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

:root{
  --paper:#fdfbf7;
  --block:#f5f5f5;
  --ink:#1a1a1a;
  --line:#e2ded6;
  --line-soft:#ece8e0;
  --mute:#6c6860;
  --serif:"Songti SC","STSong","Noto Serif SC","SimSun",serif;
  --sans:"Poppins","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  --disp:"Righteous","Songti SC","STSong","SimSun",serif;
  --edge:clamp(16px,5vw,40px);
}

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

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

body{
  margin:0;
  background:var(--paper);
  color:var(--ink);
  font:400 17px/1.8 var(--sans);
  overflow-x:hidden;
}

body::after{
  content:"";
  position:fixed;
  inset:0;
  z-index:200;
  pointer-events:none;
  opacity:.045;
  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='0.75' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)'/%3E%3C/svg%3E");
}

a{color:inherit}
img{max-width:100%;height:auto;display:block}
p{margin:0}

a:focus-visible,
button:focus-visible,
input:focus-visible{outline:2px solid var(--ink);outline-offset:3px}

/* ---------- 顶部两行 ---------- */
.site-top{
  position:sticky;
  top:0;
  z-index:90;
  background:var(--paper);
  border-bottom:1px solid var(--ink);
}

.brand-line{
  max-width:1120px;
  margin:0 auto;
  padding:6px var(--edge);
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:12px;
}

.brand{
  display:flex;
  align-items:center;
  min-height:44px;
  padding:6px 0;
  font-family:var(--disp);
  font-size:19px;
  letter-spacing:.02em;
  text-decoration:none;
}
.brand-logo{height:30px;width:auto}

.burger{
  display:flex;
  align-items:center;
  gap:9px;
  min-height:44px;
  padding:11px 13px;
  background:none;
  border:1px solid var(--ink);
  color:var(--ink);
  font:500 13px/1 var(--sans);
  letter-spacing:.14em;
  cursor:pointer;
}
.burger-mark{
  display:block;
  width:10px;
  height:10px;
  border:1px solid var(--ink);
  background:transparent;
}
body.menu-open .burger-mark{background:var(--ink)}

.tool-line{
  border-top:1px solid var(--line-soft);
  padding:0 var(--edge);
}
.fsearch{
  max-width:1120px;
  margin:0 auto;
  display:flex;
}
.fsearch input{
  flex:1;
  width:100%;
  min-height:44px;
  padding:11px 0;
  border:0;
  border-bottom:1px solid transparent;
  background:transparent;
  color:var(--ink);
  font:400 16px/1.2 var(--sans);
  outline:none;
}
.fsearch input::placeholder{color:var(--mute);letter-spacing:.08em}
.fsearch input:focus{border-bottom-color:var(--ink)}

/* ---------- 全屏遮罩菜单 ---------- */
.veil{
  position:fixed;
  inset:0;
  z-index:80;
  padding:114px var(--edge) 40px;
  overflow:auto;
  background:var(--paper);
  visibility:hidden;
}
body.menu-open .veil{visibility:visible}
body.menu-open{overflow:hidden}

.veil ol{
  counter-reset:m;
  list-style:none;
  max-width:760px;
  margin:0 auto;
  padding:0;
  border-top:1px solid var(--line);
}
.veil li{
  counter-increment:m;
  display:flex;
  align-items:baseline;
  gap:14px;
  border-bottom:1px solid var(--line);
}
.veil li[hidden]{display:none}
.veil li::before{
  content:counter(m,decimal-leading-zero);
  flex:none;
  width:22px;
  font:500 12px/1 var(--sans);
  letter-spacing:.14em;
  color:var(--mute);
}
.veil a{
  flex:1;
  display:block;
  min-height:56px;
  padding:14px 0;
  font-family:var(--disp);
  font-size:clamp(20px,4.4vw,30px);
  line-height:1.3;
  text-decoration:none;
}
.veil a::after{content:"→";float:right;font-size:.7em;opacity:.32}
.veil a:hover,.veil a:focus-visible{background:var(--block)}

/* ---------- 首屏 ---------- */
.hero{
  position:relative;
  max-width:1120px;
  margin:0 auto;
  padding:70px var(--edge) 46px;
  min-height:45vh;
  display:flex;
  flex-direction:column;
  justify-content:center;
  border-bottom:1px solid var(--line);
}
.badge{
  position:absolute;
  top:22px;
  right:var(--edge);
  margin:0;
  padding:5px 10px;
  border:1px solid var(--ink);
  font:500 11px/1.5 var(--sans);
  letter-spacing:.2em;
}
.hero h1{
  margin:0;
  max-width:18em;
  font-family:var(--disp);
  font-weight:400;
  font-size:clamp(34px,7.6vw,66px);
  line-height:1.08;
  letter-spacing:.01em;
  word-break:break-word;
}
.hero .lede{
  margin:18px 0 0;
  max-width:42em;
  color:var(--mute);
  font-family:var(--serif);
  font-size:16px;
  line-height:1.85;
}

/* ---------- 主体：侧栏在左 ---------- */
.wrap{
  max-width:1120px;
  margin:0 auto;
  padding:34px var(--edge) 60px;
  display:grid;
  grid-template-columns:196px minmax(0,1fr);
  gap:48px;
  align-items:start;
}

