/* ===== 01 重置与变量 ===== */
*,*::before,*::after{box-sizing:border-box}
:root{
  --c-tianshan:#1B4F72;
  --c-gold:#C9A227;
  --c-rose:#C2185B;
  --c-jade:#2E7D5B;
  --c-ink:#0B1620;
  --c-sand:#F5EFE3;
  --c-mist:#FBF9F5;
  --c-night:#0E2A47;
  --c-bronze:#8C6A2F;
  --c-line:#D7E5F0;
  --c-ink-72:rgba(11,22,32,.72);
  --c-ink-56:rgba(11,22,32,.56);
  --c-light-82:rgba(251,249,245,.82);
  --f-head:"Songti SC","STSong","Source Han Serif SC","Noto Serif CJK SC",serif;
  --f-body:"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Source Han Sans SC",sans-serif;
  --f-mono:"SFMono-Regular","JetBrains Mono",Menlo,Consolas,"Courier New",monospace;
  --shell-max:1320px;
  --gutter:clamp(18px,4vw,52px);
  --header-h:78px;
  --dur:.26s;
}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:132px}
body{
  margin:0;
  background-color:var(--c-sand);
  background-image:linear-gradient(180deg,rgba(245,239,227,0) 0%,rgba(245,239,227,0) 62%,rgba(215,229,240,.34) 100%);
  color:var(--c-ink);
  font-family:var(--f-body);
  font-size:17px;
  line-height:1.75;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3,h4,h5{margin:0;font-family:var(--f-head);font-weight:400;letter-spacing:.04em;line-height:1.22}
p{margin:0 0 1em}
ul,ol{margin:0;padding:0;list-style:none}
img,svg,video{display:block;max-width:100%;height:auto}
button{font:inherit;color:inherit;background:none;border:0;padding:0;cursor:pointer}
a{color:inherit;text-decoration:none}
strong{font-weight:600}
.num,code,kbd{font-family:var(--f-mono);font-variant-numeric:tabular-nums;letter-spacing:.04em}
:focus-visible{outline:2px solid var(--c-rose);outline-offset:3px}
#main-content{display:block;scroll-margin-top:132px}

/* ===== 02 布局骨架 ===== */
.shell{width:100%;max-width:var(--shell-max);margin-inline:auto;padding-inline:var(--gutter)}
.page-main{display:block;padding-block:clamp(28px,5vw,64px) clamp(64px,9vw,120px)}
.grid-12{display:grid;grid-template-columns:repeat(12,minmax(0,1fr));gap:clamp(14px,1.8vw,26px)}
.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-12{grid-column:span 12}
.panel-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(248px,1fr));gap:clamp(14px,1.8vw,26px)}
.rule{height:1px;border:0;background:var(--c-line);margin:clamp(24px,4vw,48px) 0}
.eyebrow{font-family:var(--f-mono);font-size:12px;letter-spacing:.26em;color:var(--c-bronze);margin:0 0 10px}
.note{font-size:13.5px;line-height:1.8;color:var(--c-bronze);margin:0}
.prose{max-width:68ch}
.prose p{margin:0 0 1.1em}

/* ===== 03 页头：框架式导航 ===== */
.skip-link{
  position:fixed;top:10px;left:var(--gutter);z-index:140;
  padding:10px 18px;background:var(--c-gold);color:var(--c-night);
  font-size:14px;font-weight:600;letter-spacing:.12em;
  transform:translateY(-220%);
  transition:transform var(--dur) ease;
}
.skip-link:focus,.skip-link:focus-visible{transform:translateY(0)}
.site-header{
  position:sticky;top:0;z-index:80;
  background:linear-gradient(180deg,#0A1D32 0%,var(--c-night) 42%,var(--c-tianshan) 100%);
  color:var(--c-mist);
  border-bottom:2px solid var(--c-gold);
}
.header-ruler{
  height:9px;
  border-bottom:1px solid rgba(215,229,240,.24);
  background-image:repeating-linear-gradient(90deg,rgba(215,229,240,.48) 0 1px,transparent 1px 36px);
}
.header-frame{
  display:grid;
  grid-template-columns:auto 1fr auto auto;
  align-items:center;
  gap:clamp(12px,2vw,34px);
  min-height:var(--header-h);
  padding-block:12px;
  position:relative;
}
.brand{display:inline-flex;align-items:center;gap:12px;padding-block:4px}
.brand-mark{
  width:46px;height:46px;display:grid;place-items:center;
  background:var(--c-gold);color:var(--c-night);
  font-family:var(--f-head);font-size:24px;line-height:1;
  border:1px solid rgba(11,22,32,.18);
  transition:background-color var(--dur) ease,color var(--dur) ease;
}
.brand-text{display:flex;flex-direction:column;line-height:1.2}
.brand-name{font-family:var(--f-head);font-size:20px;letter-spacing:.16em;color:var(--c-mist)}
.brand-sub{font-family:var(--f-mono);font-size:10px;letter-spacing:.24em;text-transform:uppercase;color:rgba(215,229,240,.68)}
.brand:hover .brand-mark{background:var(--c-rose);color:var(--c-mist)}

