/* =========================================================
   6686主站 · /assets/site.css
   技术蓝图网格 + 纸张档案层 · 共享外壳与通用组件
   ========================================================= */

/* ---------- 1. 变量 ---------- */
:root{
  --ink-950:#050D18;
  --ink-900:#081527;
  --ink-800:#0B1D33;
  --ink-700:#122A45;
  --grid:#2A3B52;
  --gold:#C9A227;
  --gold-soft:#E8D9A8;
  --red:#C0392B;
  --cool:#2E6FBF;
  --hot:#E07B39;
  --paper:#F5F2EA;
  --paper-2:#E7E1D2;
  --paper-line:#D5CCB6;
  --ink-text:#14181F;
  --ink-text-soft:#4A5361;
  --on-dark:#DCE3EC;
  --on-dark-soft:#93A4BC;

  --rail-w:248px;
  --head-h:60px;
  --step:8px;

  --f-sans:"Source Han Sans SC","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
  --f-mono:ui-monospace,"SFMono-Regular","JetBrains Mono",Menlo,Consolas,"Liberation Mono",monospace;

  --shadow-paper:0 1px 0 rgba(255,255,255,.65) inset,0 12px 26px -20px rgba(5,13,24,.6);
  --ease:cubic-bezier(.22,.61,.36,1);
}

@media (min-width:768px){:root{--head-h:68px}}
@media (min-width:1080px){:root{--head-h:76px}}

/* ---------- 2. Reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{
  margin:0;
  min-height:100vh;
  padding-top:var(--head-h);
  background:var(--ink-800);
  color:var(--on-dark);
  font-family:var(--f-sans);
  font-size:16px;
  line-height:1.75;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
@media (min-width:1080px){body{padding-left:var(--rail-w)}}
@media (max-width:1079px){body.nav-open{overflow:hidden}}

/* 蓝图网格底纹 */
body::before{
  content:"";
  position:fixed;
  inset:0;
  z-index:0;
  pointer-events:none;
  background-image:
    linear-gradient(to right,rgba(42,59,82,.42) 1px,transparent 1px),
    linear-gradient(to bottom,rgba(42,59,82,.42) 1px,transparent 1px);
  background-size:64px 64px;
  opacity:.55;
}
main,.site-footer{position:relative;z-index:1}

img,svg,video{max-width:100%;display:block;height:auto}
a{color:inherit}
h1,h2,h3,h4,p,ul,ol,dl,dd,figure,blockquote{margin:0}
ul,ol{padding:0}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
table{border-collapse:collapse}
[hidden]{display:none!important}

:focus-visible{outline:2px solid var(--gold);outline-offset:3px;border-radius:1px}
::selection{background:var(--gold);color:var(--ink-900)}

/* ---------- 3. 中文排版与文本工具 ---------- */
h1,h2,h3,h4{font-weight:800;line-height:1.12;letter-spacing:-.012em;color:#fff}
h1{font-size:clamp(40px,7vw,84px);font-weight:900;line-height:1.05}
h2{font-size:clamp(26px,3.4vw,38px)}
h3{font-size:clamp(19px,2vw,24px)}
h4{font-size:17px}

.mono{font-family:var(--f-mono);font-variant-numeric:tabular-nums;font-feature-settings:"tnum" 1;letter-spacing:.02em}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.eyebrow{font-family:var(--f-mono);font-size:12px;letter-spacing:.2em;text-transform:uppercase;color:var(--gold);display:inline-block}
.lede{font-size:17px;line-height:1.7;color:#BCC8DA;max-width:38em}
.rule{display:block;height:1px;background:linear-gradient(90deg,var(--gold),rgba(201,162,39,0));border:0;margin:0}
.prose{max-width:38em;line-height:1.78;color:var(--on-dark)}
.prose p{margin-bottom:1.05em}
.prose strong{color:#fff}
.prose a{color:var(--gold-soft);text-decoration:underline;text-underline-offset:3px}

/* ---------- 4. 布局外壳 ---------- */
.shell{width:min(1240px,calc(100% - 40px));margin-inline:auto}
@media (min-width:768px){.shell{width:min(1240px,calc(100% - 64px))}}
.band{position:relative;padding:64px 0}
.band--paper{background:var(--paper);color:var(--ink-text)}
.band--paper h2,.band--paper h3,.band--paper h1{color:var(--ink-text)}
.band--paper .lede,.band--paper .prose{color:var(--ink-text-soft)}
.band--ink{background:var(--ink-900);border-top:1px solid var(--grid);border-bottom:1px solid var(--grid)}

