:root{
  --ink:#0f1f1a;
  --ink-2:#16281f;
  --paper:#f6f4ee;
  --paper-2:#efeee6;
  --line:#d7d3c6;
  --line-strong:#b9b3a2;
  --green:#1f4d3d;
  --green-soft:#5c8577;
  --amber:#b4762a;
  --amber-soft:#e6cba4;
  --text:#20261f;
  --muted:#5d635a;
  --rail:236px;
  --radius:3px;
  --font-title:"Songti SC","Noto Serif SC",Georgia,"Source Han Serif SC",serif;
  --font-body:-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  --font-num:"SF Mono",ui-monospace,"Menlo","Consolas",monospace;
}

*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0;
  background:var(--paper);
  color:var(--text);
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.75;
  letter-spacing:.01em;
}
img{max-width:100%;height:auto;display:block}
a{color:var(--green);text-decoration:none}
a:hover{text-decoration:underline}
h1,h2,h3,h4{font-family:var(--font-title);font-weight:700;line-height:1.32;margin:0 0 .6em;color:var(--ink)}
p{margin:0 0 1.05em}
ul,ol{margin:0 0 1.05em;padding-left:1.25em}
li{margin-bottom:.4em}
hr{border:0;border-top:1px solid var(--line);margin:2em 0}
:focus-visible{outline:2px solid var(--amber);outline-offset:2px}

.topbar{background:var(--ink);color:#e9e6db;border-bottom:3px solid var(--amber)}
.topbar-in{max-width:1240px;margin:0 auto;padding:0 20px;display:flex;align-items:center;gap:18px;min-height:64px}
.brand{display:flex;align-items:center;gap:10px;color:#f3f0e5;text-decoration:none;flex:0 0 auto}
.brand:hover{text-decoration:none}
.brand img{width:34px;height:34px;border-radius:4px;background:#0a1613}
.brand-txt{display:flex;flex-direction:column;line-height:1.15}
.brand-name{font-family:var(--font-title);font-size:1.08rem;letter-spacing:.06em}
.brand-sub{font-size:.66rem;color:#9fb0a6;letter-spacing:.16em;text-transform:uppercase}

.topnav{margin-left:auto;display:flex;align-items:center;gap:2px;flex-wrap:wrap}
.topnav a{color:#c9d4cc;font-size:.9rem;padding:8px 11px;border-radius:2px;border-bottom:2px solid transparent}
.topnav a:hover{color:#fff;background:rgba(255,255,255,.07);text-decoration:none}
.topnav a.is-active{color:#fff;border-bottom-color:var(--amber)}

.menu-btn{display:none;margin-left:auto;background:transparent;color:#e9e6db;border:1px solid #3a5147;border-radius:2px;padding:8px 12px;font-size:.86rem;font-family:var(--font-body);cursor:pointer}

.shell{max-width:1240px;margin:0 auto;padding:0 20px;display:grid;grid-template-columns:var(--rail) minmax(0,1fr);gap:38px;align-items:start}
.rail{position:sticky;top:18px;padding:22px 0 40px;border-right:1px solid var(--line);padding-right:20px;font-size:.9rem}
.rail-h{font-size:.68rem;letter-spacing:.2em;text-transform:uppercase;color:var(--green-soft);margin:0 0 12px;font-family:var(--font-body)}
.rail-tree{list-style:none;margin:0 0 26px;padding:0}
.rail-tree li{margin:0}
.rail-tree a{display:block;padding:7px 0 7px 14px;color:#3f4a42;border-left:2px solid transparent;font-size:.92rem}
.rail-tree a::before{content:"— ";color:var(--line-strong)}
.rail-tree a:hover{color:var(--green);border-left-color:var(--amber-soft);text-decoration:none}
.rail-tree a.is-active{color:var(--ink);font-weight:600;border-left-color:var(--amber)}

