/* =========================================================
   亿博品牌 · 共享样式表 /assets/site.css
   框架式导航：顶部定框 + 底部卷轴轨，中央为纵向叙事长卷
   ========================================================= */

/* ---------- 1. Reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body,figure,figcaption,blockquote,dl,dd,h1,h2,h3,h4,h5,h6,p,ul,ol{margin:0}
ul,ol{padding:0;list-style:none}
img,svg,video{display:block;max-width:100%}
button,input,select,textarea{font:inherit;color:inherit}
button{background:none;border:0;padding:0;cursor:pointer}
a{color:inherit;text-decoration:none}
table{border-collapse:collapse;width:100%}
[hidden]{display:none !important}

/* ---------- 2. 设计变量 ---------- */
:root{
  --ink:#0B1B2B;
  --ink-2:#12293F;
  --ink-3:#183650;
  --mist:#F5F7F8;
  --haze:#C9D6DC;
  --fog:#7E96A3;
  --amber:#F2A03D;
  --amber-deep:#C97A22;
  --jade:#35D0A5;
  --clay:#A9595B;
  --line:#E8EDF0;
  --line-dark:rgba(201,214,220,.18);
  --line-darker:rgba(201,214,220,.09);

  --wrap:1240px;
  --frame-base:78px;
  --frame-h:78px;
  --rail-h:44px;
  --r:4px;
  --ease:cubic-bezier(.22,.61,.36,1);

  --sans:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
  --serif:"Noto Serif SC","Source Han Serif SC","Songti SC",Georgia,"Times New Roman",serif;
  --mono:"JetBrains Mono","Source Han Mono","SFMono-Regular",Menlo,Consolas,"Courier New",monospace;
}

/* ---------- 3. 中文排版与基础体 ---------- */
body{
  margin:0;
  background:var(--ink);
  color:var(--mist);
  font-family:var(--sans);
  font-size:16px;
  font-weight:400;
  line-height:1.9;
  padding-top:var(--frame-base);
  padding-bottom:var(--rail-h);
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
  overflow-x:hidden;
}
body.nav-open{overflow:hidden}

@media (prefers-reduced-motion: no-preference){
  html{scroll-behavior:smooth}
}

.wrap{
  width:100%;
  max-width:var(--wrap);
  margin-inline:auto;
  padding-inline:clamp(18px,4vw,40px);
}

#main-content{scroll-margin-top:calc(var(--frame-h) + 12px)}
[data-chapter]{scroll-margin-top:calc(var(--frame-h) + 28px)}

p{max-width:42em}
strong{font-weight:700;color:var(--mist)}

a{transition:color .2s var(--ease),border-color .2s var(--ease),background-color .2s var(--ease)}

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

.visually-hidden{
  position:absolute !important;
  width:1px;height:1px;
  margin:-1px;padding:0;border:0;
  clip:rect(0 0 0 0);clip-path:inset(50%);
  overflow:hidden;white-space:nowrap;
}

/* ---------- 4. 排版组件 ---------- */
.display{
  font-family:var(--sans);
  font-weight:900;
  font-size:clamp(2.25rem,5.4vw,3.5rem);
  line-height:1.14;
  letter-spacing:-.01em;
  color:var(--mist);
}
.h2{
  font-family:var(--sans);
  font-weight:900;
  font-size:clamp(1.75rem,3.8vw,2.5rem);
  line-height:1.22;
  color:var(--mist);
}
.h3{
  font-family:var(--serif);
  font-weight:600;
  font-size:clamp(1.125rem,2vw,1.375rem);
  line-height:1.55;
  color:var(--mist);
}
.lede{
  font-size:clamp(1rem,1.6vw,1.125rem);
  line-height:1.9;
  color:var(--haze);
  max-width:36em;
}
.prose{color:var(--haze);max-width:36em;line-height:1.95}
.prose p + p{margin-top:1em}
.prose ul{margin-top:1em;display:grid;gap:.5em}
.prose li{padding-left:1.2em;position:relative}
.prose li::before{
  content:"";position:absolute;left:0;top:.85em;
  width:8px;height:1px;background:var(--amber);
}
.mono{
  font-family:var(--mono);
  font-size:.8125rem;
  line-height:1.7;
  letter-spacing:.01em;
  color:var(--fog);
  font-variant-numeric:tabular-nums;
}
.eyebrow{
  display:inline-flex;align-items:center;gap:10px;
  font-family:var(--mono);
  font-size:.75rem;
  letter-spacing:.16em;
  color:var(--fog);
}
.eyebrow::before{content:"";width:22px;height:2px;background:var(--amber);flex:0 0 auto}
.chapter-num{
  display:block;
  font-family:var(--serif);
  font-weight:600;
  font-size:clamp(2.5rem,6vw,4.25rem);
  line-height:1;
  color:var(--amber);
}
.chapter-band{
  display:block;
  height:2px;
  background:linear-gradient(90deg,var(--amber) 0 22%,var(--jade) 22% 34%,var(--line-dark) 34% 100%);
}
.divider{height:1px;background:var(--line-dark);border:0;width:100%}
.stack{display:grid;gap:var(--stack-gap,20px)}

