*,*::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,dl,dd,dt{margin:0}
ul,ol{padding:0;list-style:none}
img,svg{max-width:100%}
a{color:inherit}
button{font:inherit;color:inherit}

:root{
  --paper:#F6EFE2;
  --ink:#2A1E17;
  --ink-soft:#5A4A3C;
  --vermilion:#B32B21;
  --vermilion-deep:#7E1C15;
  --butter:#D9A227;
  --butter-pale:#F0D9A0;
  --navy:#12314F;
  --navy-night:#0B1F33;
  --jade:#1F6F63;
  --jade-mist:#A8CFC4;
  --line:#C9BBA6;

  --font-serif:"Noto Serif SC","Source Han Serif SC","Songti SC","SimSun",serif;
  --font-sans:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;

  --w:1480px;
  --pad:clamp(16px,3.2vw,44px);
  --header-h:78px;
  --header-h-sm:58px;
}

body{
  font-family:var(--font-sans);
  font-size:16px;
  line-height:1.75;
  color:var(--ink);
  background-color:var(--paper);
  background-image:
    linear-gradient(90deg,rgba(42,30,23,.05) 1px,transparent 1px),
    linear-gradient(0deg,rgba(42,30,23,.05) 1px,transparent 1px);
  background-size:96px 96px;
}

h1,h2,h3,h4{font-family:var(--font-serif);font-weight:700;line-height:1.28}
h1{font-size:clamp(30px,4.4vw,44px);line-height:1.2}
h2{font-size:clamp(24px,3vw,32px)}
h3{font-size:clamp(18px,2.2vw,22px)}
p{line-height:1.8}

:focus-visible{outline:2px solid var(--vermilion);outline-offset:2px}
.site-footer :focus-visible,.section--navy :focus-visible,.section--night :focus-visible,.guide-rail :focus-visible{outline-color:var(--butter)}

/* ---------- skip link ---------- */
.skip-link{
  position:fixed;top:10px;left:10px;z-index:300;
  transform:translateY(-220%);
  padding:10px 18px;
  background:var(--navy);color:var(--butter-pale);
  border:1px solid var(--butter);
  font-size:13px;font-weight:700;letter-spacing:.12em;
  text-decoration:none;
}
.skip-link:focus{transform:translateY(0)}

/* ---------- header ---------- */
.site-header{
  position:sticky;top:0;z-index:80;
  background-color:var(--paper);
  border-bottom:1px solid var(--line);
  transition:box-shadow .2s ease;
}
.header-inner{
  position:relative;
  max-width:var(--w);
  margin:0 auto;
  padding:0 var(--pad);
  min-height:var(--header-h);
  display:flex;
  align-items:stretch;
  justify-content:space-between;
  gap:clamp(10px,2vw,32px);
}
.brand-plate{
  display:flex;flex-direction:column;justify-content:center;gap:2px;
  margin:10px 0;
  padding:8px 18px 8px 15px;
  background:var(--navy);
  color:var(--butter-pale);
  border-left:3px solid var(--butter);
  text-decoration:none;
  transition:background-color .18s ease;
}
.brand-plate:hover{background:var(--navy-night)}
.brand-plate__mark{
  font-size:20px;font-weight:700;line-height:1.2;
  letter-spacing:.22em;white-space:nowrap;
}
.brand-plate__domain{
  font-family:var(--font-mono);font-size:10px;line-height:1.4;
  letter-spacing:.14em;color:rgba(240,217,160,.72);white-space:nowrap;
}
.site-header[data-condensed]{box-shadow:0 2px 0 rgba(42,30,23,.08)}
.site-header[data-condensed] .header-inner{min-height:var(--header-h-sm)}
.site-header[data-condensed] .brand-plate{margin:8px 0;padding:5px 14px 5px 12px}
.site-header[data-condensed] .brand-plate__mark{font-size:16px;letter-spacing:.18em}
.site-header[data-condensed] .brand-plate__domain{display:none}
.site-header[data-condensed] .primary-nav__link{font-size:14px}