.rail-note{border:1px solid var(--line);background:var(--paper-2);padding:14px 15px;margin-bottom:22px;border-radius:var(--radius)}
.rail-note h4{font-size:.82rem;margin:0 0 6px;letter-spacing:.04em}
.rail-note p{font-size:.8rem;color:var(--muted);margin:0;line-height:1.6}

.rail-mini{list-style:none;margin:0;padding:0;font-size:.85rem}
.rail-mini li{padding:6px 0;border-bottom:1px dotted var(--line)}
.rail-mini a{color:#3f4a42}
.rail-mini .num{font-family:var(--font-num);color:var(--amber);font-size:.78rem;margin-right:6px}

main{min-width:0;padding:26px 0 56px}

.crumb,.breadcrumb{font-size:.82rem;color:var(--muted);margin-bottom:20px}
.crumb a,.breadcrumb a{color:var(--green-soft)}
.crumb span,.breadcrumb span{margin:0 7px;color:var(--line-strong)}

.eyebrow{display:inline-block;font-size:.7rem;letter-spacing:.2em;text-transform:uppercase;color:var(--amber);margin-bottom:12px;font-weight:600}
.lede{font-size:1.02rem;color:#3b443c;max-width:64ch}
.rule{height:1px;background:var(--line);margin:26px 0}

.doc-head{display:grid;grid-template-columns:minmax(0,1.35fr) minmax(0,.85fr);gap:30px;align-items:end;border-bottom:2px solid var(--ink);padding-bottom:22px;margin-bottom:26px}
.doc-head h1{font-size:clamp(1.72rem,3.6vw,2.5rem);margin:0 0 12px;letter-spacing:.01em}
.doc-head .lede{margin-bottom:0}
.doc-head figure{margin:0}
.doc-head figure img{border:1px solid var(--line);border-radius:var(--radius)}
.doc-head figcaption{font-size:.74rem;color:var(--muted);margin-top:7px;letter-spacing:.02em}

.factrow{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));border-top:1px solid var(--line);border-left:1px solid var(--line);margin-bottom:34px}
.factrow div{border-right:1px solid var(--line);border-bottom:1px solid var(--line);padding:14px 15px;background:#fbfaf5}
.factrow .k{font-family:var(--font-num);font-size:1.3rem;color:var(--green);display:block;line-height:1.2}
.factrow .v{font-size:.76rem;color:var(--muted);letter-spacing:.06em}

section{margin-bottom:42px}
.sec-head{display:flex;align-items:baseline;gap:14px;border-bottom:1px solid var(--line-strong);padding-bottom:9px;margin-bottom:20px}
.sec-head h2{font-size:1.24rem;margin:0}
.sec-head .tag{font-size:.72rem;color:var(--green-soft);letter-spacing:.14em;text-transform:uppercase}
.sec-head .more{margin-left:auto;font-size:.82rem;color:var(--amber)}

.ledger{width:100%;border-collapse:collapse;font-size:.94rem}
.ledger caption{text-align:left;font-size:.8rem;color:var(--muted);padding-bottom:8px}
.ledger th,.ledger td{text-align:left;padding:11px 10px;border-bottom:1px solid var(--line);vertical-align:top}
.ledger th{font-size:.72rem;letter-spacing:.14em;text-transform:uppercase;color:var(--green-soft);font-weight:600;border-bottom:1px solid var(--line-strong)}
.ledger td.idx{font-family:var(--font-num);color:var(--amber);width:46px;font-size:.82rem}
.ledger td .cat{font-size:.74rem;color:var(--muted);display:block;margin-top:3px}
.ledger tr:hover td{background:#fbfaf4}

.grid-cats{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:1px;background:var(--line);border:1px solid var(--line)}
.grid-cats a{display:block;background:#fbfaf5;padding:18px 18px 20px;color:var(--text)}
.grid-cats a:hover{background:#f2f0e6;text-decoration:none}
.grid-cats h3{font-size:1rem;margin:0 0 6px;color:var(--ink)}
.grid-cats p{font-size:.83rem;color:var(--muted);margin:0}
.grid-cats .n{font-family:var(--font-num);font-size:.74rem;color:var(--amber);display:block;margin-bottom:8px}

