/* ============ 1. Reset 与基础 ============ */
*,*::before,*::after{box-sizing:border-box;}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;}
body{margin:0;min-height:100vh;display:flex;flex-direction:column;}
main{flex:1 0 auto;}
h1,h2,h3,h4,h5,h6,p,figure,blockquote,ul,ol,dl{margin:0;}
ul,ol{list-style:none;padding:0;}
a{color:inherit;text-decoration:none;}
button{font:inherit;color:inherit;background:none;border:0;padding:0;cursor:pointer;}
img,svg{display:block;max-width:100%;height:auto;}
table{border-collapse:collapse;width:100%;}
[hidden]{display:none !important;}

/* ============ 2. 色彩与字体变量 ============ */
:root{
  --night:#0B1B2B;
  --alley:#132C44;
  --alley-deep:#0f2537;
  --lamp:#F3A24B;
  --amber:#FFC978;
  --neon:#4FD1C5;
  --sign-red:#8E3B46;
  --mist:#AAB8C6;
  --paper:#F4EBDD;
  --ink:#06111C;
  --copper:#B9794A;

  --line:rgba(170,184,198,.2);
  --line-strong:rgba(170,184,198,.42);

  --font-route:'Barlow Condensed','Noto Sans SC','PingFang SC','Hiragino Sans GB',sans-serif;
  --font-editorial:'Noto Serif SC','Songti SC','Source Han Serif SC',serif;
  --font-body:'Noto Sans SC','PingFang SC','Hiragino Sans GB','Microsoft YaHei',sans-serif;
  --font-mono:'IBM Plex Mono','JetBrains Mono',ui-monospace,SFMono-Regular,Consolas,monospace;

  --step-h1:clamp(2.2rem,5vw,4.8rem);
  --step-h2:clamp(1.5rem,2.8vw,2.6rem);
  --step-h3:clamp(1.15rem,1.8vw,1.5rem);
  --step-caption:.78rem;

  --gutter:clamp(1.1rem,4vw,2.5rem);
  --gap:clamp(1rem,2.2vw,1.6rem);
  --radius-lg:26px;
  --radius-md:16px;
  --radius-pill:999px;
  --ease:cubic-bezier(.22,.61,.36,1);
}

body{
  font-family:var(--font-body);
  font-size:1rem;
  line-height:1.75;
  color:var(--paper);
  background:
    radial-gradient(120% 78% at 84% -12%, rgba(243,162,75,.14), transparent 62%),
    radial-gradient(88% 58% at 6% 2%, rgba(79,209,197,.07), transparent 58%),
    var(--night);
  -webkit-font-smoothing:antialiased;
  letter-spacing:.01em;
}

::selection{background:rgba(243,162,75,.35);color:var(--paper);}

:focus-visible{
  outline:2px solid var(--amber);
  outline-offset:3px;
  border-radius:6px;
}

#main-content{display:block;scroll-margin-top:1.2rem;}

/* ============ 3. 容器与排版工具 ============ */
.container{
  width:100%;
  max-width:1180px;
  margin-inline:auto;
  padding-inline:var(--gutter);
}

.page-shell{padding-block:clamp(1.5rem,4vw,2.8rem) 0;}

.section{padding-block:clamp(2rem,5vw,3.8rem);}
.section--band{
  background:linear-gradient(180deg,rgba(19,44,68,.72),rgba(19,44,68,.42));
  border-block:1px solid var(--line);
}
.section-head{display:grid;gap:.55rem;max-width:62ch;margin-bottom:clamp(1.2rem,3vw,2rem);}

.eyebrow{
  display:inline-flex;align-items:center;gap:.5rem;
  font-family:var(--font-mono);
  font-size:.7rem;letter-spacing:.18em;text-transform:uppercase;
  color:var(--copper);
}
.route-number{
  display:inline-flex;align-items:center;
  font-family:var(--font-mono);
  font-size:.72rem;letter-spacing:.12em;
  color:var(--amber);
  background:rgba(142,59,70,.35);
  border:1px solid rgba(185,121,74,.5);
  padding:.1rem .55rem;
  border-radius:var(--radius-pill);
}

