*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:120px}
body{margin:0}
h1,h2,h3,h4,p,ul,ol,figure,blockquote{margin:0}
ul,ol{padding:0;list-style:none}
img,svg,picture{max-width:100%}
button{font:inherit;color:inherit}

:root{
  --paper:#F6F0E4;
  --paper-deep:#EADFCB;
  --ink:#2A211C;
  --ink-soft:rgba(42,33,28,.72);
  --cinnabar:#B5412F;
  --ember:#D96C3B;
  --azurite:#2F6473;
  --ochre:#C89B4A;
  --pine:#29473A;
  --sand:#D9C7A3;
  --font-display:"Songti SC","Source Han Serif SC","Noto Serif SC","STZhongsong",serif;
  --font-body:"Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --shell-w:1240px;
  --gutter:clamp(1rem,4vw,2.5rem);
  --header-h:78px;
  --ease:cubic-bezier(.22,.61,.36,1);
}

body{
  background:var(--paper);
  color:var(--ink);
  font-family:var(--font-body);
  font-size:17px;
  line-height:1.75;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
h1,h2,h3,h4{font-family:var(--font-display);font-weight:800;line-height:1.14;letter-spacing:.01em;text-wrap:balance}
p{text-wrap:pretty}
a{color:var(--azurite)}
a:hover{color:var(--cinnabar)}
:where(a,button,summary,[tabindex]):focus-visible{outline:3px solid var(--azurite);outline-offset:3px;border-radius:1px}
.site-footer :where(a,button):focus-visible{outline-color:var(--ochre)}

.shell{width:min(var(--shell-w),100% - var(--gutter) * 2);margin-inline:auto}
.page-main{display:block;padding-bottom:clamp(2rem,5vw,4rem)}
.content{max-width:72ch;font-size:1.02rem}
.prose{max-width:74ch;font-size:1.02rem;color:var(--ink)}
.prose h2{font-size:clamp(1.5rem,3vw,2.1rem);margin:2.4rem 0 .9rem}
.prose h3{font-size:1.22rem;margin:1.9rem 0 .6rem;color:var(--pine)}
.prose p{margin:0 0 1.1rem}
.prose ul,.prose ol{margin:0 0 1.2rem;padding-left:1.25rem;list-style:disc}
.prose li{margin-bottom:.45rem}
.prose a{text-decoration:underline;text-underline-offset:3px}

/* ---------- skip link ---------- */
.skip-link{
  position:fixed;left:1rem;top:-4.5rem;z-index:200;
  background:var(--ink);color:var(--paper);text-decoration:none;
  padding:.7rem 1.15rem;font-size:.86rem;letter-spacing:.04em;border-radius:2px;
  transition:top .22s var(--ease);
}
.skip-link:focus{top:.75rem;color:var(--paper)}

/* ---------- header ---------- */
.site-header{position:sticky;top:0;z-index:100;isolation:isolate}
.utility-bar{
  background:var(--ink);color:rgba(246,240,228,.84);
  font-family:var(--font-mono);font-size:.72rem;letter-spacing:.05em;
  max-height:44px;overflow:hidden;
  transition:max-height .34s var(--ease),opacity .26s var(--ease);
}
.site-header[data-scrolled="true"] .utility-bar{max-height:0;opacity:0}
.utility-bar__inner{display:flex;align-items:center;gap:.85rem;min-height:34px}
.utility-bar__mark{width:9px;height:9px;background:var(--ochre);flex:none}
.utility-bar__text{margin:0;flex:1;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.utility-bar__link{color:var(--paper);text-decoration:none;white-space:nowrap;border-bottom:1px solid var(--ember);padding-bottom:1px}
.utility-bar__link:hover{color:var(--ember)}

.command-bar{position:relative;background:var(--paper);border-bottom:1px solid var(--sand)}
.command-bar__inner{display:flex;align-items:stretch;gap:clamp(.6rem,2vw,1.75rem);min-height:var(--header-h)}
.command-bar__tail{display:flex;align-items:center;gap:.6rem;margin-left:.25rem;flex:none}

