/* =====================================================================
   新世纪 New Century — /assets/site.css
   共享层：重置 / 令牌 / 中文排版 / 页头 / 页脚 / 通用组件
   ===================================================================== */

/* ---------- 1. Reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:120px}
body,h1,h2,h3,h4,h5,h6,p,ul,ol,li,figure,blockquote,dl,dt,dd{margin:0;padding:0}
ul,ol{list-style:none}
img,svg,video{display:block;max-width:100%}
button,input,select,textarea{font:inherit;color:inherit}
button{background:none;border:0;cursor:pointer}
a{color:var(--blue);text-decoration:none}
a:hover{text-decoration:underline;text-underline-offset:3px}
table{border-collapse:collapse;width:100%}
[hidden]{display:none !important}
:focus-visible{outline:2px solid var(--orange);outline-offset:3px;border-radius:2px}

/* ---------- 2. Tokens ---------- */
:root{
  --ink:#071A33;
  --navy:#0B2545;
  --blue:#2F6BFF;
  --orange:#FF6A2B;
  --silver:#E9EDF2;
  --mist:#F6F8FB;
  --gray:#6B7A8F;
  --line:#C3CAD6;
  --teal:#14B8C4;
  --white:#FFFFFF;

  --font-sans:"Inter","Helvetica Neue","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Noto Serif SC","Songti SC","Source Han Serif SC",Georgia,"Times New Roman",serif;
  --font-mono:"JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;

  --shell:1240px;
  --narrow:860px;
  --gutter:clamp(18px,4vw,56px);
  --radius:2px;
  --header-h:72px;

  --shadow-soft:0 1px 0 rgba(7,26,51,.05),0 20px 34px -30px rgba(7,26,51,.55);
  --shadow-card:0 1px 0 rgba(7,26,51,.04),0 18px 30px -28px rgba(7,26,51,.5);
  --ease:cubic-bezier(.22,.61,.36,1);
}

/* ---------- 3. 基础中文排版 ---------- */
body{
  background:var(--white);
  color:var(--ink);
  font-family:var(--font-body);
  font-size:17px;
  line-height:1.8;
  letter-spacing:.01em;
  font-weight:400;
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3,h4,h5,h6{
  font-family:var(--font-sans);
  font-weight:900;
  line-height:1.14;
  letter-spacing:-.01em;
  color:var(--ink);
}
h1{font-size:clamp(34px,5vw,48px)}
h2{font-size:clamp(26px,3.4vw,36px)}
h3{font-size:clamp(21px,2.4vw,28px)}
h4{font-size:22px;font-weight:800}
p{margin:0}
strong{font-weight:700}
code,kbd,samp{font-family:var(--font-mono);font-size:.94em}

/* ---------- 4. 容器与网格 ---------- */
.shell{
  width:100%;
  max-width:var(--shell);
  margin-inline:auto;
  padding-inline:var(--gutter);
}
.shell--narrow{max-width:var(--narrow)}

.grid-12{
  display:grid;
  grid-template-columns:repeat(12,minmax(0,1fr));
  gap:clamp(16px,2.2vw,30px);
}
.col-3{grid-column:span 3}
.col-4{grid-column:span 4}
.col-5{grid-column:span 5}
.col-6{grid-column:span 6}
.col-7{grid-column:span 7}
.col-8{grid-column:span 8}
.col-9{grid-column:span 9}
.col-12{grid-column:span 12}
.col-annot{grid-column:span 3}
.col-main{grid-column:span 9}

.layout-editorial{
  display:grid;
  grid-template-columns:minmax(150px,220px) minmax(0,1fr);
  gap:clamp(20px,3vw,48px);
  align-items:start;
}
.annot{
  font-size:14px;
  line-height:1.75;
  color:var(--gray);
  border-left:1px solid var(--line);
  padding-left:16px;
}
.annot__title{
  display:block;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--gray);
  margin-bottom:8px;
}