/* ---------- 5. 章节带（底色分区） ---------- */
.section{padding-block:clamp(56px,9vw,120px)}
.section--tight{padding-block:clamp(36px,5vw,64px)}
.band{position:relative;background:var(--ink);color:var(--haze)}
.band--night{background:var(--ink-2)}
.band--mist{background:var(--mist);color:#3A4E5A}
.band--mist .display,
.band--mist .h2,
.band--mist .h3,
.band--mist strong{color:var(--ink)}
.band--mist .mono{color:#5E7480}
.band--mist .prose,
.band--mist .lede{color:#43585F}
.band--mist .eyebrow{color:var(--amber-deep)}
.band--mist .chapter-band{background:linear-gradient(90deg,var(--amber-deep) 0 22%,var(--jade) 22% 34%,rgba(11,27,43,.18) 34% 100%)}
.band--mist .divider{background:rgba(11,27,43,.14)}
.band--mist .btn--ghost{border-color:rgba(11,27,43,.28);color:var(--ink)}
.band--mist .btn--ghost:hover{border-color:var(--amber-deep);color:var(--amber-deep);background:rgba(242,160,61,.08)}

/* ---------- 6. 按钮 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:10px 18px;
  border:1px solid transparent;
  border-radius:2px;
  font-size:.875rem;
  line-height:1.4;
  letter-spacing:.02em;
  white-space:nowrap;
  cursor:pointer;
}
.btn--amber{background:var(--amber);color:#08131F;font-weight:500}
.btn--amber:hover{background:var(--amber-deep);color:#08131F}
.btn--ghost{border-color:var(--line-dark);color:var(--haze)}
.btn--ghost:hover{border-color:var(--amber);color:var(--mist);background:rgba(242,160,61,.08)}
.btn--ink{background:var(--ink);color:var(--mist)}
.btn--ink:hover{background:var(--amber-deep);color:#08131F}

/* ---------- 7. 框架式头部 ---------- */
.skip-link{
  position:fixed;top:10px;left:10px;z-index:200;
  padding:10px 16px;
  background:var(--amber);color:#08131F;
  border-radius:2px;font-size:.875rem;
  transform:translateY(-180%);
  transition:transform .2s var(--ease);
}
.skip-link:focus{transform:none}

.site-frame{
  position:fixed;inset:0 0 auto 0;
  z-index:90;
  pointer-events:none;
  --frame-h:78px;
}
.site-frame[data-shrink]{--frame-h:60px}

.site-frame__bar{
  pointer-events:auto;
  height:var(--frame-h);
  background:rgba(11,27,43,.9);
  backdrop-filter:blur(10px);
  -webkit-backdrop-filter:blur(10px);
  border-bottom:2px solid var(--amber);
  transition:height .3s var(--ease),background-color .3s var(--ease);
}
.site-frame[data-shrink] .site-frame__bar{background:rgba(9,22,35,.97)}

.site-frame__inner{
  height:100%;
  display:flex;
  align-items:center;
  gap:clamp(14px,2.4vw,34px);
}

