:root{
  --ink-950:#080D18;
  --ink-900:#0E1730;
  --ink-800:#182747;
  --ink-700:#2A3A63;
  --ink-600:#1B2740;
  --paper:#F5F1E6;
  --paper-bright:#FDFCF7;
  --blue:#3B7DBF;
  --green:#2F8362;
  --yellow:#E6B94A;
  --red:#C34C3F;
  --amber:#E88B3C;
  --mist:#A0A9BE;
  --line:#2A3A63;

  --fg:var(--paper-bright);
  --fg-muted:var(--mist);
  --rule:var(--line);
  --link:var(--yellow);

  --font-display:"Noto Serif SC","Source Han Serif SC","Songti SC",STSong,SimSun,serif;
  --font-body:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,"SF Mono",Menlo,Consolas,monospace;

  --wrap-w:1240px;
  --gutter:clamp(1.25rem,4vw,3.25rem);
  --header-h:80px;
  --radius:2px;
}
@media (max-width:1023.98px){
  :root{--header-h:64px}
}

*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:calc(var(--header-h) + 1.25rem)}
body{
  margin:0;
  min-height:100vh;
  background:var(--ink-900);
  color:var(--fg);
  font-family:var(--font-body);
  font-size:clamp(1rem,.96rem + .18vw,1.0625rem);
  line-height:1.75;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
body.nav-open{overflow:hidden}
h1,h2,h3,h4{
  margin:0;
  font-family:var(--font-display);
  font-weight:600;
  line-height:1.22;
  letter-spacing:-.02em;
  color:var(--fg);
}
p{margin:0}
img,svg{display:block;max-width:100%}
img{height:auto}
ul,ol{margin:0;padding:0;list-style:none}
button{font:inherit;color:inherit}
a{color:var(--link);text-decoration-thickness:1px;text-underline-offset:.22em}
a:hover{color:var(--amber)}
strong{font-weight:600}
hr{border:0;border-top:1px solid var(--rule);margin:0}
::selection{background:var(--amber);color:var(--ink-900)}
:focus-visible{outline:2px solid var(--yellow);outline-offset:3px;border-radius:2px}
#main-content{padding-top:var(--header-h)}
#main-content.is-flush{padding-top:0}
#main-content:focus{outline:none}

.wrap{width:min(calc(100% - var(--gutter) * 2),var(--wrap-w));margin-inline:auto}

.mono{font-family:var(--font-mono);font-size:.75rem;letter-spacing:.12em}
.muted{color:var(--fg-muted)}
.eyebrow{
  display:inline-flex;align-items:center;gap:.55rem;
  font-family:var(--font-mono);font-size:.72rem;letter-spacing:.18em;
  color:var(--fg-muted);text-transform:none;
}
.eyebrow::before{content:"";width:18px;height:1px;background:var(--amber)}
.flag-rule{
  display:block;height:4px;width:100%;
  background:linear-gradient(90deg,
    var(--blue) 0 22%,
    var(--paper-bright) 22% 44%,
    var(--red) 44% 62%,
    var(--green) 62% 80%,
    var(--yellow) 80% 100%);
  opacity:.9;
}

.section{padding-block:clamp(3rem,7vw,6.5rem)}
.section--tight{padding-block:clamp(2rem,4vw,3.25rem)}
.section--paper{
  background:var(--paper);
  color:var(--ink-800);
  --fg:var(--ink-800);
  --fg-muted:#55627C;
  --rule:#D7CFBB;
  --link:var(--blue);
  --surface:var(--paper);
}
.section--ink{
  background:var(--ink-950);
  color:var(--paper-bright);
  --fg:var(--paper-bright);
  --fg-muted:var(--mist);
  --rule:#1D2942;
  --link:var(--yellow);
  --surface:var(--ink-950);
}

.section-head{display:grid;gap:.55rem;margin-bottom:clamp(1.5rem,3vw,2.5rem)}
.section-head__num{
  font-family:var(--font-mono);font-size:.74rem;letter-spacing:.18em;
  color:var(--amber);
}
.section-head__title{font-size:clamp(1.8rem,3.6vw,3rem)}
.section-head__meta{max-width:62ch;color:var(--fg-muted);font-size:.95rem}

