:root{
  --bg:#F4F7FB;
  --surface:#FFFFFF;
  --ink:#0B1B34;
  --ink-soft:#4A5A72;
  --brand:#1B5CFF;
  --brand-deep:#0E3FAE;
  --signal:#0FB8AD;
  --accent:#FF7A45;
  --line:#D8E0EC;
  --line-soft:#EAF0F8;
  --h2-inset:16px;
  --radius:14px;
  --shadow:0 6px 24px rgba(11,27,52,.08);
  --header-h:64px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;background:var(--bg);color:var(--ink);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  font-size:16px;line-height:1.75;-webkit-font-smoothing:antialiased;
}
a{color:var(--brand);text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%}
h1,h2,h3,h4,h5,h6{color:var(--ink);line-height:1.35;font-weight:700}
h1{font-size:30px;margin:0 0 12px}
h2{font-size:23px;margin:34px 0 14px;padding-left:0}
h3{font-size:19px;margin:26px 0 10px}
p{margin:0 0 16px}
ul,ol{padding-left:22px;margin:0 0 16px}
li{margin:6px 0}

/* ===== Header ===== */
.fkr-header{position:fixed;top:0;left:0;right:0;z-index:50;height:var(--header-h);
  background:rgba(255,255,255,.92);backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line);}
.fkr-header-inner{max-width:1200px;margin:0 auto;height:100%;display:flex;align-items:center;gap:18px;padding:0 16px}
.fkr-logo{display:flex;align-items:center;gap:8px;font-weight:800;font-size:20px;color:var(--ink)}
.fkr-logo-mark{width:22px;height:22px;border-radius:6px;
  background:linear-gradient(135deg,var(--brand),var(--signal));box-shadow:0 2px 8px rgba(27,92,255,.4)}
.fkr-logo-dot{color:var(--brand)}
.fkr-nav{display:flex;align-items:center;gap:4px;margin-left:auto;flex-wrap:wrap}
.fkr-nav>a,.fkr-nav details.fkr-nav-cat>summary{display:inline-flex;align-items:center;padding:8px 12px;border-radius:8px;
  color:var(--ink-soft);font-weight:600;cursor:pointer;list-style:none;user-select:none}
.fkr-nav>a:hover,.fkr-nav summary:hover{background:var(--line-soft);text-decoration:none;color:var(--brand)}
.fkr-nav-cat{position:relative}
.fkr-nav-sub{position:absolute;top:100%;left:0;min-width:150px;background:#fff;border:1px solid var(--line);
  border-radius:10px;box-shadow:var(--shadow);padding:6px;display:none}
.fkr-nav-cat[open]>.fkr-nav-sub{display:block}
.fkr-nav-sub a{display:block;padding:7px 10px;border-radius:6px;color:var(--ink-soft)}
.fkr-nav-sub a:hover{background:var(--line-soft);color:var(--brand)}
.fkr-nav-toggle{display:none;flex-direction:column;gap:4px;width:40px;height:40px;border:1px solid var(--line);
  background:#fff;border-radius:8px;cursor:pointer;margin-left:auto}
.fkr-nav-toggle span{display:block;height:2px;background:var(--ink);border-radius:2px;margin:0 9px}

/* ===== Main / pagewrap ===== */
.fkr-main{padding-top:var(--header-h)}
.fkr-pagewrap{max-width:1200px;margin:0 auto;padding:24px var(--h2-inset) 56px}
.fkr-pagewrap--page{padding:28px 48px 56px}
.fkr-pagewrap--wide{max-width:1280px}

/* ===== Breadcrumb (left edge aligns with H2) ===== */
.fkr-breadcrumb{margin:0 0 18px;font-size:13.5px;color:var(--ink-soft)}
.fkr-breadcrumb-list{list-style:none;display:flex;flex-wrap:wrap;gap:6px;padding:0;margin:0}
.fkr-breadcrumb-list li{margin:0;display:flex;align-items:center}
.fkr-breadcrumb-list li:not(:last-child)::after{content:"›";margin-left:6px;color:#9fb0c7}
.fkr-breadcrumb-list a{color:var(--ink-soft)}
.fkr-breadcrumb-list .is-current span{color:var(--ink);font-weight:600}