.side{
  position:sticky;
  top:126px;
  border-top:2px solid var(--ink);
  padding-top:14px;
}
.rot{
  margin:0 0 22px;
  padding:12px 12px 14px;
  background:var(--block);
  border:1px solid var(--line);
}
.rot-k{
  margin:0 0 6px;
  font:500 11px/1.4 var(--sans);
  letter-spacing:.2em;
  color:var(--mute);
}
.rot-v{
  display:block;
  min-height:24px;
  font-family:var(--disp);
  font-size:17px;
  line-height:1.4;
  text-decoration:none;
  border-bottom:1px solid var(--line);
}
.side-h{
  margin:0 0 8px;
  font-family:var(--disp);
  font-weight:400;
  font-size:15px;
  letter-spacing:.14em;
}
.side-list{list-style:none;margin:0;padding:0}
.side-list li{border-bottom:1px solid var(--line)}
.side-list a{
  display:block;
  min-height:40px;
  padding:8px 0;
  font-size:16px;
  line-height:1.5;
  text-decoration:none;
  color:#3b3833;
}
.side-list a:hover{color:var(--ink);text-decoration:underline;text-underline-offset:3px}

.body-sec{min-width:0}

.content{
  max-width:38em;
  font-family:var(--serif);
  font-size:17.5px;
  line-height:1.95;
}
.content > section{
  padding:36px 0 10px;
  border-top:1px solid var(--line);
  scroll-margin-top:126px;
}
.content > section:first-child{border-top:0;padding-top:0}

.content h2{
  display:block;
  margin:0 0 14px;
  font-family:var(--disp);
  font-weight:400;
  font-size:clamp(23px,3.6vw,32px);
  line-height:1.3;
}
.content h2 span::before{
  content:"";
  display:inline-block;
  width:8px;
  height:8px;
  margin-right:12px;
  vertical-align:.1em;
  background:var(--ink);
}
.content h3{
  margin:1.5em 0 .6em;
  font-family:var(--disp);
  font-weight:400;
  font-size:20px;
  line-height:1.4;
}
.content p{margin:0 0 1.15em}
.content ul,.content ol{margin:0 0 1.2em;padding-left:1.35em}
.content li{margin:.32em 0}
.content a{text-decoration:underline;text-underline-offset:3px;text-decoration-thickness:1px}
.content blockquote{
  margin:1.4em 0;
  padding:2px 0 2px 18px;
  border-left:2px solid var(--ink);
  color:#38352f;
}
.content img{margin:1.2em 0;border:1px solid var(--line)}
.content table{width:100%;border-collapse:collapse;font-family:var(--sans);font-size:15px}
.content th,.content td{border:1px solid var(--line);padding:8px 10px;text-align:left}
.content code{
  font-family:ui-monospace,Menlo,Consolas,monospace;
  font-size:.9em;
  background:var(--block);
  padding:1px 5px;
}
.content time{font-family:var(--sans);font-size:15px;letter-spacing:.04em;color:var(--mute)}

.rv{opacity:0;transform:translateY(13px);transition:opacity .22s linear,transform .22s ease-out}
.rv.in{opacity:1;transform:none}

/* ---------- 页脚 ---------- */
.site-foot{
  margin-top:64px;
  border-top:2px solid var(--ink);
  background:var(--block);
  display:grid;
  grid-template-columns:repeat(3,1fr);
}

.site-foot > article{padding:28px 24px 32px;border-right:1px solid var(--line)}

.cta{
  grid-column:1/-1;
  display:flex;
  flex-wrap:wrap;
  gap:24px;
  align-items:flex-end;
  justify-content:space-between;
  padding:54px 24px !important;
  border-right:0 !important;
  border-bottom:1px solid var(--line);
}
.cta h2{
  margin:0;
  max-width:20em;
  font-family:var(--disp);
  font-weight:400;
  font-size:clamp(26px,5.2vw,44px);
  line-height:1.1;
}
.totop{
  min-height:48px;
  padding:15px 22px;
  border:1px solid var(--ink);
  background:var(--ink);
  color:var(--paper);
  font:500 14px/1 var(--sans);
  letter-spacing:.18em;
  cursor:pointer;
}
.totop:hover{background:var(--paper);color:var(--ink)}

.fcol h3{
  margin:0 0 14px;
  font-family:var(--disp);
  font-weight:400;
  font-size:13px;
  letter-spacing:.2em;
  color:var(--mute);
}
.fcol ol{list-style:none;margin:0;padding:0}
.fcol li{border-bottom:1px solid var(--line)}
.fcol a{
  display:block;
  min-height:40px;
  padding:8px 0;
  font-size:16px;
  line-height:1.5;
  text-decoration:none;
}
.fcol a:hover{text-decoration:underline;text-underline-offset:3px}
.fbrand{margin:0}
.fbrand .brand-logo{height:26px;width:auto}

.copy{
  grid-column:1/-1;
  margin:0;
  padding:16px 24px;
  border-top:1px solid var(--line);
  font-size:14px;
  letter-spacing:.06em;
  color:var(--mute);
}

/* ---------- 断点 ---------- */
@media (max-width:880px){
  .wrap{grid-template-columns:1fr;gap:30px;padding-top:26px}
  .side{position:static}
  .rot{margin-bottom:18px}
  .side-list{display:grid;grid-template-columns:1fr 1fr;gap:0 20px}
  .site-foot{grid-template-columns:1fr 1fr}
  .fcol--brand{grid-column:1/-1;border-right:0;border-bottom:1px solid var(--line)}
  .content{max-width:none}
  .hero{min-height:0;padding-top:64px;padding-bottom:38px}
}

@media (max-width:560px){
  .site-foot{grid-template-columns:1fr}
  .site-foot > article{border-right:0;border-bottom:1px solid var(--line)}
  .copy{padding:14px 24px}
  .side-list{grid-template-columns:1fr}
  .veil{padding-top:108px}
  .badge{top:16px}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .rv{opacity:1 !important;transform:none !important;transition:none !important}
}

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