.primary-nav{
  display:flex;
  align-items:stretch;
  gap:clamp(6px,1.4vw,24px);
  margin-left:auto;
}
.primary-nav__list{display:flex;align-items:stretch;gap:clamp(0px,.6vw,8px)}
.primary-nav__item{display:flex}
.primary-nav__link{
  display:inline-flex;align-items:center;gap:7px;
  padding:0 clamp(6px,.9vw,12px);
  font-size:15px;font-weight:700;letter-spacing:.08em;
  color:var(--ink);text-decoration:none;
  border-bottom:3px solid transparent;
  transition:color .16s ease,border-color .16s ease,background-color .16s ease;
}
.primary-nav__num{
  font-family:var(--font-mono);font-size:11px;font-weight:400;
  letter-spacing:.06em;color:var(--line);
  transition:color .16s ease;
}
.primary-nav__link:hover{color:var(--vermilion);border-bottom-color:var(--butter)}
.primary-nav__link:hover .primary-nav__num{color:var(--butter)}
.primary-nav__link[aria-current="page"]{color:var(--vermilion);border-bottom-color:var(--vermilion)}
.primary-nav__link[aria-current="page"] .primary-nav__num{color:var(--vermilion)}

.header-meta{
  display:flex;align-items:center;gap:12px;
  padding-left:clamp(8px,1.4vw,20px);
  border-left:1px solid var(--line);
}
.lang-badge{
  display:inline-flex;align-items:center;gap:6px;
  padding:4px 8px;
  border:1px solid var(--line);
  background:rgba(240,217,160,.3);
  color:var(--navy);
  font-size:12px;font-weight:700;letter-spacing:.12em;white-space:nowrap;
}
.lang-badge__dot{width:6px;height:6px;background:var(--jade);display:block}
.search-link{
  display:inline-flex;align-items:center;gap:8px;
  padding:4px 2px;
  font-size:13px;font-weight:700;letter-spacing:.1em;
  color:var(--navy);text-decoration:none;
  border-bottom:1px solid transparent;
  transition:color .16s ease,border-color .16s ease;
}
.search-link:hover{color:var(--vermilion);border-bottom-color:var(--vermilion)}
.search-link__icon{
  position:relative;display:block;width:11px;height:11px;
  border:2px solid currentColor;
}
.search-link__icon::after{
  content:"";position:absolute;right:-5px;bottom:-5px;
  width:6px;height:2px;background:currentColor;
  transform:rotate(45deg);transform-origin:left center;
}
.search-link__text{display:inline}

.nav-toggle{
  display:none;align-items:center;gap:8px;
  margin:auto 0;
  padding:8px 12px;
  background:transparent;border:1px solid var(--line);
  color:var(--navy);font-size:13px;font-weight:700;letter-spacing:.12em;
  cursor:pointer;
}
.nav-toggle:hover{border-color:var(--vermilion);color:var(--vermilion)}
.nav-toggle__bars{display:flex;flex-direction:column;gap:3px;width:16px}
.nav-toggle__bar{display:block;height:2px;background:currentColor;transition:transform .18s ease,opacity .18s ease}
.nav-toggle__label{display:inline}
.site-header[data-open] .nav-toggle{border-color:var(--vermilion);color:var(--vermilion)}
.site-header[data-open] .nav-toggle__bar:nth-child(1){transform:translateY(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(-5px) rotate(-45deg)}

.scroll-line{
  position:absolute;left:0;bottom:-1px;
  width:100%;height:2px;
  background:var(--vermilion);
  transform:scaleX(0);transform-origin:0 50%;
  pointer-events:none;
}

/* ---------- floating guide rail ---------- */
.guide-rail{
  position:fixed;right:0;top:50%;z-index:70;
  display:flex;flex-direction:column;gap:1px;
  background:var(--navy-night);
  border-left:1px solid var(--navy-night);
  opacity:0;pointer-events:none;
  transform:translate(100%,-50%);
  transition:transform .28s ease,opacity .28s ease;
}
.guide-rail[data-visible]{transform:translate(0,-50%);opacity:1;pointer-events:auto}
.guide-rail__link{
  display:flex;align-items:center;justify-content:center;
  writing-mode:vertical-rl;
  padding:18px 10px;
  background:var(--navy);color:var(--butter-pale);
  font-size:13px;font-weight:700;letter-spacing:.2em;
  text-decoration:none;
  transition:background-color .16s ease,color .16s ease;
}
.guide-rail__link:hover{background:var(--navy-night);color:#fff}
.guide-rail__link--primary{background:var(--vermilion)}
.guide-rail__link--primary:hover{background:var(--vermilion-deep)}
.guide-rail__link--find{background:var(--butter);color:var(--navy-night)}
.guide-rail__link--find:hover{background:var(--butter-pale);color:var(--navy)}
.guide-rail__label{display:block}
.guide-rail__icon{display:none}