.brand{display:flex;align-items:center;gap:.7rem;text-decoration:none;color:var(--ink);padding:.5rem 0;flex:none}
.brand:hover{color:var(--ink)}
.brand__gate{position:relative;display:block;width:25px;height:31px;flex:none}
.brand__gate i{position:absolute;top:7px;bottom:0;width:3px;background:var(--cinnabar)}
.brand__gate i:nth-child(1){left:0}
.brand__gate i:nth-child(2){right:0}
.brand__gate b{position:absolute;left:0;right:0;top:0;height:4px;background:var(--ochre)}
.brand__text{display:flex;flex-direction:column;line-height:1.15}
.brand__name{font-family:var(--font-display);font-weight:800;font-size:1.3rem;letter-spacing:.1em}
.brand__line{font-family:var(--font-mono);font-size:.6rem;letter-spacing:.16em;color:var(--azurite)}

.nav{display:flex;align-items:stretch;margin-left:auto}
.nav__list{display:flex;height:100%;align-items:stretch;gap:.05rem}
.nav__link{
  position:relative;display:flex;align-items:center;gap:.4rem;height:100%;
  padding:.4rem .74rem;text-decoration:none;color:var(--ink-soft);
  font-size:.9rem;font-weight:500;letter-spacing:.02em;
  transition:color .2s var(--ease),background .2s var(--ease);
}
.nav__idx{font-family:var(--font-mono);font-size:.6rem;letter-spacing:.06em;color:var(--azurite);transition:color .2s var(--ease)}
.nav__link::after{
  content:"";position:absolute;left:0;right:0;bottom:0;height:3px;
  background:var(--cinnabar);transform:scaleX(0);transform-origin:left;
  transition:transform .28s var(--ease),background .2s var(--ease);
}
.nav__link:hover{color:var(--ink);background:var(--paper-deep)}
.nav__link:hover .nav__idx{color:var(--cinnabar)}
.nav__link:hover::after{transform:scaleX(1);background:var(--ember)}
.nav__link[aria-current="page"]{color:var(--ink);font-weight:600}
.nav__link[aria-current="page"] .nav__idx{color:var(--cinnabar)}
.nav__link[aria-current="page"]::after{transform:scaleX(1)}

.nav-toggle{
  display:none;align-items:center;gap:.55rem;
  background:transparent;border:1px solid var(--sand);border-radius:2px;
  padding:.55rem .8rem;color:var(--ink);cursor:pointer;
  font-family:var(--font-mono);font-size:.7rem;letter-spacing:.12em;
  transition:border-color .2s var(--ease),background .2s var(--ease);
}
.nav-toggle:hover{border-color:var(--ink);background:var(--paper-deep)}
.nav-toggle__bars{position:relative;display:block;width:18px;height:12px;flex:none}
.nav-toggle__bars::before,.nav-toggle__bars::after{
  content:"";position:absolute;left:0;right:0;height:2px;background:var(--ink);
  transition:transform .26s var(--ease),top .26s var(--ease),bottom .26s var(--ease);
}
.nav-toggle__bars::before{top:0}
.nav-toggle__bars::after{bottom:0}
.site-header[data-nav-open="true"] .nav-toggle__bars::before{top:5px;transform:rotate(45deg)}
.site-header[data-nav-open="true"] .nav-toggle__bars::after{bottom:5px;transform:rotate(-45deg)}
.nav-toggle__label{display:block}

.progress{position:absolute;left:0;right:0;bottom:-1px;height:2px;pointer-events:none}
.progress__fill{display:block;width:0;height:100%;background:linear-gradient(90deg,var(--cinnabar),var(--ember));transition:width .12s linear}