/* 品牌 */
.brand{display:flex;align-items:center;gap:12px;flex:0 0 auto}
.brand__mark{
  width:24px;height:24px;flex:0 0 auto;
  background:linear-gradient(135deg,var(--amber) 0 44%,transparent 44% 56%,var(--jade) 56% 100%);
}
.brand__text{display:flex;flex-direction:column;line-height:1.25}
.brand__name{
  font-family:var(--serif);
  font-weight:600;
  font-size:1.125rem;
  letter-spacing:.04em;
  color:var(--mist);
}
.brand__tagline{
  display:none;
  font-size:.6875rem;
  letter-spacing:.06em;
  color:var(--fog);
}

/* 主导航 */
.frame-nav{flex:1 1 auto;display:none}
.frame-nav__list{display:flex;align-items:center;justify-content:center;gap:clamp(8px,1.6vw,22px)}
.frame-nav__link{
  position:relative;
  display:inline-block;
  padding:9px 2px;
  font-size:.9375rem;
  color:var(--haze);
}
.frame-nav__link::after{
  content:"";
  position:absolute;left:0;right:0;bottom:2px;height:2px;
  background:var(--amber);
  transform:scaleX(0);
  transform-origin:left center;
  transition:transform .28s var(--ease),background-color .28s var(--ease);
}
.frame-nav__link:hover{color:var(--mist)}
.frame-nav__link:hover::after{transform:scaleX(1)}
.frame-nav__link[aria-current="page"]{color:var(--mist);font-weight:500}
.frame-nav__link[aria-current="page"]::after{transform:scaleX(1);background:var(--jade)}

/* 行动区 */
.frame-actions{display:flex;align-items:center;gap:10px;flex:0 0 auto;margin-left:auto}

/* 移动导航按钮 */
.nav-toggle{
  display:inline-flex;align-items:center;gap:9px;
  padding:9px 12px;
  border:1px solid var(--line-dark);
  border-radius:2px;
  color:var(--haze);
  font-size:.8125rem;
  letter-spacing:.04em;
}
.nav-toggle:hover{border-color:var(--amber);color:var(--amber)}
.nav-toggle__bars{position:relative;width:18px;height:12px;flex:0 0 auto}
.nav-toggle__bars::before,
.nav-toggle__bars::after{
  content:"";position:absolute;left:0;right:0;height:2px;
  background:currentColor;
  transition:transform .24s var(--ease);
}
.nav-toggle__bars::before{top:1px}
.nav-toggle__bars::after{bottom:1px}
.site-frame[data-open] .nav-toggle{border-color:var(--amber);color:var(--amber)}
.site-frame[data-open] .nav-toggle__bars::before{transform:translateY(4px) rotate(45deg)}
.site-frame[data-open] .nav-toggle__bars::after{transform:translateY(-4px) rotate(-45deg)}

/* 底部卷轴轨 */
.site-frame__rail{
  pointer-events:auto;
  position:fixed;left:0;right:0;bottom:0;
  height:var(--rail-h);
  background:rgba(9,22,35,.94);
  backdrop-filter:blur(8px);
  -webkit-backdrop-filter:blur(8px);
  border-top:1px solid var(--line-dark);
  z-index:90;
}
.rail-inner{height:100%;display:flex;align-items:center;gap:clamp(10px,2vw,22px)}
.rail-chapter{
  flex:0 0 auto;
  font-size:.6875rem;
  letter-spacing:.14em;
  color:var(--fog);
  white-space:nowrap;
}
.rail-track{
  flex:1 1 auto;
  position:relative;
  height:2px;
  background:var(--line-darker);
  overflow:hidden;
  min-width:40px;
}
.rail-track__fill{
  display:block;
  width:0;
  height:100%;
  background:linear-gradient(90deg,var(--amber),var(--jade));
  transition:width .14s linear;
}
.rail-meta{flex:0 0 auto;font-size:.6875rem;letter-spacing:.1em;color:var(--fog);white-space:nowrap}
.rail-top{
  flex:0 0 auto;
  font-family:var(--mono);
  font-size:.6875rem;
  letter-spacing:.12em;
  color:var(--haze);
  padding:4px 8px;
  border:1px solid transparent;
  border-radius:2px;
}
.rail-top:hover{color:var(--amber);border-color:rgba(242,160,61,.4)}

