:root{
  --navy:#0B1B3A;
  --navy-2:#122B52;
  --navy-3:#08152C;
  --gold:#D4A853;
  --cyan:#35E0C8;
  --cyan-ink:#0F7C6F;
  --paper:#F4F1E8;
  --edge:#E8E2D2;
  --stone:#6E7480;
  --moss:#4F6B52;
  --clay:#B4694A;
  --ink:#0A0F18;
  --ink-soft:#3A414F;
  --line:rgba(232,226,210,.16);
  --line-strong:rgba(232,226,210,.3);
  --max:1200px;
  --header-h:76px;
  --font-sans:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-mono:"JetBrains Mono","IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --ease:cubic-bezier(.22,.61,.36,1);
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:calc(var(--header-h) + 20px)}
body,h1,h2,h3,h4,p,ul,ol,li,figure,dl,dd{margin:0}
ul,ol{padding:0;list-style:none}
img,svg,picture,video{display:block;max-width:100%}
button,input{font:inherit;color:inherit}
button{background:none;border:0;cursor:pointer}
a{color:inherit;text-decoration:none}
[hidden]{display:none !important}
:focus-visible{outline:2px solid var(--cyan);outline-offset:3px;border-radius:2px}
html{scroll-behavior:smooth}
body{
  background:var(--navy);
  color:rgba(244,241,232,.88);
  font-family:var(--font-sans);
  font-size:clamp(.95rem,1.05vw,1.0625rem);
  line-height:1.8;
  letter-spacing:.01em;
  min-height:100vh;
  overflow-x:hidden;
}
body.nav-open{overflow:hidden}
h1,h2,h3,h4{font-weight:700;letter-spacing:.03em;line-height:1.35;color:var(--paper)}
h1{font-size:clamp(2.25rem,5.5vw,4.25rem);font-weight:800;letter-spacing:.06em;line-height:1.18}
h2{font-size:clamp(1.25rem,2.2vw,1.75rem)}
h3{font-size:clamp(1.0625rem,1.5vw,1.25rem)}
::selection{background:rgba(53,224,200,.28);color:var(--paper)}
.skip-link{
  position:absolute;left:1rem;top:-120px;z-index:200;
  padding:.7rem 1.1rem;background:var(--gold);color:#0A1526;
  font-size:.875rem;letter-spacing:.08em;border-radius:2px;
  transition:top .2s var(--ease);
}
.skip-link:focus{top:1rem}
.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;
}
/* ---------- layout ---------- */
.container{width:min(100% - 2.5rem,var(--max));margin-inline:auto}
.container--narrow{width:min(100% - 2.5rem,780px);margin-inline:auto}
.section{padding-block:clamp(2.75rem,7vw,5.5rem)}
.section--tight{padding-block:clamp(1.75rem,4vw,3rem)}
.section--navy{background:var(--navy)}
.section--paper{background:var(--paper);color:var(--ink)}
.section--paper h1,.section--paper h2,.section--paper h3,.section--paper h4{color:var(--ink)}
.section--paper .lede{color:var(--ink-soft)}
.section--paper .eyebrow{color:var(--cyan-ink)}
.section-head{
  display:flex;flex-wrap:wrap;align-items:flex-end;justify-content:space-between;
  gap:1rem;margin-bottom:clamp(1.5rem,3vw,2.5rem);
}
.rule{height:1px;background:var(--line);border:0}
.layout-rail{display:grid;grid-template-columns:minmax(140px,196px) minmax(0,1fr);gap:clamp(1.5rem,4vw,3rem)}
.grid{display:grid;gap:clamp(1rem,2.4vw,1.75rem)}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid--auto{grid-template-columns:repeat(auto-fit,minmax(258px,1fr))}
.cta-row{display:flex;flex-wrap:wrap;gap:.85rem;align-items:center}
.eyebrow{
  font-family:var(--font-mono);font-size:.75rem;font-weight:500;
  letter-spacing:.22em;text-transform:uppercase;color:var(--cyan);
  margin-bottom:.85rem;
}
.section-title{font-size:clamp(1.25rem,2.2vw,1.75rem);font-weight:700;letter-spacing:.03em;color:var(--paper)}
