@import url('https://fonts.googleapis.com/css2?family=Fira+Code:wght@400;500;600;700&family=Fira+Sans:wght@300;400;500;600;700&display=swap');

:root{
  --ink:#172623;
  --ink-soft:#3a4d46;
  --celadon:#5cc6b0;
  --celadon-deep:#2c8171;
  --sand:#d4c4a8;
  --sand-soft:#e8dbc6;
  --clay:#c67b5c;
  --olive:#6b7b3c;
  --paper:#f7f0e6;
  --card:#fdf9f2;
  --radius:4px;
  --shadow-soft:0 8px 22px rgba(23,38,35,.09);
  --shadow-lift:0 16px 38px rgba(23,38,35,.17);
  --mono:"Fira Code",ui-monospace,SFMono-Regular,monospace;
  --sans:"Fira Sans",system-ui,-apple-system,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
}

*,*::before,*::after{box-sizing:border-box}

html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}

body{
  margin:0;
  min-height:100vh;
  font-family:var(--sans);
  font-size:17px;
  line-height:1.72;
  color:var(--ink);
  background:
    radial-gradient(1100px 560px at 12% -6%,#fcf6ed 0%,rgba(252,246,237,0) 62%),
    linear-gradient(180deg,#f7f0e6 0%,#efe6d7 58%,#e9dccb 100%);
  background-attachment:fixed;
}

body::after{
  content:"";
  position:fixed;
  inset:0;
  z-index:9;
  pointer-events:none;
  opacity:.07;
  mix-blend-mode:multiply;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)' opacity='0.5'/%3E%3C/svg%3E");
  background-size:140px 140px;
}

img{max-width:100%}
a{color:var(--celadon-deep)}

.sr-only{
  position:absolute;
  width:1px;height:1px;
  overflow:hidden;
  clip:rect(0 0 0 0);
  white-space:nowrap;
}

.skip{
  position:absolute;
  left:14px;
  top:-64px;
  z-index:40;
  padding:12px 18px;
  background:var(--ink);
  color:#f7f0e6;
  text-decoration:none;
  border-radius:var(--radius);
}
.skip:focus{top:12px}

/* 头部 */
.site-head{
  position:relative;
  z-index:20;
  background:linear-gradient(180deg,rgba(247,240,230,.97),rgba(247,240,230,.74));
  border-bottom:1px solid rgba(23,38,35,.12);
}

.brand-row{
  display:flex;
  justify-content:center;
  padding:14px 20px 4px;
}

.brand{
  display:inline-flex;
  align-items:center;
  gap:10px;
  padding:8px 12px;
  min-height:44px;
  font-family:var(--mono);
  font-size:19px;
  font-weight:600;
  letter-spacing:.16em;
  color:var(--ink);
  text-decoration:none;
  border-radius:var(--radius);
  transition:color .2s ease-out,background .2s ease-out;
}
.brand:hover{color:var(--celadon-deep);background:rgba(92,198,176,.14)}
.brand-mark{width:28px;height:28px;object-fit:contain;border-radius:3px}

.nav-row{
  display:flex;
  align-items:center;
  gap:14px;
  flex-wrap:wrap;
  max-width:1180px;
  margin:0 auto;
  padding:0 20px 12px;
}

.menu-btn{
  display:none;
  align-items:center;
  min-height:42px;
  padding:0 16px;
  font:inherit;
  font-size:16px;
  font-family:var(--sans);
  color:var(--ink);
  background:var(--card);
  border:1px solid var(--sand);
  border-radius:var(--radius);
  cursor:pointer;
}
.menu-btn:hover{border-color:var(--celadon);color:var(--celadon-deep)}

.site-nav{flex:1 1 auto}
.site-nav ul{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:4px;
  margin:0;
  padding:0;
  list-style:none;
}
.nav-item{position:relative}

