:root{
  --paper:#ffffff;
  --ash:#f5f5f5;
  --ink:#1f1f1f;
  --ink-2:#3a3a3a;
  --mute:#7b7b7b;
  --line:#e7e7e7;
  --e1:0 1px 2px rgba(31,31,31,.06),0 1px 1px rgba(31,31,31,.04);
  --e2:0 4px 14px rgba(31,31,31,.07),0 2px 4px rgba(31,31,31,.05);
  --e3:0 14px 32px rgba(31,31,31,.10),0 6px 12px rgba(31,31,31,.06);
  --e4:0 28px 64px rgba(31,31,31,.15),0 12px 22px rgba(31,31,31,.09);
  --radius:28px;
}
*,*::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/1.75 Barlow,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  overflow-x:hidden;
}
body::before{
  content:"";position:fixed;inset:0;z-index:0;pointer-events:none;
  background:
    radial-gradient(62vw 52vh at 84% -10%,#f5f5f5 0%,rgba(245,245,245,0) 72%),
    radial-gradient(48vw 38vh at 6% 24%,#f8f8f8 0%,rgba(248,248,248,0) 74%);
}
img{max-width:100%;height:auto}
a{color:var(--ink)}
h1,h2,h3{font-family:"Barlow Condensed","PingFang SC",system-ui,sans-serif}
.sr{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.shell{position:relative;z-index:1;max-width:1180px;margin:0 auto;padding:0 20px}
.skip{
  position:absolute;left:12px;top:-56px;z-index:90;
  background:var(--ink);color:#fff;text-decoration:none;
  padding:12px 18px;border-radius:999px;font-size:16px;
  transition:top .2s;
}
.skip:focus{top:12px}

/* 头部：品牌居中，胶囊菜单分列两侧 */
.masthead{
  display:grid;
  grid-template-columns:1fr auto 1fr;
  grid-template-areas:"l brand r";
  align-items:center;
  gap:14px;
  padding:20px 0 18px;
}
.mast-side{display:flex;align-items:center;gap:10px}
.mast-side--l{grid-area:l;justify-content:flex-start}
.mast-side--r{grid-area:r;justify-content:flex-end}
.menu{display:flex;gap:6px;flex-wrap:wrap;margin:0;padding:0}
.pill{
  display:inline-flex;align-items:center;min-height:44px;padding:0 15px;
  border-radius:999px;background:var(--ash);color:var(--ink-2);
  text-decoration:none;font-size:16px;line-height:1.2;
  transition:background .2s,color .2s,box-shadow .2s,transform .2s;
}
.pill:hover{background:#ececec;color:var(--ink);box-shadow:var(--e1);transform:translateY(-1px)}
.pill:focus-visible{outline:2px solid var(--ink);outline-offset:2px}
.mast-side--l .pill:first-child{background:var(--ink);color:#fff;box-shadow:var(--e2)}
.brand{
  grid-area:brand;justify-self:center;display:inline-flex;align-items:center;gap:8px;
  padding:8px 12px;border-radius:16px;text-decoration:none;color:var(--ink);
  transition:box-shadow .25s,transform .25s;
}
.brand:hover{box-shadow:var(--e2);transform:translateY(-1px)}
.brandmark{font-size:20px;line-height:1}
.brandname{
  font-family:"Barlow Condensed",system-ui,sans-serif;
  font-weight:700;font-size:22px;letter-spacing:.004em;white-space:nowrap;
}
.seek{
  display:flex;align-items:center;
  background:var(--ash);border:1px solid transparent;border-radius:999px;
  padding:4px 6px 4px 14px;transition:border-color .2s,background .2s,box-shadow .2s;
}
.seek:focus-within{background:#fff;border-color:var(--ink);box-shadow:var(--e2)}
.seek input{
  border:0;background:transparent;outline:none;color:var(--ink);
  font:inherit;font-size:16px;width:110px;padding:9px 0;
}

/* 二级粘性锚点条 */
.marker{
  position:sticky;top:0;z-index:60;
  background:rgba(255,255,255,.82);
  -webkit-backdrop-filter:blur(14px) saturate(1.15);
  backdrop-filter:blur(14px) saturate(1.15);
  border-top:1px solid var(--line);border-bottom:1px solid var(--line);
}
.marker-in{
  display:flex;gap:8px;overflow-x:auto;padding:9px 20px;
  scrollbar-width:none;-ms-overflow-style:none;
}
.marker-in::-webkit-scrollbar{display:none}
.mark{
  flex:0 0 auto;display:inline-flex;align-items:center;min-height:40px;padding:0 14px;
  border-radius:999px;background:var(--ash);color:var(--ink-2);
  text-decoration:none;font-size:16px;line-height:1.2;
  transition:background .2s,color .2s,box-shadow .2s;
}
.mark:hover{background:#ececec;color:var(--ink)}
.mark.is-on{background:var(--ink);color:#fff;box-shadow:var(--e2)}
.mark:focus-visible{outline:2px solid var(--ink);outline-offset:2px}