.primary-nav{min-width:0}
.nav-list{display:flex;align-items:center;justify-content:center;gap:clamp(6px,1.6vw,26px)}
.nav-item{position:relative}
.nav-link{
  position:relative;display:inline-block;padding:10px 2px;
  font-size:15px;letter-spacing:.1em;color:var(--c-light-82);
  transition:color var(--dur) ease;
}
.nav-link::after{
  content:"";position:absolute;left:0;right:0;bottom:4px;height:1px;
  background:var(--c-gold);transform:scaleX(0);transform-origin:left;
  transition:transform var(--dur) ease,background-color var(--dur) ease;
}
.nav-link:hover{color:var(--c-mist)}
.nav-link:hover::after{transform:scaleX(1)}
.nav-link[aria-current="page"]{color:var(--c-gold)}
.nav-link[aria-current="page"]::after{transform:scaleX(1);height:2px;background:var(--c-rose)}

.help-anchor{
  display:flex;flex-direction:column;gap:2px;
  padding:12px 20px;background:var(--c-gold);color:var(--c-night);
  clip-path:polygon(12px 0,100% 0,100% calc(100% - 12px),calc(100% - 12px) 100%,0 100%,0 12px);
  transition:background-color var(--dur) ease,color var(--dur) ease;
}
.help-anchor-index{font-family:var(--f-mono);font-size:10px;letter-spacing:.22em;opacity:.74}
.help-anchor-text{font-size:15px;font-weight:600;letter-spacing:.08em}
.help-anchor:hover{background:var(--c-rose);color:var(--c-mist)}
.help-anchor:focus-visible{outline:2px solid var(--c-mist);outline-offset:-5px}

.nav-toggle{
  display:none;align-items:center;gap:10px;
  padding:10px 14px;border:1px solid rgba(215,229,240,.42);
  color:var(--c-mist);font-size:13px;letter-spacing:.16em;
  transition:border-color var(--dur) ease,color var(--dur) ease;
}
.nav-toggle:hover{border-color:var(--c-gold);color:var(--c-gold)}
.nav-toggle-icon{display:flex;flex-direction:column;justify-content:space-between;width:16px;height:12px}
.nav-toggle-bar{display:block;width:100%;height:1px;background:currentColor;transition:transform var(--dur) ease,opacity var(--dur) ease}
.nav-toggle-label{font-family:var(--f-mono)}
.site-header[data-open] .nav-toggle-bar:nth-child(1){transform:translateY(5.5px) rotate(45deg)}
.site-header[data-open] .nav-toggle-bar:nth-child(2){opacity:0}
.site-header[data-open] .nav-toggle-bar:nth-child(3){transform:translateY(-5.5px) rotate(-45deg)}

.scroll-progress{
  position:absolute;left:0;bottom:0;height:2px;width:0;
  background:linear-gradient(90deg,var(--c-gold),var(--c-rose),var(--c-jade));
}
.mobile-help-dock{display:none}