.section{margin-block:64px}
.section__head{
  display:flex;flex-wrap:wrap;align-items:baseline;gap:6px 16px;
  padding-bottom:10px;margin-bottom:26px;
  border-bottom:1px solid var(--grid);
}
.band--paper .section__head{border-bottom-color:var(--paper-line)}

.grid{display:grid;gap:24px}
@media (min-width:1024px){
  .grid--3-9{grid-template-columns:3fr 9fr}
  .grid--4-8{grid-template-columns:4fr 8fr}
  .grid--5-7{grid-template-columns:5fr 7fr}
}

/* ---------- 5. 按钮与标签 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:11px 20px;border:1px solid var(--grid);border-radius:2px;
  background:transparent;color:var(--on-dark);
  font-size:14px;font-weight:700;letter-spacing:.02em;line-height:1.2;
  text-decoration:none;white-space:nowrap;
  transition:background .18s var(--ease),border-color .18s var(--ease),color .18s var(--ease),transform .18s var(--ease);
}
.btn:hover{transform:translateY(-1px)}
.btn--gold{background:var(--gold);border-color:var(--gold);color:#1B1405}
.btn--gold:hover{background:var(--gold-soft);border-color:var(--gold-soft)}
.btn--ghost:hover{border-color:var(--gold);color:var(--gold-soft)}
.btn--sm{padding:8px 14px;font-size:13px}

.tag,.chip{
  display:inline-flex;align-items:center;gap:6px;
  padding:3px 9px;border:1px solid var(--grid);border-radius:2px;
  font-family:var(--f-mono);font-size:11px;letter-spacing:.14em;text-transform:uppercase;
  color:var(--on-dark-soft);
}
.chip{color:var(--gold);border-color:rgba(201,162,39,.5);background:rgba(201,162,39,.08)}
.tag--hot{color:var(--hot);border-color:rgba(224,123,57,.5)}
.tag--cool{color:var(--cool);border-color:rgba(46,111,191,.55)}
.tag--alert{color:#F0B4AC;border-color:rgba(192,57,43,.65);background:rgba(192,57,43,.14)}

/* ---------- 6. 卡片 / 表格 / 媒体 / 提示 ---------- */
.card{
  position:relative;
  padding:22px;border:1px solid var(--grid);border-radius:2px;
  background:linear-gradient(180deg,rgba(18,42,69,.55),rgba(8,21,39,.35));
}
.card--paper{
  background:var(--paper);color:var(--ink-text);
  border-color:var(--paper-line);
  box-shadow:var(--shadow-paper);
}
.card--paper h3,.card--paper h4{color:var(--ink-text)}
.card__tag{
  position:absolute;top:-1px;right:-1px;
  padding:3px 9px;background:var(--ink-900);color:var(--gold);
  border:1px solid var(--grid);
  font-family:var(--f-mono);font-size:11px;letter-spacing:.14em;
}

.tbl-wrap{overflow-x:auto;border:1px solid var(--grid);border-radius:2px;background:rgba(8,21,39,.4)}
.tbl{width:100%;min-width:560px;font-size:14px}
.tbl caption{text-align:left;padding:12px 16px;color:var(--on-dark-soft);font-size:13px}
.tbl th,.tbl td{padding:11px 16px;text-align:left;border-bottom:1px solid rgba(42,59,82,.75);vertical-align:top}
.tbl th{
  font-family:var(--f-mono);font-size:12px;letter-spacing:.12em;text-transform:uppercase;
  color:var(--gold);background:rgba(8,21,39,.85);white-space:nowrap;
}
.tbl tbody tr:hover{background:rgba(201,162,39,.06)}
.tbl td.num,.tbl th.num{font-family:var(--f-mono);font-variant-numeric:tabular-nums;white-space:nowrap}
.band--paper .tbl-wrap{background:#fff;border-color:var(--paper-line)}
.band--paper .tbl th{background:var(--paper-2);color:#6A5410;border-bottom-color:var(--paper-line)}
.band--paper .tbl th,.band--paper .tbl td{border-bottom-color:var(--paper-line);color:var(--ink-text)}

.media{
  position:relative;width:100%;aspect-ratio:16/10;overflow:hidden;
  display:grid;place-items:center;
  border:1px solid var(--grid);border-radius:2px;
  background:
    linear-gradient(to right,rgba(42,59,82,.5) 1px,transparent 1px) 0 0/32px 32px,
    linear-gradient(to bottom,rgba(42,59,82,.5) 1px,transparent 1px) 0 0/32px 32px,
    var(--ink-900);
}
.media img{width:100%;height:100%;object-fit:cover}
.media--wide{aspect-ratio:21/9}
.media--tall{aspect-ratio:4/5}
.media--square{aspect-ratio:1/1}
.media__cap{
  margin-top:8px;font-family:var(--f-mono);font-size:12px;letter-spacing:.08em;color:var(--on-dark-soft);
}

