/* ===== reset ===== */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body,h1,h2,h3,h4,p,ul,ol,figure,blockquote{margin:0}
ul,ol{padding:0;list-style:none}
a{color:inherit;text-decoration:none}
button{font:inherit;color:inherit;background:none;border:0;padding:0;cursor:pointer}
img,svg{display:block;max-width:100%;height:auto}
b,strong{font-weight:700}

/* ===== tokens ===== */
:root{
  --ink-green:#0B1F1A;
  --ink-green-2:#12332A;
  --slate:#7C8C86;
  --paper:#F2EBDD;
  --amber:#E8A13A;
  --amber-soft:#F2B455;
  --teal:#4DE0C1;
  --brown:#1C1A16;
  --mist:#E7EFEA;
  --rust:#C8552F;
  --rule:rgba(124,140,134,.28);
  --rule-strong:rgba(124,140,134,.46);
  --rule-paper:rgba(28,26,22,.18);
  --max:1240px;
  --gutter:clamp(18px,4vw,56px);
  --mono:"IBM Plex Mono","JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --sans:"Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,sans-serif;
}

/* ===== base ===== */
body{
  font-family:var(--sans);
  font-size:16px;
  font-weight:400;
  line-height:1.8;
  color:var(--mist);
  background:var(--ink-green);
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3,h4{font-weight:800;letter-spacing:-.02em;line-height:1.16}
[tabindex="-1"]:focus{outline:none}
:focus-visible{outline:2px solid var(--teal);outline-offset:3px}
::selection{background:var(--amber);color:var(--ink-green)}
[id]{scroll-margin-top:152px}

/* ===== utilities ===== */
.wrap{width:100%;max-width:var(--max);margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-block:clamp(48px,7vw,96px)}
.label{font-family:var(--mono);font-size:12px;letter-spacing:.18em;text-transform:uppercase;color:var(--slate)}
.num{font-family:var(--mono);font-variant-numeric:tabular-nums}
.prose{max-width:68ch}
.prose p+p{margin-top:1em}

.band--paper{background:var(--paper);color:var(--brown)}
.band--paper .label{color:#6E7C76}
.band--deep{background:var(--ink-green);color:var(--mist)}
.band--layer{background:var(--ink-green-2);color:var(--mist)}

#main-content:focus{outline:2px dashed var(--teal);outline-offset:-6px}
.skip-link{
  position:fixed;top:8px;left:8px;z-index:200;
  padding:10px 16px;
  background:var(--amber);color:var(--ink-green);
  font-size:13px;font-weight:700;letter-spacing:.08em;
  transform:translateY(-180%);
  transition:transform .18s ease;
}
.skip-link:focus{transform:translateY(0)}

/* ===== buttons ===== */
.btn{
  display:inline-flex;align-items:center;gap:10px;
  padding:13px 22px;
  font-size:14px;font-weight:500;letter-spacing:.05em;
  border:1px solid transparent;
  border-radius:0;
  transition:background-color .18s ease,color .18s ease,border-color .18s ease;
}
.btn--amber{background:var(--amber);border-color:var(--amber);color:var(--ink-green)}
.btn--amber:hover{background:var(--amber-soft);border-color:var(--amber-soft)}
.btn--ghost{background:transparent;border-color:rgba(231,239,234,.34);color:var(--mist)}
.btn--ghost:hover{border-color:var(--teal);color:var(--teal)}
.btn--teal{background:var(--teal);border-color:var(--teal);color:var(--ink-green)}
.btn--teal:hover{background:#79ecd4;border-color:#79ecd4}
.btn--sm{padding:8px 14px;font-size:12px;letter-spacing:.14em}

/* ===== header ===== */
.site-header{
  position:sticky;top:0;z-index:80;
  background:var(--ink-green);
  color:var(--mist);
  border-bottom:1px solid rgba(124,140,134,.26);
}
.masthead{
  display:grid;
  grid-template-columns:1fr auto 1fr;
  align-items:center;
  gap:clamp(12px,2vw,28px);
  width:100%;max-width:var(--max);
  margin-inline:auto;
  padding:12px var(--gutter) 10px;
}
.masthead__tag{
  font-family:var(--mono);
  font-size:12px;letter-spacing:.16em;
  color:var(--slate);
  white-space:nowrap;
}
.brand{
  justify-self:center;
  display:flex;flex-direction:column;align-items:center;gap:4px;
  text-align:center;
}
.brand__mark{
  font-size:clamp(21px,2.4vw,28px);
  font-weight:800;letter-spacing:.02em;line-height:1;
  color:var(--mist);
  transition:color .16s ease;
}
.brand:hover .brand__mark{color:var(--teal)}
.brand__sub{
  font-family:var(--mono);
  font-size:10px;letter-spacing:.22em;
  color:var(--teal);
}
.masthead__side{
  justify-self:end;
  display:flex;align-items:center;gap:12px;
}
.batch-chip{
  display:inline-flex;align-items:center;gap:8px;
  padding:7px 12px;
  border:1px solid rgba(232,161,58,.45);
  background:rgba(232,161,58,.08);
  font-family:var(--mono);font-size:11px;letter-spacing:.12em;
  color:var(--amber);
  white-space:nowrap;
  transition:background-color .16s ease,border-color .16s ease;
}
.batch-chip:hover{background:rgba(232,161,58,.18);border-color:var(--amber)}
.batch-chip__dot{width:6px;height:6px;background:var(--amber);box-shadow:0 0 0 3px rgba(232,161,58,.16)}
.batch-chip__key{color:rgba(232,161,58,.72)}
.batch-chip__val{font-weight:700;font-variant-numeric:tabular-nums}