/* ---------- buttons ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.45rem;
  font-family:var(--font-body);font-size:.9rem;font-weight:600;line-height:1;
  padding:.85rem 1.35rem;border:1px solid transparent;border-radius:2px;
  text-decoration:none;cursor:pointer;
  transition:background .22s var(--ease),color .22s var(--ease),border-color .22s var(--ease),transform .22s var(--ease);
}
.btn--sm{padding:.6rem 1rem;font-size:.82rem}
.btn--solid{background:var(--cinnabar);color:var(--paper);border-color:var(--cinnabar)}
.btn--solid:hover{background:var(--ember);border-color:var(--ember);color:#FFF9F0;transform:translateY(-1px)}
.btn--ghost{background:transparent;color:var(--ink);border-color:var(--sand)}
.btn--ghost:hover{background:var(--ink);border-color:var(--ink);color:var(--paper)}
.btn--quiet{
  background:transparent;color:var(--azurite);border-color:transparent;border-radius:0;
  padding:.3rem 0;border-bottom:1px solid currentColor;
}
.btn--quiet:hover{color:var(--cinnabar)}

/* ---------- generic layout ---------- */
.grid{display:grid;gap:clamp(1rem,2.5vw,2rem)}
.grid--12{grid-template-columns:repeat(12,1fr)}
.span-3{grid-column:span 3}
.span-4{grid-column:span 4}
.span-6{grid-column:span 6}
.span-8{grid-column:span 8}
.span-12{grid-column:span 12}
.stack > * + *{margin-top:var(--stack,1.25rem)}

.breadcrumb{padding:1.15rem 0 0;font-family:var(--font-mono);font-size:.7rem;letter-spacing:.08em;color:var(--ink-soft)}
.breadcrumb__list{display:flex;flex-wrap:wrap;align-items:center;gap:.45rem}
.breadcrumb__list li{display:flex;align-items:center;gap:.45rem}
.breadcrumb__list li:not(:last-child)::after{content:"/";color:var(--sand)}
.breadcrumb a{color:var(--azurite);text-decoration:none}
.breadcrumb a:hover{color:var(--cinnabar);text-decoration:underline}
.breadcrumb__current{color:var(--ink)}

.eyebrow{
  display:inline-flex;align-items:center;gap:.55rem;
  font-family:var(--font-mono);font-size:.68rem;letter-spacing:.2em;text-transform:uppercase;
  color:var(--azurite);margin-bottom:.7rem;
}
.eyebrow::before{content:"";width:22px;height:2px;background:var(--cinnabar);flex:none}

.section-head{
  display:grid;grid-template-columns:auto 1fr;align-items:end;gap:.5rem 1.25rem;
  padding-bottom:1rem;margin-bottom:1.75rem;border-bottom:1px solid var(--sand);
}
.chapter-num{font-family:var(--font-mono);font-size:clamp(1.5rem,3vw,2.3rem);line-height:1;color:var(--ochre);letter-spacing:-.02em}
.section-head__title{font-size:clamp(1.6rem,3.4vw,2.6rem);color:var(--ink)}

.rule{display:flex;align-items:center;gap:.8rem;margin:2.2rem 0;height:1px}
.rule::before,.rule::after{content:"";flex:1;height:1px;background:var(--sand)}
.rule__mark{width:8px;height:8px;background:var(--cinnabar);transform:rotate(45deg);flex:none}

/* ---------- tags / placard / panels ---------- */
.tag{
  display:inline-flex;align-items:center;gap:.35rem;
  font-family:var(--font-mono);font-size:.65rem;letter-spacing:.1em;
  padding:.26rem .55rem;border:1px solid var(--sand);border-radius:2px;
  color:var(--ink-soft);background:rgba(246,240,228,.6);
}
.tag--ochre{border-color:var(--ochre);color:#6B5220;background:rgba(200,155,74,.16)}
.tag--cinnabar{border-color:var(--cinnabar);color:var(--cinnabar);background:rgba(181,65,47,.1)}
.tag--azurite{border-color:var(--azurite);color:var(--azurite);background:rgba(47,100,115,.1)}
.tag--pine{border-color:var(--pine);color:var(--pine);background:rgba(41,71,58,.1)}