.callout{
  padding:14px 18px;border-left:3px solid var(--gold);
  background:rgba(201,162,39,.08);color:var(--on-dark);
}
.callout--alert{border-left-color:var(--red);background:rgba(192,57,43,.1)}

.stat{display:grid;gap:4px;padding:16px;border:1px solid var(--grid);border-radius:2px;background:rgba(8,21,39,.45)}
.stat__num{font-family:var(--f-mono);font-variant-numeric:tabular-nums;font-size:clamp(24px,3vw,34px);font-weight:700;color:var(--gold);line-height:1.1}
.stat__label{font-size:13px;letter-spacing:.06em;color:var(--on-dark-soft)}

.breadcrumb{font-size:13px;margin-bottom:22px}
.breadcrumb__list{display:flex;flex-wrap:wrap;gap:8px;list-style:none;color:var(--on-dark-soft)}
.breadcrumb__list li+li::before{content:"/";margin-right:8px;color:var(--grid)}
.breadcrumb__list a{text-decoration:none;color:var(--on-dark-soft)}
.breadcrumb__list a:hover{color:var(--gold-soft)}
.breadcrumb__list [aria-current="page"]{color:var(--gold)}

/* 显现动效 */
.reveal{opacity:0;transform:translateY(15px);transition:opacity .5s var(--ease),transform .5s var(--ease)}
.reveal.is-visible{opacity:1;transform:none}

/* ---------- 7. 跳至主内容 ---------- */
.skip-link{
  position:fixed;top:0;left:0;z-index:200;
  padding:10px 18px;background:var(--gold);color:var(--ink-900);
  font-weight:700;font-size:14px;text-decoration:none;
  transform:translateY(-120%);
  transition:transform .18s var(--ease);
}
.skip-link:focus{transform:translateY(0)}

/* ---------- 8. 顶部航标条 ---------- */
.site-header{position:relative;z-index:80}
.topbar{
  position:fixed;top:0;left:0;right:0;
  height:var(--head-h);z-index:70;
  background:var(--ink-900);
  border-bottom:1px solid var(--grid);
}
.topbar__inner{
  display:flex;align-items:center;gap:16px;
  height:100%;width:min(1560px,100%);margin-inline:auto;
  padding-inline:16px;
}
@media (min-width:768px){.topbar__inner{padding-inline:24px;gap:24px}}

.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:#fff;min-width:0}
.brand__mark{
  flex:none;display:grid;place-items:center;
  width:36px;height:36px;
  background:linear-gradient(140deg,var(--gold),#8E6F14);
  color:var(--ink-950);
  font-family:var(--f-mono);font-size:15px;font-weight:700;letter-spacing:.02em;
  border-radius:2px;
}
.brand__text{display:flex;flex-direction:column;min-width:0}
.brand__name{font-size:17px;font-weight:900;line-height:1.15;letter-spacing:.01em}
.brand__tag{
  display:none;
  font-size:11px;line-height:1.3;color:var(--on-dark-soft);
  font-family:var(--f-mono);letter-spacing:.04em;
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
}
@media (min-width:700px){.brand__tag{display:block}}

.topbar__utility{display:none;align-items:center;gap:6px;margin-left:auto}
@media (min-width:1080px){.topbar__utility{display:flex}}
.u-link{
  padding:6px 10px;border-radius:2px;
  font-size:13px;color:var(--on-dark-soft);text-decoration:none;
  border:1px solid transparent;
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.u-link:hover{color:var(--gold-soft);border-color:var(--grid)}

.topbar__cta{display:flex;align-items:center;gap:8px;margin-left:auto}
.topbar__utility+.topbar__cta{margin-left:0}
.topbar__cta .btn--ghost{display:none}
@media (min-width:900px){.topbar__cta .btn--ghost{display:inline-flex}}

