:root{
  --ink:#000;
  --paper:#fff;
  --mute:#565656;
  --line:rgba(0,0,0,.14);
  --glass:rgba(255,255,255,.58);
  --r:18px;
  --pad:clamp(16px,4vw,44px);
  --bar-h:64px;
  --display:'Anton','Epilogue','PingFang SC','Hiragino Sans GB','Microsoft YaHei',sans-serif;
  --text:'Epilogue',-apple-system,BlinkMacSystemFont,'Segoe UI','PingFang SC','Hiragino Sans GB','Microsoft YaHei',sans-serif;
}
*,*::before,*::after{box-sizing:border-box}
[hidden]{display:none!important}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;
  font-family:var(--text);
  font-size:17px;
  line-height:1.7;
  color:var(--ink);
  background:var(--paper);
  padding-bottom:calc(var(--bar-h) + 28px);
  -webkit-font-smoothing:antialiased;
}
a{color:inherit}
a:focus-visible,button:focus-visible{outline:2px solid var(--ink);outline-offset:2px}

/* ---------- 底部固定条 ---------- */
.bar{
  position:fixed;
  left:0;right:0;bottom:0;
  z-index:60;
  display:flex;
  align-items:center;
  gap:8px;
  min-height:var(--bar-h);
  padding:8px clamp(8px,2vw,16px);
  background:rgba(0,0,0,.84);
  backdrop-filter:blur(14px) saturate(150%);
  -webkit-backdrop-filter:blur(14px) saturate(150%);
  border-top:1px solid rgba(255,255,255,.2);
  color:#fff;
}
.mark{display:inline-flex;align-items:center;gap:8px;min-height:40px;padding:0 4px;text-decoration:none;color:#fff;font-weight:600;font-size:16px;white-space:nowrap}
.mark-dot{width:11px;height:11px;background:#fff;border-radius:50%;flex:none}
.mark-txt{letter-spacing:.02em}
.bar-nav{flex:1 1 auto;min-width:0;overflow-x:auto;scrollbar-width:none}
.bar-nav::-webkit-scrollbar{display:none}
.bar-nav > p{display:flex;gap:2px;margin:0;padding:0}
.bar-nav a{
  display:inline-flex;align-items:center;min-height:40px;padding:0 10px;
  color:#fff;text-decoration:none;font-size:16px;line-height:1.2;white-space:nowrap;
  border-radius:10px;transition:background .18s ease;
}
.bar-nav a:hover{background:rgba(255,255,255,.18)}
.grp-btn{
  flex:none;min-height:40px;padding:0 12px;font:inherit;font-size:16px;
  color:#fff;background:transparent;border:1px solid rgba(255,255,255,.55);
  border-radius:10px;cursor:pointer;transition:background .18s ease;
}
.grp-btn:hover{background:rgba(255,255,255,.16)}
.panel{
  position:absolute;left:clamp(8px,2vw,16px);right:clamp(8px,2vw,16px);
  bottom:calc(100% + 10px);
  display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;
  padding:16px;border-radius:var(--r);
  background:rgba(255,255,255,.86);
  backdrop-filter:blur(18px) saturate(160%);
  -webkit-backdrop-filter:blur(18px) saturate(160%);
  border:1px solid rgba(0,0,0,.16);
  box-shadow:0 18px 44px rgba(0,0,0,.22);
  max-height:58vh;overflow:auto;
  color:#000;
}
.grp-h{font-family:var(--display);font-size:14px;letter-spacing:.22em;font-weight:700;margin:0 0 6px}
.grp-links{display:flex;flex-direction:column;gap:2px;margin:0}
.grp-links a{display:flex;align-items:center;min-height:40px;padding:0 8px;border-radius:10px;text-decoration:none;font-size:16px}
.grp-links a:hover{background:rgba(0,0,0,.07)}

