#c9d0d8;
  --text:#1b2430;
  --text-soft:#5c6772;
  --text-faint:#8992a0;
  --primary:#0d7a70;
  --primary-dark:#0a5f57;
  --primary-soft:#e4f3f1;
  --accent:#b5792a;
  --accent-soft:#f7ecdb;
  --danger:#b6462c;
  --radius-sm:6px;
  --radius:10px;
  --radius-lg:16px;
  --shadow-sm:0 1px 2px rgba(20,30,40,0.06);
  --shadow:0 4px 16px rgba(20,30,40,0.08);
  --maxw:1120px;
  --maxw-prose:760px;
  font-size:16px;
}

*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei","Hiragino Sans GB",sans-serif;
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block;}
a{color:var(--primary);text-decoration:none;}
a:hover{text-decoration:underline;}
ul,ol{padding-left:1.3em;}
code{background:var(--surface-soft);padding:1px 6px;border-radius:4px;font-size:0.92em;color:#8a3f19;}
.visually-hidden{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0;}

/* ---------- Header ---------- */
.site-header{
  position:sticky;top:0;z-index:50;
  background:rgba(255,255,255,0.92);
  backdrop-filter:saturate(180%) blur(6px);
  border-bottom:1px solid var(--border);
}
.header-inner{
  max-width:var(--maxw);margin:0 auto;
  display:flex;align-items:center;justify-content:space-between;
  padding:12px 20px;gap:16px;
}
.brand{display:flex;align-items:center;gap:10px;flex-shrink:0;}
.brand-mark{
  width:34px;height:34px;border-radius:8px;
  background:linear-gradient(135deg,var(--primary),var(--primary-dark));
  color:#fff;font-weight:700;font-size:16px;
  display:flex;align-items:center;justify-content:center;
  flex-shrink:0;
}
.brand-text{display:flex;flex-direction:column;line-height:1.2;}
.brand-cn{font-weight:700;font-size:16px;color:var(--text);}
.brand-en{font-size:11px;color:var(--text-faint);letter-spacing:0.03em;}

.nav-toggle{
  display:flex;flex-direction:column;justify-content:center;gap:4px;
  width:34px;height:34px;background:none;border:1px solid var(--border);border-radius:8px;cursor:pointer;
}
.nav-toggle span{display:block;width:16px;height:2px;background:var(--text);margin:0 auto;}

.nav-wrap{display:flex;align-items:center;gap:18px;}
.site-nav ul{list-style:none;display:flex;gap:4px;margin:0;padding:0;}
.site-nav a{
  display:block;padding:8px 10px;border-radius:7px;color:var(--text-soft);font-size:14px;font-weight:600;white-space:nowrap;
}
.site-nav a:hover,.site-nav a[aria-current="page"]{color:var(--primary);background:var(--primary-soft);text-decoration:none;}

@media (max-width:860px){
  .nav-toggle{display:flex;}
  .nav-wrap{
    position:fixed;top:59px;left:0;right:0;bottom:0;
    background:var(--surface);
    flex-direction:column;align-items:stretch;
    padding:16px 20px;overflow-y:auto;
    transform:translateX(100%);transition:transform .18s ease;
    border-top:1px solid var(--border);
  }
  .nav-wrap.is-open{transform:translateX(0);}
  .site-nav ul{flex-direction:column;gap:2px;}
  .site-nav a{padding:12px 10px;font-size:15px;}
}
@media (min-width:861px){
  .nav-toggle{display:none;}
}

/* ---------- Breadcrumb ---------- */
.breadcrumb{
  max-width:var(--maxw);margin:0 auto;padding:14px 20px 0;
  font-size:13px;color:var(--text-faint);
}
.breadcrumb a{color:var(--text-soft);}