.site-nav a,
.group-btn{
  display:inline-flex;
  align-items:center;
  min-height:42px;
  padding:0 13px;
  font-family:var(--sans);
  font-size:16px;
  color:var(--ink);
  text-decoration:none;
  background:none;
  border:1px solid transparent;
  border-radius:var(--radius);
  cursor:pointer;
  transition:background .2s ease-out,border-color .2s ease-out,color .2s ease-out;
}
.site-nav a:hover,
.group-btn:hover,
.nav-group:hover .group-btn{
  background:var(--card);
  border-color:var(--sand);
  color:var(--celadon-deep);
}

.group-btn::after{
  content:"";
  width:6px;
  height:6px;
  margin-left:8px;
  border-right:1.5px solid currentColor;
  border-bottom:1.5px solid currentColor;
  transform:rotate(45deg) translateY(-2px);
}

.group-panel{
  position:absolute;
  top:calc(100% + 6px);
  left:0;
  z-index:26;
  min-width:200px;
  display:none;
  flex-direction:column;
  gap:2px;
  padding:8px;
  background:var(--card);
  border:1px solid var(--sand);
  border-radius:var(--radius);
  box-shadow:var(--shadow-lift);
}
.nav-group.open .group-panel{display:flex}
.group-panel a{min-height:42px;width:100%}

.search{
  display:flex;
  align-items:center;
  gap:8px;
  margin-left:auto;
}
.search input{
  width:160px;
  min-height:42px;
  padding:0 12px;
  font:inherit;
  font-size:16px;
  color:var(--ink);
  background:#fff;
  border:1px solid var(--sand);
  border-radius:var(--radius);
}
.search input:focus{outline:2px solid var(--celadon);outline-offset:1px}
.search button{
  min-height:42px;
  padding:0 16px;
  font:inherit;
  font-size:16px;
  color:#f7f0e6;
  background:var(--ink);
  border:1px solid var(--ink);
  border-radius:var(--radius);
  cursor:pointer;
  transition:background .2s ease-out,border-color .2s ease-out;
}
.search button:hover{background:var(--celadon-deep);border-color:var(--celadon-deep)}

/* 吸顶锚点条 */
.anchor-bar{
  position:sticky;
  top:0;
  z-index:18;
  display:flex;
  gap:6px;
  overflow-x:auto;
  padding:8px 16px;
  background:rgba(239,230,215,.94);
  backdrop-filter:blur(8px);
  border-bottom:1px solid rgba(23,38,35,.15);
  scrollbar-width:thin;
}
.anchor-bar a{
  display:inline-flex;
  align-items:center;
  gap:8px;
  min-height:42px;
  padding:0 14px;
  font-size:16px;
  white-space:nowrap;
  color:var(--ink-soft);
  text-decoration:none;
  border:1px solid transparent;
  border-radius:var(--radius);
  transition:background .2s ease-out,border-color .2s ease-out,color .2s ease-out;
}
.anchor-bar a:hover{background:var(--card);border-color:var(--sand);color:var(--ink)}
.bar-num{font-family:var(--mono);font-size:14px;letter-spacing:.08em;color:var(--clay)}

/* Hero */
.hero{
  position:relative;
  isolation:isolate;
  display:grid;
  place-items:center;
  min-height:45vh;
  padding:34px 20px;
  overflow:hidden;
  background:
    repeating-linear-gradient(0deg,rgba(23,38,35,.07) 0 1px,transparent 1px 28px),
    repeating-linear-gradient(90deg,rgba(23,38,35,.07) 0 1px,transparent 1px 28px),
    radial-gradient(80% 120% at 50% 0%,#3f6157 0%,#25403a 45%,#152421 100%);
}
.hero-img{
  position:absolute;
  inset:0;
  z-index:-2;
  width:100%;
  height:100%;
  object-fit:cover;
  opacity:.82;
}
.hero::after{
  content:"";
  position:absolute;
  inset:0;
  z-index:-1;
  background:linear-gradient(180deg,rgba(23,38,35,.28),rgba(23,38,35,.74));
}

.hero-copy{position:relative;max-width:920px;text-align:center}
.hero-kicker{
  margin:0 0 12px;
  font-family:var(--mono);
  font-size:15px;
  letter-spacing:.34em;
  color:#cdf0e8;
}
.hero h1{
  margin:0;
  font-size:clamp(26px,4.6vw,44px);
  font-weight:600;
  line-height:1.34;
  letter-spacing:.01em;
  color:#fbf6ec;
  text-shadow:0 2px 20px rgba(0,0,0,.38);
}

