:root{
  --bg:#0a0a0f;
  --bg2:#12121a;
  --card:#16161f;
  --card2:#1b1b26;
  --red:#e11d2e;
  --red2:#ff3b4e;
  --gold:#f5b301;
  --ink:#e8e6f0;
  --muted:#8b88a0;
  --rule:#262633;
  --accent-glow:rgba(225,29,46,.35);
  --maxw:1240px;
  --sidebar-w:280px;
  --radius:14px;
  --mono:"JetBrains Mono","SFMono-Regular","Consolas","Courier New",monospace;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:"Segoe UI","PingFang SC","Microsoft YaHei",-apple-system,sans-serif;
  background:var(--bg);
  color:var(--ink);
  line-height:1.75;
}
body::before{
  content:"";position:fixed;inset:0;z-index:-2;
  background:
    radial-gradient(900px 500px at 85% -10%, rgba(225,29,46,.16), transparent 60%),
    radial-gradient(700px 500px at 0% 110%, rgba(245,181,3,.07), transparent 55%),
    var(--bg);
}
a{color:inherit;text-decoration:none}
code{font-family:var(--mono);font-size:.9em;background:rgba(225,29,46,.12);color:var(--red2);padding:2px 6px;border-radius:5px}
pre{background:#0d0d14;border:1px solid var(--rule);border-radius:var(--radius);padding:18px 20px;overflow-x:auto;margin:16px 0;position:relative}
pre code{background:none;color:#d7d5e6;padding:0;display:block;font-size:.88rem;line-height:1.7}
pre.dark-block{background:linear-gradient(135deg,rgba(225,29,46,.08),rgba(18,18,26,0));border-color:rgba(225,29,46,.25)}

/* ---- nav ---- */
nav{position:fixed;top:0;left:0;right:0;z-index:100;background:rgba(10,10,15,.8);backdrop-filter:blur(14px);border-bottom:1px solid var(--rule)}
.nav-inner{max-width:var(--maxw);margin:0 auto;padding:0 24px;height:62px;display:flex;align-items:center;justify-content:space-between}
.logo{display:flex;align-items:center;gap:10px;font-weight:800}
.logo .mark{width:30px;height:30px;border-radius:8px;background:linear-gradient(135deg,var(--red),var(--red2));display:grid;place-items:center;font-size:15px;color:#fff;box-shadow:0 0 18px var(--accent-glow)}
.logo .mark span{transform:rotate(45deg)}
.logo b{color:#fff}
.nav-links{display:flex;gap:22px;align-items:center;font-size:14px;color:var(--muted)}
.nav-links a:hover{color:var(--red2)}
.nav-links .back{color:var(--red2);font-weight:700}
.nav-links .back:hover{color:var(--gold)}

/* ---- layout ---- */
.layout{display:flex;max-width:var(--maxw);margin:0 auto;padding-top:62px;min-height:calc(100vh - 62px)}
.sidebar{width:var(--sidebar-w);flex-shrink:0;position:sticky;top:62px;align-self:flex-start;height:calc(100vh - 62px);overflow-y:auto;border-right:1px solid var(--rule);padding:22px 14px 50px;scrollbar-width:thin;scrollbar-color:var(--rule) transparent}
.sidebar::-webkit-scrollbar{width:6px}
.sidebar::-webkit-scrollbar-thumb{background:var(--rule);border-radius:3px}
.sb-group{margin-bottom:26px}
.sb-title{font-size:12px;font-weight:800;letter-spacing:1.5px;color:var(--muted);text-transform:uppercase;padding:0 12px;margin-bottom:10px}
.sb-item{display:flex;align-items:center;gap:10px;padding:9px 12px;border-radius:9px;font-size:14px;color:var(--muted);transition:.2s;margin-bottom:2px}
.sb-item .ic{width:18px;text-align:center;font-size:14px}
.sb-item:hover{background:rgba(255,255,255,.04);color:var(--ink)}
.sb-item.active{background:linear-gradient(135deg,rgba(225,29,46,.16),rgba(225,29,46,.05));color:var(--red2);font-weight:700}
.sb-sub{padding-left:22px}
.sb-sub .sb-item{font-size:13px;padding:7px 12px}

