:root{
  --brand:#087bc8;--brand-dark:#0564a4;--brand-light:#eaf4fc;
  --ink:#172c43;--muted:#536b83;--line:#e2e8f0;--wash:#f8fafc;
  --warn-bg:#fffbeb;--warn-ink:#92400e;--warn-border:#fde68a;
  --ok-bg:#f0fdf4;--ok-ink:#166534;--ok-border:#bbf7d0;
  --info-bg:#eff6ff;--info-ink:#1e40af;--info-border:#bfdbfe;
  --danger-bg:#fef2f2;--danger-ink:#991b1b;--danger-border:#fecaca;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;color:var(--ink);background:#fff;line-height:1.8;-webkit-font-smoothing:antialiased;font-size:15px}
a{color:var(--brand);text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%;display:block}
.wrap{max-width:860px;margin:0 auto;padding:0 24px}

/* Header */
.site-header{border-bottom:1px solid var(--line);background:#fff;position:sticky;top:0;z-index:50}
.site-nav{max-width:860px;margin:0 auto;padding:12px 24px;display:flex;align-items:center;justify-content:space-between;gap:24px}
.site-nav nav{display:flex;gap:20px;font-size:13.5px;font-weight:500}
.site-nav nav a{color:var(--muted);text-decoration:none;transition:color .15s}
.site-nav nav a:hover{color:var(--brand)}
@media(max-width:760px){.site-nav nav{display:none}}
.brand{display:flex;align-items:center;gap:8px;font-weight:700;font-size:16px;letter-spacing:-.3px;color:var(--ink)}
.brand .brand-dot{width:8px;height:8px;border-radius:1px;background:var(--brand)}
.brand span{color:var(--brand)}
.back-home{font-size:13.5px;font-weight:500;color:var(--muted)}
.back-home:hover{color:var(--brand);text-decoration:none}

/* Page head */
.page-head{padding:36px 0 20px;margin-bottom:28px}
.eyebrow{font-size:12px;font-weight:600;letter-spacing:1px;text-transform:uppercase;color:var(--brand);margin-bottom:8px;display:block}
.page-head h1{font-size:26px;font-weight:700;letter-spacing:-.5px;line-height:1.3;color:var(--ink)}
.page-head p{color:var(--muted);font-size:14.5px;margin-top:8px;max-width:680px}

/* Content typography */
.content{padding-bottom:40px;max-width:820px}
.content h2{font-size:19px;font-weight:700;color:var(--ink);margin:32px 0 12px;padding-top:18px;border-top:1px solid var(--line)}
.content h2:first-child{border-top:none;padding-top:0}
.content h3{font-size:15.5px;font-weight:650;color:var(--ink);margin:22px 0 8px}
.content h4{font-size:14.5px;font-weight:600;color:var(--ink);margin:16px 0 6px}
.content p{color:var(--ink);margin-bottom:10px}
.content ul,.content ol{margin:0 0 14px 22px;color:var(--ink)}
.content li{margin-bottom:5px;line-height:1.75}
.content strong{color:var(--ink);font-weight:650}
.content code{background:var(--wash);color:var(--brand);padding:2px 6px;border-radius:3px;font-size:13.5px;font-family:"SF Mono",Consolas,monospace}
.content blockquote{border-left:3px solid var(--brand);padding:10px 16px;margin:14px 0;background:var(--wash);color:var(--muted);font-size:14px}

/* Callout boxes */
.callout{display:flex;gap:12px;padding:12px 16px;margin:14px 0;border-radius:6px;font-size:13.5px;line-height:1.7}
.callout-icon{flex:none;font-size:15px;line-height:1.7}
.callout p{margin:0}
.callout.tip{background:var(--info-bg);border:1px solid var(--info-border);border-left:3px solid #3b82f6;color:var(--info-ink)}
.callout.warn{background:var(--warn-bg);border:1px solid var(--warn-border);border-left:3px solid #f59e0b;color:var(--warn-ink)}
.callout.ok{background:var(--ok-bg);border:1px solid var(--ok-border);border-left:3px solid #22c55e;color:var(--ok-ink)}
.callout.danger{background:var(--danger-bg);border:1px solid var(--danger-border);border-left:3px solid #ef4444;color:var(--danger-ink)}