/* 主体 */
main{display:block}

.shell{
  display:grid;
  grid-template-columns:254px minmax(0,1fr);
  gap:30px;
  align-items:start;
  max-width:1180px;
  margin:0 auto;
  padding:36px 20px 64px;
}

.side{
  position:sticky;
  top:66px;
  padding:18px;
  background:var(--card);
  border:1px solid var(--sand);
  border-radius:var(--radius);
  box-shadow:var(--shadow-soft);
}
.side h2{
  margin:0;
  font-family:var(--mono);
  font-size:15px;
  font-weight:600;
  letter-spacing:.24em;
  color:var(--ink);
}
.subtitle{
  margin:.35em 0 1em;
  font-family:var(--mono);
  font-size:15px;
  letter-spacing:.12em;
  color:var(--olive);
}

.toc{
  display:flex;
  flex-direction:column;
  gap:2px;
  margin:0;
  padding:0;
  list-style:none;
}
.toc a{
  display:flex;
  align-items:baseline;
  gap:9px;
  min-height:42px;
  padding:8px 9px;
  font-size:16px;
  line-height:1.4;
  color:var(--ink-soft);
  text-decoration:none;
  border-left:2px solid transparent;
  border-radius:0 var(--radius) var(--radius) 0;
  transition:background .2s ease-out,border-color .2s ease-out,color .2s ease-out;
}
.toc a:hover{background:#fff;border-left-color:var(--celadon);color:var(--ink)}
.t-num{font-family:var(--mono);font-size:14px;color:var(--clay)}

.prose{min-width:0;counter-reset:sec}
.prose > section{
  position:relative;
  counter-increment:sec;
  padding-bottom:34px;
  border-bottom:1px dashed rgba(23,38,35,.2);
  scroll-margin-top:116px;
}
.prose > section + section{margin-top:34px}
.prose > section:last-child{border-bottom:0;padding-bottom:6px}

.js .prose > section{
  opacity:0;
  transform:translateY(16px);
  transition:opacity .55s ease-out,transform .55s ease-out;
}
.js .prose > section.is-in{opacity:1;transform:none}

.prose > section > h2::before{
  content:counter(sec,decimal-leading-zero);
  display:block;
  margin-bottom:8px;
  font-family:var(--mono);
  font-size:14px;
  letter-spacing:.12em;
  color:var(--clay);
}

.prose h2{
  margin:.1em 0 .35em;
  font-size:clamp(21px,2.6vw,27px);
  font-weight:600;
  line-height:1.36;
  color:var(--ink);
}
.prose h3{
  margin:1.5em 0 .4em;
  font-size:19px;
  line-height:1.4;
  color:var(--celadon-deep);
}
.prose p{margin:0 0 1.05em}
.prose ul,.prose ol{margin:0 0 1.1em;padding-left:1.35em}
.prose li{margin:.28em 0}
.prose a{
  color:var(--celadon-deep);
  text-decoration:underline;
  text-underline-offset:3px;
  text-decoration-thickness:1px;
}
.prose a:hover{color:var(--ink);background:rgba(92,198,176,.24)}
.prose strong{color:var(--ink);font-weight:600}

.prose table{
  display:block;
  width:100%;
  overflow-x:auto;
  margin:0 0 1.2em;
  border:1px solid var(--sand);
  border-radius:var(--radius);
  box-shadow:var(--shadow-soft);
  background:var(--card);
  font-size:16px;
  border-collapse:collapse;
}
.prose th,.prose td{padding:11px 13px;text-align:left;border-bottom:1px solid var(--sand-soft)}
.prose th{
  font-family:var(--mono);
  font-size:15px;
  letter-spacing:.06em;
  background:rgba(212,196,168,.42);
}
.prose tr:last-child td{border-bottom:0}

.prose blockquote{
  margin:0 0 1.2em;
  padding:12px 16px;
  background:rgba(92,198,176,.12);
  border-left:3px solid var(--celadon);
  border-radius:0 var(--radius) var(--radius) 0;
}
.prose blockquote p:last-child{margin-bottom:0}