/* ---------- shared layout ---------- */
.container{width:100%;max-width:var(--w);margin:0 auto;padding:0 var(--pad)}
.section{padding:clamp(40px,6vw,88px) 0}
.section--paper{background-color:var(--paper)}
.section--navy{background-color:var(--navy);color:var(--butter-pale)}
.section--night{background-color:var(--navy-night);color:rgba(246,239,226,.86)}
.section--navy .section-title,.section--night .section-title{color:var(--butter-pale)}
.section--navy .prose,.section--night .prose{color:rgba(246,239,226,.86)}
.grid-12{display:grid;grid-template-columns:repeat(12,minmax(0,1fr));gap:clamp(16px,2vw,32px)}
.rule{border:0;border-top:1px solid var(--line);margin:clamp(20px,3vw,32px) 0}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}

.eyebrow{
  display:inline-flex;align-items:center;gap:10px;
  font-size:12px;font-weight:700;letter-spacing:.24em;
  color:var(--vermilion);margin-bottom:10px;
}
.eyebrow::before{content:"";display:block;width:28px;height:2px;background:var(--vermilion)}
.section-title{font-family:var(--font-serif);font-size:clamp(24px,3vw,32px);line-height:1.3;margin:0 0 16px}

.prose{max-width:36em;font-size:16px;line-height:1.85;color:var(--ink)}
.prose > * + *{margin-top:1.1em}
.prose h2{font-size:clamp(21px,2.4vw,28px);margin-top:2em;padding-left:14px;border-left:4px solid var(--vermilion)}
.prose h3{font-family:var(--font-sans);font-size:19px;font-weight:700;letter-spacing:.06em;margin-top:1.8em}
.prose ul,.prose ol{list-style:none}
.prose li{position:relative;padding-left:1.6em}
.prose li + li{margin-top:.5em}
.prose ul > li::before{content:"—";position:absolute;left:0;color:var(--vermilion)}
.prose ol{counter-reset:step}
.prose ol > li{counter-increment:step}
.prose ol > li::before{
  content:counter(step,decimal-leading-zero);
  position:absolute;left:0;top:.4em;
  font-family:var(--font-mono);font-size:13px;color:var(--vermilion);
}

/* ---------- buttons ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:12px 20px;
  font-family:var(--font-sans);font-size:14px;font-weight:700;letter-spacing:.1em;
  text-decoration:none;border:1px solid transparent;border-radius:0;
  background:var(--navy);color:var(--butter-pale);
  cursor:pointer;
  transition:background-color .16s ease,color .16s ease,border-color .16s ease;
}
.btn:hover{background:var(--navy-night)}
.btn--primary{background:var(--vermilion);color:#fff}
.btn--primary:hover{background:var(--vermilion-deep)}
.btn--ghost{background:transparent;border-color:var(--ink);color:var(--ink)}
.btn--ghost:hover{background:var(--ink);color:var(--paper)}
.btn--gold{background:var(--butter);color:var(--navy-night)}
.btn--gold:hover{background:var(--butter-pale);color:var(--navy)}

/* ---------- tags & badges ---------- */
.plate-tag{
  display:inline-flex;align-items:baseline;gap:8px;
  padding:6px 10px;
  background:var(--paper);
  border:1px solid var(--line);
  color:var(--ink);
  font-size:13px;letter-spacing:.06em;
}
.plate-tag__num{font-family:var(--font-mono);font-size:12px;color:var(--vermilion)}

.badge{
  display:inline-flex;align-items:center;gap:6px;
  padding:3px 8px;
  border:1px solid currentColor;background:transparent;
  font-size:12px;font-weight:700;letter-spacing:.1em;
}
.badge--jade{color:var(--jade);background:rgba(168,207,196,.35)}
.badge--butter{color:var(--navy-night);background:var(--butter);border-color:var(--butter)}
.badge--navy{color:var(--butter-pale);background:var(--navy);border-color:var(--navy)}
.badge--vermilion{color:#fff;background:var(--vermilion);border-color:var(--vermilion)}

/* ---------- breadcrumb ---------- */
.breadcrumb{
  display:flex;flex-wrap:wrap;align-items:center;gap:8px;
  padding:18px 0 0;
  font-size:13px;letter-spacing:.04em;color:var(--ink-soft);
}
.breadcrumb a{text-decoration:none;border-bottom:1px solid var(--line)}
.breadcrumb a:hover{color:var(--vermilion);border-bottom-color:var(--vermilion)}
.breadcrumb__sep{color:var(--line)}
.breadcrumb__current{color:var(--ink);font-weight:700}