/* Download list */
.dl-list{list-style:none;margin:0 0 18px;padding:0}
.dl-list li{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:9px 14px;border:1px solid var(--line);border-radius:6px;margin-bottom:5px;font-size:13.5px;transition:border-color .15s}
.dl-list li:hover{border-color:var(--brand)}
.dl-list .dl-name{font-weight:500;color:var(--ink)}
.dl-list .dl-size{font-size:12px;color:var(--muted);font-weight:400;margin-left:8px}
.dl-list .dl-pwd{font-size:12px;color:var(--muted);background:var(--wash);padding:1px 6px;border-radius:3px;margin-left:8px;font-weight:500}
.dl-list a{font-size:13px;font-weight:500;white-space:nowrap;padding:4px 12px;border-radius:4px;text-decoration:none;transition:all .15s}
.dl-list a:hover{text-decoration:none}
.dl-list a[href^="downloads/"]{background:var(--brand);color:#fff}
.dl-list a[href^="downloads/"]:hover{background:var(--brand-dark)}
.dl-list a.lanzou{background:#fff;color:var(--brand);border:1px solid var(--brand)}
.dl-list a.lanzou:hover{background:var(--brand-light)}
.local-badge{display:inline-block;font-size:11px;font-weight:600;color:#fff;background:#166534;padding:1px 6px;border-radius:3px;margin-left:6px}

/* Tables */
.table-wrap{overflow-x:auto;margin:14px 0;border:1px solid var(--line);border-radius:6px}
table{width:100%;border-collapse:collapse;font-size:14px}
th{background:var(--wash);font-weight:600;text-align:left;padding:9px 14px;border-bottom:1px solid var(--line);color:var(--ink)}
td{padding:9px 14px;border-bottom:1px solid var(--line);color:var(--ink)}
tr:last-child td{border-bottom:none}
tr:hover td{background:var(--wash)}

/* Steps */
.step-list{list-style:none;margin:0 0 18px;padding:0;counter-reset:step}
.step-list li{counter-increment:step;padding:10px 0 10px 38px;position:relative;border-left:2px solid var(--line);margin-left:10px}
.step-list li::before{content:counter(step);position:absolute;left:-12px;top:10px;width:22px;height:22px;border-radius:50%;background:var(--brand);color:#fff;font-size:11px;font-weight:600;display:flex;align-items:center;justify-content:center}

/* Hero */
.hero{padding:40px 24px 32px;text-align:left;background:var(--wash);border-bottom:1px solid var(--line)}
.hero > *{max-width:860px;margin-left:auto;margin-right:auto}
.hero .eyebrow{font-size:12px;font-weight:600;letter-spacing:1.5px;text-transform:uppercase;color:var(--brand);margin-bottom:14px;display:block}
.hero h1{font-size:32px;font-weight:750;letter-spacing:-1px;line-height:1.25;color:var(--ink)}
.hero h1 .accent{color:var(--brand)}
.hero .sub{font-size:15px;color:var(--muted);margin-top:14px;max-width:680px;line-height:1.7}
.hero .tagline{margin-top:6px;font-size:13.5px;color:var(--muted)}
.hero .actions{display:flex;gap:10px;margin-top:20px;flex-wrap:wrap}
.button{display:inline-block;padding:8px 18px;border-radius:6px;font-size:13.5px;font-weight:600;background:var(--brand);color:#fff;text-decoration:none;transition:background .15s}
.button:hover{background:var(--brand-dark);text-decoration:none}
.button.secondary{background:#fff;color:var(--brand);border:1px solid var(--brand)}
.button.secondary:hover{background:var(--brand-light)}
.pre-row{display:flex;gap:10px;margin-top:16px;flex-wrap:wrap}
.pre-chip{display:inline-flex;align-items:center;gap:8px;padding:5px 12px;background:#fff;border:1px solid var(--line);border-radius:6px;font-size:13px;color:var(--ink);text-decoration:none}
.pre-chip:hover{border-color:var(--brand);text-decoration:none}
.dl-badge{display:inline-block;font-size:11px;font-weight:600;color:#fff;background:#166534;padding:1px 6px;border-radius:3px}