.section-title::after{content:"";display:block;width:46px;height:2px;background:var(--gold);margin-top:.8rem}
.section--paper .section-title{color:var(--ink)}
.lede{font-size:clamp(1rem,1.4vw,1.125rem);line-height:1.95;color:rgba(244,241,232,.78);max-width:62ch}
.prose{max-width:68ch}
.prose p + p{margin-top:1.1em}
.prose h2{margin-top:2.2em;margin-bottom:.6em}
.prose h3{margin-top:1.8em;margin-bottom:.5em}
/* ---------- buttons ---------- */
.btn{
  display:inline-flex;align-items:center;gap:.5rem;
  padding:.85rem 1.5rem;border:1px solid transparent;border-radius:2px;
  font-size:.9375rem;font-weight:500;letter-spacing:.08em;
  transition:background-color .22s var(--ease),color .22s var(--ease),border-color .22s var(--ease),transform .22s var(--ease);
}
.btn:hover{transform:translateY(-2px)}
.btn--gold{background:var(--gold);color:#0A1526;border-color:var(--gold)}
.btn--gold:hover{background:#E0B96A;border-color:#E0B96A}
.btn--cyan{background:transparent;color:var(--cyan);border-color:rgba(53,224,200,.6)}
.btn--cyan:hover{background:rgba(53,224,200,.12);border-color:var(--cyan)}
.btn--ghost{background:transparent;color:var(--gold);border-color:rgba(212,168,83,.55)}
.btn--ghost:hover{background:rgba(212,168,83,.12);border-color:var(--gold)}
.section--paper .btn--ghost{color:#8A6A22;border-color:rgba(138,106,34,.45)}
.section--paper .btn--ghost:hover{background:rgba(212,168,83,.18)}
/* ---------- tags / index ---------- */
.tag{
  display:inline-flex;align-items:center;gap:.35rem;
  padding:.22rem .6rem;border:1px solid currentColor;border-radius:2px;
  font-size:.75rem;font-weight:500;letter-spacing:.12em;line-height:1.5;
}
.tag--register{color:var(--moss)}
.tag--notice{color:var(--clay)}
.tag--version{color:#8A6A22}
.tag--adapt{color:var(--cyan-ink)}
.idx{font-family:var(--font-mono);font-size:.75rem;letter-spacing:.1em;color:var(--gold)}
/* ---------- cards ---------- */
.card{
  position:relative;background:var(--paper);color:var(--ink);
  border:1px solid var(--edge);border-radius:2px;
  padding:clamp(1.25rem,2.4vw,1.75rem);
  box-shadow:6px 6px 0 rgba(6,14,30,.28);
  transition:transform .25s var(--ease),box-shadow .25s var(--ease),border-color .25s var(--ease);
}
.card:hover{transform:translateY(-3px);border-color:var(--gold);box-shadow:9px 11px 0 rgba(6,14,30,.34)}
.card--navy{background:var(--navy-2);color:rgba(244,241,232,.86);border-color:var(--line)}
.card--navy .card-title{color:var(--paper)}
.card--navy .card-text{color:rgba(244,241,232,.72)}
.card-head{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:.75rem;margin-bottom:.85rem}
.card-title{font-size:1.0625rem;font-weight:700;letter-spacing:.03em;color:var(--ink)}
.card-text{font-size:.9375rem;line-height:1.85;color:var(--ink-soft)}
.card-meta{display:flex;flex-wrap:wrap;gap:.75rem;margin-top:1rem;font-family:var(--font-mono);font-size:.75rem;letter-spacing:.08em;color:var(--stone)}
/* ---------- media ---------- */
.media{
  position:relative;overflow:hidden;border:1px solid var(--edge);border-radius:2px;
  background:linear-gradient(155deg,var(--navy-2),var(--navy) 70%);
}
.media img,.media video{width:100%;height:100%;object-fit:cover}
.media--16x9{aspect-ratio:16/9}
.media--4x3{aspect-ratio:4/3}