/* ===== 04 页脚 ===== */
.site-footer{
  position:relative;
  background:linear-gradient(180deg,var(--c-night) 0%,#08131F 100%);
  color:var(--c-light-82);
  border-top:2px solid var(--c-gold);
}
.site-footer::before{
  content:"";position:absolute;top:0;bottom:0;left:0;width:5px;
  background:linear-gradient(180deg,var(--c-gold),var(--c-rose) 50%,var(--c-tianshan));
}
.footer-grid{
  display:grid;grid-template-columns:1.5fr 1fr 1fr 1.3fr;
  gap:clamp(24px,3.4vw,56px);
  padding-block:clamp(40px,6vw,76px) clamp(28px,4vw,44px);
}
.footer-brand{min-width:0}
.footer-logo{font-family:var(--f-head);font-size:26px;letter-spacing:.16em;color:var(--c-mist);margin:0 0 12px}
.footer-note{font-size:14px;line-height:1.95;color:rgba(251,249,245,.7);margin:0 0 14px;max-width:34ch}
.footer-origin{font-family:var(--f-mono);font-size:11px;letter-spacing:.24em;color:var(--c-gold);margin:0}
.footer-col{min-width:0}
.footer-title{
  position:relative;margin:0 0 16px;padding-bottom:10px;
  font-size:13px;font-weight:600;letter-spacing:.24em;color:var(--c-mist);
}
.footer-title::after{content:"";position:absolute;left:0;bottom:0;width:30px;height:1px;background:var(--c-gold)}
.footer-list{display:grid;gap:10px;font-size:15px}
.footer-list a{
  color:rgba(251,249,245,.76);
  border-bottom:1px solid transparent;
  transition:color var(--dur) ease,border-color var(--dur) ease;
}
.footer-list a:hover{color:var(--c-gold);border-bottom-color:var(--c-gold)}
.contact-list{gap:14px}
.contact-label{display:block;font-family:var(--f-mono);font-size:10.5px;letter-spacing:.2em;color:rgba(215,229,240,.55)}
.copy-chip{
  display:inline-flex;align-items:center;gap:8px;text-align:left;
  padding-bottom:2px;font-size:14.5px;color:var(--c-mist);
  border-bottom:1px dashed rgba(215,229,240,.4);
  transition:color var(--dur) ease,border-color var(--dur) ease;
}
.copy-chip::after{
  content:"复制";font-family:var(--f-mono);font-size:10px;letter-spacing:.14em;
  color:var(--c-gold);border:1px solid rgba(201,162,39,.5);padding:1px 4px;
}
.copy-chip:hover{color:var(--c-gold);border-bottom-color:var(--c-gold)}
.copy-chip[data-copied]{color:var(--c-jade);border-bottom-color:var(--c-jade)}
.copy-chip[data-copied]::after{content:"已复制";color:var(--c-jade);border-color:var(--c-jade)}
.contact-value{display:block;font-size:14px;line-height:1.7;color:rgba(251,249,245,.68)}
.footer-base{
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;
  gap:12px 28px;padding-block:18px 26px;
  border-top:1px solid rgba(215,229,240,.16);
  font-family:var(--f-mono);font-size:12.5px;letter-spacing:.06em;color:rgba(215,229,240,.6);
}
.footer-icp,.footer-copy,.footer-region{margin:0}

/* ===== 05 按钮与标签 ===== */
.btn{
  display:inline-flex;align-items:center;gap:10px;
  padding:14px 26px;border:1px solid var(--c-tianshan);
  background:transparent;color:var(--c-tianshan);
  font-size:15px;letter-spacing:.1em;
  transition:background-color var(--dur) ease,color var(--dur) ease,border-color var(--dur) ease;
}
.btn:hover{background:var(--c-tianshan);color:var(--c-mist)}
.btn--solid{background:var(--c-tianshan);color:var(--c-mist)}
.btn--solid:hover{background:var(--c-night);border-color:var(--c-night)}
.btn--gold{background:var(--c-gold);border-color:var(--c-gold);color:var(--c-night)}
.btn--gold:hover{background:var(--c-rose);border-color:var(--c-rose);color:var(--c-mist)}
.btn--line{border-color:var(--c-bronze);color:var(--c-bronze)}
.btn--line:hover{background:var(--c-bronze);border-color:var(--c-bronze);color:var(--c-mist)}
.tag{
  display:inline-block;padding:4px 10px;border:1px solid currentColor;
  font-family:var(--f-mono);font-size:11px;letter-spacing:.16em;
}
.tag--gold{color:var(--c-gold)}
.tag--rose{color:var(--c-rose)}
.tag--green{color:var(--c-jade)}
.tag--blue{color:var(--c-tianshan)}