/* Disclaimer */
.disclaimer{display:flex;gap:10px;align-items:flex-start;padding:12px 16px;background:var(--warn-bg);border:1px solid var(--warn-border);border-radius:6px;margin:20px 0;font-size:13.5px;color:var(--warn-ink)}
.disclaimer p{margin:0}

/* Stats */
.stats-row{display:flex;gap:32px;justify-content:center;flex-wrap:wrap;margin:14px 0;padding:12px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.stat{text-align:center}
.stat .num{font-size:24px;font-weight:700;color:var(--brand);line-height:1}
.stat .label{font-size:12px;color:var(--muted);margin-top:3px}

/* Sections */
.section{padding:24px 0}
.card-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:0;border:1px solid var(--line);border-radius:6px;overflow:hidden}
@media(max-width:800px){.card-grid{grid-template-columns:1fr}}

/* Resource cards */
.resource-card{display:flex;align-items:flex-start;gap:10px;background:#fff;border:none;border-right:1px solid var(--line);border-bottom:1px solid var(--line);border-left:3px solid transparent;padding:11px 14px;transition:all .15s;text-decoration:none;color:var(--ink)}
.resource-card:nth-child(2n){border-right:none}
.resource-card:nth-last-child(-n+2){border-bottom:none}
@media(max-width:800px){.resource-card{border-right:none}.resource-card:last-child{border-bottom:none}}
.resource-card:hover{background:var(--wash);border-left-color:var(--brand);text-decoration:none}
.rc-icon{flex:none;width:26px;height:26px;border-radius:5px;background:var(--brand-light);color:var(--brand);display:flex;align-items:center;justify-content:center;margin-top:2px}
.rc-body{flex:1;min-width:0}
.resource-card h3{font-size:13.5px;font-weight:650;color:var(--ink);margin-bottom:2px;line-height:1.4}
.resource-card p{font-size:12px;color:var(--muted);line-height:1.5;margin:0}
.r-badge{display:inline-block;font-size:10px;font-weight:600;color:#fff;background:var(--brand);padding:0 4px;border-radius:3px;margin-left:2px;vertical-align:middle}

/* Footer */
.site-footer{border-top:1px solid var(--line);padding:24px 0;margin-top:32px;background:var(--wash)}
.footer-inner{max-width:860px;margin:0 auto;padding:0 24px;text-align:center}
.footer-brand{font-weight:700;font-size:14px;color:var(--ink);margin-bottom:4px}
.footer-brand span{color:var(--brand)}
.footer-inner p{color:var(--muted);font-size:12.5px}
.footer-bottom{display:flex;justify-content:space-between;margin-top:10px;padding-top:10px;border-top:1px solid var(--line);font-size:12px;color:var(--muted)}
.footer-nav{display:flex;justify-content:center;gap:16px;margin:12px 0 8px;flex-wrap:wrap}
.footer-nav a{font-size:12.5px;color:var(--muted);text-decoration:none}
.footer-nav a:hover{color:var(--brand);text-decoration:none}

/* TOC */
.toc{background:var(--wash);border:1px solid var(--line);border-radius:6px;padding:14px 18px;margin:16px 0;font-size:13px}
.toc-title{font-weight:600;margin-bottom:6px;color:var(--ink);font-size:12px;text-transform:uppercase;letter-spacing:1px;color:var(--muted)}
.toc ol{margin:0 0 0 18px;padding:0}
.toc li{margin-bottom:3px}