.placard{position:relative;background:var(--paper-deep);border-left:3px solid var(--ochre);padding:1.05rem 1.15rem 1.05rem 1.3rem}
.placard__label{font-family:var(--font-mono);font-size:.64rem;letter-spacing:.16em;color:var(--ink-soft);margin-bottom:.3rem}
.placard__body{font-size:.93rem;color:var(--ink)}

.cut-panel{
  background:var(--paper-deep);border-top:3px solid var(--cinnabar);
  padding:clamp(1.25rem,3vw,2rem);
  clip-path:polygon(0 0,calc(100% - 26px) 0,100% 26px,100% 100%,0 100%);
}
.cut-panel--azurite{border-top-color:var(--azurite);background:#EDE6D6}
.cut-panel--pine{border-top-color:var(--pine);background:#E7E3D2}

.index-card{
  position:relative;display:block;background:var(--paper);
  border:1px solid var(--sand);padding:1.35rem 1.2rem;text-decoration:none;color:inherit;
  transition:transform .26s var(--ease),box-shadow .26s var(--ease),border-color .26s var(--ease);
}
.index-card::after{content:"";position:absolute;top:0;right:0;width:10px;height:10px;background:var(--sand);transition:background .26s var(--ease)}
.index-card:hover,.index-card:focus-visible{
  transform:translateY(-3px);border-color:var(--cinnabar);
  box-shadow:0 18px 34px -22px rgba(42,33,28,.55);color:inherit;
}
.index-card:hover::after{background:var(--cinnabar)}

/* ---------- media ---------- */
.media-frame{
  position:relative;display:block;overflow:hidden;aspect-ratio:16/9;
  background:linear-gradient(155deg,var(--paper-deep),#DFD2B8);
  border:1px solid var(--sand);
}
.media-frame > img,.media-frame > picture > img{display:block;width:100%;height:100%;object-fit:cover}
.media-frame::before{
  content:"";position:absolute;left:0;right:0;bottom:0;height:3px;z-index:2;
  background:linear-gradient(90deg,var(--azurite) 0 33%,var(--cinnabar) 33% 66%,var(--ochre) 66% 100%);
}
.media-frame--wide{aspect-ratio:21/9}
.media-frame--tall{aspect-ratio:4/5}

/* ---------- fold ---------- */
.fold{border:1px solid var(--sand);background:var(--paper);margin-bottom:.6rem}
.fold__summary{
  display:flex;align-items:center;gap:.7rem;
  padding:.95rem 1.1rem;cursor:pointer;list-style:none;
  font-family:var(--font-display);font-weight:700;font-size:1.02rem;
  background:var(--paper-deep);transition:background .22s var(--ease),color .22s var(--ease);
}
.fold__summary::-webkit-details-marker{display:none}
.fold__summary::after{content:"+";margin-left:auto;font-family:var(--font-mono);color:var(--cinnabar);font-size:1.05rem}
.fold[open] .fold__summary{background:var(--pine);color:var(--paper)}
.fold[open] .fold__summary::after{content:"–";color:var(--ochre)}
.fold__body{padding:1.05rem 1.1rem;border-top:1px solid var(--sand);font-size:.95rem;color:var(--ink)}

/* ---------- timeline ---------- */
.timeline{position:relative;border-left:2px solid var(--sand);padding-left:1.5rem}
.timeline__item{position:relative;padding-bottom:1.6rem}
.timeline__item:last-child{padding-bottom:0}
.timeline__item::before{
  content:"";position:absolute;left:calc(-1.5rem - 6px);top:.45rem;
  width:10px;height:10px;background:var(--paper);border:2px solid var(--cinnabar);border-radius:50%;
}
.timeline__date{font-family:var(--font-mono);font-size:.72rem;letter-spacing:.08em;color:var(--azurite)}
.timeline__title{font-family:var(--font-display);font-size:1.08rem;font-weight:700;margin:.15rem 0 .3rem}