.nav-toggle{
  display:none;
  align-items:center;gap:8px;
  padding:8px 12px;
  border:1px solid var(--rule-strong);
  font-family:var(--mono);font-size:11px;letter-spacing:.16em;
  color:var(--mist);
  transition:border-color .16s ease,color .16s ease;
}
.nav-toggle__bars{display:grid;gap:3px;width:16px}
.nav-toggle__bars i{display:block;height:1.5px;background:currentColor;transition:transform .18s ease,opacity .18s ease}
.nav-toggle[aria-expanded="true"]{border-color:var(--teal);color:var(--teal)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(1){transform:translateY(4.5px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(3){transform:translateY(-4.5px) rotate(-45deg)}

.masthead-nav{
  width:100%;max-width:var(--max);
  margin-inline:auto;
  padding:0 var(--gutter);
  border-top:1px solid rgba(124,140,134,.18);
}
.nav-list{
  display:flex;justify-content:center;align-items:stretch;flex-wrap:wrap;
  gap:clamp(16px,3.2vw,44px);
}
.nav-list__link{
  position:relative;display:block;
  padding:13px 2px 12px;
  font-size:14px;font-weight:500;letter-spacing:.06em;
  color:rgba(231,239,234,.82);
  transition:color .16s ease;
}
.nav-list__link::after{
  content:"";position:absolute;left:0;right:0;bottom:0;
  height:2px;background:var(--teal);
  transform:scaleX(0);transform-origin:left center;
  transition:transform .22s ease;
}
.nav-list__link:hover{color:var(--teal)}
.nav-list__link:hover::after{transform:scaleX(1)}
.nav-list__link[aria-current="page"]{color:var(--teal)}
.nav-list__link[aria-current="page"]::after{transform:scaleX(1);background:var(--amber)}

.tape{
  position:relative;
  background:var(--ink-green-2);
  border-top:1px solid rgba(77,224,193,.16);
}
.tape__inner{
  display:flex;align-items:center;gap:clamp(10px,2vw,26px);
  width:100%;max-width:var(--max);margin-inline:auto;
  padding:7px var(--gutter);
  font-family:var(--mono);font-size:11px;letter-spacing:.12em;
  color:var(--slate);
}
.tape__item{display:inline-flex;align-items:center;gap:7px;white-space:nowrap}
.tape__dot{width:5px;height:5px;background:var(--rust);box-shadow:0 0 0 3px rgba(200,85,47,.14)}
.tape__num{color:var(--teal);font-weight:600;font-variant-numeric:tabular-nums}
.tape__item--mute{color:rgba(124,140,134,.86)}
.tape__item--end{margin-left:auto}
.tape__key{color:rgba(124,140,134,.66)}
.tape__track{height:2px;background:rgba(124,140,134,.2)}
.tape__bar{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--teal),var(--amber))}