/* Back to top */
.back-top{position:fixed;bottom:20px;right:20px;width:34px;height:34px;border-radius:6px;background:#fff;border:1px solid var(--line);color:var(--muted);display:flex;align-items:center;justify-content:center;font-size:15px;cursor:pointer;opacity:0;visibility:hidden;transition:all .2s;z-index:100;text-decoration:none}
.back-top.show{opacity:1;visibility:visible}
.back-top:hover{border-color:var(--brand);color:var(--brand);text-decoration:none}
@media(max-width:600px){.back-top{bottom:16px;right:16px}}

/* Price table */
.price-table{width:100%;border-collapse:collapse;font-size:13.5px;margin:14px 0}
.price-table th{background:var(--wash);text-align:left;padding:9px 12px;border:1px solid var(--line);font-weight:600}
.price-table td{padding:9px 12px;border:1px solid var(--line)}
.price-table tr:hover td{background:var(--wash)}

/* Tag pills */
.tag{display:inline-block;font-size:11px;font-weight:500;padding:2px 8px;border-radius:4px;background:var(--wash);color:var(--muted);margin:0 4px 6px 0}
.tag.green{background:#dcfce7;color:#166534}
.tag.orange{background:#ffedd5;color:#9a3412}
.tag.purple{background:#ede9fe;color:#5b21b6}

/* Nav actions */
.nav-actions{display:flex;gap:6px;align-items:center}
.nav-btn{width:32px;height:32px;border:1px solid var(--line);border-radius:6px;background:#fff;color:var(--muted);cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:600;transition:all .15s;padding:0}
.nav-btn:hover{border-color:var(--brand);color:var(--brand)}
.nav-btn.lang-toggle{width:auto;padding:0 10px;font-size:12px;gap:4px}
.nav-btn.lang-toggle .lang-text{font-size:12px;font-weight:600}

/* Search overlay */
.search-overlay{position:fixed;inset:0;background:rgba(23,44,67,.4);z-index:200;display:none;align-items:flex-start;justify-content:center;padding-top:100px}
.search-overlay.open{display:flex}
.search-box{width:90%;max-width:560px;background:#fff;border-radius:10px;box-shadow:0 20px 60px rgba(0,0,0,.15);overflow:hidden}
.search-input-wrap{display:flex;align-items:center;gap:10px;padding:14px 18px;border-bottom:1px solid var(--line);color:var(--muted)}
.search-input-wrap input{flex:1;border:none;outline:none;font-size:15px;color:var(--ink);background:transparent}
.search-input-wrap kbd{font-size:11px;color:var(--muted);background:var(--wash);border:1px solid var(--line);border-radius:4px;padding:2px 6px;font-family:inherit}
.search-results{max-height:400px;overflow-y:auto}
.sr-item{display:block;padding:10px 18px;border-bottom:1px solid var(--line);text-decoration:none;transition:background .1s}
.sr-item:hover{background:var(--wash);text-decoration:none}
.sr-title{font-size:14px;font-weight:600;color:var(--ink);display:block}
.sr-title em{font-style:normal;color:var(--muted);font-weight:400;font-size:12px;margin-left:6px}
.sr-desc{font-size:12.5px;color:var(--muted);margin-top:2px;display:block}
.sr-empty{padding:24px 18px;text-align:center;color:var(--muted);font-size:14px}
.sr-section{padding:8px 18px 4px;font-size:11px;font-weight:600;text-transform:uppercase;letter-spacing:1px;color:var(--muted);background:var(--wash)}

/* Related pages */
.related{margin-top:32px;padding-top:20px;border-top:1px solid var(--line)}
.related-title{font-size:12px;font-weight:600;text-transform:uppercase;letter-spacing:1px;color:var(--muted);margin-bottom:10px}
.related-links{display:flex;flex-wrap:wrap;gap:6px}
.related-links a{display:inline-block;padding:5px 12px;background:var(--wash);border:1px solid var(--line);border-radius:5px;font-size:12.5px;color:var(--ink);text-decoration:none;transition:all .15s}
.related-links a:hover{border-color:var(--brand);color:var(--brand);text-decoration:none}