.display-1{
  font-family:var(--font-route);
  font-weight:700;
  font-size:var(--step-h1);
  line-height:1.04;
  letter-spacing:.05em;
  color:var(--paper);
}
.display-2{
  font-family:var(--font-editorial);
  font-weight:600;
  font-size:var(--step-h2);
  line-height:1.28;
  letter-spacing:.01em;
  color:var(--paper);
}
.display-3{
  font-family:var(--font-editorial);
  font-weight:600;
  font-size:var(--step-h3);
  line-height:1.45;
  color:var(--paper);
}
.mono-label{
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.1em;
  color:var(--mist);
}
.lede{
  font-size:clamp(1rem,1.6vw,1.12rem);
  line-height:1.85;
  color:var(--mist);
  max-width:58ch;
}
.prose{max-width:70ch;}
.prose > * + *{margin-top:1.05em;}
.prose h2{font-family:var(--font-editorial);font-size:var(--step-h2);font-weight:600;line-height:1.32;}
.prose h3{font-family:var(--font-editorial);font-size:var(--step-h3);font-weight:600;line-height:1.4;}
.prose p,.prose li{color:rgba(244,235,221,.86);}
.prose ul,.prose ol{padding-left:1.15rem;list-style:disc;}
.prose a{color:var(--amber);border-bottom:1px solid rgba(243,162,75,.4);}

/* ============ 4. 栅格 ============ */
.grid{display:grid;gap:var(--gap);}
.grid-2{grid-template-columns:repeat(auto-fit,minmax(min(100%,260px),1fr));}
.grid-3{grid-template-columns:repeat(auto-fit,minmax(min(100%,220px),1fr));}
.split{
  display:grid;
  grid-template-columns:minmax(0,1.15fr) minmax(0,.85fr);
  gap:clamp(1.5rem,4vw,3rem);
  align-items:start;
}

/* ============ 5. 按钮 / 标签 / 链接 ============ */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.45rem;
  padding:.6rem 1.15rem;
  border-radius:var(--radius-pill);
  font-family:var(--font-body);
  font-size:.88rem;font-weight:500;line-height:1.3;
  letter-spacing:.02em;
  border:1px solid transparent;
  white-space:nowrap;
  transition:background .18s var(--ease),color .18s var(--ease),
             border-color .18s var(--ease),box-shadow .18s var(--ease),
             transform .18s var(--ease);
}
.btn--primary{
  background:var(--lamp);
  color:var(--ink);
  border-color:var(--lamp);
}
.btn--primary:hover{
  background:var(--amber);
  border-color:var(--amber);
  box-shadow:0 8px 26px -12px rgba(255,201,120,.95);
}
.btn--ghost{
  background:rgba(19,44,68,.72);
  color:var(--paper);
  border-color:rgba(79,209,197,.45);
}
.btn--ghost:hover{
  color:var(--amber);
  border-color:var(--neon);
  box-shadow:0 0 0 3px rgba(79,209,197,.12);
}
.btn--quiet{
  background:transparent;
  color:var(--paper);
  border-color:var(--line-strong);
}
.btn--quiet:hover{color:var(--amber);border-color:var(--lamp);}
.btn:active{transform:translateY(1px);}

.tag{
  display:inline-flex;align-items:center;gap:.35rem;
  padding:.16rem .62rem;
  border-radius:var(--radius-pill);
  font-family:var(--font-mono);
  font-size:.7rem;letter-spacing:.08em;
  background:rgba(19,44,68,.9);
  border:1px solid var(--line-strong);
  color:var(--mist);
}
.tag--lamp{background:var(--lamp);border-color:var(--lamp);color:var(--ink);}
.tag--neon{background:rgba(79,209,197,.1);border-color:rgba(79,209,197,.55);color:var(--neon);}
.tag--red{background:rgba(142,59,70,.3);border-color:rgba(142,59,70,.7);color:#EAC8CD;}