/* ---------- media frames ---------- */
.media-frame{
  position:relative;display:block;overflow:hidden;
  border:1px solid var(--line);
  background-color:var(--paper);
  background-image:
    repeating-linear-gradient(0deg,rgba(42,30,23,.07) 0 1px,transparent 1px 24px),
    repeating-linear-gradient(90deg,rgba(42,30,23,.07) 0 1px,transparent 1px 24px);
  margin:0;
}
.media-frame img{display:block;width:100%;height:100%;object-fit:cover}
.media-frame figcaption{
  position:absolute;left:0;bottom:0;
  max-width:100%;padding:6px 10px;
  background:rgba(11,31,51,.86);color:var(--butter-pale);
  font-size:12px;letter-spacing:.08em;
}
.media-frame--wide{aspect-ratio:16/9}
.media-frame--band{aspect-ratio:21/9}
.media-frame--square{aspect-ratio:1/1}
.media-frame--tall{aspect-ratio:3/4}

/* ---------- reveal & toc ---------- */
.has-js [data-reveal]{
  opacity:0;transform:translateY(16px);
  transition:opacity .5s ease,transform .5s cubic-bezier(.2,.7,.2,1);
  transition-delay:var(--reveal-delay,0s);
}
.has-js [data-reveal].is-visible{opacity:1;transform:none}
.toc-link{
  display:flex;align-items:baseline;gap:10px;
  padding:6px 0;
  color:var(--ink-soft);text-decoration:none;
  font-size:14px;border-left:2px solid var(--line);padding-left:12px;
  transition:color .18s ease,border-color .18s ease;
}
.toc-link:hover{color:var(--vermilion);border-left-color:var(--butter)}
.toc-link[data-current="true"]{color:var(--vermilion);border-left-color:var(--vermilion);font-weight:700}

/* ---------- footer ---------- */
.site-footer{
  position:relative;
  margin-top:clamp(48px,7vw,96px);
  padding:clamp(40px,5vw,64px) 0 24px;
  background-color:var(--navy-night);
  background-image:
    linear-gradient(90deg,rgba(240,217,160,.08) 1px,transparent 1px),
    linear-gradient(0deg,rgba(240,217,160,.08) 1px,transparent 1px);
  background-size:72px 72px;
  color:rgba(246,239,226,.8);
  border-top:4px solid var(--vermilion);
}
.footer-inner{max-width:var(--w);margin:0 auto;padding:0 var(--pad)}
.footer-grid{
  display:grid;
  grid-template-columns:1.5fr 1fr 1fr 1fr;
  gap:clamp(26px,4vw,52px) clamp(18px,3vw,40px);
  padding-bottom:28px;
  border-bottom:1px solid rgba(240,217,160,.22);
}
.footer-brand__plate{
  display:inline-block;
  padding:8px 16px;
  background:var(--navy);
  border:1px solid rgba(240,217,160,.4);
  border-left:3px solid var(--vermilion);
  color:var(--butter-pale);
  font-size:19px;font-weight:700;letter-spacing:.24em;
  text-decoration:none;
  transition:background-color .18s ease,border-color .18s ease;
}
.footer-brand__plate:hover{background:var(--vermilion);border-color:var(--vermilion);color:#fff}
.footer-brand__domain{
  margin-top:10px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;
  color:rgba(240,217,160,.7);
}
.footer-brand__note{
  margin-top:14px;max-width:30em;
  font-size:13px;line-height:1.9;
  color:rgba(246,239,226,.62);
}
.footer-col__title{
  display:inline-block;
  margin:0 0 16px;padding:5px 10px;
  background:rgba(240,217,160,.08);
  border:1px solid rgba(240,217,160,.35);
  color:var(--butter-pale);
  font-family:var(--font-sans);font-size:12px;font-weight:700;letter-spacing:.2em;
}
.footer-col__list{display:flex;flex-direction:column;gap:2px}
.footer-col__link{
  display:inline-block;
  padding:5px 0;
  font-size:14px;
  color:rgba(246,239,226,.78);
  text-decoration:none;
  border-bottom:1px solid transparent;
  transition:color .16s ease,border-color .16s ease;
}
.footer-col__link:hover{color:var(--butter-pale);border-bottom-color:var(--butter)}
.footer-contact{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(190px,1fr));
  gap:16px 32px;
  padding:24px 0;
  border-bottom:1px solid rgba(240,217,160,.22);
}
.footer-contact__item{display:block}
.footer-contact__label{
  display:block;margin-bottom:4px;
  font-size:11px;font-weight:700;letter-spacing:.2em;
  color:var(--butter);
}
.footer-contact__value{
  display:block;
  font-size:14px;line-height:1.7;
  color:rgba(246,239,226,.86);
  word-break:break-word;
}
.footer-legal{
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;
  gap:8px 20px;
  padding-top:20px;
  font-size:12px;letter-spacing:.06em;
  color:rgba(246,239,226,.55);
}
.footer-legal__icp{font-family:var(--font-mono);letter-spacing:.04em;margin:0}
.footer-legal__meta{margin:0}