/* ===== 06 面包屑与章节 ===== */
.crumbs{
  display:flex;flex-wrap:wrap;align-items:center;gap:8px;
  margin:0 0 clamp(20px,3vw,34px);
  font-family:var(--f-mono);font-size:12px;letter-spacing:.14em;color:var(--c-bronze);
}
.crumbs a{transition:color var(--dur) ease}
.crumbs a:hover{color:var(--c-tianshan)}
.crumbs-sep{color:rgba(140,106,47,.6)}
.chapter{margin:0 0 clamp(44px,7vw,92px)}
.chapter-head{
  display:grid;grid-template-columns:auto 1fr;align-items:end;gap:8px 20px;
  padding-bottom:16px;margin-bottom:clamp(18px,2.6vw,30px);
  border-bottom:1px solid var(--c-line);
}
.chapter-index{font-family:var(--f-mono);font-size:13px;letter-spacing:.22em;color:var(--c-gold)}
.chapter-title{font-size:clamp(28px,3.4vw,40px);letter-spacing:.06em}
.chapter-lead{grid-column:2;margin:0;font-size:17px;color:var(--c-ink-72);max-width:62ch}
.chapter-body{font-size:16.5px;line-height:1.85;color:var(--c-ink-72)}
.side-index{display:grid;gap:2px}
.side-index a{
  display:block;padding:8px 0 8px 14px;border-left:2px solid var(--c-line);
  font-size:14px;color:var(--c-ink-56);
  transition:color var(--dur) ease,border-color var(--dur) ease;
}
.side-index a:hover{color:var(--c-tianshan)}
.side-index a.is-active{color:var(--c-tianshan);border-left-color:var(--c-gold);font-weight:600}

/* ===== 07 面板与研究板卡片 ===== */
.panel{
  position:relative;padding:clamp(20px,2.4vw,32px);
  background:var(--c-mist);border:1px solid var(--c-line);
}
.panel::before{content:"";position:absolute;top:-1px;left:-1px;width:46px;height:3px;background:var(--c-gold)}
.panel-index{display:block;margin-bottom:10px;font-family:var(--f-mono);font-size:11.5px;letter-spacing:.22em;color:var(--c-bronze)}
.panel-title{font-size:20px;letter-spacing:.04em;margin:0 0 10px}
.panel-text{font-size:15.5px;line-height:1.82;color:var(--c-ink-72);margin:0 0 14px}
.panel--ink{background:var(--c-night);border-color:rgba(215,229,240,.2);color:var(--c-mist)}
.panel--ink .panel-title{color:var(--c-mist)}
.panel--ink .panel-text{color:rgba(251,249,245,.76)}
.panel--ink .panel-index{color:var(--c-gold)}
.slant-block{
  padding:clamp(20px,3vw,36px);
  background:linear-gradient(135deg,var(--c-tianshan),var(--c-night) 70%,#0A1D32);
  color:var(--c-mist);
  clip-path:polygon(0 0,100% 0,100% calc(100% - 24px),calc(100% - 24px) 100%,0 100%);
}

/* ===== 08 索引列表 / 折叠 / 表格 / 标签页 ===== */
.index-list{display:grid}
.index-item{
  display:grid;gap:4px;padding:16px 2px;
  border-bottom:1px solid var(--c-line);
  transition:background-color var(--dur) ease,padding-left var(--dur) ease;
}
.index-item:hover{background:rgba(27,79,114,.045);padding-left:8px}
.index-term{font-size:16px;font-weight:600;letter-spacing:.02em}
.index-desc{font-size:14.5px;line-height:1.8;color:var(--c-ink-72);margin:0}
.fold{margin:0 0 12px;background:var(--c-mist);border:1px solid var(--c-line)}
.fold-trigger{
  display:flex;align-items:center;justify-content:space-between;gap:16px;
  padding:16px 20px;font-size:17px;font-weight:600;cursor:pointer;list-style:none;
  transition:background-color var(--dur) ease,color var(--dur) ease;
}
.fold-trigger::-webkit-details-marker{display:none}
.fold-trigger::after{content:"＋";font-family:var(--f-mono);color:var(--c-gold)}
.fold-trigger:hover{background:rgba(27,79,114,.05)}
.fold[open]>.fold-trigger{background:rgba(27,79,114,.06);color:var(--c-tianshan)}
.fold[open]>.fold-trigger::after{content:"－";color:var(--c-rose)}
.fold-panel{padding:0 20px 20px;font-size:15.5px;line-height:1.85;color:var(--c-ink-72)}
.spec-table{width:100%;border-collapse:collapse;font-size:15px}
.spec-table th,.spec-table td{padding:12px 14px;border:1px solid var(--c-line);text-align:left;vertical-align:top}
.spec-table th{background:rgba(27,79,114,.06);font-weight:600;letter-spacing:.04em}
.spec-table tbody tr:hover{background:rgba(201,162,39,.07)}
.tabs{display:grid}
.tab-list{display:flex;flex-wrap:wrap;border-bottom:1px solid var(--c-line)}
.tab-btn{
  padding:12px 20px;border-bottom:2px solid transparent;
  font-family:var(--f-mono);font-size:13px;letter-spacing:.14em;color:var(--c-ink-56);
  transition:color var(--dur) ease,border-color var(--dur) ease,background-color var(--dur) ease;
}
.tab-btn:hover{color:var(--c-tianshan)}
.tab-btn.is-active,.tab-btn[aria-selected="true"]{
  color:var(--c-tianshan);background:var(--c-mist);border-bottom-color:var(--c-gold);
}
.tab-panel{display:none;padding:22px 0 0;font-size:16px;line-height:1.85;color:var(--c-ink-72)}
.tab-panel.is-active{display:block}