/* ---------- Hero ---------- */
.hero{padding:40px 20px 30px;}
.hero-inner{max-width:var(--maxw);margin:0 auto;text-align:center;}
.hero-eyebrow{
  display:inline-block;font-size:12.5px;font-weight:700;color:var(--primary);
  background:var(--primary-soft);padding:4px 12px;border-radius:20px;margin-bottom:16px;letter-spacing:0.02em;
}
.hero h1{font-size:clamp(24px,4vw,36px);margin:0 0 14px;line-height:1.35;}
.hero-sub{color:var(--text-soft);font-size:16px;max-width:640px;margin:0 auto 26px;}
.hero-search{max-width:560px;margin:0 auto;position:relative;}
.hero-search-inner{display:flex;background:var(--surface);border:1px solid var(--border-strong);border-radius:12px;box-shadow:var(--shadow-sm);overflow:hidden;}
.hero-search input[type="search"]{
  flex:1;border:0;padding:14px 16px;font-size:15px;background:transparent;color:var(--text);outline:none;
}
.hero-search button{
  border:0;background:var(--primary);color:#fff;font-weight:700;padding:0 22px;cursor:pointer;font-size:14px;
}
.hero-search button:hover{background:var(--primary-dark);}
.search-results{
  text-align:left;margin-top:10px;background:var(--surface);border:1px solid var(--border);border-radius:10px;
  box-shadow:var(--shadow);overflow:hidden;
}
.search-results:empty{display:none;}
.search-results a{display:block;padding:12px 16px;border-bottom:1px solid var(--border);color:var(--text);}
.search-results a:last-child{border-bottom:0;}
.search-results a:hover{background:var(--surface-soft);text-decoration:none;}
.search-results .sr-tag{color:var(--primary);font-size:12px;font-weight:700;margin-right:8px;}
.search-empty{padding:14px 16px;color:var(--text-faint);font-size:14px;}

/* ---------- Stats bar ---------- */
.stats-bar{
  max-width:var(--maxw);margin:0 auto;padding:0 20px 40px;
  display:grid;grid-template-columns:repeat(3,1fr);gap:14px;
}
.stat-item{
  background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  padding:18px 12px;text-align:center;
}
.stat-num{font-size:24px;font-weight:800;color:var(--primary);}
.stat-label{font-size:12.5px;color:var(--text-soft);margin-top:4px;}
@media (max-width:560px){
  .stats-bar{grid-template-columns:1fr;}
}

/* ---------- Sections ---------- */
.section{max-width:var(--maxw);margin:0 auto;padding:36px 20px;}
.section-head{margin-bottom:22px;}
.section-eyebrow{font-size:12.5px;font-weight:700;color:var(--primary);text-transform:uppercase;letter-spacing:0.04em;}
.section-title{font-size:22px;margin:6px 0 8px;}
.section-desc{color:var(--text-soft);font-size:14.5px;max-width:640px;}
.section-foot{margin-top:20px;}

/* ---------- Quicklinks ---------- */
.quicklink-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:12px;}
.quicklink-item{
  display:flex;align-items:center;justify-content:space-between;gap:10px;
  background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  padding:14px 16px;font-weight:600;font-size:14.5px;color:var(--text);
}
.quicklink-item:hover{border-color:var(--primary);color:var(--primary);text-decoration:none;background:var(--primary-soft);}
.quicklink-item .qi-arrow{color:var(--text-faint);flex-shrink:0;}

/* ---------- Card grids ---------- */
.cat-grid,.hub-grid,.featured-grid{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px;
}
.cat-card,.hub-card,.featured-card{
  background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-lg);
  padding:20px;display:flex;flex-direction:column;gap:8px;
}
.cat-card:hover,.hub-card:hover,.featured-card:hover{border-color:var(--primary);box-shadow:var(--shadow);text-decoration:none;}
.card-tag{
  align-self:flex-start;font-size:11.5px;font-weight:700;color:var(--primary);
  background:var(--primary-soft);padding:3px 10px;border-radius:20px;
}
.cat-card h3,.hub-card h3,.featured-card h3{margin:2px 0 0;font-size:16.5px;color:var(--text);}
.cat-card p,.hub-card p,.featured-card p{margin:0;color:var(--text-soft);font-size:13.8px;flex:1;}
.card-arrow{font-size:13px;font-weight:700;color:var(--primary);margin-top:4px;}

/* ---------- Client grid ---------- */
.client-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:16px;}
.client-card{
  background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-lg);padding:20px;
  display:flex;flex-direction:column;gap:10px;
}
.client-card-head{display:flex;align-items:center;gap:10px;}
.client-icon{
  width:38px;height:38px;border-radius:9px;background:var(--surface-soft);
  display:flex;align-items:center;justify-content:center;font-weight:800;color:var(--primary);flex-shrink:0;
}
.client-card h3{margin:0;font-size:16.5px;}
.badge-row{display:flex;flex-wrap:wrap;gap:6px;}
.badge{
  font-size:11px;font-weight:700;padding:3px 9px;border-radius:20px;
  background:var(--surface-soft);color:var(--text-soft);border:1px solid var(--border);
}
.badge-primary{background:var(--primary-soft);color:var(--primary-dark);border-color:transparent;}
.platform-row{display:flex;flex-wrap:wrap;gap:6px;font-size:12px;color:var(--text-faint);}
.platform-row span{background:var(--bg);border:1px solid var(--border);border-radius:5px;padding:2px 7px;}
.client-card p{margin:0;font-size:13.8px;color:var(--text-soft);}
.client-cta-row{display:flex;gap:8px;margin-top:auto;flex-wrap:wrap;}