.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.5rem;
  padding:.78rem 1.25rem;
  border:1px solid transparent;border-radius:var(--radius);
  font-family:var(--font-body);font-size:.9rem;font-weight:500;letter-spacing:.02em;
  text-decoration:none;cursor:pointer;
  transition:background-color 200ms ease,border-color 200ms ease,color 200ms ease,transform 200ms ease;
}
.btn--primary{background:var(--amber);border-color:var(--amber);color:var(--ink-900)}
.btn--primary:hover{background:#F09A50;border-color:#F09A50;color:var(--ink-900);transform:translateY(-1px)}
.btn--ghost{background:transparent;border-color:rgba(253,252,247,.28);color:var(--paper-bright)}
.btn--ghost:hover{border-color:var(--amber);color:var(--amber);background:rgba(232,139,60,.08)}
.btn--sm{padding:.48rem .85rem;font-size:.8rem}
.btn--block{width:100%}

.tag{
  display:inline-flex;align-items:center;gap:.35rem;
  padding:.18em .6em;border:1px solid var(--rule);border-radius:999px;
  font-family:var(--font-mono);font-size:.68rem;letter-spacing:.08em;
  line-height:1.6;color:var(--fg-muted);
  background:transparent;white-space:nowrap;
}
.tag--blue{color:#9CC6EE;border-color:rgba(59,125,191,.6);background:rgba(59,125,191,.16)}
.tag--green{color:#8FCDB4;border-color:rgba(47,131,98,.6);background:rgba(47,131,98,.16)}
.tag--yellow{color:var(--yellow);border-color:rgba(230,185,74,.55);background:rgba(230,185,74,.12)}
.tag--red{color:#E79C92;border-color:rgba(195,76,63,.6);background:rgba(195,76,63,.16)}
.tag--amber{color:#F3B47F;border-color:rgba(232,139,60,.6);background:rgba(232,139,60,.14)}
.section--paper .tag--blue{color:#2C6098;background:rgba(59,125,191,.1)}
.section--paper .tag--green{color:#21624A;background:rgba(47,131,98,.1)}
.section--paper .tag--yellow{color:#8A6812;background:rgba(230,185,74,.16)}
.section--paper .tag--red{color:#A63A2F;background:rgba(195,76,63,.1)}
.section--paper .tag--amber{color:#A85E17;background:rgba(232,139,60,.12)}

.echo-mark{position:relative;display:inline-block;width:44px;height:44px;flex:none}
.echo-mark__ring{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);border-radius:50%;border:1px solid var(--blue)}
.echo-mark__ring:nth-child(1){width:100%;height:100%;opacity:.34}
.echo-mark__ring:nth-child(2){width:64%;height:64%;border-color:var(--yellow);opacity:.62}
.echo-mark__ring:nth-child(3){width:30%;height:30%;background:var(--amber);border-color:var(--amber)}
.echo-mark--sm{width:34px;height:34px}
.echo-mark--footer{width:56px;height:56px}

.skip-link{
  position:fixed;top:.9rem;left:.9rem;z-index:200;
  padding:.6rem 1rem;border-radius:var(--radius);
  background:var(--paper-bright);color:var(--ink-900);
  font-size:.85rem;font-weight:500;text-decoration:none;
  transform:translateY(-220%);
  transition:transform 180ms ease;
}
.skip-link:focus,.skip-link:focus-visible{transform:translateY(0);outline:2px solid var(--amber);outline-offset:2px}

.reading-progress{
  position:fixed;top:0;left:0;right:0;height:2px;z-index:140;
  background:rgba(42,58,99,.5);pointer-events:none;
}
.reading-progress__bar{
  display:block;height:100%;width:0;
  background:linear-gradient(90deg,var(--blue) 0,var(--amber) 58%,var(--yellow) 100%);
  transition:width 120ms linear;
}

.site-header{
  position:fixed;top:0;left:0;right:0;z-index:100;
  background:linear-gradient(180deg,rgba(14,23,48,.94) 0%,rgba(14,23,48,.72) 62%,rgba(14,23,48,0) 100%);
  border-bottom:1px solid transparent;
  transition:background-color 240ms ease,border-color 240ms ease;
}
.site-header__inner{
  display:flex;align-items:center;gap:clamp(.75rem,2vw,1.75rem);
  min-height:var(--header-h);
}
.site-header[data-scrolled="true"]{
  background:var(--ink-800);
  border-bottom-color:var(--line);
}
.site-header[data-open="true"]{
  background:var(--ink-800);
  border-bottom-color:var(--line);
}