/* ===== footer ===== */
.site-footer{
  position:relative;
  background:var(--ink-green);
  color:var(--mist);
  border-top:1px solid rgba(124,140,134,.24);
}
.footer__ticks{
  height:10px;
  background-image:repeating-linear-gradient(90deg,rgba(77,224,193,.3) 0 1px,transparent 1px 24px);
  border-bottom:1px solid rgba(124,140,134,.18);
  background-color:rgba(18,51,42,.55);
}
.footer__grid{
  display:grid;
  grid-template-columns:minmax(0,1.1fr) minmax(0,1.9fr);
  gap:clamp(28px,4vw,64px);
  padding-block:clamp(40px,6vw,72px);
}
.footer__mark{
  display:block;
  font-size:clamp(24px,3vw,34px);font-weight:800;letter-spacing:-.01em;line-height:1.1;
}
.footer__statement{
  margin-top:12px;max-width:34ch;
  font-size:14px;line-height:1.9;color:rgba(231,239,234,.72);
}
.footer__brand .btn{margin-top:22px}
.footer__nav{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:clamp(16px,3vw,40px);
}
.footer__col{min-width:0}
.footer__title{
  margin-bottom:14px;
  font-family:var(--mono);font-size:11px;font-weight:500;
  letter-spacing:.22em;color:var(--amber);
}
.footer__list{display:grid;gap:9px}
.footer__list a{
  font-size:14px;color:rgba(231,239,234,.78);
  transition:color .16s ease;
}
.footer__list a:hover{color:var(--teal)}
.footer__meta{
  padding-block:20px 26px;
  border-top:1px solid rgba(124,140,134,.2);
}
.footer__contact{display:flex;flex-wrap:wrap;gap:6px 28px;margin-bottom:16px}
.footer__contact-item{display:flex;align-items:baseline;gap:10px;font-size:13px;color:rgba(231,239,234,.72)}
.footer__key{font-family:var(--mono);font-size:10px;letter-spacing:.18em;color:var(--slate)}
.footer__val{font-family:var(--mono);font-size:12px;letter-spacing:.03em;color:rgba(231,239,234,.88)}
.footer__legal{display:flex;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:10px 24px}
.footer__copy{font-family:var(--mono);font-size:11px;letter-spacing:.08em;color:rgba(124,140,134,.92)}
.footer__legal-links{display:flex;flex-wrap:wrap;gap:18px;font-family:var(--mono);font-size:11px;letter-spacing:.14em}
.footer__legal-links a{color:rgba(231,239,234,.7);transition:color .16s ease}
.footer__legal-links a:hover{color:var(--amber)}

/* ===== breadcrumbs ===== */
.crumbs{
  padding-block:14px;
  border-bottom:1px solid rgba(124,140,134,.2);
  font-family:var(--mono);font-size:11px;letter-spacing:.1em;
}
.crumbs__list{display:flex;flex-wrap:wrap;align-items:center;gap:8px;color:var(--slate)}
.crumbs__item+.crumbs__item::before{content:"/";margin-right:8px;color:rgba(124,140,134,.55)}
.crumbs__link{color:rgba(231,239,234,.8)}
.crumbs__link:hover{color:var(--teal)}
.crumbs__current{color:var(--amber)}
.band--paper .crumbs{border-bottom-color:var(--rule-paper)}
.band--paper .crumbs__list{color:#6E7C76}
.band--paper .crumbs__link{color:#3A4A44}
.band--paper .crumbs__link:hover{color:#0B1F1A}
.band--paper .crumbs__current{color:#9A5A17}

/* ===== chapter head ===== */
.chapter-head{
  display:grid;
  grid-template-columns:auto 1fr;
  gap:6px 18px;
  align-items:baseline;
  padding-top:16px;
  border-top:1px solid var(--rule);
  margin-bottom:clamp(22px,3vw,38px);
}
.chapter-head__num{font-family:var(--mono);font-size:12px;letter-spacing:.18em;color:var(--amber)}
.chapter-head__title{font-size:clamp(26px,3.6vw,44px);font-weight:800}
.chapter-head__note{grid-column:2;font-size:14px;line-height:1.9;color:var(--slate);max-width:54ch}
.band--paper .chapter-head{border-top-color:var(--rule-paper)}
.band--paper .chapter-head__num{color:#9A5A17}
.band--paper .chapter-head__note{color:#5E6C67}

/* ===== grids ===== */
.grid{display:grid;gap:clamp(16px,2.4vw,28px)}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid--4{grid-template-columns:repeat(4,minmax(0,1fr))}
.layout-rail{
  display:grid;
  grid-template-columns:minmax(0,1fr) 232px;
  gap:clamp(24px,4vw,56px);
  align-items:start;
}

/* ===== toc ===== */
.toc{position:sticky;top:156px;border-top:1px solid var(--rule);padding-top:14px}
.toc__title{font-family:var(--mono);font-size:11px;letter-spacing:.2em;color:var(--slate);margin-bottom:12px}
.toc__list{display:grid}
.toc__item{border-bottom:1px solid rgba(124,140,134,.16)}
.toc__link{
  display:flex;align-items:baseline;gap:10px;
  padding:9px 0;
  font-size:13px;line-height:1.6;
  color:rgba(231,239,234,.7);
  transition:color .16s ease;
}
.toc__link:hover{color:var(--teal)}
.toc__link.is-active{color:var(--amber)}
.toc__idx{font-family:var(--mono);font-size:11px;color:var(--slate)}
.band--paper .toc{border-top-color:var(--rule-paper)}
.band--paper .toc__title{color:#6E7C76}
.band--paper .toc__item{border-bottom-color:rgba(28,26,22,.12)}
.band--paper .toc__link{color:#4A5952}
.band--paper .toc__link:hover{color:#0B1F1A}
.band--paper .toc__link.is-active{color:#9A5A17}
.band--paper .toc__idx{color:#8A968F}