/* ---------- motion ---------- */
.has-js [data-reveal]{opacity:0;transform:translateY(18px);transition:opacity .6s var(--ease),transform .6s var(--ease)}
.has-js [data-reveal][data-revealed="true"]{opacity:1;transform:none}
[data-spy-link][aria-current="true"]{color:var(--cinnabar);font-weight:600;border-left-color:var(--cinnabar) !important}

/* ---------- footer ---------- */
.site-footer{
  position:relative;margin-top:clamp(2.5rem,7vw,5rem);
  background:var(--ink);color:rgba(246,240,228,.86);
  padding:clamp(2.5rem,6vw,4.25rem) 0 1.4rem;
}
.site-footer::before{
  content:"";position:absolute;left:0;right:0;top:0;height:6px;
  background:linear-gradient(90deg,var(--azurite) 0 25%,var(--cinnabar) 25% 50%,var(--ochre) 50% 75%,var(--pine) 75% 100%);
}
.footer__top{
  display:grid;grid-template-columns:1.5fr .72fr .72fr 1.15fr;
  gap:clamp(1.5rem,4vw,3.25rem);
  padding-bottom:clamp(1.75rem,4vw,2.75rem);
  border-bottom:1px solid rgba(217,199,163,.22);
}
.footer__brand{min-width:0}
.footer__gate{position:relative;display:block;width:32px;height:42px;margin-bottom:1rem}
.footer__gate i{position:absolute;top:8px;bottom:0;width:3px;background:var(--ochre)}
.footer__gate i:nth-child(1){left:0}
.footer__gate i:nth-child(2){right:0}
.footer__gate b{position:absolute;left:0;right:0;top:0;height:5px;background:var(--cinnabar)}
.footer__name{font-family:var(--font-display);font-weight:800;font-size:1.85rem;letter-spacing:.12em;color:var(--paper)}
.footer__summary{margin-top:.7rem;max-width:34ch;font-size:.92rem;line-height:1.8;color:rgba(246,240,228,.7)}
.footer__cta{
  display:inline-flex;align-items:center;gap:.4rem;margin-top:1.1rem;
  font-family:var(--font-mono);font-size:.7rem;letter-spacing:.12em;
  color:var(--ochre);text-decoration:none;border-bottom:1px solid rgba(200,155,74,.5);padding-bottom:.25rem;
  transition:color .22s var(--ease),border-color .22s var(--ease);
}
.footer__cta:hover{color:var(--paper);border-color:var(--paper)}
.footer__col{min-width:0}
.footer__title{
  display:flex;align-items:center;gap:.5rem;
  font-family:var(--font-mono);font-size:.66rem;letter-spacing:.22em;font-weight:500;
  color:var(--ochre);margin-bottom:1rem;
}
.footer__title::before{content:"";width:14px;height:2px;background:var(--cinnabar);flex:none}
.footer__list{display:grid;gap:.55rem}
.footer__list a{
  display:inline-block;color:rgba(246,240,228,.82);text-decoration:none;font-size:.93rem;
  padding-left:0;border-left:2px solid transparent;
  transition:color .2s var(--ease),padding-left .2s var(--ease),border-color .2s var(--ease);
}
.footer__list a:hover{color:var(--paper);padding-left:.55rem;border-left-color:var(--ochre)}
.footer__contact{display:grid;gap:.95rem}
.footer__contact-label{display:block;font-family:var(--font-mono);font-size:.62rem;letter-spacing:.16em;color:rgba(200,155,74,.9);margin-bottom:.2rem}
.footer__contact-value{display:flex;flex-wrap:wrap;align-items:center;gap:.5rem;font-size:.9rem;line-height:1.6;color:rgba(246,240,228,.9);overflow-wrap:anywhere}