/* ---------- 5. 分区与标题 ---------- */
.section{padding-block:clamp(44px,6.5vw,92px)}
.section--mist{background:var(--mist)}
.section--silver{background:var(--silver)}
.section--ink{background:var(--navy)}
.section--ink h1,.section--ink h2,.section--ink h3,.section--ink h4{color:var(--white)}
.section--ink p,.section--ink li{color:rgba(233,237,242,.84)}
.section--ink a{color:var(--white)}
.section--ruled{border-top:1px solid var(--line)}

.section__head{display:grid;gap:12px;margin-bottom:clamp(22px,3vw,40px);max-width:64ch}
.section__head--wide{max-width:none}

.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:10px;
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.18em;
  text-transform:uppercase;
  color:var(--gray);
}
.eyebrow::before{content:"";width:26px;height:2px;background:var(--blue)}
.section--ink .eyebrow{color:rgba(195,202,214,.8)}
.section--ink .eyebrow::before{background:var(--orange)}

.lede{
  font-family:var(--font-body);
  font-size:19px;
  line-height:1.85;
  color:rgba(11,37,69,.82);
  max-width:58ch;
}
.section--ink .lede{color:rgba(233,237,242,.82)}

.prose{max-width:66ch}
.prose > * + *{margin-top:1.1em}
.prose h2{margin-top:1.6em}
.prose h3{margin-top:1.4em}
.prose ul{display:grid;gap:8px}
.prose ul li{position:relative;padding-left:20px}
.prose ul li::before{
  content:"";
  position:absolute;left:0;top:.85em;
  width:8px;height:2px;background:var(--orange);
}

/* ---------- 6. 按钮 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  gap:.55em;
  padding:.72em 1.4em;
  border:1px solid transparent;
  border-radius:var(--radius);
  font-family:var(--font-sans);
  font-size:15px;
  font-weight:700;
  letter-spacing:.02em;
  line-height:1.2;
  text-decoration:none;
  transition:background-color .22s var(--ease),color .22s var(--ease),border-color .22s var(--ease),transform .22s var(--ease);
}
.btn:hover{text-decoration:none;transform:translateY(-1px)}
.btn--primary{background:var(--blue);color:var(--white)}
.btn--primary:hover{background:#1E56DB;color:var(--white)}
.btn--accent{background:var(--orange);color:var(--white)}
.btn--accent:hover{background:#EE5A1B;color:var(--white)}
.btn--ghost{border-color:var(--line);color:var(--navy);background:transparent}
.btn--ghost:hover{border-color:var(--blue);color:var(--blue);background:rgba(47,107,255,.06)}
.btn--on-dark{border-color:rgba(195,202,214,.45);color:var(--white);background:transparent}
.btn--on-dark:hover{border-color:var(--orange);color:var(--white);background:rgba(255,106,43,.12)}
.btn--sm{font-size:13px;padding:.5em 1em}

/* ---------- 7. 卡片 / 标签 / 指标 ---------- */
.card{
  position:relative;
  display:block;
  background:var(--white);
  border:1px solid var(--line);
  padding:clamp(18px,2.2vw,28px);
  box-shadow:var(--shadow-card);
  transition:border-color .24s var(--ease),transform .24s var(--ease),box-shadow .24s var(--ease);
}
.card:hover{border-color:rgba(47,107,255,.55);transform:translateY(-2px)}
.card__title{font-family:var(--font-sans);font-size:19px;font-weight:800;margin-bottom:8px}
.card__meta{
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.06em;
  color:var(--gray);
}
.card--ink{background:var(--navy);border-color:rgba(195,202,214,.24);color:rgba(233,237,242,.86)}
.card--ink .card__title{color:var(--white)}

.tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:3px 10px;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.08em;
  text-transform:uppercase;
  color:var(--navy);
  background:var(--silver);
  border:1px solid var(--line);
}
.tag--blue{color:var(--blue);background:rgba(47,107,255,.08);border-color:rgba(47,107,255,.35)}
.tag--orange{color:var(--orange);background:rgba(255,106,43,.09);border-color:rgba(255,106,43,.35)}
.tag--teal{color:#0E8E99;background:rgba(20,184,196,.1);border-color:rgba(20,184,196,.35)}