.brand{
  display:inline-flex;align-items:center;gap:.7rem;
  color:var(--paper-bright);text-decoration:none;
  min-width:0;
}
.brand__text{display:grid;gap:.1rem;min-width:0}
.brand__line{
  display:block;
  font-family:var(--font-display);font-weight:600;
  font-size:clamp(.95rem,1.3vw,1.08rem);
  line-height:1.35;letter-spacing:.01em;white-space:nowrap;
  transition:color 200ms ease;
}
.brand__tagline{
  display:block;
  font-family:var(--font-mono);font-size:.64rem;letter-spacing:.2em;
  line-height:1.5;color:var(--mist);
}
.brand:hover .brand__line{color:var(--yellow)}

.site-nav{display:flex;align-items:center;gap:clamp(.75rem,2vw,1.75rem);margin-left:auto}
.site-nav__list{
  display:flex;align-items:center;gap:clamp(.3rem,1.3vw,1.1rem);
  counter-reset:nav-index;
}
.site-nav__item{display:flex}
.site-nav__link{
  position:relative;display:inline-flex;align-items:baseline;gap:.35rem;
  padding:.45rem .1rem;
  color:#C6D0E4;font-size:.9rem;letter-spacing:.02em;text-decoration:none;
  transition:color 200ms ease;
}
.site-nav__link::before{
  counter-increment:nav-index;content:counter(nav-index,decimal-leading-zero);
  font-family:var(--font-mono);font-size:.6rem;letter-spacing:.06em;
  color:var(--yellow);opacity:.82;
}
.site-nav__link::after{
  content:"";position:absolute;left:0;right:0;bottom:-1px;height:2px;
  background:var(--amber);transform:scaleX(0);transform-origin:left;
  transition:transform 200ms ease;
}
.site-nav__link:hover{color:var(--paper-bright)}
.site-nav__link:hover::after{transform:scaleX(1)}
.site-nav__link[aria-current="page"]{color:var(--paper-bright)}
.site-nav__link[aria-current="page"]::after{transform:scaleX(1);background:var(--amber)}
.site-nav__actions{display:flex;align-items:center;gap:.5rem}

.nav-toggle{
  display:none;align-items:center;gap:.55rem;
  margin-left:auto;padding:.45rem .7rem;
  background:transparent;border:1px solid var(--line);border-radius:var(--radius);
  color:var(--paper-bright);cursor:pointer;
  transition:border-color 200ms ease,color 200ms ease;
}
.nav-toggle:hover{border-color:var(--amber);color:var(--amber)}
.nav-toggle__box{display:grid;gap:4px;width:18px}
.nav-toggle__bar{
  display:block;height:1.5px;width:100%;background:currentColor;
  transition:transform 200ms ease,opacity 200ms ease;
}
.nav-toggle__label{
  font-family:var(--font-mono);font-size:.68rem;letter-spacing:.16em;color:var(--mist);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1){transform:translateY(5.5px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(3){transform:translateY(-5.5px) rotate(-45deg)}