/* ===== Detail layout (content + toc) ===== */
.fkr-detail-layout{display:grid;grid-template-columns:minmax(0,1fr) 240px;gap:36px;align-items:start}
.fkr-content{min-width:0}
.fkr-content h2{padding-left:0}
.fkr-toc-aside{position:sticky;top:calc(var(--header-h) + 16px);max-height:calc(100vh - var(--header-h) - 32px);overflow:auto}
.fkr-toc-panel,.fkr-cat-panel{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:12px 14px}
.fkr-toc-panel>summary,.fkr-cat-panel>summary{cursor:pointer;font-weight:700;color:var(--ink);list-style:none;
  display:flex;align-items:center;justify-content:space-between}
.fkr-toc-panel>summary::after,.fkr-cat-panel>summary::after{content:"▾";color:var(--brand);transition:transform .2s}
.fkr-toc-panel:not([open])>summary::after,.fkr-cat-panel:not([open])>summary::after{transform:rotate(-90deg)}
.fkr-toc-list{list-style:none;padding:8px 0 0;margin:0}
.fkr-toc-list li{margin:2px 0}
.fkr-toc-lv2 a{color:var(--ink-soft)}
.fkr-toc-lv3{padding-left:14px}
.fkr-toc-lv3 a{color:#7a8aa3;font-size:14px}
.fkr-toc-list a:hover{color:var(--brand)}

/* ===== Tables (covers markdown bare tables + fkr-spec) ===== */
.fkr-content table,table.fkr-spec{border-collapse:collapse;width:100%;margin:18px 0;font-size:15px;
  border:1px solid #cbd5e1;border-radius:10px;overflow:hidden}
.fkr-content table th,table.fkr-spec th{background:var(--brand);color:#fff;text-align:left;padding:10px 12px;font-weight:600}
.fkr-content table td,table.fkr-spec td{padding:9px 12px;border-top:1px solid #cbd5e1}
.fkr-content table tbody tr:nth-child(even),table.fkr-spec tbody tr:nth-child(even){background:#F2F6FC}

/* ===== Tags / time / blockquote / faq ===== */
.fkr-tag-row{margin:0 0 18px;display:flex;flex-wrap:wrap;gap:8px}
.tag-text{display:inline-block;background:var(--line-soft);color:var(--ink-soft);border-radius:999px;
  padding:3px 11px;font-size:13px;font-weight:600}
.fkr-date-line{font-size:13px;color:#8493ab;margin:0 0 16px}
.fkr-date-line time{font-style:normal}
.fkr-content blockquote{margin:16px 0;padding:12px 16px;border-left:4px solid var(--brand);background:var(--line-soft);border-radius:0 10px 10px 0;color:var(--ink-soft)}
.fkr-faq{margin:26px 0;border-top:2px solid var(--line);padding-top:14px}
.fkr-faq details{border-bottom:1px solid var(--line);padding:4px 0}
.fkr-faq details>summary{cursor:pointer;font-weight:600;color:var(--ink);padding:10px 4px;list-style:none;display:flex;justify-content:space-between;align-items:center}
.fkr-faq details>summary::after{content:"+";color:var(--brand);font-size:18px}
.fkr-faq details[open]>summary::after{content:"−"}
.fkr-faq-a{padding:0 4px 12px;color:var(--ink-soft)}
.fkr-case{margin:24px 0;background:linear-gradient(135deg,#eef4ff,#e8fbf8);border:1px solid var(--line);
  border-radius:12px;padding:14px 16px}
.fkr-case-tag{display:inline-block;background:var(--brand);color:#fff;font-size:12px;font-weight:700;border-radius:6px;padding:2px 8px;margin-bottom:8px}
.fkr-related{margin:28px 0 0;border-top:1px solid var(--line);padding-top:16px}
.fkr-related h3{margin-top:0}
.fkr-related ul{list-style:none;padding:0}
.fkr-related li{margin:8px 0}
.fkr-related a{font-weight:600}