.media--21x9{aspect-ratio:21/9}
.media--square{aspect-ratio:1/1}
.media-frame{padding:.55rem;background:var(--paper);border:1px solid var(--edge);box-shadow:8px 8px 0 rgba(6,14,30,.26)}
.media-cap{margin-top:.6rem;font-size:.8125rem;letter-spacing:.08em;color:var(--stone)}
/* ---------- crumbs ---------- */
.crumbs{padding-block:1.1rem}
.crumbs-list{display:flex;flex-wrap:wrap;align-items:center;gap:.45rem;font-size:.8125rem;letter-spacing:.06em;color:rgba(244,241,232,.58)}
.crumb{transition:color .2s var(--ease)}
.crumb:hover{color:var(--cyan)}
.crumb-sep{color:rgba(244,241,232,.28)}
.crumb--current{color:var(--gold)}
.section--paper .crumbs-list{color:#5A6270}
.section--paper .crumb-sep{color:#B9BCC4}
/* ---------- rail (章节索引) ---------- */
.rail{position:sticky;top:calc(var(--header-h) + 26px)}
.rail-list{display:flex;flex-direction:column;gap:.1rem;border-left:1px solid var(--line);padding-left:1rem}
.rail-link{display:block;padding:.35rem 0;font-size:.875rem;letter-spacing:.05em;color:rgba(244,241,232,.5);transition:color .22s var(--ease),transform .22s var(--ease)}
.rail-link:hover{color:var(--cyan);transform:translateX(2px)}
.rail-link[aria-current="true"]{color:var(--gold)}
.section--paper .rail-list{border-color:var(--edge)}
.section--paper .rail-link{color:#6E7480}
.section--paper .rail-link[aria-current="true"]{color:#8A6A22}
/* ---------- reveal ---------- */
.has-js .reveal{opacity:0;transform:translateY(14px);transition:opacity .45s var(--ease),transform .45s var(--ease)}
.has-js .reveal.is-visible{opacity:1;transform:none}
/* ---------- header ---------- */
.site-header{
  position:sticky;top:0;z-index:70;
  background:rgba(11,27,58,.95);
  -webkit-backdrop-filter:blur(10px);
  backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line);
  color:var(--paper);
  transition:background-color .25s var(--ease),box-shadow .25s var(--ease);
}
.site-header.is-scrolled{background:rgba(8,21,44,.99);box-shadow:0 12px 34px rgba(3,8,18,.5)}
.header-edge{
  position:absolute;left:0;right:0;top:0;height:2px;display:block;
  background:linear-gradient(90deg,var(--gold),rgba(212,168,83,0) 38%,rgba(53,224,200,0) 62%,var(--cyan));
  opacity:.6;
}
.progress-track{position:absolute;left:0;right:0;bottom:-1px;height:2px;background:rgba(232,226,210,.12);overflow:hidden}
.progress-bar{display:block;height:100%;width:100%;transform:scaleX(0);transform-origin:0 50%;background:linear-gradient(90deg,var(--cyan),var(--gold))}
.header-inner{
  width:min(100% - 2.5rem,var(--max));margin-inline:auto;
  min-height:var(--header-h);
  display:flex;align-items:center;justify-content:space-between;gap:1.5rem;
}
.brand{display:inline-flex;align-items:center;gap:.75rem;flex:0 0 auto}
.brand-mark{display:inline-flex;flex:0 0 auto}
.brand-text{display:flex;flex-direction:column;gap:.1rem}
.brand-name{font-size:1.0625rem;font-weight:800;letter-spacing:.18em;color:var(--paper)}
.brand-tag{font-size:.6875rem;letter-spacing:.2em;color:rgba(244,241,232,.52)}
.header-actions{display:flex;align-items:center;gap:clamp(.75rem,1.6vw,1.35rem)}
/* nav */
.site-nav{display:flex;align-items:center}
.nav-caption{display:none}
.nav-list{display:flex;align-items:center;gap:clamp(.8rem,1.9vw,1.6rem)}
.nav-item{display:flex}
.nav-link{