.link-arrow{
  display:inline-flex;align-items:center;gap:.4rem;
  color:var(--amber);
  font-size:.92rem;font-weight:500;
  border-bottom:1px solid rgba(243,162,75,.35);
  padding-bottom:.08rem;
  transition:border-color .18s var(--ease),color .18s var(--ease);
}
.link-arrow::after{content:"→";transition:transform .18s var(--ease);}
.link-arrow:hover{border-bottom-color:var(--amber);color:var(--paper);}
.link-arrow:hover::after{transform:translateX(3px);}

/* ============ 6. 页头 ============ */
.skip-link{
  position:fixed;top:.55rem;left:.55rem;z-index:400;
  transform:translateY(-180%);
  background:var(--paper);
  color:var(--ink);
  padding:.55rem 1.05rem;
  border-radius:var(--radius-pill);
  font-family:var(--font-mono);
  font-size:.78rem;letter-spacing:.06em;
  transition:transform .18s var(--ease);
}
.skip-link:focus-visible{transform:translateY(0);}

.site-header{
  position:relative;
  z-index:80;
  border-bottom:1px solid var(--line);
  background:linear-gradient(180deg,#0d2033 0%,var(--night) 100%);
}

.scroll-progress{
  position:fixed;top:0;left:0;
  width:0;height:3px;
  background:linear-gradient(90deg,var(--lamp),var(--amber) 55%,var(--neon));
  box-shadow:0 0 14px rgba(243,162,75,.55);
  z-index:300;
  pointer-events:none;
  transition:width .08s linear;
}

.header-upper{
  background:linear-gradient(180deg,var(--ink) 0%,#081724 100%);
  border-bottom:1px solid rgba(185,121,74,.3);
}
.header-upper-inner{
  display:grid;
  grid-template-columns:auto minmax(0,1fr) auto;
  align-items:center;
  gap:clamp(.9rem,2.4vw,2rem);
  padding-block:.85rem .9rem;
}

.brand{display:flex;align-items:center;gap:.8rem;min-width:0;}
.brand-mark{
  position:relative;
  flex:0 0 auto;
  width:2.6rem;height:2.6rem;
  border-radius:14px;
  border:1px solid rgba(185,121,74,.55);
  background:radial-gradient(circle at 50% 32%,rgba(255,201,120,.32),rgba(11,27,43,.92) 72%);
  display:grid;place-items:center;
  overflow:hidden;
}
.brand-mark-lamp{
  position:relative;z-index:1;
  width:.68rem;height:.68rem;
  border-radius:50%;
  background:var(--lamp);
  margin-bottom:.75rem;
  box-shadow:0 0 0 3px rgba(243,162,75,.18),0 0 16px 3px rgba(243,162,75,.6);
}
.brand-mark-pole{
  position:absolute;left:50%;bottom:0;
  width:2px;height:48%;
  background:var(--copper);
  transform:translateX(-50%);
}
.brand-text{display:grid;gap:.1rem;min-width:0;}
.brand-title{
  font-family:var(--font-route);
  font-weight:700;
  font-size:1.34rem;
  line-height:1.15;
  letter-spacing:.14em;
  color:var(--paper);
}
.brand-sub{
  font-family:var(--font-mono);
  font-size:.68rem;
  letter-spacing:.04em;
  color:var(--mist);
  white-space:nowrap;
  overflow:hidden;
  text-overflow:ellipsis;
  max-width:34ch;
}

.header-strip{
  font-family:var(--font-mono);
  font-size:.74rem;
  letter-spacing:.03em;
  color:var(--mist);
  padding-left:1.1rem;
  border-left:1px solid rgba(185,121,74,.42);
  min-width:0;
  overflow:hidden;
  text-overflow:ellipsis;
  white-space:nowrap;
}

.header-actions{
  display:flex;
  align-items:center;
  gap:.55rem;
  flex:0 0 auto;
}