.metric{
  display:block;
  font-family:var(--font-mono);
  font-size:clamp(22px,2.6vw,32px);
  line-height:1.1;
  letter-spacing:-.01em;
  color:var(--orange);
}
.metric--blue{color:var(--blue)}
.metric--line{border-bottom:1px solid var(--line);padding-bottom:10px}
.metric__label{
  display:block;
  margin-top:8px;
  font-family:var(--font-sans);
  font-size:12.5px;
  font-weight:700;
  letter-spacing:.12em;
  text-transform:uppercase;
  color:var(--gray);
}

/* ---------- 8. 主题筛选 ---------- */
.filter-bar{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  padding:12px 14px;
  background:var(--mist);
  border:1px solid var(--line);
}
.filter-btn{
  padding:.48em .95em;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.1em;
  text-transform:uppercase;
  color:var(--gray);
  background:var(--white);
  border:1px solid var(--line);
  transition:background-color .2s var(--ease),color .2s var(--ease),border-color .2s var(--ease);
}
.filter-btn:hover{border-color:var(--blue);color:var(--blue)}
.filter-btn[aria-pressed="true"]{background:var(--navy);border-color:var(--navy);color:var(--white)}
.filter-bar__count{
  margin-left:auto;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.08em;
  color:var(--gray);
}
.filter-bar__count::after{content:" 项";color:var(--line)}

/* ---------- 9. 技能树式步骤 ---------- */
.steps{position:relative;display:grid;gap:0;padding-left:26px}
.steps::before{
  content:"";
  position:absolute;
  left:5px;top:8px;bottom:8px;
  width:1px;
  background:var(--line);
}
.step{position:relative;padding:12px 0 20px;border-bottom:1px solid rgba(195,202,214,.55)}
.step:last-child{border-bottom:0;padding-bottom:6px}
.step::before{
  content:"";
  position:absolute;
  left:-26px;top:19px;
  width:11px;height:11px;
  background:var(--white);
  border:2px solid var(--line);
  border-radius:50%;
  transition:background-color .24s var(--ease),border-color .24s var(--ease),box-shadow .24s var(--ease);
}
.step[data-active="true"]::before{
  background:var(--orange);
  border-color:var(--orange);
  box-shadow:0 0 0 4px rgba(255,106,43,.16);
}
.step__index{
  display:block;
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.1em;
  color:var(--gray);
}
.step[data-active="true"] .step__index{color:var(--orange)}
.step__title{font-family:var(--font-sans);font-size:17px;font-weight:800;margin:4px 0 6px}
.step__body{font-size:15.5px;line-height:1.8;color:rgba(11,37,69,.78)}

/* ---------- 10. 层叠目录 ---------- */
.index-list{border-top:1px solid var(--line)}
.index-list__item{border-bottom:1px solid var(--line)}
.index-list__link{
  display:grid;
  grid-template-columns:58px minmax(0,1fr) auto;
  gap:16px;
  align-items:baseline;
  padding:15px 6px;
  color:var(--ink);
  text-decoration:none;
  transition:background-color .2s var(--ease),color .2s var(--ease);
}
.index-list__link:hover{background:var(--mist);color:var(--blue);text-decoration:none}
.index-list__num{
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.08em;
  color:var(--gray);
}
.index-list__link[aria-current="true"]{background:var(--mist)}
.index-list__link[aria-current="true"] .index-list__num{color:var(--orange)}
.index-list__tail{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.08em;
  color:var(--gray);
}

/* ---------- 11. 图片容器 ---------- */
.media{
  position:relative;
  display:block;
  overflow:hidden;
  background:linear-gradient(135deg,var(--silver),var(--mist));
  border:1px solid var(--line);
}
.media--wide{aspect-ratio:16/9}
.media--tall{aspect-ratio:4/5}
.media--square{aspect-ratio:1/1}
.media img,.media svg{width:100%;height:100%;object-fit:cover}
.media--frame::after{
  content:"";
  position:absolute;
  inset:10px;
  border:1px solid rgba(255,255,255,.5);
  pointer-events:none;
}
.media--corner::before{
  content:"";
  position:absolute;
  top:0;right:0;
  width:44px;height:44px;
  background:var(--orange);
  clip-path:polygon(100% 0,100% 100%,0 0);
  opacity:.9;
}
.media__cap{
  display:block;
  margin-top:10px;
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.06em;
  color:var(--gray);
}
.media-grid{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(220px,1fr));
  gap:clamp(14px,2vw,26px);
}