/* ===== panel ===== */
.panel{
  border:1px solid var(--rule);
  background:rgba(18,51,42,.42);
  padding:clamp(16px,2vw,26px);
}
.band--paper .panel{
  border-color:var(--rule-paper);
  background:rgba(255,255,255,.55);
}

/* ===== media ===== */
.media{
  position:relative;display:block;width:100%;
  overflow:hidden;
  background:var(--ink-green-2);
  border:1px solid rgba(124,140,134,.24);
}
.media__img{width:100%;height:100%;object-fit:cover;display:block}
.media__tint{
  position:absolute;inset:0;pointer-events:none;
  background:linear-gradient(180deg,rgba(11,31,26,.06),rgba(11,31,26,.58));
}
.media__cap{
  position:absolute;left:0;bottom:0;
  padding:6px 10px;
  font-family:var(--mono);font-size:10px;letter-spacing:.16em;
  background:rgba(11,31,26,.84);color:var(--teal);
}
.media--16x9{aspect-ratio:16/9}
.media--4x3{aspect-ratio:4/3}
.media--1x1{aspect-ratio:1/1}
.media--tall{aspect-ratio:3/4}
.media--wide{aspect-ratio:21/9}
.media--grid{
  background-color:var(--ink-green-2);
  background-image:
    linear-gradient(to right,rgba(77,224,193,.14) 1px,transparent 1px),
    linear-gradient(to bottom,rgba(77,224,193,.14) 1px,transparent 1px);
  background-size:32px 32px;
}

/* ===== back to top ===== */
.to-top{
  position:fixed;
  right:clamp(14px,3vw,28px);
  bottom:clamp(14px,3vw,28px);
  z-index:70;
  display:inline-flex;align-items:center;gap:8px;
  padding:10px 14px;
  background:var(--ink-green-2);
  border:1px solid rgba(77,224,193,.4);
  color:var(--teal);
  font-family:var(--mono);font-size:11px;letter-spacing:.16em;
  opacity:0;visibility:hidden;transform:translateY(10px);
  transition:opacity .2s ease,transform .2s ease,visibility .2s ease,background-color .16s ease,color .16s ease;
}
.to-top.is-on{opacity:1;visibility:visible;transform:translateY(0)}
.to-top:hover{background:var(--teal);border-color:var(--teal);color:var(--ink-green)}
.to-top__glyph{font-size:13px;line-height:1}
.to-top__text{line-height:1}

/* ===== reveal ===== */
.has-js [data-reveal]{
  opacity:0;transform:translateY(14px);
  transition:opacity .5s ease,transform .5s ease;
}
.has-js [data-reveal].is-visible{opacity:1;transform:none}

/* ===== responsive ===== */
@media (max-width:980px){
  .layout-rail{grid-template-columns:minmax(0,1fr)}
  .toc{position:static;top:auto}
}
@media (max-width:900px){
  [id]{scroll-margin-top:132px}
  .masthead{grid-template-columns:1fr auto;gap:10px;padding-block:11px 9px}
  .masthead__tag{display:none}
  .brand{justify-self:start;align-items:flex-start;text-align:left}
  .brand__sub{letter-spacing:.16em}
  .masthead__side{gap:8px}
  .batch-chip{padding:6px 9px;font-size:10px;letter-spacing:.1em}
  .nav-toggle{display:inline-flex}
  .masthead-nav{display:none;border-top:1px solid rgba(124,140,134,.2)}
  .masthead-nav[data-open]{display:block}
  .nav-list{flex-direction:column;gap:0;padding:4px 0 10px}
  .nav-list__item{border-bottom:1px solid rgba(124,140,134,.16)}
  .nav-list__item:last-child{border-bottom:0}
  .nav-list__link{padding:14px 10px;font-size:15px}
  .nav-list__link::after{display:none}
  .nav-list__link[aria-current="page"]{color:var(--amber);box-shadow:inset 2px 0 0 var(--amber)}
  .grid--3,.grid--4{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer__grid{grid-template-columns:minmax(0,1fr)}
}
@media (max-width:760px){
  .tape__item--mute{display:none}
  .tape__inner{font-size:10px;letter-spacing:.1em;gap:12px}
}
@media (max-width:620px){
  .grid--2,.grid--3,.grid--4{grid-template-columns:minmax(0,1fr)}
  .chapter-head{grid-template-columns:1fr}
  .chapter-head__note{grid-column:1}
  .footer__nav{grid-template-columns:repeat(2,minmax(0,1fr));gap:22px}
  .footer__legal{flex-direction:column;align-items:flex-start}
  .to-top{padding:9px 11px;font-size:10px}
}
@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!important;transform:none!important}
  .tape__bar{transition:none!important}
}