/* 移动目录按钮 */
.nav-toggle{
  flex:none;display:inline-flex;align-items:center;gap:8px;
  padding:8px 12px;margin-left:auto;
  border:1px solid var(--grid);border-radius:2px;
  color:var(--on-dark);font-size:13px;letter-spacing:.08em;
}
.topbar__cta+.nav-toggle,.topbar__utility+.nav-toggle{margin-left:8px}
.nav-toggle:hover{border-color:var(--gold);color:var(--gold-soft)}
.nav-toggle__bars{display:grid;gap:4px;width:16px}
.nav-toggle__bars span{display:block;height: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(6px) 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(-6px) rotate(-45deg)}
.nav-toggle__text{display:none}
@media (min-width:420px){.nav-toggle__text{display:inline}}
@media (min-width:1080px){.nav-toggle{display:none}}

/* ---------- 9. 侧边轨道导航 / 抽屉 ---------- */
.rail{
  position:fixed;
  top:var(--head-h);left:0;bottom:0;
  width:min(320px,86vw);
  z-index:60;
  display:flex;flex-direction:column;
  padding:22px 0 24px;
  background:var(--ink-900);
  border-right:1px solid var(--grid);
  overflow-y:auto;
  visibility:hidden;
  transform:translateX(-104%);
  transition:transform .26s var(--ease),visibility .26s;
}
.rail[data-open="true"]{visibility:visible;transform:none}
@media (min-width:1080px){
  .rail{
    width:var(--rail-w);
    visibility:visible;transform:none;
    transition:none;
  }
}

.rail__head{
  display:flex;align-items:baseline;justify-content:space-between;gap:10px;
  padding:0 20px 14px;
  border-bottom:1px solid var(--grid);
  margin-bottom:14px;
}
.rail__head-k{font-size:13px;font-weight:800;letter-spacing:.08em;color:#fff}
.rail__head-v{font-family:var(--f-mono);font-size:11px;letter-spacing:.22em;color:var(--gold)}

.rail__list{list-style:none;display:grid;gap:2px}
.rail__item{display:block}
.rail__link{
  display:grid;grid-template-columns:34px 1fr;align-items:center;gap:10px;
  padding:11px 20px;
  border-left:2px solid transparent;
  color:var(--on-dark);text-decoration:none;
  transition:background .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease);
}
.rail__num{font-family:var(--f-mono);font-size:11px;letter-spacing:.1em;color:#5F7characters}
.rail__num{color:#5F7391}
.rail__label{font-size:15px;font-weight:700;letter-spacing:.02em}
.rail__link:hover{background:rgba(201,162,39,.09);color:#fff}
.rail__link:hover .rail__num{color:var(--gold-soft)}
.rail__link[aria-current="page"]{
  border-left-color:var(--gold);
  background:linear-gradient(90deg,rgba(201,162,39,.18),rgba(201,162,39,0));
  color:var(--gold-soft);
}
.rail__link[aria-current="page"] .rail__num{color:var(--gold)}

.rail__foot{
  margin-top:auto;padding:18px 20px 0;
  border-top:1px solid var(--grid);
  display:grid;gap:12px;
}
.rail__status{
  display:flex;align-items:flex-start;gap:8px;
  font-size:12px;line-height:1.6;color:var(--on-dark-soft);
}
.pulse{
  flex:none;width:8px;height:8px;margin-top:6px;border-radius:50%;
  background:var(--red);
  box-shadow:0 0 0 0 rgba(192,57,43,.6);
  animation:pulse 2.4s var(--ease) infinite;
}
@keyframes pulse{
  0%{box-shadow:0 0 0 0 rgba(192,57,43,.55)}
  70%{box-shadow:0 0 0 10px rgba(192,57,43,0)}
  100%{box-shadow:0 0 0 0 rgba(192,57,43,0)}
}
.rail__utility{display:none;gap:2px;flex-wrap:wrap}
.rail__cta{display:none;gap:8px}
.rail__cta .btn{width:100%}
@media (max-width:1079px){
  .rail__utility{display:flex}
  .rail__cta{display:grid}
}

.nav-scrim{
  position:fixed;inset:0;z-index:55;
  background:rgba(5,13,24,.64);
  border:0;
}
@media (min-width:1080px){.nav-scrim{display:none!important}}

/* ---------- 10. 页脚 ---------- */
.site-footer{
  margin-top:96px;
  background:var(--ink-950);
  border-top:1px solid var(--grid);
  color:var(--on-dark);
}
.footer__grid{
  width:min(1240px,calc(100% - 40px));margin-inline:auto;
  padding:56px 0 32px;
  display:grid;gap:40px;
}
@media (min-width:768px){.footer__grid{width:min(1240px,calc(100% - 64px))}}
@media (min-width:960px){.footer__grid{grid-template-columns:minmax(260px,1.05fr) 2fr;gap:56px}}