.nav-toggle{
  display:none;
  align-items:center;
  gap:.55rem;
  padding:.5rem .85rem;
  border-radius:var(--radius-pill);
  border:1px solid var(--line-strong);
  background:rgba(19,44,68,.65);
  color:var(--paper);
  font-family:var(--font-mono);
  font-size:.74rem;
  letter-spacing:.1em;
  transition:border-color .18s var(--ease),color .18s var(--ease),background .18s var(--ease);
}
.nav-toggle:hover{border-color:var(--lamp);color:var(--amber);}
.nav-toggle[aria-expanded="true"]{
  border-color:var(--lamp);
  color:var(--amber);
  background:rgba(243,162,75,.12);
}
.nav-toggle-bars{display:inline-flex;flex-direction:column;gap:3px;width:16px;}
.nav-toggle-bars span{
  display:block;height:2px;border-radius:2px;
  background:currentColor;
  transition:transform .2s var(--ease),opacity .2s 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{line-height:1;}

.header-lower{
  position:relative;
  background:linear-gradient(180deg,rgba(19,44,68,.85),rgba(19,44,68,.55));
  border-bottom:1px solid var(--line);
}
.header-lower-inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:1rem;
  min-height:3.35rem;
  padding-block:.35rem;
  position:relative;
}

.site-nav{min-width:0;}
.nav-list{display:flex;align-items:center;flex-wrap:wrap;gap:.12rem;}
.nav-item{display:block;}
.nav-link{
  position:relative;
  display:inline-flex;align-items:center;
  padding:.48rem .8rem;
  border-radius:var(--radius-pill);
  font-size:.9rem;
  color:var(--mist);
  transition:color .18s var(--ease),background .18s var(--ease);
}
.nav-link::after{
  content:"";
  position:absolute;left:50%;bottom:.24rem;
  width:0;height:2px;border-radius:2px;
  background:var(--lamp);
  transform:translateX(-50%);
  transition:width .2s var(--ease);
}
.nav-link:hover{color:var(--paper);background:rgba(11,27,43,.6);}
.nav-link:hover::after{width:1.05rem;}
.nav-link[aria-current="page"]{
  color:var(--amber);
  background:rgba(243,162,75,.13);
}
.nav-link[aria-current="page"]::after{width:1.45rem;background:var(--amber);}

.nav-actions{display:none;}

.nav-pill{
  display:inline-flex;align-items:center;gap:.5rem;
  flex:0 0 auto;
  padding:.4rem .85rem .4rem .72rem;
  border-radius:var(--radius-pill);
  border:1px solid rgba(79,209,197,.45);
  background:linear-gradient(120deg,rgba(79,209,197,.14),rgba(243,162,75,.12));
  color:var(--paper);
  font-size:.82rem;
  transition:border-color .18s var(--ease),color .18s var(--ease),box-shadow .18s var(--ease);
}
.nav-pill:hover{
  border-color:var(--amber);
  color:var(--amber);
  box-shadow:0 0 0 3px rgba(243,162,75,.12);
}
.nav-pill-dot{
  width:.5rem;height:.5rem;border-radius:50%;
  background:var(--neon);
  box-shadow:0 0 10px rgba(79,209,197,.9);
  flex:0 0 auto;
}
.nav-pill-text{white-space:nowrap;}
.nav-pill-meta{
  font-family:var(--font-mono);
  font-size:.66rem;
  letter-spacing:.05em;
  color:var(--neon);
  padding-left:.5rem;
  border-left:1px solid rgba(79,209,197,.35);
}