.band{display:grid;grid-template-columns:minmax(0,.9fr) minmax(0,1.1fr);gap:26px;align-items:center}
.band img{border:1px solid var(--line);border-radius:var(--radius)}
.band figcaption{font-size:.74rem;color:var(--muted);margin-top:7px}

.duo{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:26px}
.duo h3{font-size:.98rem;margin-bottom:10px;padding-bottom:6px;border-bottom:1px dotted var(--line-strong)}
.duo ul{list-style:none;margin:0;padding:0;font-size:.92rem}
.duo li{padding:7px 0;border-bottom:1px solid #e6e3d8;display:flex;gap:10px}
.duo li .d{font-family:var(--font-num);font-size:.74rem;color:var(--muted);flex:0 0 76px}

.quote{border-left:3px solid var(--amber);background:#fbfaf4;padding:20px 24px;margin:0;border-radius:0 var(--radius) var(--radius) 0}
.quote p{font-family:var(--font-title);font-size:1.05rem;color:var(--ink-2);margin:0 0 8px}
.quote cite{font-size:.78rem;color:var(--muted);font-style:normal}

.steps{list-style:none;margin:0;padding:0;counter-reset:s}
.steps li{counter-increment:s;position:relative;padding:0 0 18px 42px;border-left:1px solid var(--line);margin-left:12px}
.steps li:last-child{border-left-color:transparent;padding-bottom:0}
.steps li::before{content:counter(s,decimal-leading-zero);position:absolute;left:-13px;top:0;width:26px;height:26px;background:var(--green);color:#f2efe4;border-radius:50%;font-family:var(--font-num);font-size:.72rem;display:flex;align-items:center;justify-content:center}
.steps h3{font-size:.96rem;margin:0 0 5px}
.steps p{font-size:.9rem;color:var(--muted);margin:0}

.cat-head{border-bottom:2px solid var(--ink);padding-bottom:18px;margin-bottom:24px}
.cat-head h1{font-size:clamp(1.5rem,3vw,2.05rem);margin-bottom:10px}
.cat-head p{color:#414b43;margin:0;max-width:66ch}

.cat-lead-img{margin:0 0 28px}
.cat-lead-img img{border:1px solid var(--line)}
.cat-lead-img figcaption{font-size:.74rem;color:var(--muted);margin-top:7px}

.art-head{margin-bottom:22px}
.art-head h1{font-size:clamp(1.5rem,3.2vw,2.12rem);margin-bottom:14px;letter-spacing:.005em}
.art-meta{display:flex;flex-wrap:wrap;gap:6px 18px;font-size:.82rem;color:var(--muted);padding:12px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.art-meta b{color:var(--ink-2);font-weight:600}
.art-fig{margin:24px 0 26px}
.art-fig img{border:1px solid var(--line);border-radius:var(--radius)}
.art-fig figcaption{font-size:.76rem;color:var(--muted);margin-top:8px;padding-left:2px}

.prose{max-width:70ch}
.prose h2{font-size:1.22rem;margin:1.9em 0 .7em;padding-bottom:.35em;border-bottom:1px solid var(--line)}
.prose h2:first-child{margin-top:0}
.prose h3{font-size:1.02rem;margin:1.4em 0 .5em}
.prose strong{color:var(--ink)}
.prose blockquote{margin:1.4em 0;padding:14px 20px;background:#fbfaf4;border-left:3px solid var(--green-soft);color:#414b43;font-size:.95rem}
.prose blockquote p:last-child{margin:0}
.prose table{width:100%;border-collapse:collapse;font-size:.9rem;margin:1.3em 0}
.prose th,.prose td{border:1px solid var(--line);padding:9px 11px;text-align:left}
.prose th{background:var(--paper-2);font-size:.8rem;letter-spacing:.06em}
.prose code{font-family:var(--font-num);background:var(--paper-2);padding:1px 5px;font-size:.88em;border-radius:2px}