/* Responsive improvements */
.notice-band{background:var(--wash);border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:20px 0;margin-top:32px}
.notice-band .wrap{display:flex;gap:12px;align-items:flex-start;color:var(--muted)}
.notice-band h3{font-size:14px;font-weight:600;color:var(--ink);margin-bottom:4px}
.notice-band p{font-size:13px;line-height:1.6;margin:0}
@media(max-width:760px){
  .wrap{padding:0 16px}
  .site-nav{padding:10px 16px;gap:12px}
  .brand{font-size:14px}
  .nav-actions{gap:4px}
  .back-home{display:none}
  .hero{padding:28px 16px 24px}
  .hero h1{font-size:24px}
  .page-head{padding:24px 0 16px;margin-bottom:20px}
  .page-head h1{font-size:22px}
  .stats-row{gap:16px}
  .stat .num{font-size:20px}
  .price-table{display:block;overflow-x:auto;white-space:nowrap}
  .dl-list li{flex-wrap:wrap}
  .dl-list a{margin-left:auto}
  .toc{padding:10px 14px;font-size:12.5px}
}
@media(max-width:480px){
  .hero h1{font-size:20px}
  .page-head h1{font-size:19px}
  .content h2{font-size:17px}
  .stats-row{gap:12px}
  .stat .num{font-size:18px}
  .nav-btn{width:28px;height:28px}
}

/* Utility classes */
.sub-list{margin:8px 0 0 20px;color:var(--muted);font-size:14px}
.sub-list li{margin-bottom:4px}
.mt-6{margin-top:6px}
.mt-8{margin-top:8px}
.mt-10{margin-top:10px}
.muted-small{margin:6px 0 0;color:var(--muted)}

/* Selection & focus */
::selection{background:#087bc8;color:#fff}
a:focus-visible,button:focus-visible,input:focus-visible{outline:2px solid var(--brand);outline-offset:2px;border-radius:3px}

/* Page fade-in animation */
@keyframes fadeIn{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}
.content,.hero,.quick-start{animation:fadeIn .3s ease-out}

/* Skip link (accessibility) */
.skip-link{position:absolute;top:-40px;left:0;background:var(--brand);color:#fff;padding:8px 16px;z-index:100;font-size:14px;text-decoration:none;border-radius:0 0 6px 0;transition:top .2s}
.skip-link:focus{top:0;color:#fff}

/* Print styles */
@media print{
  .site-header,.site-footer,.back-top,.nav-actions,.search-overlay,.footer-nav,.breadcrumb,.toc,.related{display:none!important}
  body{background:#fff;color:#000;font-size:12pt;line-height:1.5}
  .wrap{max-width:100%;padding:0}
  a{text-decoration:underline;color:#000}
  a[href]:after{content:" ("attr(href) ")";font-size:10pt;color:#666}
  .callout{border:1px solid #ccc;break-inside:avoid;padding:12px}
  table{border:1px solid #ccc;break-inside:avoid;font-size:10pt}
  h2{break-after:avoid}
}

/* Search highlight */
mark{background:#fef08a;padding:0 2px;border-radius:2px;color:inherit}

/* Breadcrumb */
.breadcrumb{font-size:13px;color:var(--muted);margin-bottom:20px;padding-bottom:12px;border-bottom:1px solid var(--line)}
.breadcrumb a{color:var(--muted);text-decoration:none}
.breadcrumb a:hover{color:var(--brand)}

