:root{
  --ink:#1f1f1f;
  --paper:#ffffff;
  --fog:#f5f5f5;
  --line:rgba(31,31,31,.12);
  --soft:rgba(31,31,31,.08);
  --glass:rgba(255,255,255,.72);
  --mute:#6f6f6f;
  --e1:0 1px 2px rgba(31,31,31,.07),0 2px 8px rgba(31,31,31,.05);
  --e2:0 4px 14px rgba(31,31,31,.09),0 14px 30px rgba(31,31,31,.07);
  --e3:0 12px 32px rgba(31,31,31,.13),0 34px 64px rgba(31,31,31,.09);
  --e4:0 24px 56px rgba(31,31,31,.18),0 58px 96px rgba(31,31,31,.12);
  --z1:1;--z2:2;--z3:3;--z4:4;
  --rail:224px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;background:var(--paper);color:var(--ink);
  font-family:'Outfit',"PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  font-size:17px;line-height:1.7;letter-spacing:.01em;
  background-image:radial-gradient(circle at 82% -8%,var(--fog) 0,rgba(245,245,245,0) 44%),radial-gradient(circle at 4% 92%,var(--fog) 0,rgba(245,245,245,0) 36%);
  background-attachment:fixed;
}
a{color:inherit;text-decoration:none}
img{max-width:100%;height:auto;display:block}
h1,h2,h3,h4{font-weight:900;line-height:1.15;letter-spacing:-.015em;margin:0}
h1,h2,h3,h4,.brand,.f-logo{font-family:'Outfit',"PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif}
p{margin:0 0 1em}
::selection{background:var(--ink);color:var(--paper)}
:focus-visible{outline:2px solid var(--ink);outline-offset:3px}

.rv{opacity:0;transform:translateY(24px)}
.rv.in{opacity:1;transform:none;transition:opacity .6s cubic-bezier(.2,.7,.2,1),transform .6s cubic-bezier(.2,.7,.2,1)}

.rail{
  position:fixed;top:0;left:0;bottom:0;width:var(--rail);z-index:var(--z4);
  display:flex;flex-direction:column;padding:24px 16px;
  background:rgba(255,255,255,.8);
  -webkit-backdrop-filter:blur(14px) saturate(1.1);backdrop-filter:blur(14px) saturate(1.1);
  border-right:1px solid var(--line);box-shadow:var(--e2);overflow-y:auto;
}
.brand{
  display:inline-flex;align-items:center;gap:10px;min-height:44px;
  font-size:20px;font-weight:900;letter-spacing:.08em;text-transform:uppercase;
}
.brand::before{content:"";width:11px;height:11px;background:var(--ink);box-shadow:5px 5px 0 rgba(31,31,31,.28);flex:0 0 auto}
.rail-nav{display:flex;flex-direction:column;margin-top:16px;border-top:1px solid var(--line)}
.rail-link{
  display:flex;align-items:center;min-height:44px;padding:10px 2px;
  font-size:16px;font-weight:500;border-bottom:1px solid var(--line);
  transition:padding-left .22s ease,background .22s ease;
}
.rail-link:hover,.rail-link:focus-visible{padding-left:10px;background:var(--fog)}

main{margin-left:var(--rail);position:relative;z-index:var(--z1)}

.hero{
  position:relative;min-height:70vh;display:flex;align-items:flex-end;
  padding:clamp(30px,6vw,76px);overflow:hidden;isolation:isolate;background:var(--fog);
}
.hero-media{
  position:absolute;inset:0;margin:0;z-index:0;
  clip-path:polygon(0 0,100% 0,100% 100%,0 86%);
  background:linear-gradient(140deg,var(--fog),#e9e9e9);
  will-change:transform;
}
.hero-media::after{
  content:"";position:absolute;inset:0;
  background:linear-gradient(100deg,rgba(255,255,255,.95) 0%,rgba(255,255,255,.6) 44%,rgba(31,31,31,.18) 100%);
}
.hero-media.is-blank::before{
  content:"";position:absolute;inset:auto -10% -12% auto;width:46vw;height:46vw;max-width:520px;max-height:520px;
  background:repeating-linear-gradient(45deg,rgba(31,31,31,.06) 0 2px,rgba(31,31,31,0) 2px 14px);
}
.hero-img{width:100%;height:100%;object-fit:cover}
.hero-copy{
  position:relative;z-index:var(--z3);max-width:660px;margin-top:clamp(48px,9vh,96px);
  background:rgba(255,255,255,.84);
  -webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px);
  border:1px solid var(--line);box-shadow:var(--e4);
  padding:clamp(24px,3.4vw,46px);
}
.badge{
  position:absolute;top:-18px;left:0;display:inline-flex;align-items:center;min-height:36px;
  padding:0 15px;background:var(--ink);color:var(--paper);
  font-size:14px;font-weight:700;letter-spacing:.2em;box-shadow:var(--e3);
}
.hero-copy h1{font-size:clamp(2rem,4.6vw,3.4rem);letter-spacing:-.025em;margin:.15em 0 .4em}
.lede{margin:0;font-size:clamp(1rem,1.5vw,1.15rem);color:#3d3d3d;max-width:44ch}