/* ---------- Hero ---------- */
.hero{
  position:relative;
  display:grid;
  align-content:end;
  min-height:70vh;
  padding:clamp(26px,6vw,74px) var(--pad) clamp(26px,5vw,58px);
  overflow:hidden;
  border-bottom:2px solid var(--ink);
}
.hero-figure{position:absolute;inset:0;margin:0;z-index:0}
.hero-img{display:block;width:100%;height:100%;object-fit:cover;filter:grayscale(1) contrast(1.12)}
.hero-figure::after{
  content:"";position:absolute;inset:0;
  background:linear-gradient(196deg,rgba(255,255,255,.14) 0%,rgba(255,255,255,.7) 46%,#fff 94%);
}
.hero-fallback{
  position:absolute;inset:0;display:grid;place-items:center;
  font-family:var(--display);font-weight:700;letter-spacing:-.03em;
  font-size:clamp(46px,13vw,150px);line-height:.9;color:#000;opacity:.13;white-space:nowrap;
}
.hero-cap{
  position:absolute;left:0;top:14px;z-index:2;
  padding:6px 12px;border-radius:999px;font-size:16px;
  background:rgba(255,255,255,.66);backdrop-filter:blur(10px);
  -webkit-backdrop-filter:blur(10px);border:1px solid rgba(0,0,0,.14);
}
.hero-copy{position:relative;z-index:2;margin-left:auto;max-width:min(760px,100%);text-align:right}
.kicker{margin:0 0 10px;font-size:16px;letter-spacing:.26em;color:var(--mute)}
.hero h1{
  margin:0;
  font-family:var(--display);font-weight:700;
  font-size:clamp(34px,7.2vw,82px);
  line-height:1.03;letter-spacing:-.02em;
}
.lede{margin:14px 0 0;font-size:clamp(16px,1.6vw,19px);color:#1b1b1b;max-width:44ch;margin-left:auto}
.hero-hint{margin:16px 0 0;font-size:16px;color:var(--mute);max-width:42ch;margin-left:auto}

/* ---------- 内容区 ---------- */
.doc{
  display:grid;
  grid-template-columns:220px minmax(0,1fr);
  gap:clamp(18px,3vw,46px);
  max-width:1240px;
  margin:0 auto;
  padding:clamp(26px,5vw,60px) var(--pad) clamp(20px,4vw,44px);
}
.side{
  position:sticky;top:20px;align-self:start;
  padding:16px;border-radius:var(--r);
  background:var(--glass);
  backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);
  border:1px solid var(--line);
}
.side-h{margin:0 0 8px;font-family:var(--display);font-size:16px;font-weight:700;letter-spacing:.16em}
.side hr{border:0;border-top:1px solid var(--ink);margin:0 0 10px}
.toc{list-style:none;margin:0;padding:0;display:grid;gap:2px}
.toc a{display:flex;gap:10px;align-items:baseline;min-height:40px;padding:7px 8px;border-radius:10px;text-decoration:none;font-size:16px;line-height:1.35}
.toc a:hover{background:rgba(0,0,0,.07)}
.toc b{font-family:var(--display);font-size:13px;letter-spacing:.1em;color:var(--mute);flex:none}
.side-note{margin:12px 0 0;font-size:16px;line-height:1.6;color:var(--mute)}

.prose{min-width:0;max-width:74ch}
.doc-h{margin:0 0 10px;font-family:var(--display);font-size:16px;font-weight:700;letter-spacing:.2em}
.prose > hr{border:0;border-top:2px solid var(--ink);margin:0 0 6px}
.prose h2{
  font-family:var(--display);font-weight:700;
  font-size:clamp(25px,3.6vw,40px);line-height:1.14;letter-spacing:-.01em;
  margin:1.9em 0 .45em;
}
.prose h3{font-size:clamp(19px,2.4vw,25px);font-weight:700;line-height:1.35;margin:1.5em 0 .4em}
.prose p{margin:0 0 1.05em}
.prose ul,.prose ol{margin:0 0 1.2em;padding-left:1.35em}
.prose li{margin-bottom:.42em}
.prose a{text-decoration:underline;text-decoration-thickness:1px;text-underline-offset:3px}
.prose a:hover{text-decoration-thickness:2px}
.prose hr{border:0;border-top:2px solid var(--ink);margin:.15em 0 1.15em}
.prose figure{margin:1.5em 0;border-radius:var(--r);overflow:hidden;border:1px solid var(--line)}
.prose img{display:block;width:100%;height:auto;filter:grayscale(1)}
.prose blockquote{
  margin:1.4em 0;padding:12px 18px;border-left:4px solid var(--ink);
  background:rgba(0,0,0,.045);border-radius:0 var(--r) var(--r) 0;
}
.prose blockquote p:last-child{margin-bottom:0}
.prose code{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:15px;background:rgba(0,0,0,.06);padding:1px 5px;border-radius:6px}
.prose div{
  padding-top:clamp(18px,3vw,32px);
  border-top:1px solid var(--line);
  scroll-margin-top:24px;
}
.prose div:first-of-type{border-top:0;padding-top:8px}