/* ===== 09 图片容器 ===== */
.media-frame{
  position:relative;display:block;overflow:hidden;
  background:linear-gradient(140deg,var(--c-night),var(--c-tianshan) 58%,#123A5C);
  border:1px solid var(--c-line);
  aspect-ratio:16/9;
}
.media-frame img,.media-frame svg{width:100%;height:100%;object-fit:cover}
.media-frame::after{
  content:"";position:absolute;inset:10px;pointer-events:none;
  border:1px solid rgba(215,229,240,.34);
}
.media-frame--16x9{aspect-ratio:16/9}
.media-frame--4x3{aspect-ratio:4/3}
.media-frame--1x1{aspect-ratio:1/1}
.media-frame--tall{aspect-ratio:3/4}
.media-caption{margin:10px 0 0;font-family:var(--f-mono);font-size:12px;letter-spacing:.1em;color:var(--c-bronze)}

/* ===== 10 断点 ===== */
@media (max-width:1024px){
  .col-3,.col-4,.col-5{grid-column:span 6}
  .col-7,.col-8{grid-column:span 12}
  .footer-grid{grid-template-columns:1fr 1fr}
}
@media (max-width:900px){
  .header-frame{grid-template-columns:1fr auto;gap:12px}
  .help-anchor{display:none}
  .nav-toggle{display:inline-flex;justify-self:end}
  .primary-nav{
    position:fixed;left:0;right:0;top:0;
    max-height:100vh;overflow-y:auto;
    padding:104px var(--gutter) 40px;
    background:linear-gradient(180deg,rgba(10,29,50,.985),rgba(14,42,71,.985));
    border-bottom:2px solid var(--c-gold);
    transform:translateY(-102%);visibility:hidden;
    transition:transform .3s ease,visibility .3s ease;
  }
  .site-header[data-open] .primary-nav{transform:translateY(0);visibility:visible}
  .nav-list{flex-direction:column;align-items:stretch;gap:0}
  .nav-link{display:block;width:100%;padding:18px 2px;font-size:21px;letter-spacing:.12em;border-bottom:1px solid rgba(215,229,240,.16)}
  .nav-link::after{display:none}
  .nav-link[aria-current="page"]{padding-left:14px;border-left:3px solid var(--c-rose)}
  .mobile-help-dock{
    position:fixed;left:0;right:0;bottom:0;z-index:90;
    display:flex;align-items:center;justify-content:center;gap:12px;
    min-height:58px;padding:10px var(--gutter);
    background:var(--c-gold);color:var(--c-night);
    border-top:1px solid rgba(11,22,32,.2);
    box-shadow:0 -8px 22px rgba(11,22,32,.28);
  }
  .mobile-help-dock-label{font-weight:600;letter-spacing:.14em;font-size:15px}
  .mobile-help-dock-note{font-family:var(--f-mono);font-size:11px;letter-spacing:.16em;opacity:.78}
  .site-footer{padding-bottom:60px}
}
@media (max-width:680px){
  .col-3,.col-4,.col-5,.col-6{grid-column:span 12}
  .footer-grid{grid-template-columns:1fr;padding-block:38px 28px}
  .chapter-head{grid-template-columns:1fr}
  .chapter-lead{grid-column:1}
  .brand-name{font-size:18px}
  .brand-sub{letter-spacing:.18em}
  .footer-base{justify-content:flex-start}
}

/* ===== 11 动效与可访问性 ===== */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    transition-duration:.001ms !important;
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
  }
}