/* ============ 7. 页脚 ============ */
.site-footer{
  position:relative;
  margin-top:clamp(2.4rem,6vw,4.5rem);
  background:linear-gradient(180deg,rgba(19,44,68,.92) 0%,#081724 55%,var(--ink) 100%);
  border-top:1px solid rgba(142,59,70,.55);
  overflow:hidden;
}
.site-footer::before{
  content:"";
  position:absolute;inset:0 0 auto 0;height:2px;
  background:linear-gradient(90deg,transparent,rgba(243,162,75,.75) 22%,rgba(142,59,70,.75) 62%,transparent);
}
.site-footer::after{
  content:"";
  position:absolute;
  width:min(520px,62vw);aspect-ratio:1;
  right:-8vw;top:-42%;
  border-radius:50%;
  background:radial-gradient(circle,rgba(243,162,75,.15),transparent 68%);
  pointer-events:none;
}
.footer-inner{
  position:relative;z-index:1;
  padding-block:clamp(2.1rem,5vw,3.6rem) clamp(1.4rem,3vw,2.2rem);
}
.footer-brand{
  display:grid;gap:.6rem;
  max-width:40rem;
  padding-bottom:clamp(1.2rem,3vw,2rem);
  border-bottom:1px solid var(--line);
}
.footer-brand-link{display:inline-flex;align-items:center;gap:.65rem;}
.footer-brand-mark{
  width:.6rem;height:.6rem;border-radius:50%;
  background:var(--lamp);
  flex:0 0 auto;
  box-shadow:0 0 0 4px rgba(243,162,75,.14),0 0 16px 2px rgba(243,162,75,.55);
}
.footer-brand-title{
  font-family:var(--font-route);
  font-weight:700;
  font-size:clamp(1.5rem,3vw,2rem);
  letter-spacing:.14em;
  color:var(--paper);
  line-height:1.2;
}
.footer-tagline{
  font-family:var(--font-editorial);
  font-size:clamp(.95rem,1.6vw,1.12rem);
  line-height:1.85;
  color:var(--mist);
  max-width:34ch;
}
.footer-grid{
  display:grid;
  grid-template-columns:minmax(0,.85fr) minmax(0,.85fr) minmax(0,1.5fr);
  gap:clamp(1.3rem,3vw,2.6rem);
  padding-block:clamp(1.6rem,3.5vw,2.6rem);
}
.footer-col{min-width:0;}
.footer-col-title{
  font-family:var(--font-mono);
  font-size:.7rem;font-weight:500;
  letter-spacing:.18em;
  color:var(--copper);
  margin-bottom:.8rem;
}
.footer-list{display:grid;gap:.1rem;}
.footer-link{
  display:inline-flex;align-items:center;
  padding:.28rem 0;
  font-size:.92rem;
  color:var(--mist);
  transition:color .16s var(--ease),transform .16s var(--ease);
}
.footer-link:hover{color:var(--amber);transform:translateX(3px);}

.footer-contact{display:grid;gap:.85rem;}
.footer-contact-item{display:grid;gap:.22rem;}
.footer-contact-label{
  font-family:var(--font-mono);
  font-size:.66rem;
  letter-spacing:.14em;
  color:var(--copper);
}
.footer-contact-row{
  display:flex;flex-wrap:wrap;align-items:center;gap:.5rem;
}
.footer-contact-value{
  font-size:.88rem;
  line-height:1.6;
  color:var(--paper);
  word-break:break-word;
}
.copy-btn{
  flex:0 0 auto;
  font-family:var(--font-mono);
  font-size:.66rem;
  letter-spacing:.06em;
  padding:.14rem .55rem;
  border-radius:var(--radius-pill);
  border:1px solid rgba(170,184,198,.35);
  color:var(--mist);
  transition:color .16s var(--ease),border-color .16s var(--ease),
             background .16s var(--ease),color .16s var(--ease);
}
.copy-btn:hover{color:var(--amber);border-color:var(--lamp);}
.copy-btn[data-copied="true"]{
  background:var(--neon);
  border-color:var(--neon);
  color:var(--ink);
}
.footer-note{
  font-family:var(--font-mono);
  font-size:.7rem;
  letter-spacing:.06em;
  color:var(--copper);
  margin-top:.75rem;
}

.footer-bottom{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:.6rem 1.4rem;
  padding-top:clamp(1rem,2.5vw,1.5rem);
  border-top:1px solid var(--line);
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.04em;
  color:var(--mist);
}
.footer-copy{margin:0;}
.footer-legal{
  padding:.15rem .7rem;
  border-radius:var(--radius-pill);
  background:rgba(142,59,70,.26);
  border:1px solid rgba(142,59,70,.6);
  color:#EAC8CD;
}
.footer-meta{margin:0;color:rgba(170,184,198,.8);}