.copy-btn{
  font-family:var(--font-mono);font-size:.6rem;letter-spacing:.12em;
  background:transparent;border:1px solid rgba(217,199,163,.4);color:var(--sand);
  padding:.2rem .5rem;border-radius:2px;cursor:pointer;
  transition:border-color .2s var(--ease),color .2s var(--ease),background .2s var(--ease);
}
.copy-btn:hover{border-color:var(--ochre);color:var(--ochre)}
.copy-btn[data-copied="true"]{border-color:var(--pine);background:var(--pine);color:var(--paper)}

.footer__bottom{
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:1rem;
  padding-top:1.3rem;font-family:var(--font-mono);font-size:.7rem;letter-spacing:.06em;
  color:rgba(246,240,228,.58);
}
.footer__legal{margin:0}
.footer__icp{color:var(--sand)}
.to-top{
  display:inline-flex;align-items:center;gap:.45rem;
  background:transparent;border:1px solid rgba(217,199,163,.35);color:var(--sand);
  font-family:var(--font-mono);font-size:.66rem;letter-spacing:.12em;
  padding:.5rem .8rem;border-radius:2px;cursor:pointer;
  transition:background .22s var(--ease),border-color .22s var(--ease),color .22s var(--ease);
}
.to-top::after{content:"↑";font-size:.9rem;line-height:1}
.to-top:hover{background:var(--cinnabar);border-color:var(--cinnabar);color:var(--paper)}

/* ---------- responsive ---------- */
@media (max-width:1024px){
  .command-bar__inner{min-height:68px;gap:.75rem}
  .nav{
    position:absolute;left:0;right:0;top:100%;margin:0;display:none;
    background:var(--paper-deep);border-bottom:2px solid var(--ink);
    box-shadow:0 20px 42px -18px rgba(42,33,28,.4);
  }
  .site-header[data-nav-open="true"] .nav{display:block}
  .nav__list{flex-direction:column;height:auto;gap:0;padding:.5rem var(--gutter) 1.2rem}
  .nav__link{
    height:auto;padding:.9rem .2rem;font-size:1rem;
    border-bottom:1px solid var(--sand);background:transparent;
  }
  .nav__link::after{display:none}
  .nav__link:hover{background:transparent;color:var(--cinnabar)}
  .nav__link[aria-current="page"]{color:var(--cinnabar);background:transparent}
  .nav__link[aria-current="page"] .nav__idx{color:var(--ink)}
  .nav-toggle{display:inline-flex}
  .command-bar__tail .btn{display:none}

  .grid--12{grid-template-columns:repeat(6,1fr)}
  .span-8,.span-6{grid-column:span 6}
  .span-4,.span-3{grid-column:span 3}

  .footer__top{grid-template-columns:1fr 1fr}
  .footer__brand{grid-column:1 / -1}
  .media-frame--wide{aspect-ratio:16/9}
}

@media (max-width:640px){
  body{font-size:16px}
  :root{--header-h:62px}
  html{scroll-padding-top:96px}
  .utility-bar{font-size:.62rem;max-height:38px}
  .utility-bar__inner{min-height:30px;gap:.55rem}
  .utility-bar__link{display:none}
  .brand__name{font-size:1.15rem;letter-spacing:.08em}
  .brand__line{display:none}
  .brand__gate{width:21px;height:27px}
  .nav-toggle{padding:.5rem .65rem;font-size:.64rem}
  .section-head{grid-template-columns:1fr;gap:.35rem;align-items:start}
  .grid--12{grid-template-columns:1fr}
  .span-3,.span-4,.span-6,.span-8,.span-12{grid-column:span 1}
  .footer__top{grid-template-columns:1fr;gap:1.9rem}
  .footer__name{font-size:1.55rem}
  .footer__bottom{flex-direction:column;align-items:flex-start;gap:.85rem}
  .media-frame--wide,.media-frame--tall{aspect-ratio:4/3}
}

@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  .has-js [data-reveal]{opacity:1;transform:none}
  .site-header[data-scrolled="true"] .utility-bar{max-height:44px;opacity:1}
  .progress__fill{transition:none}
}