/* ---------- 8. 页脚 ---------- */
.site-foot{
  position:relative;
  background:var(--ink);
  color:var(--haze);
  padding:clamp(48px,7vw,88px) 0 28px;
  border-top:1px solid var(--line-dark);
}
.site-foot__band{
  position:absolute;top:-1px;left:0;right:0;height:2px;
  background:linear-gradient(90deg,var(--amber) 0 30%,var(--jade) 30% 42%,rgba(126,150,163,.45) 42% 100%);
}
.site-foot__inner{
  display:grid;
  grid-template-columns:minmax(0,1.4fr) minmax(0,.8fr) minmax(0,.8fr) minmax(0,1.1fr);
  gap:clamp(24px,3.5vw,52px);
  align-items:start;
}
.site-foot__lead{display:grid;gap:14px;align-content:start}
.site-foot__brand{
  font-family:var(--serif);
  font-weight:600;
  font-size:1.375rem;
  letter-spacing:.04em;
  color:var(--mist);
}
.site-foot__intro{font-size:.9375rem;line-height:1.9;color:var(--haze);max-width:34em}
.site-foot__note{color:var(--fog);max-width:none}

.foot-col{display:grid;gap:14px;align-content:start}
.foot-col__title{
  font-family:var(--mono);
  font-size:.6875rem;
  font-weight:400;
  letter-spacing:.16em;
  color:var(--fog);
}
.foot-col__list{display:grid;gap:9px}
.foot-col__link{
  font-size:.9375rem;
  color:var(--haze);
  border-bottom:1px solid transparent;
  padding-bottom:2px;
  display:inline-block;
}
.foot-col__link:hover{color:var(--amber);border-bottom-color:var(--amber)}

.site-foot__contact{display:grid;gap:14px;align-content:start}
.contact-list{display:grid;gap:11px}
.contact-list__item{
  display:grid;gap:2px;
  font-size:.8125rem;
  color:var(--haze);
  word-break:break-word;
}
.contact-list__label{color:var(--fog);font-size:.6875rem;letter-spacing:.12em}
.site-foot__cta{justify-self:start;margin-top:4px}

.site-foot__legal{
  margin-top:clamp(32px,5vw,60px);
  padding-top:18px;
  border-top:1px solid var(--line-dark);
  display:flex;
  flex-wrap:wrap;
  gap:8px 28px;
  justify-content:space-between;
}
.site-foot__legal-line,
.site-foot__copy{font-size:.75rem;color:var(--fog);max-width:none}

/* ---------- 9. 通用组件 ---------- */
/* 网格 */
.grid{display:grid;gap:clamp(20px,3vw,36px)}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid--split{grid-template-columns:minmax(160px,.7fr) minmax(0,1.8fr)}

/* 面板 */
.panel{
  background:var(--ink-2);
  border:1px solid var(--line-dark);
  border-radius:var(--r);
  padding:clamp(20px,3vw,32px);
  box-shadow:0 1px 0 rgba(255,255,255,.02);
}
.panel--amber{border-color:rgba(242,160,61,.45)}
.panel--jade{border-left:2px solid var(--jade)}
.band--mist .panel{background:#fff;border-color:var(--line);box-shadow:0 1px 2px rgba(11,27,43,.05)}

/* 图片容器（页面阶段放入图片） */
.figure{
  position:relative;
  overflow:hidden;
  border:1px solid var(--line-dark);
  border-radius:var(--r);
  background:linear-gradient(152deg,var(--ink-2) 0%,var(--ink) 58%,#0E2136 100%);
  aspect-ratio:16/10;
}
.figure__img{width:100%;height:100%;object-fit:cover}
.figure__caption{margin-top:10px;font-family:var(--mono);font-size:.75rem;color:var(--fog)}
.figure--wide{aspect-ratio:21/9}
.figure--tall{aspect-ratio:3/4}
.figure--square{aspect-ratio:1/1}
.figure--bleed{margin-inline:calc(-1 * clamp(18px,4vw,40px));border-radius:0;border-left:0;border-right:0}
.band--mist .figure{border-color:var(--line);background:linear-gradient(152deg,#E9EEF1 0%,#DDE5E9 100%)}
.mist-layer{
  position:absolute;inset:0;pointer-events:none;opacity:.14;
  background:
    radial-gradient(120% 60% at 10% 0%,rgba(201,214,220,.95),transparent 62%),
    radial-gradient(90% 55% at 92% 100%,rgba(53,208,165,.4),transparent 66%);
}