/* Page navigation (prev/next) */
.page-nav{display:flex;justify-content:space-between;gap:16px;margin:40px 0;padding:20px 0;border-top:1px solid var(--line)}
.nav-prev,.nav-next{padding:10px 16px;border:1px solid var(--line);border-radius:6px;text-decoration:none;color:var(--ink);font-size:14px;transition:all .15s}
.nav-prev:hover,.nav-next:hover{border-color:var(--brand);color:var(--brand)}
.nav-prev.disabled,.nav-next.disabled{color:var(--muted);opacity:.5;cursor:default}
.nav-next{margin-left:auto}

/* Quick start */
.quick-start{background:var(--wash);border:1px solid var(--line);border-radius:8px;padding:24px;margin-bottom:32px}
.quick-start .step-list{margin-left:20px}
.quick-start .step-list li{margin-bottom:8px;font-size:15px}
.quick-start a{color:var(--brand);text-decoration:none;font-weight:500}
.quick-start a:hover{text-decoration:underline}

/* Table horizontal scroll on mobile */
.table-wrap{overflow-x:auto;-webkit-overflow-scrolling:touch}
.table-wrap table{min-width:500px}

/* ============================================
   Round 3 Optimizations
   ============================================ */

/* 1. Better scrollbar */
::-webkit-scrollbar{width:8px;height:8px}
::-webkit-scrollbar-track{background:var(--wash)}
::-webkit-scrollbar-thumb{background:#cbd5e1;border-radius:4px}
::-webkit-scrollbar-thumb:hover{background:#94a3b8}

/* 2. Better focus states for links */
.content a{color:var(--brand);text-decoration:none}
.content a:hover{text-decoration:underline}

/* 3. Better headings spacing */
.content h2{margin-top:32px;margin-bottom:12px}
.content h2:first-child{margin-top:0}
.content h3{margin-top:24px;margin-bottom:8px;font-size:17px}

/* 4. Better list spacing */
.content ul,.content ol{margin:10px 0 14px 24px}
.content li{margin-bottom:4px;line-height:1.7}

/* 5. Better paragraph spacing */
.content p{margin-bottom:10px;line-height:1.75}

/* 6. Better TOC on mobile */
@media(max-width:760px){
  .toc{position:static;margin:0 0 20px}
}

/* 7. Better search overlay animation */
.search-overlay.open{animation:fadeIn .15s ease-out}

/* 8. Better button press effect */
.button:active{transform:translateY(1px)}
.button{transition:all .15s}

/* 9. Better card press effect */
.resource-card:active{transform:scale(.99)}

/* 10. Better dl-list item press effect */
.dl-list li:active{background:var(--wash)}

/* ============================================
   Round 3 - Batch 2
   ============================================ */

/* 11. Smooth image rendering */
img{image-rendering:auto;max-width:100%}

/* 12. Better hr styling */
hr{border:none;border-top:1px solid var(--line);margin:24px 0}

/* 13. Better blockquote styling */
blockquote{border-left:3px solid var(--brand);padding:8px 16px;margin:16px 0;background:var(--wash);border-radius:0 6px 6px 0;color:var(--muted);font-style:italic}

/* 14. Better code styling */
code{background:var(--wash);padding:2px 6px;border-radius:3px;font-size:13px;font-family:Consolas,Monaco,monospace}
pre{background:var(--wash);padding:12px 16px;border-radius:6px;overflow-x:auto;margin:12px 0}
pre code{background:none;padding:0}

/* 15. Better strong/em */
strong{font-weight:650}

/* 16. Better table header sticky on desktop */
@media(min-width:760px){
  .price-table thead th{position:sticky;top:0;background:var(--wash);z-index:1}
}

/* 17. Better spacing between sections */
.content > *:last-child{margin-bottom:0}

/* 18. Better footer styling */
.site-footer{border-top:1px solid var(--line);margin-top:60px}

/* 19. Better notice band */
.notice-band{background:linear-gradient(135deg,#eaf4fc 0%,#dbeafe 100%)}

/* 20. Better hero gradient */
.hero{background:linear-gradient(180deg,var(--wash) 0%,#fff 100%)}