/* 版面骨架 */
.stage{
  display:grid;
  grid-template-columns:minmax(0,1fr) 316px;
  gap:clamp(20px,3vw,38px);
  align-items:start;
  padding-top:clamp(22px,3vw,36px);
  padding-bottom:20px;
  z-index:1;
}

/* 首屏 */
.hero{
  grid-column:1;
  position:relative;z-index:2;
  display:grid;grid-template-columns:minmax(0,1fr) 232px;
  align-items:center;gap:26px;
  min-height:clamp(292px,45vh,430px);
  padding:6px 0 18px;
}
.hero-copy{position:relative;z-index:3}
.badge{
  display:inline-block;margin-bottom:14px;
  background:var(--ink);color:#fff;border-radius:999px;
  padding:7px 15px;box-shadow:var(--e2);
  font-family:"Barlow Condensed",system-ui,sans-serif;
  font-weight:600;font-size:14px;line-height:1.4;letter-spacing:.12em;
  transform:rotate(-2.5deg);
}
.hero h1{
  margin:0 0 14px;
  font-size:clamp(32px,5.2vw,56px);
  line-height:1.03;font-weight:700;letter-spacing:-.015em;
}
.lede{margin:0;max-width:46ch;color:var(--ink-2);font-size:17px}
.hero-art{
  position:relative;margin:0;width:100%;aspect-ratio:1/1.06;z-index:2;
  will-change:transform;
}
.art-layer{position:absolute;inset:0;border-radius:26px;transition:transform .5s cubic-bezier(.2,.7,.3,1)}
.art-layer--back{
  background:var(--ash);border:1px solid var(--line);box-shadow:var(--e1);z-index:1;
  transform:translate3d(-13%,9%,0) rotate(-7deg);
}
.art-layer--mid{
  background:#fff;border:1px solid var(--line);box-shadow:var(--e2);z-index:2;
  transform:translate3d(-5%,4%,0) rotate(-3deg);
}
.art-layer--front{
  background:#fff;border:1px solid var(--line);box-shadow:var(--e4);z-index:3;
  display:grid;place-items:center;overflow:hidden;
  animation:bob 6.5s ease-in-out infinite;
}
.hero-art:hover .art-layer--front{transform:translate3d(0,-7px,0)}
.hero-img{width:100%;height:100%;object-fit:cover;display:block}
@keyframes bob{
  0%,100%{transform:translate3d(0,0,0)}
  50%{transform:translate3d(0,-9px,0)}
}

/* 正文卡片层叠 */
.doc{grid-column:1;position:relative}
.doc > article{
  position:relative;
  background:var(--paper);
  border:1px solid var(--line);
  border-radius:var(--radius);
  padding:clamp(22px,3vw,36px);
  box-shadow:var(--e3);
  margin-top:26px;
  transition:box-shadow .35s ease,transform .35s ease;
  scroll-margin-top:110px;
}
.doc > article:first-child{margin-top:0}
.doc > article::after{
  content:"";position:absolute;z-index:-1;
  inset:14px -10px -12px 16px;
  border-radius:var(--radius);
  background:var(--ash);
  box-shadow:var(--e1);
}
.doc > article:nth-of-type(4n+1){z-index:1}
.doc > article:nth-of-type(4n+2){z-index:2}
.doc > article:nth-of-type(4n+3){z-index:3}
.doc > article:nth-of-type(4n+4){z-index:4}
.doc > article:hover{box-shadow:var(--e4);transform:translateY(-3px)}
.doc small{
  display:block;margin-bottom:6px;
  font-family:"Barlow Condensed",system-ui,sans-serif;
  font-weight:600;font-size:14px;line-height:1.4;letter-spacing:.16em;
  color:var(--mute);
}
.doc h2{
  margin:0 0 12px;
  font-size:clamp(24px,3.4vw,34px);line-height:1.14;font-weight:600;letter-spacing:.004em;
}
.doc h3{margin:24px 0 8px;font-size:21px;line-height:1.3;font-weight:600}
.doc p{margin:0 0 14px;color:var(--ink-2)}
.doc p:last-child{margin-bottom:0}
.doc ul,.doc ol{margin:0 0 14px;padding-left:1.25em}
.doc li{margin:7px 0}
.doc a{color:var(--ink);text-decoration-thickness:2px;text-underline-offset:3px}
.doc a:hover{background:var(--ash)}
.doc figure{margin:18px 0}
.doc figure img{border-radius:20px;box-shadow:var(--e2)}
.doc blockquote{
  margin:18px 0;padding:14px 18px;border-left:3px solid var(--ink);
  background:var(--ash);border-radius:0 18px 18px 0;color:var(--ink-2);
}