  position:relative;display:inline-flex;align-items:center;gap:.4rem;
  padding:.55rem 0;font-size:.9rem;letter-spacing:.07em;
  color:rgba(244,241,232,.8);
  transition:color .22s var(--ease);
}
.nav-link .idx{font-size:.6875rem;color:rgba(212,168,83,.85);transition:color .22s var(--ease)}
.nav-link::after{
  content:"";position:absolute;left:0;right:0;bottom:0;height:2px;
  background:var(--cyan);transform:scaleX(0);transform-origin:0 50%;
  transition:transform .25s var(--ease),background-color .25s var(--ease);
}
.nav-link:hover{color:var(--cyan)}
.nav-link:hover::after{transform:scaleX(1)}
.nav-link[aria-current="page"]{color:var(--paper)}
.nav-link[aria-current="page"] .idx{color:var(--gold)}
.nav-link[aria-current="page"]::after{transform:scaleX(1);background:var(--gold)}
/* search toggle */
.search-toggle{
  display:inline-flex;align-items:center;gap:.5rem;
  padding:.5rem .85rem;border:1px solid rgba(53,224,200,.55);border-radius:2px;
  color:var(--cyan);font-size:.875rem;letter-spacing:.1em;
  transition:background-color .22s var(--ease),border-color .22s var(--ease);
}
.search-toggle:hover{background:rgba(53,224,200,.12);border-color:var(--cyan)}
.search-toggle-icon{display:inline-flex}
/* nav toggle */
.nav-toggle{display:none;align-items:center;justify-content:center;width:44px;height:44px;border:1px solid var(--line-strong);border-radius:2px;color:var(--paper)}
.nav-toggle-bars{position:relative;display:block;width:18px;height:2px;border-radius:2px;background:var(--paper);transition:background-color .2s var(--ease)}
.nav-toggle-bars::before,.nav-toggle-bars::after{
  content:"";position:absolute;left:0;width:18px;height:2px;border-radius:2px;background:var(--paper);
  transition:transform .25s var(--ease),background-color .25s var(--ease);
}
.nav-toggle-bars::before{top:-6px}
.nav-toggle-bars::after{top:6px}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars{background:transparent}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::before{transform:translateY(6px) rotate(45deg);background:var(--gold)}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::after{transform:translateY(-6px) rotate(-45deg);background:var(--gold)}
/* search panel */
.search-panel{
  position:fixed;left:0;right:0;top:var(--header-h);z-index:66;
  background:#0C2143;
  border-bottom:1px solid rgba(212,168,83,.4);
  box-shadow:0 28px 56px rgba(3,8,18,.55);
  max-height:calc(100vh - var(--header-h));
  overflow-y:auto;
  opacity:0;visibility:hidden;transform:translateY(-10px);
  transition:opacity .25s var(--ease),transform .25s var(--ease),visibility .25s linear;
}
.search-panel[data-open]{opacity:1;visibility:visible;transform:none}
.search-panel-inner{width:min(100% - 2.5rem,var(--max));margin-inline:auto;padding:1.75rem 0 2.25rem}
.search-label{display:block;font-family:var(--font-mono);font-size:.75rem;letter-spacing:.2em;color:var(--gold);margin-bottom:.7rem}
.search-input{
  width:100%;padding:.85rem 1rem;
  background:rgba(244,241,232,.06);border:1px solid var(--line-strong);border-radius:2px;
  color:var(--paper);font-family:var(--font-mono);font-size:.9375rem;letter-spacing:.05em;
  transition:border-color .2s var(--ease),background-color .2s var(--ease);
}
.search-input::placeholder{color:rgba(244,241,232,.4)}