.prose img{
  height:auto;
  border-radius:var(--radius);
  box-shadow:var(--shadow-soft);
}

/* 页脚 */
.site-foot{
  margin-top:44px;
  padding:42px 20px 24px;
  background:linear-gradient(180deg,#172623,#0e1a17);
  color:#e4dbcd;
}
.foot-inner{max-width:1180px;margin:0 auto}

.foot-brand{
  margin:0 0 26px;
  font-family:var(--mono);
  font-size:clamp(34px,8.6vw,80px);
  font-weight:600;
  line-height:1.02;
  letter-spacing:-.02em;
  color:#f4ede1;
  opacity:.94;
}

.foot-grid{
  display:grid;
  grid-template-columns:minmax(0,1.4fr) minmax(0,1fr);
  gap:26px;
  padding-top:24px;
  border-top:1px solid rgba(212,196,168,.26);
}

.foot-nav dl{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:8px 18px;
  margin:0;
}
.foot-nav dt{
  font-family:var(--mono);
  font-size:15px;
  letter-spacing:.2em;
  color:var(--celadon);
  margin-bottom:2px;
}
.foot-nav dd{margin:0}
.foot-nav dd a{
  display:inline-flex;
  align-items:center;
  min-height:42px;
  font-size:16px;
  color:#dcd2c3;
  text-decoration:none;
  transition:color .2s ease-out;
}
.foot-nav dd a:hover{color:var(--celadon)}

address{
  font-style:normal;
  font-family:var(--mono);
  font-size:16px;
  line-height:1.9;
  color:#bdb3a2;
  word-break:break-all;
}

.foot-bar{
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:16px;
  flex-wrap:wrap;
  margin-top:26px;
  padding-top:16px;
  border-top:1px solid rgba(212,196,168,.26);
  font-size:16px;
  color:#b3a998;
}
.foot-links{
  display:flex;
  flex-wrap:wrap;
  gap:14px;
  margin:0;
  padding:0;
  list-style:none;
}
.foot-links a{
  display:inline-flex;
  align-items:center;
  min-height:42px;
  color:#dcd2c3;
  text-decoration:none;
  transition:color .2s ease-out;
}
.foot-links a:hover{color:var(--celadon)}

@media (min-width:901px){
  .nav-group:hover .group-panel{display:flex}
}

@media (max-width:900px){
  .menu-btn{display:inline-flex}

  .site-nav{display:none;flex:1 1 100%;order:3}
  .site-nav.open{display:block}
  .site-nav ul{flex-direction:column;align-items:stretch;gap:2px}
  .site-nav a,.group-btn{width:100%;justify-content:space-between;border-color:var(--sand-soft)}
  .group-panel{
    position:static;
    display:none;
    min-width:0;
    margin:2px 0 6px 10px;
    padding:4px 0 4px 10px;
    background:none;
    border:0;
    border-left:2px solid var(--celadon);
    border-radius:0;
    box-shadow:none;
  }
  .nav-group.open .group-panel{display:flex}

  .search{margin-left:0;order:4;width:100%}
  .search input{flex:1 1 auto;width:auto}

  .shell{grid-template-columns:minmax(0,1fr);padding-top:24px;gap:22px}
  .side{position:static}
  .toc{flex-direction:row;flex-wrap:wrap;gap:4px}
  .toc a{border-left:0;border-bottom:2px solid transparent;border-radius:var(--radius)}
  .toc a:hover{border-left:0;border-bottom-color:var(--celadon)}

  .hero{min-height:44vh;padding:28px 16px}

  .foot-grid{grid-template-columns:minmax(0,1fr)}
  .foot-brand{font-size:clamp(30px,11vw,56px)}
  .foot-bar{justify-content:flex-start}
}

@media (max-width:420px){
  .foot-nav dl{grid-template-columns:repeat(2,minmax(0,1fr))}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition:none!important;animation:none!important}
  .js .prose > section{opacity:1;transform:none}
}

button[aria-expanded]{min-width:44px;min-height:44px}