/* 右侧栏 */
.rail{
  grid-column:2;grid-row:1 / span 2;
  position:sticky;top:72px;z-index:5;
  padding:20px 18px;
  border:1px solid var(--line);border-radius:var(--radius);
  background:rgba(255,255,255,.8);
  -webkit-backdrop-filter:blur(12px);
  backdrop-filter:blur(12px);
  box-shadow:var(--e3);
}
.rail small{
  display:block;margin-bottom:4px;
  font-family:"Barlow Condensed",system-ui,sans-serif;
  font-weight:600;font-size:14px;line-height:1.4;letter-spacing:.16em;color:var(--mute);
}
.rail h2{margin:0 0 10px;font-size:24px;line-height:1.2;font-weight:600}
.rail-list{list-style:none;margin:0;padding:0;counter-reset:ix}
.rail-list li{counter-increment:ix;border-top:1px solid var(--line)}
.rail-list li:first-child{border-top:0}
.rail-list a{
  display:flex;align-items:center;gap:10px;min-height:44px;padding:6px 0;
  color:var(--ink-2);text-decoration:none;font-size:16px;line-height:1.3;
}
.rail-list a::before{
  content:counter(ix,decimal-leading-zero);
  font-family:"Barlow Condensed",system-ui,sans-serif;
  font-size:13px;letter-spacing:.1em;color:var(--mute);
}
.rail-list a:hover{color:var(--ink)}
.totop-in{
  display:inline-flex;align-items:center;min-height:44px;margin-top:10px;
  font-size:15px;color:var(--ink-2);text-decoration:none;
}
.totop-in:hover{color:var(--ink);text-decoration:underline}

/* 页脚 */
.foot{
  position:relative;z-index:1;
  display:flex;flex-wrap:wrap;align-items:center;gap:10px 24px;
  max-width:1180px;margin:44px auto 0;padding:22px 20px 36px;
  border-top:1px solid var(--line);
}
.foot-brand .brandname{font-size:17px;font-weight:600}
.foot dl{display:flex;flex-wrap:wrap;gap:2px 18px;margin:0}
.foot dt{margin:0}
.foot dt a{
  display:inline-flex;align-items:center;min-height:44px;
  color:var(--ink-2);text-decoration:none;font-size:16px;
}
.foot dt a:hover{color:var(--ink);text-decoration:underline}
.cop{margin-left:auto;color:var(--mute);font-size:14px;line-height:1.6}

.totop{
  position:fixed;right:16px;bottom:16px;z-index:70;
  display:inline-flex;align-items:center;min-height:44px;padding:0 16px;
  border-radius:999px;background:var(--ink);color:#fff;
  text-decoration:none;font-size:15px;box-shadow:var(--e3);
  opacity:0;transform:translateY(12px);pointer-events:none;
  transition:opacity .3s,transform .3s;
}
.totop.is-show{opacity:1;transform:none;pointer-events:auto}

/* 层叠错位（桌面） */
@media (min-width:900px){
  .doc > article:nth-of-type(2n){margin-left:24px;margin-right:-4px}
  .doc > article:nth-of-type(3n){margin-left:8px;margin-right:16px}
}

@media (max-width:900px){
  .stage{grid-template-columns:minmax(0,1fr)}
  .hero{grid-template-columns:minmax(0,1fr) 168px;min-height:0;gap:18px}
  .doc{grid-column:1}
  .rail{grid-column:1;grid-row:auto;position:static;margin-top:26px}
  .doc > article:nth-of-type(n){margin-left:0;margin-right:0}
}

@media (max-width:760px){
  .masthead{
    grid-template-columns:1fr;
    grid-template-areas:"brand" "l" "r";
    justify-items:center;gap:10px;padding:14px 0 12px;
  }
  .mast-side{width:100%;justify-content:center;flex-wrap:wrap}
  .menu{justify-content:center}
  .seek{width:100%}
  .seek input{width:100%}
  .brandname{font-size:20px}
  .hero{grid-template-columns:1fr}
  .hero-art{max-width:190px;margin:8px auto 0}
  .doc > article{border-radius:24px}
  .doc > article::after{inset:12px -7px -10px 12px;border-radius:24px}
  .foot{flex-direction:column;align-items:flex-start;gap:6px}
  .cop{margin-left:0;width:100%}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation:none!important;transition:none!important}
}

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