.stage{
  max-width:1180px;margin:0 auto;
  padding:clamp(30px,5vw,72px) clamp(18px,4vw,56px);
  display:grid;grid-template-columns:225px minmax(0,1fr);
  gap:clamp(22px,3vw,44px);align-items:start;
}

.toc{
  position:sticky;top:96px;z-index:var(--z2);
  background:var(--glass);-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);
  border:1px solid var(--line);box-shadow:var(--e2);padding:18px 16px;
}
.toc small{display:block;font-size:13px;font-weight:700;letter-spacing:.22em;color:var(--mute)}
.toc h2{font-size:19px;margin:4px 0 12px;letter-spacing:.06em}
.toc-list{list-style:none;margin:0;padding:0;border-top:1px solid var(--line)}
.toc-list a{
  display:flex;gap:10px;align-items:baseline;min-height:40px;padding:10px 4px;
  font-size:16px;border-bottom:1px solid var(--soft);
  transition:background .2s ease,padding-left .2s ease;
}
.toc-list a:hover,.toc-list a:focus-visible{background:var(--fog);padding-left:10px}
.toc-n{font-size:12px;font-weight:700;letter-spacing:.08em;color:#8c8c8c;font-variant-numeric:tabular-nums}

.entry{position:relative;z-index:var(--z1);min-width:0;max-width:768px}
.entry > section{
  position:relative;background:var(--glass);
  -webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);
  border:1px solid var(--line);box-shadow:var(--e2);
  padding:clamp(22px,3vw,42px);scroll-margin-top:104px;
  transition:box-shadow .38s ease,transform .38s ease;
}
.entry > section + section{margin-top:26px}
.entry > section:nth-child(even){margin-left:clamp(0px,2.4vw,28px);box-shadow:var(--e3)}
.entry > section:nth-child(odd){margin-right:clamp(0px,2.4vw,28px)}
.entry > section:hover{box-shadow:var(--e4);transform:translateY(-4px)}
.entry h2{font-size:clamp(1.5rem,2.6vw,2rem);margin:0 0 .65em;padding-bottom:.4em;border-bottom:2px solid var(--ink)}
.entry h3{font-size:1.2rem;margin:1.5em 0 .5em}
.entry h4{font-size:1.05rem;margin:1.3em 0 .4em}
.entry p,.entry li{font-size:1rem}
.entry ul,.entry ol{margin:0 0 1em;padding-left:1.25em}
.entry li{margin:.4em 0}
.entry a{text-decoration:underline;text-underline-offset:3px;text-decoration-thickness:1px}
.entry a:hover{background:var(--fog)}
.entry figure{position:relative;z-index:var(--z1);margin:1.5em 0;border:1px solid var(--line);box-shadow:var(--e2);background:var(--fog)}
.entry figcaption{font-size:15px;color:var(--mute);padding:9px 12px;border-top:1px solid var(--line)}
.entry blockquote{margin:1.5em 0;padding:14px 18px;background:var(--fog);border-left:4px solid var(--ink);box-shadow:var(--e1)}
.entry blockquote p:last-child{margin:0}
.entry table{width:100%;border-collapse:collapse;font-size:16px;margin:1.4em 0;background:var(--paper)}
.entry th,.entry td{border:1px solid var(--line);padding:9px 11px;text-align:left;vertical-align:top}
.entry th{background:var(--fog);font-weight:700}
.entry code{font-size:.95em;padding:1px 5px;background:var(--fog);border:1px solid var(--soft)}
.entry hr{border:none;border-top:1px solid var(--line);margin:2em 0}