.search-input:focus{border-color:var(--cyan);background:rgba(53,224,200,.08);outline:none}
.search-hint{margin-top:.7rem;font-size:.8125rem;letter-spacing:.05em;color:rgba(244,241,232,.55)}
.search-list{display:grid;grid-template-columns:repeat(auto-fit,minmax(190px,1fr));gap:.55rem;margin-top:1.35rem}
.search-link{
  display:flex;align-items:center;gap:.6rem;
  padding:.7rem .9rem;border:1px solid var(--line);border-radius:2px;
  background:rgba(18,43,82,.55);font-size:.875rem;letter-spacing:.05em;color:rgba(244,241,232,.85);
  transition:border-color .22s var(--ease),color .22s var(--ease),transform .22s var(--ease),background-color .22s var(--ease);
}
.search-link:hover,.search-link:focus-visible{border-color:var(--cyan);color:var(--cyan);background:rgba(53,224,200,.1);transform:translateX(2px)}
.search-link .idx{color:var(--gold)}
.search-empty{margin-top:1.2rem;font-size:.875rem;color:var(--clay)}
/* ---------- footer ---------- */
.site-footer{
  position:relative;overflow:hidden;
  background:var(--navy-3);color:rgba(244,241,232,.82);
  border-top:1px solid rgba(212,168,83,.4);
}
.site-footer::before{
  content:"";position:absolute;top:-200px;right:-100px;width:560px;height:560px;
  background:radial-gradient(circle,rgba(53,224,200,.16),rgba(53,224,200,0) 62%);
  pointer-events:none;
}
.site-footer::after{
  content:"";position:absolute;left:0;right:0;top:0;height:220px;
  background:linear-gradient(180deg,rgba(212,168,83,.09),rgba(212,168,83,0));
  pointer-events:none;
}
.footer-inner{
  position:relative;z-index:1;
  width:min(100% - 2.5rem,var(--max));margin-inline:auto;
  padding-block:clamp(2.5rem,6vw,4.5rem) 1.75rem;
}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1.35fr;gap:clamp(1.75rem,4vw,3.5rem)}
.footer-col{min-width:0}
.footer-brand{display:inline-flex;align-items:center;gap:.7rem;color:var(--paper)}
.footer-name{font-size:1.0625rem;font-weight:800;letter-spacing:.16em}
.footer-slogan{margin-top:1rem;font-size:1.125rem;font-weight:700;letter-spacing:.1em;color:var(--gold)}
.footer-note{margin-top:.75rem;max-width:36ch;font-size:.875rem;line-height:1.9;color:rgba(244,241,232,.6)}
.footer-heading{font-size:.8125rem;font-weight:700;letter-spacing:.2em;color:var(--gold);margin-bottom:1.1rem}
.footer-list li + li{margin-top:.6rem}
.footer-link{
  font-size:.9rem;letter-spacing:.05em;color:rgba(244,241,232,.78);
  border-bottom:1px solid transparent;transition:color .2s var(--ease),border-color .2s var(--ease);
}
.footer-link:hover{color:var(--cyan);border-color:rgba(53,224,200,.55)}
.footer-meta{margin-top:1.4rem;display:grid;gap:.65rem}
.meta-item{display:flex;gap:.75rem;font-size:.8125rem;line-height:1.7}
.meta-label{flex:0 0 4.6em;color:rgba(244,241,232,.45);letter-spacing:.1em}
.meta-value{font-family:var(--font-mono);font-size:.8125rem;letter-spacing:.03em;color:rgba(244,241,232,.88);word-break:break-word}
.footer-bottom{
  margin-top:clamp(2rem,5vw,3.25rem);padding-top:1.25rem;
  border-top:1px solid var(--line);
  display:flex;flex-wrap:wrap;gap:.85rem;justify-content:space-between;align-items:center;
  font-size:.8125rem;color:rgba(244,241,232,.52);
}
.footer-legal{font-family:var(--font-mono);letter-spacing:.06em}
.footer-update{display:inline-flex;align-items:center;gap:.55rem;letter-spacing:.05em}