/* 表格 */
.table{font-size:.9375rem}
.table th,.table td{
  text-align:left;
  padding:14px 16px;
  border-bottom:1px solid var(--line-dark);
  vertical-align:top;
}
.table th{
  font-family:var(--mono);
  font-weight:400;
  font-size:.75rem;
  letter-spacing:.1em;
  color:var(--fog);
  background:rgba(201,214,220,.06);
}
.table--light th,.table--light td{border-bottom-color:rgba(11,27,43,.12)}
.table--light th{background:var(--haze);color:#28414C}
.table--light td{color:#3A4E5A}

/* 状态标记 */
.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:3px 10px;
  border:1px solid currentColor;
  border-radius:999px;
  font-family:var(--mono);
  font-size:.6875rem;
  letter-spacing:.1em;
  line-height:1.7;
  color:var(--fog);
}
.tag--amber{color:var(--amber)}
.tag--jade{color:var(--jade)}
.tag--clay{color:var(--clay)}

/* 可展开内容组 */
.disclosure{
  background:var(--ink-2);
  border:1px solid var(--line-dark);
  border-radius:var(--r);
  transition:border-color .24s var(--ease),background-color .24s var(--ease);
}
.disclosure + .disclosure{margin-top:10px}
.disclosure[data-open]{border-color:var(--amber)}
.disclosure__toggle{
  width:100%;
  display:flex;align-items:center;gap:16px;
  padding:18px 20px;
  text-align:left;
  font-size:1rem;
  font-weight:500;
  color:var(--mist);
  line-height:1.7;
}
.disclosure__index{
  font-family:var(--mono);
  font-size:.75rem;
  color:var(--fog);
  flex:0 0 auto;
}
.disclosure[data-open] .disclosure__index{color:var(--amber)}
.disclosure__label{flex:1 1 auto}
.disclosure__icon{position:relative;width:14px;height:14px;flex:0 0 auto;color:var(--fog)}
.disclosure[data-open] .disclosure__icon{color:var(--amber)}
.disclosure__icon::before,
.disclosure__icon::after{
  content:"";position:absolute;background:currentColor;
  transition:transform .24s var(--ease),opacity .24s var(--ease);
}
.disclosure__icon::before{left:0;right:0;top:6px;height:2px}
.disclosure__icon::after{top:0;bottom:0;left:6px;width:2px}
.disclosure[data-open] .disclosure__icon::after{transform:scaleY(0);opacity:0}
.disclosure__panel{display:none;border-top:1px solid var(--line-dark)}
.disclosure[data-open] .disclosure__panel{display:block;animation:disclosure-in .28s var(--ease)}
.disclosure__body{padding:18px 20px 22px;color:var(--haze);max-width:44em;line-height:1.95}
.band--mist .disclosure{background:#fff;border-color:var(--line)}
.band--mist .disclosure__toggle{color:var(--ink)}
.band--mist .disclosure__body{color:#3A4E5A}
.band--mist .disclosure__panel{border-top-color:var(--line)}

@keyframes disclosure-in{
  from{opacity:0;transform:translateY(-6px)}
  to{opacity:1;transform:none}
}