/* ============ 8. 通用组件 ============ */
.breadcrumb{
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.04em;
  color:var(--mist);
  margin-bottom:clamp(1rem,2.5vw,1.6rem);
}
.breadcrumb-list{display:flex;flex-wrap:wrap;align-items:center;gap:.45rem;}
.breadcrumb-item{display:inline-flex;align-items:center;gap:.45rem;}
.breadcrumb-item + .breadcrumb-item::before{
  content:"/";
  color:rgba(185,121,74,.85);
}
.breadcrumb-link{color:var(--mist);transition:color .16s var(--ease);}
.breadcrumb-link:hover{color:var(--amber);}
.breadcrumb-item[aria-current="page"]{color:var(--paper);}

.card{
  position:relative;
  display:grid;
  gap:.55rem;
  padding:clamp(1.05rem,2.4vw,1.55rem);
  border-radius:var(--radius-lg);
  border:1px solid var(--line);
  background:linear-gradient(160deg,rgba(19,44,68,.94),rgba(11,27,43,.92));
  transition:border-color .18s var(--ease),box-shadow .18s var(--ease),transform .18s var(--ease);
}
.card:hover{
  border-color:rgba(243,162,75,.6);
  box-shadow:0 20px 46px -32px rgba(243,162,75,.95);
  transform:translateY(-2px);
}
.card-title{
  font-family:var(--font-editorial);
  font-weight:600;
  font-size:var(--step-h3);
  line-height:1.4;
  color:var(--paper);
}
.card-meta{
  font-family:var(--font-mono);
  font-size:.7rem;
  letter-spacing:.09em;
  color:var(--copper);
}
.panel{
  padding:clamp(1rem,2vw,1.35rem);
  border-radius:var(--radius-md);
  border:1px solid var(--line);
  background:rgba(19,44,68,.5);
}
.panel--accent{
  border-color:rgba(79,209,197,.42);
  background:rgba(79,209,197,.07);
}

.divider-street{
  position:relative;
  height:1px;border:0;
  margin-block:clamp(1.6rem,4vw,2.6rem);
  background:linear-gradient(90deg,rgba(185,121,74,.8),rgba(170,184,198,.3) 46%,transparent);
}
.divider-street::after{
  content:"";position:absolute;left:0;top:-3px;
  width:7px;height:7px;border-radius:50%;
  background:var(--lamp);
  box-shadow:0 0 12px rgba(243,162,75,.85);
}

.media-frame{
  position:relative;
  overflow:hidden;
  border-radius:var(--radius-lg);
  border:1px solid var(--line);
  background:linear-gradient(160deg,#0f2537,#06111c);
  aspect-ratio:4 / 3;
  isolation:isolate;
}
.media-frame img{
  width:100%;height:100%;
  object-fit:cover;
}
.media-frame::after{
  content:"";
  position:absolute;inset:0;
  background:linear-gradient(180deg,rgba(6,17,28,0) 42%,rgba(6,17,28,.58) 100%);
  pointer-events:none;
}
.media-frame--wide{aspect-ratio:16 / 9;}
.media-frame--portrait{aspect-ratio:3 / 4;}
.media-caption{
  font-family:var(--font-mono);
  font-size:.7rem;
  letter-spacing:.05em;
  color:var(--mist);
  margin-top:.55rem;
}

.toc{display:grid;gap:.15rem;}
.toc-link{
  display:block;
  padding:.4rem .75rem;
  border-radius:var(--radius-pill);
  border-left:2px solid transparent;
  font-size:.88rem;
  color:var(--mist);
  transition:color .18s var(--ease),background .18s var(--ease),border-color .18s var(--ease);
}
.toc-link:hover{color:var(--paper);background:rgba(19,44,68,.75);}
.toc-link[aria-current="true"]{
  color:var(--amber);
  background:rgba(243,162,75,.1);
  border-left-color:var(--lamp);
}