/* ---------- 12. 刻度与分隔 ---------- */
.tick-rule{
  display:block;
  height:8px;
  background-image:repeating-linear-gradient(90deg,currentColor 0 1px,transparent 1px 10px);
  background-size:10px 5px;
  background-position:0 100%;
  background-repeat:repeat-x;
  color:var(--line);
  opacity:.55;
}
.tick-rule--footer{color:var(--silver);min-width:120px;flex:1 1 120px}

/* ---------- 13. 面包屑 ---------- */
.crumbs ol{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:0 10px;
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.06em;
}
.crumbs li{display:inline-flex;align-items:center;gap:10px;color:var(--gray)}
.crumbs li + li::before{content:"/";color:var(--line)}
.crumbs a{color:var(--gray)}
.crumbs a:hover{color:var(--blue);text-decoration:none}
.crumbs [aria-current="page"]{color:var(--ink)}

/* ---------- 14. 滚动渐显 ---------- */
[data-reveal]{
  opacity:0;
  transform:translateY(14px);
  transition:opacity .36s var(--ease),transform .36s var(--ease);
}
[data-reveal].is-visible{opacity:1;transform:none}

/* ---------- 15. 页头 ---------- */
.skip-link{
  position:absolute;
  left:14px;top:-70px;
  z-index:200;
  padding:10px 16px;
  background:var(--orange);
  color:var(--white);
  font-family:var(--font-sans);
  font-size:14px;
  font-weight:700;
  border-radius:var(--radius);
  transition:top .2s var(--ease);
}
.skip-link:focus{top:12px;text-decoration:none;color:var(--white)}

.site-header{
  position:sticky;
  top:0;
  z-index:80;
  background:var(--navy);
  box-shadow:0 16px 32px -28px rgba(7,26,51,.95);
}

.header-scale{background:#05152B;border-bottom:1px solid rgba(195,202,214,.16)}
.header-scale__inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:18px;
  min-height:38px;
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.08em;
  color:rgba(195,202,214,.78);
}
.header-scale__meta{
  display:inline-flex;
  align-items:center;
  gap:10px;
  margin:0;
  white-space:nowrap;
  overflow:hidden;
  text-overflow:ellipsis;
}
.header-scale__dot{
  flex:0 0 auto;
  width:7px;height:7px;
  border-radius:50%;
  background:var(--teal);
  box-shadow:0 0 0 3px rgba(20,184,196,.18);
}
.utility-nav{display:flex;align-items:center;gap:22px;flex:0 0 auto}
.utility-nav a{
  color:rgba(233,237,242,.8);
  padding-bottom:2px;
  border-bottom:1px solid transparent;
  transition:color .2s var(--ease),border-color .2s var(--ease);
}
.utility-nav a:hover{color:var(--white);border-bottom-color:var(--orange);text-decoration:none}

.header-main{background:var(--navy);border-bottom:1px solid rgba(195,202,214,.14)}
.header-main__inner{
  position:relative;
  display:flex;
  align-items:center;
  gap:clamp(14px,2.4vw,34px);
  min-height:var(--header-h);
}

.brand{display:inline-flex;align-items:center;gap:12px;color:var(--white);text-decoration:none}
.brand:hover{text-decoration:none;color:var(--white)}
.brand__mark{
  position:relative;
  display:grid;
  place-items:center;
  width:38px;height:38px;
  font-family:var(--font-mono);
  font-size:14px;
  font-weight:700;
  letter-spacing:.04em;
  color:var(--white);
  background:linear-gradient(140deg,var(--blue),#1B3E86);
  border:1px solid rgba(47,107,255,.75);
}
.brand__mark::after{
  content:"";
  position:absolute;
  right:-3px;bottom:-3px;
  width:9px;height:9px;
  background:var(--orange);
}
.brand__text{display:flex;flex-direction:column;line-height:1.15}
.brand__name{font-family:var(--font-sans);font-size:17px;font-weight:900;letter-spacing:.02em}
.brand__latin{
  font-family:var(--font-mono);
  font-size:10.5px;
  letter-spacing:.22em;
  text-transform:uppercase;
  color:rgba(195,202,214,.8);
}