.site-footer{
  background:var(--ink-950);color:var(--paper-bright);
  border-top:1px solid var(--ink-600);
  padding-top:clamp(2.5rem,5vw,4.5rem);
  --fg:var(--paper-bright);--fg-muted:var(--mist);--rule:#1D2942;
}
.site-footer__inner{padding-bottom:1.5rem}
.site-footer__top{
  display:grid;
  grid-template-columns:minmax(0,1.5fr) repeat(2,minmax(0,.8fr)) minmax(0,1.2fr);
  gap:clamp(1.5rem,3vw,3rem);
  padding-bottom:clamp(2rem,4vw,3rem);
}
.site-footer__brand{display:grid;justify-items:start;gap:.7rem}
.site-footer__name{
  font-family:var(--font-display);font-size:1.02rem;font-weight:600;letter-spacing:.01em;
  color:var(--paper-bright);
}
.site-footer__motto{max-width:34ch;font-size:.88rem;line-height:1.8;color:var(--mist)}
.site-footer__flag{max-width:132px;margin-top:.4rem}
.site-footer__title{
  display:flex;align-items:center;gap:.5rem;
  margin-bottom:.9rem;
  font-family:var(--font-mono);font-size:.72rem;font-weight:500;letter-spacing:.16em;
  color:var(--mist);
}
.site-footer__title::before{content:"";width:6px;height:6px;border-radius:50%;background:var(--amber)}
.site-footer__top > :nth-child(2) .site-footer__title::before{background:var(--blue)}
.site-footer__top > :nth-child(3) .site-footer__title::before{background:var(--green)}
.site-footer__top > :nth-child(4) .site-footer__title::before{background:var(--yellow)}
.site-footer__list{display:grid;gap:.15rem}
.site-footer__link{
  display:inline-block;padding:.28rem 0;
  color:#C6D0E4;font-size:.92rem;text-decoration:none;
  transition:color 200ms ease;
}
.site-footer__link:hover{color:var(--amber);text-decoration:underline}
.site-footer__contact-line{
  display:grid;grid-template-columns:3rem minmax(0,1fr);gap:.6rem;
  padding:.22rem 0;font-size:.9rem;line-height:1.7;color:#D3DAE7;
  overflow-wrap:anywhere;
}
.site-footer__label{
  font-family:var(--font-mono);font-size:.68rem;letter-spacing:.12em;color:var(--mist);
  padding-top:.15rem;
}
.site-footer__note{
  margin-top:.7rem;max-width:36ch;
  font-size:.78rem;line-height:1.75;color:var(--mist);
}
.site-footer__meta{
  display:flex;flex-wrap:wrap;align-items:center;gap:.6rem 1.5rem;
  padding-top:1.25rem;border-top:1px solid var(--ink-600);
  font-family:var(--font-mono);font-size:.7rem;letter-spacing:.06em;color:var(--mist);
}
.site-footer__region{color:var(--mist)}
.site-footer__legal{color:#BCC6D9}
.site-footer__metalinks{display:flex;flex-wrap:wrap;gap:.5rem 1.1rem;margin-left:auto}
.site-footer__metalink{color:var(--mist);text-decoration:none;transition:color 200ms ease}
.site-footer__metalink:hover{color:var(--amber);text-decoration:underline}

.breadcrumbs{font-family:var(--font-mono);font-size:.72rem;letter-spacing:.08em}
.breadcrumbs__list{display:flex;flex-wrap:wrap;align-items:center;gap:.4rem .5rem}
.breadcrumbs__item{display:inline-flex;align-items:center;gap:.5rem;color:var(--fg-muted)}
.breadcrumbs__item + .breadcrumbs__item::before{content:"/";color:var(--rule)}
.breadcrumbs__link{color:var(--fg-muted);text-decoration:none}
.breadcrumbs__link:hover{color:var(--amber)}
.breadcrumbs__current{color:var(--fg)}

.prose{max-width:68ch;line-height:1.85}
.prose > * + *{margin-top:1.1rem}
.prose h2{font-size:clamp(1.5rem,2.6vw,2.1rem);margin-top:2.2rem}
.prose h3{font-size:clamp(1.15rem,1.8vw,1.4rem);margin-top:1.7rem}
.prose ul{list-style:disc;padding-left:1.25em}
.prose ol{list-style:decimal;padding-left:1.35em}
.prose li + li{margin-top:.4rem}
.prose blockquote{
  margin:1.6rem 0;padding:.2rem 0 .2rem 1.1rem;
  border-left:2px solid var(--amber);color:var(--fg-muted);
}
.prose a{color:var(--link)}

.index-list{border-top:1px solid var(--rule)}
.index-list__item{border-bottom:1px solid var(--rule)}
.index-list__link{
  display:grid;grid-template-columns:auto minmax(0,1fr) auto;
  gap:1rem;align-items:baseline;
  padding:1rem .2rem;color:var(--fg);text-decoration:none;
  transition:background-color 180ms ease,color 180ms ease;
}
.index-list__link:hover{background:rgba(232,139,60,.07);color:var(--fg)}
.index-list__num{
  font-family:var(--font-mono);font-size:.74rem;letter-spacing:.1em;color:var(--yellow);
}
.index-list__meta{
  font-family:var(--font-mono);font-size:.7rem;letter-spacing:.08em;color:var(--fg-muted);
}