.accordion{border-top:1px solid var(--line);}
.accordion-item{border-bottom:1px solid var(--line);}
.accordion-trigger{
  width:100%;
  display:flex;align-items:center;justify-content:space-between;gap:1rem;
  padding:1rem .15rem;
  text-align:left;
  font-family:var(--font-editorial);
  font-size:1.02rem;font-weight:600;
  line-height:1.5;
  color:var(--paper);
  transition:color .18s var(--ease);
}
.accordion-trigger:hover{color:var(--amber);}
.accordion-icon{
  position:relative;
  width:1rem;height:1rem;
  flex:0 0 auto;
  color:var(--lamp);
}
.accordion-icon::before,
.accordion-icon::after{
  content:"";
  position:absolute;left:50%;top:50%;
  background:currentColor;
  border-radius:2px;
  transform:translate(-50%,-50%);
  transition:transform .2s var(--ease),opacity .2s var(--ease);
}
.accordion-icon::before{width:12px;height:2px;}
.accordion-icon::after{width:2px;height:12px;}
.accordion-trigger[aria-expanded="true"] .accordion-icon::after{
  transform:translate(-50%,-50%) rotate(90deg);
  opacity:0;
}
.accordion-panel{
  padding:0 .15rem 1.1rem;
  max-width:66ch;
  font-size:.95rem;
  line-height:1.8;
  color:rgba(244,235,221,.82);
}

/* ============ 9. 显现动效 ============ */
html.js-reveal [data-reveal]{
  opacity:0;
  transform:translateY(12px);
  transition:opacity .32s var(--ease),transform .32s var(--ease);
}
html.js-reveal [data-reveal].is-visible{
  opacity:1;
  transform:none;
}

/* ============ 10. 响应式 ============ */
@media (max-width:1024px){
  .header-strip{display:none;}
  .header-upper-inner{grid-template-columns:minmax(0,1fr) auto;}
  .header-actions{display:none;}
  .nav-toggle{display:inline-flex;}
  .header-lower-inner{flex-wrap:wrap;gap:.5rem;}
  .site-nav{
    position:absolute;
    top:calc(100% + .55rem);
    left:var(--gutter);
    right:var(--gutter);
    display:none;
    padding:.9rem;
    border-radius:22px;
    border:1px solid rgba(79,209,197,.28);
    background:linear-gradient(180deg,#10283c,#0b1c2c);
    box-shadow:0 30px 66px -30px rgba(0,0,0,.95);
    z-index:90;
  }
  .site-nav[data-open]{display:block;}
  .nav-list{flex-direction:column;align-items:stretch;gap:.12rem;}
  .nav-link{
    padding:.7rem .85rem;
    font-size:.98rem;
    border-radius:14px;
  }
  .nav-link::after{display:none;}
  .nav-link[aria-current="page"]{border-left:2px solid var(--amber);}
  .nav-actions{
    display:grid;
    gap:.55rem;
    margin-top:.8rem;
    padding-top:.8rem;
    border-top:1px solid var(--line);
  }
  .nav-actions .btn{width:100%;}
}

@media (max-width:860px){
  .split{grid-template-columns:1fr;}
  .footer-grid{grid-template-columns:1fr 1fr;}
  .footer-col--contact{grid-column:1 / -1;}
}

@media (max-width:640px){
  body{font-size:.98rem;}
  .brand-title{font-size:1.18rem;}
  .brand-sub{max-width:24ch;font-size:.64rem;}
  .brand-mark{width:2.3rem;height:2.3rem;border-radius:12px;}
  .nav-pill{padding:.38rem .7rem;font-size:.78rem;}
  .nav-pill-meta{font-size:.62rem;padding-left:.4rem;}
  .header-lower-inner{padding-block:.45rem;}
  .footer-grid{grid-template-columns:1fr;gap:1.4rem;}
  .footer-bottom{flex-direction:column;align-items:flex-start;gap:.5rem;}
  .media-frame{aspect-ratio:5 / 4;}
}

@media (max-width:400px){
  .nav-pill-meta{display:none;}
  .brand-sub{display:none;}
}

/* ============ 11. 可访问性与动效偏好 ============ */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto;}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
  html.js-reveal [data-reveal]{opacity:1 !important;transform:none !important;}
  .card:hover{transform:none;}
  .footer-link:hover{transform:none;}
  .link-arrow:hover::after{transform:none;}
  .scroll-progress{transition:none;}
}