/* ---------- 页脚 ---------- */
.foot{
  display:grid;
  grid-template-columns:repeat(4,minmax(0,1fr));
  gap:clamp(12px,2vw,22px);
  margin-top:clamp(28px,5vw,56px);
  padding:clamp(28px,5vw,56px) var(--pad) 0;
  border-top:2px solid var(--ink);
}
.foot-cta{grid-column:1/-1}
.foot-cta h2{
  margin:0 0 .35em;max-width:24ch;
  font-family:var(--display);font-weight:700;
  font-size:clamp(24px,4.4vw,50px);line-height:1.08;letter-spacing:-.015em;
}
.foot-cta hr{border:0;border-top:2px solid var(--ink);margin:0 0 1em}
.foot-cta p{margin:0 0 .7em;max-width:62ch;color:#1b1b1b}
.foot-back a{display:inline-flex;align-items:center;min-height:40px;padding:0 14px;border:1px solid var(--ink);border-radius:999px;text-decoration:none;font-weight:600;transition:background .18s ease,color .18s ease}
.foot-back a:hover{background:var(--ink);color:#fff}
.foot-col{
  padding:16px;border-radius:var(--r);
  background:var(--glass);
  backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);
  border:1px solid var(--line);
}
.foot-col h2{margin:0 0 .5em;font-family:var(--display);font-size:16px;font-weight:700;letter-spacing:.14em}
.foot-col hr{border:0;border-top:1px solid var(--ink);margin:0 0 .8em}
.foot-col p{margin:0 0 .6em;font-size:16px;line-height:1.6}
.foot-col p:last-child{margin-bottom:0}
.foot-base{
  grid-column:1/-1;
  display:grid;gap:6px;justify-items:center;text-align:center;
  margin-top:4px;padding:18px 0 26px;
  border-top:1px solid var(--line);
  color:var(--mute);font-size:16px;
}
.foot-base p{margin:0}

/* ---------- 动效 ---------- */
.rv{opacity:0;transform:translateY(10px)}
.rv.in{opacity:1;transform:none;transition:opacity .5s ease,transform .5s ease}
.side,.foot-col{transition:transform .2s ease,box-shadow .2s ease}
.side:hover,.foot-col:hover{transform:translateY(-2px);box-shadow:0 12px 26px rgba(0,0,0,.09)}

/* ---------- 断点 ---------- */
@media(max-width:860px){
  .doc{grid-template-columns:1fr;padding-top:20px}
  .side{position:static}
  .prose{max-width:none}
  .foot{grid-template-columns:repeat(2,minmax(0,1fr))}
  .hero{min-height:64vh}
  .hero-copy{text-align:right}
}
@media(max-width:560px){
  .mark-txt{font-size:15px}
  .bar{gap:6px}
  .panel{grid-template-columns:1fr}
  .foot{grid-template-columns:1fr}
  .hero-print{display:none}
}
@media(max-width:400px){
  .mark-txt{display:none}
  .grp-btn{padding:0 10px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *{transition:none!important;animation:none!important}
  .rv{opacity:1;transform:none}
  .side:hover,.foot-col:hover{transform:none}
}

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