/* ---------- Product strip ---------- */
.product-strip{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:14px;}
.product-card{
  background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  padding:16px;display:flex;flex-direction:column;gap:8px;font-size:13.8px;
}
.product-card.is-primary{border:1.5px solid var(--accent);background:var(--accent-soft);}
.product-rank{font-size:11.5px;font-weight:700;color:var(--text-faint);}
.product-card.is-primary .product-rank{color:var(--accent);}
.product-card h3{margin:0;font-size:15.5px;}
.product-card p{margin:0;color:var(--text-soft);flex:1;}
.product-cta-row{display:flex;gap:8px;flex-wrap:wrap;}

/* ---------- Buttons ---------- */
.btn{
  display:inline-block;padding:9px 16px;border-radius:8px;font-weight:700;font-size:13.8px;
  border:1px solid transparent;cursor:pointer;text-align:center;
}
.btn:hover{text-decoration:none;}
.btn-primary{background:var(--primary);color:#fff;}
.btn-primary:hover{background:var(--primary-dark);}
.btn-outline{background:var(--surface);border-color:var(--border-strong);color:var(--text);}
.btn-outline:hover{border-color:var(--primary);color:var(--primary);}
.btn-ghost{background:transparent;color:var(--text-soft);}
.btn-ghost:hover{color:var(--primary);}
.btn-gold{background:var(--accent);color:#fff;}
.btn-gold:hover{background:#96631f;}
.btn-sm{padding:6px 12px;font-size:12.5px;}
.hero-ctas{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin-top:18px;}

/* ---------- FAQ ---------- */
.faq-list{display:flex;flex-direction:column;gap:8px;}
.faq-item{
  background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  padding:4px 16px;
}
.faq-item summary{cursor:pointer;padding:12px 0;font-weight:700;font-size:14.5px;list-style:none;position:relative;padding-right:24px;}
.faq-item summary::-webkit-details-marker{display:none;}
.faq-item summary::after{content:"+";position:absolute;right:0;top:10px;color:var(--primary);font-size:18px;font-weight:400;}
.faq-item[open] summary::after{content:"–";}
.faq-a{margin:0 0 14px;color:var(--text-soft);font-size:14px;}

/* ---------- Article / prose ---------- */
.article-wrap{max-width:var(--maxw-prose);margin:0 auto;padding:20px 20px 60px;}
.article-header h1{font-size:clamp(22px,3.6vw,30px);margin:6px 0 12px;line-height:1.4;}
.article-meta{display:flex;flex-wrap:wrap;gap:14px;font-size:13px;color:var(--text-faint);margin-bottom:18px;}
.lede{font-size:16px;color:var(--text-soft);margin:0 0 24px;padding-bottom:20px;border-bottom:1px solid var(--border);}
.toc{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:16px 20px;margin-bottom:26px;}
.toc h2{font-size:14px;margin:0 0 8px;color:var(--text-soft);text-transform:uppercase;letter-spacing:0.03em;}
.toc ol{margin:0;padding-left:1.2em;font-size:14.5px;}
.toc li{margin-bottom:4px;}
.prose h2{font-size:20px;margin:34px 0 12px;padding-top:6px;}
.prose h3{font-size:16.5px;margin:22px 0 8px;}
.prose p{margin:0 0 14px;color:var(--text);}
.prose ul,.prose ol{margin:0 0 14px;color:var(--text);}
.prose li{margin-bottom:6px;}
.key-takeaway{
  background:var(--primary-soft);border-left:3px solid var(--primary);border-radius:0 var(--radius) var(--radius) 0;
  padding:14px 18px;margin:22px 0;
}
.key-takeaway h3{margin:0 0 6px;font-size:14.5px;color:var(--primary-dark);}
.key-takeaway p{margin:0;font-size:14px;color:var(--text);}
.callout{
  background:var(--surface-soft);border:1px solid var(--border);border-radius:var(--radius);
  padding:14px 18px;margin:18px 0;font-size:14px;color:var(--text-soft);
}
.quick-access{
  display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;
  background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  padding:16px 20px;margin-bottom:22px;
}
.qa-text h3{margin:0 0 4px;font-size:15px;}
.qa-text p{margin:0 0 8px;font-size:13.8px;color:var(--text-soft);}
.promo-pill{
  display:inline-block;font-size:12.5px;background:var(--accent-soft);border:1px solid #e6cfa4;
  border-radius:20px;padding:4px 12px;color:#6b4a1a;
}
.disclosure-banner{
  background:var(--accent-soft);border:1px solid #e6cfa4;border-radius:var(--radius);
  padding:12px 16px;font-size:13.5px;color:#6b4a1a;margin-bottom:22px;
}
.table-wrap{overflow-x:auto;margin:0 0 16px;}
.data-table{width:100%;border-collapse:collapse;font-size:13.8px;background:var(--surface);}
.data-table th,.data-table td{padding:10px 12px;border:1px solid var(--border);text-align:left;vertical-align:top;}
.data-table th{background:var(--surface-soft);font-weight:700;white-space:nowrap;}
.compare-table .col-wuyou{background:var(--accent-soft);}
.compare-table th.col-wuyou{background:#eddcb8;}
.spec-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:10px;margin:0 0 14px;}
.spec-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-sm);padding:12px 14px;}
.spec-label{font-size:11.5px;color:var(--text-faint);font-weight:700;text-transform:uppercase;letter-spacing:0.02em;margin-bottom:4px;}
.spec-value{font-size:13.8px;color:var(--text);}
.spec-note,.fineprint{font-size:12.5px;color:var(--text-faint);margin:0 0 20px;}
.two-col{display:grid;grid-template-columns:1fr 1fr;gap:18px;}
@media (max-width:640px){.two-col{grid-template-columns:1fr;}}
.pro-list h4,.caution-list h4{margin:0 0 8px;font-size:14px;}
.pro-list ul,.caution-list ul{margin:0;padding-left:1.2em;font-size:13.8px;color:var(--text-soft);}
.step-list{list-style:none;margin:0 0 16px;padding:0;counter-reset:step;}
.step-list li{
  position:relative;padding:4px 0 16px 40px;counter-increment:step;
}
.step-list li::before{
  content:counter(step);position:absolute;left:0;top:2px;width:28px;height:28px;border-radius:50%;
  background:var(--primary);color:#fff;font-weight:700;font-size:13px;display:flex;align-items:center;justify-content:center;
}
.step-list h4{margin:0 0 4px;font-size:14.5px;}
.step-list p{margin:0;color:var(--text-soft);font-size:13.8px;}
.related-links{
  margin-top:36px;padding:18px 20px;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
}
.related-links h4{margin:0 0 10px;font-size:14px;}
.related-links ul{margin:0;padding-left:1.2em;font-size:14px;}
.related-links li{margin-bottom:6px;}