/* ---------- tablet ---------- */
@media (max-width:1100px){
  .primary-nav__link{font-size:14px;letter-spacing:.04em}
  .primary-nav__num{display:none}
  .grid-12{grid-template-columns:repeat(6,minmax(0,1fr))}
}

/* ---------- mobile ---------- */
@media (max-width:960px){
  .nav-toggle{display:inline-flex}
  .header-inner{min-height:var(--header-h-sm)}
  .brand-plate{margin:8px 0;padding:6px 14px;border-left-width:2px}
  .brand-plate__mark{font-size:17px;letter-spacing:.18em}
  .brand-plate__domain{font-size:9px}
  .primary-nav{
    position:absolute;left:0;right:0;top:100%;
    display:none;
    flex-direction:column;align-items:stretch;gap:0;
    margin:0;
    background-color:var(--paper);
    border-top:1px solid var(--line);
    border-bottom:1px solid var(--line);
    box-shadow:0 24px 40px rgba(11,31,51,.18);
    max-height:calc(100vh - var(--header-h-sm));
    overflow-y:auto;
    z-index:90;
  }
  .site-header[data-open] .primary-nav,
  .primary-nav[data-open]{display:flex}
  .primary-nav__list{flex-direction:column;gap:0}
  .primary-nav__item{display:block}
  .primary-nav__link{
    display:flex;width:100%;
    padding:14px 20px;
    font-size:16px;
    border-bottom:1px solid var(--line);
    border-left:3px solid transparent;
    background-color:var(--paper);
  }
  .primary-nav__num{display:inline;font-size:12px;color:var(--line)}
  .primary-nav__link:hover{border-bottom-color:var(--line);background-color:rgba(217,162,39,.14)}
  .primary-nav__link[aria-current="page"]{
    border-bottom-color:var(--line);
    border-left-color:var(--vermilion);
    background-color:rgba(179,43,33,.08);
  }
  .header-meta{
    padding:14px 20px;
    border-left:0;
    border-top:1px solid var(--line);
    justify-content:flex-start;
    gap:18px;
  }
  .guide-rail{
    top:auto;bottom:0;left:0;right:0;
    flex-direction:row;align-items:stretch;gap:1px;
    border-left:0;border-top:1px solid var(--navy-night);
    transform:translateY(100%);
  }
  .guide-rail[data-visible]{transform:translateY(0)}
  .guide-rail__link{
    writing-mode:horizontal-tb;
    flex:1 1 auto;
    padding:14px 8px;
    font-size:14px;letter-spacing:.12em;
  }
  .guide-rail__link--find{flex:0 0 62px}
  .guide-rail__link--find .guide-rail__label{display:none}
  .guide-rail__link--find .guide-rail__icon{
    display:block;position:relative;
    width:14px;height:14px;
    border:2px solid currentColor;
  }
  .guide-rail__link--find .guide-rail__icon::after{
    content:"";position:absolute;right:-6px;bottom:-6px;
    width:7px;height:2px;background:currentColor;
    transform:rotate(45deg);transform-origin:left center;
  }
  body{padding-bottom:56px}
  .footer-grid{grid-template-columns:1fr 1fr}
  .footer-legal{justify-content:flex-start}
}

@media (max-width:600px){
  .grid-12{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-grid{grid-template-columns:1fr;gap:26px}
  .footer-contact{grid-template-columns:1fr;gap:14px}
  .breadcrumb{font-size:12px}
}

@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    transition-delay:0s !important;
  }
  .has-js [data-reveal]{opacity:1;transform:none}
  .guide-rail{transition:none}
}