.footer-update-dot{width:7px;height:7px;border-radius:50%;background:var(--cyan);box-shadow:0 0 0 4px rgba(53,224,200,.16)}
/* ---------- back to top ---------- */
.back-to-top{
  position:fixed;right:1.5rem;bottom:1.5rem;z-index:55;
  width:46px;height:46px;border-radius:50%;
  display:grid;place-items:center;
  background:rgba(18,43,82,.94);border:1px solid rgba(53,224,200,.55);color:var(--cyan);
  opacity:0;visibility:hidden;transform:translateY(10px);
  transition:opacity .25s var(--ease),transform .25s var(--ease),visibility .25s linear,background-color .25s var(--ease);
}
.back-to-top.is-visible{opacity:1;visibility:visible;transform:none}
.back-to-top:hover{background:var(--navy-2);border-color:var(--cyan)}
/* ---------- responsive ---------- */
@media (max-width:1000px){
  :root{--header-h:64px}
  .brand-tag{display:none}
  .site-nav{
    position:fixed;top:var(--header-h);right:0;bottom:0;z-index:65;
    width:min(340px,88vw);
    display:block;overflow-y:auto;
    padding:1.75rem 1.5rem 3rem;
    background:#0E2144;
    border-left:1px solid rgba(212,168,83,.4);
    box-shadow:-18px 0 40px rgba(3,8,18,.5);
    transform:translateX(102%);
    transition:transform .28s var(--ease);
  }
  .site-nav[data-open]{transform:translateX(0)}
  .nav-caption{
    display:block;font-family:var(--font-mono);font-size:.75rem;letter-spacing:.22em;
    color:rgba(244,241,232,.45);padding-bottom:.85rem;margin-bottom:1rem;
    border-bottom:1px solid var(--line);
  }
  .nav-list{flex-direction:column;align-items:stretch;gap:0}
  .nav-item{border-bottom:1px solid var(--line)}
  .nav-item .nav-link{width:100%;padding:.95rem 0;font-size:1rem;letter-spacing:.08em;gap:.75rem}
  .nav-link::after{display:none}
  .nav-link[aria-current="page"]{color:var(--gold)}
  .nav-link[aria-current="page"] .idx{color:var(--cyan)}
  .nav-toggle{display:inline-flex}
  .search-toggle{
    position:fixed;right:1.25rem;bottom:1.25rem;z-index:55;
    width:54px;height:54px;padding:0;border-radius:50%;
    justify-content:center;
    background:rgba(18,43,82,.94);
    box-shadow:0 10px 26px rgba(3,8,18,.5);
  }
  .search-toggle-text{display:none}
  .back-to-top{right:1.25rem;bottom:5.5rem;width:44px;height:44px}
  .layout-rail{grid-template-columns:minmax(0,1fr)}
  .rail{position:static}
  .rail-list{flex-direction:row;flex-wrap:wrap;gap:.35rem;border-left:0;padding-left:0;border-bottom:1px solid var(--line);padding-bottom:.75rem}
  .rail-link{padding:.3rem .6rem;border:1px solid var(--line);border-radius:2px}
}
@media (max-width:760px){
  .grid--2,.grid--3{grid-template-columns:minmax(0,1fr)}
  .footer-grid{grid-template-columns:minmax(0,1fr)}
  .footer-note{max-width:none}
  .search-list{grid-template-columns:minmax(0,1fr)}
  .header-inner{width:min(100% - 1.75rem,var(--max))}
  .container,.container--narrow,.footer-inner,.search-panel-inner{width:min(100% - 1.75rem,var(--max))}
}
@media (max-width:420px){
  .brand-name{font-size:1rem;letter-spacing:.14em}
  .nav-toggle{width:40px;height:40px}
}
/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.001ms !important;transition-duration:.001ms !important}
  .has-js .reveal{opacity:1;transform:none}
  .btn:hover,.card:hover,.search-link:hover{transform:none}
}