.foot{
  margin-left:var(--rail);margin-top:clamp(44px,7vw,96px);
  background:var(--fog);border-top:1px solid var(--ink);
  box-shadow:0 -18px 44px rgba(31,31,31,.08);
  display:grid;grid-template-columns:1.5fr .9fr .9fr .8fr;
  gap:clamp(18px,3vw,40px);
  padding:clamp(30px,5vw,64px) clamp(18px,4vw,56px) 0;
  position:relative;z-index:var(--z1);
}
.foot > section{padding-bottom:clamp(22px,4vw,38px);min-width:0}
.f-logo{
  display:inline-flex;align-items:center;min-height:44px;font-size:20px;font-weight:900;
  letter-spacing:.08em;text-transform:uppercase;border-bottom:2px solid var(--ink);
}
.f-brand p{margin:14px 0 0;font-size:16px;color:#4d4d4d;max-width:34ch}
.f-h{font-size:16px;font-weight:700;letter-spacing:.2em;margin:0 0 12px;text-transform:uppercase}
.f-map dl{margin:0;display:grid;grid-template-columns:30px minmax(0,1fr);align-items:center}
.f-map dt{font-size:12px;font-weight:700;letter-spacing:.08em;color:#8c8c8c;font-variant-numeric:tabular-nums}
.f-map dd{margin:0;border-bottom:1px solid rgba(31,31,31,.09)}
.f-map dd a{display:flex;align-items:center;min-height:42px;font-size:16px;padding:6px 0}
.f-map dd a:hover{background:rgba(255,255,255,.8);padding-left:8px}
.sub{display:flex;max-width:330px}
.sub input{
  flex:1 1 auto;min-width:0;min-height:46px;padding:0 12px;font:inherit;font-size:16px;
  background:var(--paper);color:var(--ink);border:1px solid var(--ink);border-right:none;border-radius:0;
}
.sub button{
  flex:0 0 auto;min-height:46px;padding:0 16px;font:inherit;font-size:16px;font-weight:700;cursor:pointer;
  background:var(--ink);color:var(--paper);border:1px solid var(--ink);border-radius:0;
}
.sub button:hover{background:#000}
.to-top{
  display:inline-flex;align-items:center;min-height:44px;font-size:16px;font-weight:500;
  border-bottom:2px solid var(--ink);
}
.f-bottom{
  grid-column:1 / -1;display:flex;justify-content:space-between;align-items:center;gap:14px;flex-wrap:wrap;
  border-top:1px solid var(--line);padding:16px 0 20px;font-size:16px;
}
.f-bottom .copy{margin:0;color:#4d4d4d}
.f-legal{display:flex;gap:20px;flex-wrap:wrap}
.f-legal a{display:inline-flex;align-items:center;min-height:40px}
.f-legal a:hover{text-decoration:underline;text-underline-offset:4px}

@media (max-width:1024px){
  .rail{
    position:sticky;top:0;bottom:auto;left:auto;width:auto;
    flex-direction:row;align-items:center;gap:12px;padding:8px 14px;
    border-right:none;border-bottom:1px solid var(--line);box-shadow:var(--e2);overflow:visible;
  }
  .brand{flex:0 0 auto;font-size:18px}
  .rail-nav{
    flex-direction:row;flex:1 1 auto;margin-top:0;border-top:none;gap:2px;
    overflow-x:auto;scrollbar-width:none;
  }
  .rail-nav::-webkit-scrollbar{display:none}
  .rail-link{border-bottom:none;border:1px solid transparent;padding:10px 11px;white-space:nowrap}
  .rail-link:hover,.rail-link:focus-visible{padding-left:11px;border-color:var(--line);background:var(--fog)}
  main,.foot{margin-left:0}
  .stage{grid-template-columns:minmax(0,1fr)}
  .toc{position:static;order:-1}
  .toc-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));border-top:none}
  .toc-list a{border-bottom:1px solid var(--soft)}
  .entry{max-width:none}
  .foot{grid-template-columns:1fr 1fr}
  .hero{min-height:auto}
}
@media (max-width:720px){
  body{font-size:16px}
  .hero{padding:54px 16px 34px;align-items:flex-end}
  .hero-copy{padding:22px;margin-top:0}
  .hero-copy h1{font-size:clamp(1.7rem,7.6vw,2.3rem)}
  .badge{font-size:13px;padding:0 12px}
  .stage{padding:24px 16px}
  .toc-list{grid-template-columns:minmax(0,1fr)}
  .entry > section:nth-child(even),.entry > section:nth-child(odd){margin-left:0;margin-right:0}
  .entry > section{padding:20px 16px;scroll-margin-top:120px}
  .foot{grid-template-columns:minmax(0,1fr);padding:26px 16px 0}
  .f-bottom{flex-direction:column;align-items:flex-start;gap:6px}
  .sub{max-width:none}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .rv{opacity:1;transform:none;transition:none}
  .entry > section{transition:none}
  .entry > section:hover{transform:none}
  .hero-media{transform:none !important}
}
</style_placeholder>

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