.header-rule{
  flex:1 1 auto;
  min-width:34px;
  height:9px;
  align-self:center;
  background-image:repeating-linear-gradient(90deg,rgba(195,202,214,.5) 0 1px,transparent 1px 11px);
  background-size:11px 5px;
  background-position:0 100%;
  background-repeat:repeat-x;
  border-bottom:1px solid rgba(195,202,214,.22);
}

.primary-nav__list{display:flex;align-items:center;gap:clamp(12px,1.5vw,26px)}
.primary-nav a{
  position:relative;
  display:inline-block;
  padding:6px 2px 10px;
  font-family:var(--font-sans);
  font-size:15px;
  font-weight:700;
  color:rgba(233,237,242,.78);
  text-decoration:none;
  transition:color .2s var(--ease);
}
.primary-nav a::after{
  content:"";
  position:absolute;
  left:0;right:0;bottom:0;
  height:2px;
  background:transparent;
  transform:scaleX(.25);
  transform-origin:0 50%;
  transition:transform .24s var(--ease),background-color .24s var(--ease);
}
.primary-nav a:hover{color:var(--white);text-decoration:none}
.primary-nav a:hover::after{background:var(--blue);transform:scaleX(1)}
.primary-nav a[aria-current="page"]{color:var(--white)}
.primary-nav a[aria-current="page"]::after{background:var(--orange);transform:scaleX(1)}

.nav-toggle{
  display:none;
  align-items:center;
  gap:9px;
  padding:8px 12px;
  border:1px solid rgba(195,202,214,.45);
  color:var(--white);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.14em;
  transition:border-color .2s var(--ease),color .2s var(--ease);
}
.nav-toggle:hover{border-color:var(--blue)}
.nav-toggle[aria-expanded="true"]{border-color:var(--orange);color:var(--orange)}
.nav-toggle__bars{display:inline-flex;flex-direction:column;justify-content:space-between;width:16px;height:12px}
.nav-toggle__bars span{display:block;height:2px;background:currentColor;transition:transform .24s var(--ease),opacity .24s var(--ease)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(1){transform:translateY(5px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(3){transform:translateY(-5px) rotate(-45deg)}
.nav-toggle__label{white-space:nowrap}

.scroll-progress{
  position:absolute;
  left:0;bottom:0;
  width:100%;height:2px;
  background:linear-gradient(90deg,var(--blue),var(--teal),var(--orange));
  transform:scaleX(0);
  transform-origin:0 50%;
  opacity:0;
  transition:transform .12s linear,opacity .24s var(--ease);
}

/* ---------- 16. 页脚 ---------- */
.site-footer{
  position:relative;
  background:var(--ink);
  color:rgba(233,237,242,.76);
  padding-bottom:6px;
}
.footer-rule{
  height:3px;
  background:linear-gradient(90deg,var(--orange) 0 20%,var(--blue) 20% 62%,var(--teal) 62% 100%);
}
.footer-inner{padding-block:clamp(38px,5vw,68px) 24px}

.footer-grid{
  display:grid;
  grid-template-columns:minmax(210px,1.25fr) minmax(140px,.8fr) minmax(140px,.8fr) minmax(250px,1.4fr);
  gap:clamp(24px,3vw,48px);
  padding-bottom:clamp(26px,3vw,42px);
  border-bottom:1px solid rgba(195,202,214,.18);
}
.footer-brand{display:grid;align-content:start;gap:0}
.brand--footer .brand__mark{background:linear-gradient(140deg,var(--blue),#12305F)}
.brand--footer .brand__name{color:var(--white)}
.footer-brand__line{
  margin-top:16px;
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.1em;
  color:rgba(195,202,214,.72);
}
.footer-col{display:grid;align-content:start}
.footer-col__title{
  display:flex;
  align-items:center;
  gap:9px;
  margin-bottom:16px;
  font-family:var(--font-sans);
  font-size:12.5px;
  font-weight:800;
  letter-spacing:.18em;
  text-transform:uppercase;
  color:var(--white);
}
.footer-col__title::before{content:"";width:14px;height:2px;background:var(--orange);flex:0 0 auto}
.footer-links{display:grid;gap:10px}
.footer-links a{
  color:rgba(233,237,242,.76);
  font-size:15px;
  text-decoration:none;
  transition:color .2s var(--ease);
}
.footer-links a:hover{color:var(--white);text-decoration:underline;text-underline-offset:4px}