.tail{margin-top:40px;padding-top:22px;border-top:2px solid var(--ink);display:grid;grid-template-columns:minmax(0,1fr) minmax(0,300px);gap:30px}
.tail h2{font-size:1rem;margin-bottom:12px}
.tail-list{list-style:none;margin:0;padding:0;font-size:.92rem}
.tail-list li{padding:9px 0;border-bottom:1px dotted var(--line)}
.tail-list .cat{font-size:.74rem;color:var(--muted);display:block}

.back-cat{font-size:.84rem;margin-top:18px}
.back-cat a{color:var(--amber)}

.site-foot{background:var(--ink);color:#b8c4bc;margin-top:0;border-top:3px solid var(--amber)}
.foot-in{max-width:1240px;margin:0 auto;padding:38px 20px 26px;display:grid;grid-template-columns:1.15fr 1fr 1fr;gap:34px}
.foot-brand{display:flex;gap:12px;align-items:flex-start}
.foot-brand img{width:38px;height:38px;border-radius:4px}
.foot-brand strong{display:block;color:#f0ede1;font-family:var(--font-title);letter-spacing:.06em;margin-bottom:6px}
.foot-brand p{font-size:.82rem;line-height:1.7;margin:0;color:#9aaba1}
.foot-col h4{color:#e7e3d6;font-size:.8rem;letter-spacing:.14em;text-transform:uppercase;margin:0 0 12px;font-family:var(--font-body)}
.foot-col ul{list-style:none;margin:0;padding:0;font-size:.86rem}
.foot-col li{margin-bottom:8px}
.foot-col a{color:#b8c4bc}
.foot-col a:hover{color:#fff}
.foot-meta{border-top:1px solid #2b4038;padding:16px 20px 22px;max-width:1240px;margin:0 auto;font-size:.8rem;color:#8fa198;line-height:1.9}
.foot-meta span{display:inline-block;margin-right:18px}
.foot-meta a{color:#8fa198}

.rail-toggle{display:none}

@media (max-width:960px){
  .shell{grid-template-columns:minmax(0,1fr);gap:0}
  .rail{position:static;border-right:0;padding:0;margin-bottom:8px;border-bottom:1px solid var(--line)}
  .rail-toggle{display:block;width:100%;text-align:left;background:transparent;border:0;padding:10px 0;font-size:.86rem;color:var(--green);cursor:pointer;font-family:var(--font-body)}
  .rail-tree{display:none;margin-bottom:0}
  .rail.is-open .rail-tree{display:block;padding-bottom:12px}
  .rail-note,.rail-mini-wrap{display:none}
  .doc-head{grid-template-columns:minmax(0,1fr)}
  .factrow{grid-template-columns:repeat(2,minmax(0,1fr))}
  .grid-cats{grid-template-columns:repeat(2,minmax(0,1fr))}
  .band,.duo,.tail{grid-template-columns:minmax(0,1fr)}
  .foot-in{grid-template-columns:minmax(0,1fr);gap:24px;padding:30px 20px 20px}
}
@media (max-width:768px){
  body{font-size:15.5px}
  .topnav{display:none;flex-direction:column;align-items:stretch;width:100%;padding:6px 0 12px}
  .topbar-in{flex-wrap:wrap;padding:10px 16px 12px}
  .topnav.is-open{display:flex}
  .topnav a{padding:11px 12px;border-bottom:0;border-left:2px solid transparent}
  .topnav a.is-active{border-left-color:var(--amber)}
  .menu-btn{display:block}
  .shell,.foot-in,.foot-meta{padding-left:16px;padding-right:16px}
  .grid-cats{grid-template-columns:minmax(0,1fr)}
  .ledger th:nth-child(3),.ledger td:nth-child(3){display:none}
  .tail{padding-top:18px}
}