/* article/tutorial listing */
.list-count{color:var(--text-soft);font-size:14px;margin-bottom:18px;}

/* sitemap page */
.sitemap-cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:24px;}
.sitemap-cols h3{font-size:14.5px;margin:0 0 10px;color:var(--primary-dark);}
.sitemap-cols ul{list-style:none;padding:0;margin:0 0 20px;font-size:14px;}
.sitemap-cols li{margin-bottom:6px;}

/* ---------- Footer ---------- */
.site-footer{border-top:1px solid var(--border);background:var(--surface);margin-top:20px;}
.footer-inner{
  max-width:var(--maxw);margin:0 auto;padding:40px 20px 24px;
  display:grid;grid-template-columns:1.4fr 1fr 1fr 1.4fr;gap:24px;
}
@media (max-width:760px){.footer-inner{grid-template-columns:1fr 1fr;}}
@media (max-width:480px){.footer-inner{grid-template-columns:1fr;}}
.footer-logo{display:flex;align-items:center;gap:8px;font-weight:700;margin-bottom:8px;}
.footer-col h4{font-size:13px;margin:0 0 10px;color:var(--text-faint);text-transform:uppercase;letter-spacing:0.03em;}
.footer-col ul{list-style:none;padding:0;margin:0;font-size:13.8px;}
.footer-col li{margin-bottom:7px;}
.footer-col p{font-size:13.5px;color:var(--text-soft);margin:0;}
.friend-links{display:flex;flex-wrap:wrap;gap:8px;}
.friend-links li{margin:0;}
.friend-links a{
  display:inline-block;font-size:12.5px;background:var(--surface-soft);border:1px solid var(--border);
  border-radius:20px;padding:4px 11px;color:var(--text-soft);
}
.friend-links a:hover{color:var(--primary);border-color:var(--primary);text-decoration:none;}
.footer-bottom{
  max-width:var(--maxw);margin:0 auto;padding:18px 20px 30px;border-top:1px solid var(--border);
  font-size:12.3px;color:var(--text-faint);
}
.footer-disclosure{margin:0 0 10px;}

/* ---------- 404 ---------- */
.error-page{text-align:center;padding:90px 20px;}
.error-code{font-size:60px;font-weight:800;color:var(--primary);margin-bottom:8px;}
.error-page h1{font-size:24px;margin-bottom:12px;}
.error-page p{color:var(--text-soft);max-width:480px;margin:0 auto 24px;}