.contact-list{display:grid;gap:10px;font-size:14.5px}
.contact-list__item{display:grid;grid-template-columns:52px minmax(0,1fr);gap:10px;align-items:start}
.contact-list__key{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.14em;
  text-transform:uppercase;
  color:rgba(195,202,214,.6);
  padding-top:5px;
}
.contact-list__val{color:rgba(233,237,242,.88);line-height:1.6}
.contact-list__val--mono{font-family:var(--font-mono);font-size:13.5px;letter-spacing:.02em;word-break:break-all}
.footer-note{
  margin-top:16px;
  max-width:52ch;
  font-size:13.5px;
  line-height:1.8;
  color:rgba(195,202,214,.62);
}

.footer-bottom{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:14px 26px;
  padding-top:22px;
}
.footer-legal{
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.06em;
  color:rgba(195,202,214,.72);
}

/* ---------- 17. 平板 ---------- */
@media (max-width:1024px){
  .col-annot,.col-main,.col-7,.col-8,.col-9{grid-column:span 12}
  .col-5,.col-6{grid-column:span 6}
  .layout-editorial{grid-template-columns:1fr;gap:22px}
  .annot{border-left:0;border-top:1px solid var(--line);padding-left:0;padding-top:14px}
  .footer-grid{grid-template-columns:1fr 1fr}
  .footer-brand{grid-column:1/-1}
}

/* ---------- 18. 移动端 ---------- */
@media (max-width:900px){
  html{scroll-padding-top:96px}
  .nav-toggle{display:inline-flex}
  .header-rule{display:none}
  .brand{margin-right:auto}
  .primary-nav{
    position:absolute;
    left:0;right:0;top:100%;
    z-index:70;
    background:var(--navy);
    border-top:1px solid rgba(195,202,214,.22);
    border-bottom:1px solid rgba(195,202,214,.22);
    max-height:0;
    overflow:hidden;
    visibility:hidden;
    box-shadow:0 24px 38px -26px rgba(7,26,51,.9);
    transition:max-height .3s var(--ease),visibility .3s var(--ease);
  }
  .primary-nav[data-open]{max-height:76vh;overflow-y:auto;visibility:visible}
  .primary-nav__list{
    flex-direction:column;
    align-items:stretch;
    gap:0;
    padding:6px var(--gutter) 18px;
  }
  .primary-nav li{border-bottom:1px solid rgba(195,202,214,.14)}
  .primary-nav li:last-child{border-bottom:0}
  .primary-nav a{display:block;padding:15px 2px;font-size:16px}
  .primary-nav a::after{display:none}
  .primary-nav a[aria-current="page"]{
    color:var(--white);
    padding-left:14px;
    box-shadow:inset 3px 0 0 var(--orange);
  }
}

@media (max-width:720px){
  body{font-size:16.5px}
  .col-4,.col-5,.col-6{grid-column:span 12}
  .header-scale__meta{font-size:11.5px}
  .filter-bar__count{margin-left:0;width:100%}
  .index-list__link{grid-template-columns:44px minmax(0,1fr);gap:12px}
  .index-list__tail{display:none}
  .footer-grid{grid-template-columns:1fr;gap:28px}
  .contact-list__item{grid-template-columns:52px minmax(0,1fr)}
  .footer-bottom{flex-direction:column;align-items:flex-start}
  .tick-rule--footer{width:100%;flex:0 0 auto}
}

/* ---------- 19. 无障碍与降级 ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  [data-reveal]{opacity:1;transform:none}
  .scroll-progress{transition:none}
}