/* ===== List / category layout ===== */
.fkr-list-layout{display:grid;grid-template-columns:240px minmax(0,1fr);gap:26px;align-items:start}
.fkr-cat-side{position:sticky;top:calc(var(--header-h) + 16px)}
.fkr-cat-list{list-style:none;padding:10px 0 0;margin:0}
.fkr-cat-list li{margin:0}
.fkr-cat-list a{display:block;padding:8px 12px;border-radius:8px;color:var(--ink-soft);font-weight:600}
.fkr-cat-list a:hover{background:var(--line-soft);color:var(--brand);text-decoration:none}
.fkr-cat-list .is-active a{background:var(--brand);color:#fff}
.fkr-cat-head{margin:0 0 16px}
.fkr-cat-head h1{margin-bottom:6px}
.fkr-cat-desc{color:var(--ink-soft);margin:0 0 8px}

/* ===== Cards (article/product grids) ===== */
.fkr-card-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:18px}
.fkr-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:18px;
  box-shadow:var(--shadow);transition:transform .18s,box-shadow .18s;display:flex;flex-direction:column}
.fkr-card:hover{transform:translateY(-3px);box-shadow:0 12px 30px rgba(11,27,52,.12)}
.fkr-card h3{margin:0 0 8px;font-size:18px}
.fkr-card h3 a{color:var(--ink)}
.fkr-card .fkr-card-meta{font-size:13px;color:#8493ab;margin:0 0 8px}
.fkr-card .fkr-card-ex{color:var(--ink-soft);font-size:14px;margin:0 0 12px;flex:1}
.fkr-card .fkr-card-tag{font-size:12px;color:var(--brand);font-weight:600}
.fkr-card-cat{display:inline-block;background:var(--line-soft);color:var(--signal);font-weight:700;border-radius:6px;padding:2px 8px;font-size:12px;margin-bottom:8px}

/* ===== Product detail ===== */
.fkr-prod-head{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin-bottom:6px}
.fkr-prod-status{background:var(--signal);color:#fff;font-size:12px;font-weight:700;border-radius:6px;padding:2px 9px}
.fkr-param-table{margin:18px 0}
.fkr-scenarios li{margin:8px 0}
.fkr-scenarios b{color:var(--brand)}

/* ===== Float capsule ===== */
.fkr-float{position:fixed;right:18px;top:50%;transform:translateY(-50%);z-index:60;
  display:flex;flex-direction:column;gap:10px}
.fkr-float-btn{width:54px;height:54px;border:none;border-radius:16px;cursor:pointer;
  background:linear-gradient(135deg,var(--brand),var(--signal));color:#fff;
  display:flex;flex-direction:column;align-items:center;justify-content:center;gap:2px;
  box-shadow:0 8px 22px rgba(27,92,255,.35);transition:transform .15s,filter .15s}
.fkr-float-btn:hover{transform:scale(1.06);filter:brightness(1.06);text-decoration:none}
.fkr-float-ico{font-size:18px;line-height:1}
.fkr-float-txt{font-size:11px;font-weight:700}
.fkr-card-overlay{position:fixed;inset:0;z-index:70;background:rgba(11,27,52,.55);
  display:flex;align-items:center;justify-content:center;padding:20px}
.fkr-card-overlay[hidden]{display:none}
.fkr-card-pop{position:relative;background:#fff;border-radius:16px;padding:10px;box-shadow:0 20px 60px rgba(0,0,0,.3)}
.fkr-card-img{display:block;border-radius:8px;width:300px;height:500px;object-fit:contain}
.fkr-card-close{position:absolute;top:-14px;right:-14px;width:34px;height:34px;border-radius:50%;
  border:none;background:#fff;color:var(--ink);font-size:22px;cursor:pointer;box-shadow:var(--shadow)}