.content{flex:1;min-width:0;padding:40px 56px 90px}
.content main{max-width:860px}
/* ---- page head ---- */
.pagehead{margin-bottom:40px;padding-bottom:28px;border-bottom:1px solid var(--rule)}
.breadcrumb{font-size:13px;color:var(--muted);margin-bottom:14px;display:flex;gap:8px;align-items:center}
.breadcrumb a:hover{color:var(--red2)}
.breadcrumb .sep{opacity:.5}
.pagehead h1{font-size:clamp(28px,4vw,40px);font-weight:900;letter-spacing:-.5px;line-height:1.2;margin-bottom:12px}
.pagehead h1 .grad{background:linear-gradient(120deg,#fff 20%,var(--red2) 70%,var(--gold) 100%);-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent}
.pagehead .lead{color:var(--muted);font-size:16px;max-width:720px}
.pagehead .meta{display:flex;flex-wrap:wrap;gap:10px;margin-top:18px}
.tag{font-size:12px;font-weight:700;color:var(--gold);border:1px solid rgba(245,181,3,.3);background:rgba(245,181,3,.06);padding:3px 12px;border-radius:50px}
.tag.blue{color:var(--red2);border-color:rgba(225,29,46,.35);background:rgba(225,29,46,.08)}

/* ---- typography ---- */
h2{font-size:26px;font-weight:800;margin:46px 0 16px;padding-bottom:10px;border-bottom:1px solid var(--rule)}
h2 .num{color:var(--red2);margin-right:10px;font-family:var(--mono)}
h3{font-size:20px;font-weight:800;margin:34px 0 12px;color:#fff}
h3::before{content:"";display:inline-block;width:4px;height:18px;background:linear-gradient(var(--red),var(--red2));border-radius:2px;margin-right:10px;vertical-align:-2px}
h4{font-size:17px;font-weight:700;margin:26px 0 10px;color:var(--red2)}
p{margin:14px 0;color:var(--ink)}
p.muted{color:var(--muted)}
ul,ol{margin:14px 0;padding-left:26px}
li{margin:8px 0}
li::marker{color:var(--red2)}
strong{color:#fff;font-weight:700}
em{color:var(--gold);font-style:normal}

/* ---- components ---- */
.callout{border-left:4px solid var(--red2);background:rgba(225,29,46,.07);padding:16px 20px;border-radius:0 var(--radius) var(--radius) 0;margin:20px 0}
.callout.gold{border-left-color:var(--gold);background:rgba(245,181,3,.06)}
.callout.blue{border-left-color:#4db2ff;background:rgba(77,178,255,.06)}
.callout .co-title{font-weight:800;margin-bottom:6px;display:flex;align-items:center;gap:8px}
.callout.red .co-title{color:var(--red2)}
.callout.gold .co-title{color:var(--gold)}
.callout.blue .co-title{color:#4db2ff}
.callout p{margin:6px 0;font-size:14.5px}
.card{background:var(--card);border:1px solid var(--rule);border-radius:var(--radius);padding:24px;margin:18px 0}
.card h4{margin-top:0}
.grid2{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:16px;margin:18px 0}
.grid2 .card{margin:0}
table{width:100%;border-collapse:collapse;margin:18px 0;font-size:14px;background:var(--card);border-radius:var(--radius);overflow:hidden}
th,td{padding:12px 16px;text-align:left;border-bottom:1px solid var(--rule);vertical-align:top}
th{background:rgba(225,29,46,.1);color:var(--red2);font-weight:800;font-size:13px;letter-spacing:.5px}
tr:last-child td{border-bottom:none}
tr:hover td{background:rgba(255,255,255,.02)}
.note-list li{display:flex;gap:12px;align-items:flex-start}
.note-list .marker{color:var(--red2);font-weight:900;flex-shrink:0}
.steps{counter-reset:step;list-style:none;padding-left:0;margin:18px 0}
.steps>li{counter-increment:step;position:relative;padding:0 0 22px 52px}
.steps>li::before{content:counter(step);position:absolute;left:0;top:0;width:34px;height:34px;border-radius:50%;background:linear-gradient(135deg,var(--red),var(--red2));color:#fff;font-weight:800;display:grid;place-items:center;font-size:15px;box-shadow:0 4px 12px var(--accent-glow)}
.steps>li::after{content:"";position:absolute;left:17px;top:40px;bottom:0;width:2px;background:var(--rule)}
.steps>li:last-child::after{display:none}
.steps strong{display:block;margin-bottom:4px}
.steps .step-txt{color:var(--muted);font-size:14.5px}
.steps .step-txt code{font-size:.85em}
.flow{display:flex;flex-direction:column;gap:0;background:#0d0d14;border:1px solid var(--rule);border-radius:var(--radius);padding:20px;margin:18px 0;font-family:var(--mono);font-size:13px}
.flow .node{display:flex;align-items:center;gap:10px;padding:8px 12px;background:var(--card);border:1px solid var(--rule);border-radius:8px}
.flow .node.red{border-color:rgba(225,29,46,.4);background:rgba(225,29,46,.08)}
.flow .node.gold{border-color:rgba(245,181,3,.4);background:rgba(245,181,3,.06)}
.flow .node .lbl{font-weight:700}
.flow .node .desc{color:var(--muted);font-size:12px}
.flow .arrow{text-align:center;color:var(--red2);padding:2px 0;font-size:14px}
.flow .branch{padding-left:24px;border-left:2px dashed var(--rule);margin-left:8px}