.note{
  border-left:2px solid var(--amber);padding-left:.95rem;
  color:var(--fg-muted);font-size:.88rem;line-height:1.8;
}

.grid{display:grid;gap:clamp(1.25rem,2.6vw,2.25rem)}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid--aside{grid-template-columns:minmax(0,.32fr) minmax(0,.68fr)}

.media{margin:0;min-width:0}
.media__frame{
  position:relative;overflow:hidden;
  border:1px solid var(--rule);border-radius:var(--radius);
  background:var(--ink-800);
}
.media__frame::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  box-shadow:inset 0 0 0 1px rgba(253,252,247,.06);
}
.media__frame img,.media__frame svg{display:block;width:100%;height:100%;object-fit:cover}
.media--wide .media__frame{aspect-ratio:16/9}
.media--portrait .media__frame{aspect-ratio:4/5}
.media--square .media__frame{aspect-ratio:1/1}
.media__caption{
  margin-top:.6rem;font-family:var(--font-mono);font-size:.7rem;
  letter-spacing:.06em;line-height:1.7;color:var(--fg-muted);
}

.chapter-rail{display:flex;flex-wrap:wrap;gap:.35rem 1rem;font-family:var(--font-mono);font-size:.72rem;letter-spacing:.08em}
.chapter-rail__link{
  padding:.3rem .05rem;color:var(--fg-muted);text-decoration:none;
  border-bottom:1px solid transparent;transition:color 180ms ease,border-color 180ms ease;
}
.chapter-rail__link:hover{color:var(--fg)}
.chapter-rail__link.is-active{color:var(--amber);border-bottom-color:var(--amber)}

.js [data-reveal]{opacity:0;transform:translateY(14px);transition:opacity 460ms ease,transform 460ms ease}
.js [data-reveal].is-revealed{opacity:1;transform:none}

@media (max-width:1023.98px){
  .nav-toggle{display:inline-flex}
  .site-nav{
    position:absolute;top:100%;left:0;right:0;
    display:grid;gap:1rem;
    margin-left:0;
    padding:1rem var(--gutter) 1.5rem;
    background:var(--ink-800);
    border-bottom:1px solid var(--line);
    max-height:calc(100dvh - var(--header-h) - 1px);
    overflow-y:auto;
    opacity:0;visibility:hidden;pointer-events:none;
    transform:translateY(-8px);
    transition:opacity 240ms ease,transform 240ms ease,visibility 240ms ease;
  }
  .site-nav[data-open="true"],
  .site-header[data-open="true"] .site-nav{
    opacity:1;visibility:visible;pointer-events:auto;transform:none;
  }
  .site-nav__list{display:grid;gap:0}
  .site-nav__item{border-bottom:1px solid var(--ink-700)}
  .site-nav__link{
    width:100%;padding:.85rem .15rem;
    font-family:var(--font-display);font-size:1.02rem;
    justify-content:flex-start;gap:.6rem;
  }
  .site-nav__link::after{display:none}
  .site-nav__link::before{font-size:.66rem}
  .site-nav__link[aria-current="page"]{color:var(--yellow)}
  .site-nav__actions{display:grid;gap:.55rem}
  .site-nav__actions .btn{width:100%}
  .brand__tagline{display:none}
  .site-footer__top{grid-template-columns:repeat(2,minmax(0,1fr));gap:2rem 1.5rem}
  .site-footer__brand{grid-column:1 / -1}
  .grid--3{grid-template-columns:repeat(2,minmax(0,1fr))}
  .grid--aside{grid-template-columns:1fr}
}
@media (max-width:720px){
  .site-header__inner{gap:.5rem}
  .brand__line{font-size:.92rem;white-space:normal}
  .nav-toggle__label{display:none}
  .site-footer__top{grid-template-columns:1fr}
  .site-footer__meta{flex-direction:column;align-items:flex-start}
  .site-footer__metalinks{margin-left:0}
  .grid--2,.grid--3{grid-template-columns:1fr}
  .index-list__link{grid-template-columns:auto minmax(0,1fr);gap:.6rem}
  .index-list__meta{display:none}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition-duration:.001ms !important;animation-duration:.001ms !important;animation-iteration-count:1 !important}
  .js [data-reveal]{opacity:1;transform:none}
  .reading-progress__bar{transition:none}
  .btn--primary:hover{transform:none}
}