.footer__brand{display:grid;gap:18px;align-content:start}
.brand--footer .brand__name{color:#fff}
.brand--footer .brand__tag{display:block;white-space:normal}
.footer__lead{font-size:14px;line-height:1.7;color:var(--on-dark-soft);max-width:32em}

.footer__meta{display:grid;gap:0;border-top:1px solid var(--grid)}
.footer__meta-row{
  display:flex;justify-content:space-between;gap:16px;
  padding:9px 0;border-bottom:1px solid rgba(42,59,82,.6);
  font-size:13px;
}
.footer__meta-row dt{color:var(--on-dark-soft);letter-spacing:.06em}
.footer__meta-row dd{margin:0;font-family:var(--f-mono);font-variant-numeric:tabular-nums;color:var(--gold-soft)}

.footer__cols{display:grid;gap:28px;grid-template-columns:repeat(auto-fit,minmax(150px,1fr))}
.footer__col{display:grid;gap:12px;align-content:start}
.footer__col-title{
  font-family:var(--f-mono);font-size:12px;font-weight:700;
  letter-spacing:.18em;text-transform:uppercase;color:var(--gold);
  padding-bottom:10px;border-bottom:1px solid var(--grid);
}
.footer__links{list-style:none;display:grid;gap:9px}
.footer__links a{
  display:inline-flex;align-items:center;gap:8px;
  font-size:14px;color:#AFBCCF;text-decoration:none;
  transition:color .18s var(--ease);
}
.footer__links a::before{
  content:"";width:10px;height:1px;background:var(--grid);
  transition:width .18s var(--ease),background .18s var(--ease);
}
.footer__links a:hover{color:var(--gold-soft)}
.footer__links a:hover::before{width:18px;background:var(--gold)}

.footer__contact{
  width:min(1240px,calc(100% - 40px));margin-inline:auto;
  padding:22px 0;
  border-top:1px solid var(--grid);
  display:grid;gap:6px;
}
@media (min-width:768px){.footer__contact{width:min(1240px,calc(100% - 64px))}}
.footer__address{font-style:normal;display:grid;gap:4px;font-size:13px;color:#B7C4D6}
.footer__line{display:block}
.footer__line .mono{color:var(--gold-soft)}
.footer__note{font-size:12px;color:var(--on-dark-soft)}

.footer__bottom{
  width:min(1240px,calc(100% - 40px));margin-inline:auto;
  padding:16px 0 28px;
  border-top:1px dashed rgba(42,59,82,.9);
  display:flex;flex-wrap:wrap;gap:8px 24px;justify-content:space-between;
  font-size:12px;color:var(--on-dark-soft);
}
@media (min-width:768px){.footer__bottom{width:min(1240px,calc(100% - 64px))}}
.footer__legal,.footer__copy{font-family:var(--f-mono);letter-spacing:.04em}

/* ---------- 11. JS 注入件：进度条与返回顶部 ---------- */
.scroll-progress{
  position:fixed;left:0;right:0;top:calc(var(--head-h) - 2px);
  height:2px;z-index:75;pointer-events:none;background:transparent;
}
.scroll-progress__bar{
  display:block;height:100%;width:100%;
  transform:scaleX(0);transform-origin:0 50%;
  background:linear-gradient(90deg,var(--gold),var(--gold-soft));
}
.to-top{
  position:fixed;right:16px;bottom:20px;z-index:65;
  display:inline-flex;align-items:center;gap:6px;
  padding:10px 14px;
  border:1px solid var(--grid);border-radius:2px;
  background:rgba(8,21,39,.92);color:var(--gold-soft);
  font-family:var(--f-mono);font-size:12px;letter-spacing:.1em;
  opacity:0;transform:translateY(10px);pointer-events:none;
  transition:opacity .22s var(--ease),transform .22s var(--ease),border-color .18s var(--ease);
}
.to-top.is-on{opacity:1;transform:none;pointer-events:auto}
.to-top:hover{border-color:var(--gold);color:#fff}
@media (min-width:1080px){.to-top{right:28px;bottom:28px}}

/* 章节目录（可选，页面阶段自带 [data-toc]） */
[data-toc] a{color:var(--on-dark-soft);text-decoration:none}
[data-toc] a.is-active,[data-toc] a[aria-current="true"]{color:var(--gold)}

/* ---------- 12. 无障碍降级 ---------- */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms!important;
    animation-iteration-count:1!important;
    transition-duration:.001ms!important;
  }
  .reveal{opacity:1;transform:none}
  .pulse{animation:none;box-shadow:none}
}