/* ---- kbd ---- */
kbd{font-family:var(--mono);background:var(--card2);border:1px solid var(--rule);border-bottom-width:2px;border-radius:6px;padding:2px 8px;font-size:12px;color:var(--ink)}

/* ---- expandable ---- */
details{background:var(--card);border:1px solid var(--rule);border-radius:var(--radius);margin:14px 0;overflow:hidden}
details>summary{cursor:pointer;padding:16px 20px;font-weight:700;color:var(--ink);list-style:none;position:relative;user-select:none;transition:.2s}
details>summary:hover{background:rgba(225,29,46,.06)}
details>summary::after{content:"▾";position:absolute;right:20px;color:var(--red2);transition:.2s}
details[open]>summary::after{transform:rotate(180deg)}
details .det-body{padding:0 20px 18px;color:var(--muted);font-size:14.5px}

/* ---- toc ---- */
.toc{background:var(--card);border:1px solid var(--rule);border-radius:var(--radius);padding:20px 24px;margin:24px 0}
.toc .toc-title{font-size:13px;font-weight:800;letter-spacing:1px;color:var(--muted);text-transform:uppercase;margin-bottom:12px}
.toc a{display:block;padding:6px 0;color:var(--muted);font-size:14px;border-left:2px solid transparent;padding-left:12px;transition:.2s}
.toc a:hover{color:var(--red2);border-left-color:var(--red2)}
.toc a.lv2{padding-left:28px;font-size:13px}

/* ---- next/prev ---- */
.doc-nav{display:flex;justify-content:space-between;gap:16px;margin-top:56px;padding-top:28px;border-top:1px solid var(--rule)}
.doc-nav a{flex:1;background:var(--card);border:1px solid var(--rule);border-radius:var(--radius);padding:18px 22px;transition:.25s;display:block}
.doc-nav a:hover{border-color:var(--red2);transform:translateY(-2px)}
.doc-nav .dir{font-size:12px;color:var(--muted);letter-spacing:1px;text-transform:uppercase}
.doc-nav .ttl{font-size:16px;font-weight:800;margin-top:4px;color:var(--ink)}
.doc-nav a:hover .ttl{color:var(--red2)}
.doc-nav .next{text-align:right}

/* ---- download btn ---- */
.btn{display:inline-flex;align-items:center;gap:8px;padding:12px 22px;border-radius:10px;font-weight:700;font-size:14px;transition:.3s;margin:6px 6px 6px 0}
.btn-primary{background:linear-gradient(135deg,var(--red),var(--red2));color:#fff;box-shadow:0 6px 18px var(--accent-glow)}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 10px 26px rgba(225,29,46,.5)}
.btn-ghost{border:1px solid var(--rule);color:var(--ink);background:rgba(255,255,255,.02)}
.btn-ghost:hover{border-color:var(--red2);color:var(--red2)}

/* ---- footer ---- */
footer{background:var(--bg);border-top:1px solid var(--rule);padding:30px 0;text-align:center;color:var(--muted);font-size:13.5px}
footer b{color:var(--ink)}
footer .links{display:flex;gap:22px;justify-content:center;margin:10px 0 6px;flex-wrap:wrap}
footer .links a{color:var(--muted);font-size:13.5px}
footer .links a:hover{color:var(--red2)}
footer .disc{margin-top:8px;opacity:.65;font-size:12.5px}

/* ---- responsive ---- */
.menu-toggle{display:none;align-items:center;justify-content:center;width:40px;height:40px;border:1px solid var(--rule);border-radius:8px;background:rgba(255,255,255,.03);cursor:pointer;color:var(--ink);font-size:18px}
.sidebar-backdrop{display:none;position:fixed;inset:0;background:rgba(0,0,0,.5);z-index:80}
@media(max-width:900px){
  .menu-toggle{display:flex!important}
  .nav-links .back{display:none}
  .sidebar{position:fixed;left:-100%;transition:left .3s;box-shadow:0 20px 50px rgba(0,0,0,.6);background:var(--bg);z-index:90}
  .sidebar.open{left:0}
  .sidebar-backdrop.show{display:block}
  .content{padding:28px 22px 80px}
}