/* 横向卡带 */
.hrail{display:grid;gap:16px}
.hrail__track{
  display:flex;
  gap:clamp(16px,2.5vw,28px);
  overflow-x:auto;
  scroll-snap-type:x proximity;
  padding-bottom:14px;
  scrollbar-width:thin;
  scrollbar-color:var(--fog) transparent;
}
.hrail__track > *{scroll-snap-align:start;flex:0 0 min(320px,78vw)}
.hrail__track::-webkit-scrollbar{height:4px}
.hrail__track::-webkit-scrollbar-thumb{background:var(--line-dark)}
.hrail__nav{display:flex;gap:8px}
.hrail__step{
  width:38px;height:38px;
  display:grid;place-items:center;
  border:1px solid var(--line-dark);
  border-radius:2px;
  color:var(--haze);
  font-family:var(--mono);
  font-size:.875rem;
}
.hrail__step:hover{border-color:var(--amber);color:var(--amber)}

/* 面包屑 */
.crumb{
  display:flex;flex-wrap:wrap;align-items:center;gap:8px;
  font-family:var(--mono);
  font-size:.75rem;
  color:var(--fog);
}
.crumb a:hover{color:var(--amber)}
.crumb__sep{opacity:.55}

/* ---------- 10. 进入视口显现 ---------- */
.has-js [data-reveal]{
  opacity:0;
  transform:translateY(14px);
  transition:opacity .42s var(--ease),transform .42s var(--ease);
}
.has-js [data-reveal].is-in{opacity:1;transform:none}

/* ---------- 11. 断点 ---------- */
@media (min-width:960px){
  .frame-nav{display:block}
  .nav-toggle{display:none}
}
@media (min-width:1100px){
  .brand__tagline{display:block}
}
@media (max-width:1079px){
  .frame-actions .btn--ghost{display:none}
  .site-foot__inner{grid-template-columns:repeat(2,minmax(0,1fr))}
  .site-foot__lead{grid-column:1 / -1}
}
@media (max-width:959px){
  :root{--frame-base:70px;--frame-h:70px}
  .site-frame{--frame-h:70px}
  .site-frame[data-shrink]{--frame-h:58px}
  .frame-nav{
    position:fixed;
    top:var(--frame-h);
    left:0;right:0;
    display:block;
    padding:6px 0 24px;
    background:var(--ink-2);
    border-bottom:2px solid var(--amber);
    max-height:calc(100vh - var(--frame-h));
    overflow-y:auto;
    opacity:0;
    visibility:hidden;
    transform:translateY(-10px);
    pointer-events:none;
    transition:opacity .26s var(--ease),transform .26s var(--ease),visibility .26s var(--ease);
  }
  .site-frame[data-open] .frame-nav{
    opacity:1;
    visibility:visible;
    transform:none;
    pointer-events:auto;
    box-shadow:0 18px 40px rgba(0,0,0,.4);
  }
  .frame-nav__list{
    flex-direction:column;
    align-items:stretch;
    gap:0;
    padding-inline:clamp(18px,4vw,40px);
  }
  .frame-nav__link{
    display:block;
    padding:15px 2px;
    font-size:1rem;
    border-bottom:1px solid var(--line-darker);
  }
  .frame-nav__link::after{display:none}
  .frame-nav__link[aria-current="page"]{color:var(--amber);padding-left:12px;border-left:2px solid var(--amber)}
  .grid--3{grid-template-columns:repeat(2,minmax(0,1fr))}
  .figure--bleed{margin-inline:0;border-radius:var(--r);border-left:1px solid var(--line-dark);border-right:1px solid var(--line-dark)}
}
@media (max-width:800px){
  .grid--split{grid-template-columns:1fr}
  .rail-meta{display:none}
}
@media (max-width:720px){
  .grid--2,.grid--3{grid-template-columns:1fr}
  .table{font-size:.875rem}
  .table th,.table td{padding:11px 12px}
  .figure--tall{aspect-ratio:4/5}
}
@media (max-width:639px){
  .frame-actions .btn--amber{display:none}
  .rail-chapter{letter-spacing:.08em}
  .site-foot__inner{grid-template-columns:1fr}
  .site-foot__lead{grid-column:auto}
  .site-foot__legal{flex-direction:column;gap:6px}
}

/* ---------- 12. 动效偏好 ---------- */
@media (prefers-reduced-motion: reduce){
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
  .has-js [data-reveal]{opacity:1;transform:none}
  .rail-track__fill{transition:none}
}