/* ===== Footer ===== */
.fkr-footer{background:#0B1B34;color:#c7d3e6;margin-top:40px}
.fkr-footer-inner{max-width:1200px;margin:0 auto;padding:40px 16px 24px;display:grid;
  grid-template-columns:1.6fr 1fr 1fr 1fr;gap:24px}
.fkr-footer-logo{font-size:20px;font-weight:800;color:#fff;margin-bottom:10px}
.fkr-footer-desc{font-size:14px;color:#9fb0c7;max-width:320px}
.fkr-footer h3{color:#fff;font-size:15px;margin:0 0 12px}
.fkr-footer a{display:block;color:#c7d3e6;font-size:14px;padding:4px 0}
.fkr-footer a:hover{color:var(--signal);text-decoration:none}
.fkr-footer-bottom{border-top:1px solid #1c2c47;padding:14px 16px;text-align:center;font-size:13px;color:#7a8aa3}

/* ===== Homepage ===== */
.fkr-hero{background:linear-gradient(135deg,#0B1B34,#10307a);color:#fff;border-radius:0 0 28px 28px;padding:54px 16px 46px}
.fkr-hero-inner{max-width:1200px;margin:0 auto}
.fkr-hero h1{color:#fff;font-size:38px;margin:0 0 14px}
.fkr-hero p{color:#c7d3e6;font-size:17px;max-width:680px}
.fkr-hero-tags{margin-top:18px;display:flex;flex-wrap:wrap;gap:10px}
.fkr-hero-tags span{background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.2);border-radius:999px;padding:5px 14px;font-size:13.5px}
.fkr-section{max-width:1200px;margin:40px auto;padding:0 16px}
.fkr-section h2{font-size:26px;margin:0 0 6px}
.fkr-section .fkr-section-sub{color:var(--ink-soft);margin:0 0 22px}
.fkr-colorcode{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:12px;margin-top:10px}
.fkr-colorcode .cc{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:14px;box-shadow:var(--shadow)}
.fkr-colorcode .cc .dot{width:26px;height:26px;border-radius:50%;margin-bottom:8px}
.fkr-colorcode .cc b{display:block;font-size:14px}
.fkr-colorcode .cc small{color:var(--ink-soft);font-size:12.5px}
.fkr-page-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:24px 28px;box-shadow:var(--shadow)}
.fkr-page-card h2{padding-left:0}
.fkr-archive-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:16px}
.fkr-archive-col h3{margin:0 0 10px;font-size:17px}
.fkr-archive-col ul{list-style:none;padding:0;margin:0}
.fkr-archive-col li{margin:6px 0}
.fkr-archive-col a{font-weight:600}

/* ===== Responsive ===== */
@media (max-width:1024px){
  .fkr-nav{display:none;position:absolute;top:var(--header-h);left:0;right:0;background:#fff;
    flex-direction:column;align-items:stretch;padding:10px 16px;border-bottom:1px solid var(--line);box-shadow:var(--shadow)}
  .fkr-nav.is-open{display:flex}
  .fkr-nav-cat{position:static}
  .fkr-nav-sub{position:static;box-shadow:none;border:none;padding:0 0 0 12px;display:block}
  .fkr-nav-toggle{display:flex}
  .fkr-detail-layout{grid-template-columns:1fr}
  .fkr-toc-aside{position:static;max-height:none}
  .fkr-list-layout{grid-template-columns:1fr}
  .fkr-cat-side{position:static}
  .fkr-pagewrap--page{padding:24px 18px 48px}
}
@media (max-width:768px){
  h1{font-size:25px}
  .fkr-hero h1{font-size:28px}
  .fkr-footer-inner{grid-template-columns:1fr 1fr}
}