:root{
  --ochre:#8C3B2A;
  --ochre-deep:#6B2A1C;
  --night:#4A1C12;
  --gobi:#C9963F;
  --sand:#E3C58B;
  --bone:#F4EFE6;
  --card:#FBF6EC;
  --cyan:#1F6F78;
  --cyan-bright:#2C8E97;
  --lime:#B7F34A;
  --ink:#171310;
  --muted:#6E6258;
  --veil:rgba(201,150,63,.18);
  --rule:rgba(23,19,16,.16);
  --rule-soft:rgba(23,19,16,.075);
  --rule-dark:rgba(227,197,139,.26);
  --shadow-hard:6px 6px 0 var(--ink);
  --shadow-soft:3px 3px 0 var(--ink);
  --font-display:"Alibaba PuHuiTi 3.0 115 Black","Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  --font-body:"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","Roboto Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --wrap:1280px;
  --gutter:clamp(16px,4vw,56px);
  --header-h:112px;
}

*,
*::before,
*::after{box-sizing:border-box;}

html{-webkit-text-size-adjust:100%;text-size-adjust:100%;}

@media (prefers-reduced-motion:no-preference){
  html{scroll-behavior:smooth;}
}

body{
  margin:0;
  color:var(--ink);
  background-color:var(--bone);
  background-image:
    repeating-linear-gradient(90deg,var(--rule-soft) 0 1px,transparent 1px 104px),
    repeating-linear-gradient(180deg,rgba(23,19,16,.05) 0 1px,transparent 1px 104px);
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.75;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}

h1,h2,h3,h4,h5,h6,p,figure,blockquote,dl,dd,ul,ol{margin:0;}
ul,ol{padding:0;list-style:none;}
img,svg,video{display:block;max-width:100%;}
button{font:inherit;color:inherit;background:none;border:0;}
a{color:inherit;text-decoration:none;}
address{font-style:normal;}
::selection{background:var(--gobi);color:var(--ink);}

:focus-visible{
  outline:3px solid var(--cyan);
  outline-offset:3px;
}

.link{
  color:var(--cyan);
  border-bottom:2px solid rgba(31,111,120,.32);
  transition:color .18s ease,border-color .18s ease;
}
.link:hover{color:var(--ochre);border-bottom-color:var(--ochre);}

/* ---------- skip link ---------- */
.skip-link{
  position:absolute;
  left:16px;
  top:-120px;
  z-index:200;
  padding:12px 20px;
  background:var(--ink);
  color:var(--lime);
  border:2px solid var(--lime);
  font-family:var(--font-mono);
  font-size:.76rem;
  letter-spacing:.14em;
  transition:top .2s ease;
}
.skip-link:focus{top:12px;}

/* ---------- header ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:60;
  background:var(--bone);
  border-bottom:3px solid var(--ink);
}

.header-coord{
  display:flex;
  align-items:center;
  gap:clamp(8px,1.4vw,18px);
  height:34px;
  padding:0 var(--gutter);
  background:var(--night);
  color:var(--sand);
  font-family:var(--font-mono);
  font-size:.65rem;
  letter-spacing:.18em;
  text-transform:uppercase;
  white-space:nowrap;
  overflow:hidden;
}
.coord-tick{color:var(--gobi);}
.coord-rule{
  flex:0 0 auto;
  width:clamp(18px,4vw,64px);
  height:1px;
  background:linear-gradient(90deg,var(--gobi),rgba(201,150,63,0));
}
.coord-id{color:rgba(227,197,139,.62);}
.coord-note{
  margin-left:auto;
  font-family:var(--font-body);
  font-size:.68rem;
  letter-spacing:.06em;
  text-transform:none;
  color:rgba(183,243,74,.82);
}

.header-bar{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:clamp(12px,2vw,32px);
  padding:0 var(--gutter);
  min-height:78px;
}

.brand{
  display:flex;
  align-items:center;
  gap:14px;
  flex:0 0 auto;
  padding:14px 0;
}
.brand-mark{
  position:relative;
  display:block;
  width:12px;
  height:46px;
  background:var(--ochre);
  box-shadow:5px 0 0 0 var(--gobi);
  flex:0 0 auto;
}
.brand-mark::after{
  content:"";
  position:absolute;
  left:0;
  right:-5px;
  bottom:-9px;
  height:3px;
  background:var(--ink);
}
.brand-name{
  display:block;
  font-family:var(--font-display);
  font-weight:900;
  font-size:clamp(1.15rem,1.6vw,1.42rem);
  line-height:1.15;
  letter-spacing:-.01em;
}
.brand-sub{
  display:block;
  margin-top:3px;
  font-size:.7rem;
  letter-spacing:.1em;
  color:var(--muted);
}

.nav-toggle{
  display:none;
  align-items:center;
  gap:10px;
  padding:10px 14px;
  background:transparent;
  border:2px solid var(--ink);
  color:var(--ink);
  font-family:var(--font-mono);
  font-size:.68rem;
  letter-spacing:.16em;
  text-transform:uppercase;
  cursor:pointer;
  transition:background-color .18s ease;
}
.nav-toggle:hover{background:var(--sand);}
.nav-toggle-bars{display:grid;gap:4px;width:18px;}
.nav-toggle-bars i{
  display:block;
  height:2px;
  width:100%;
  background:var(--ink);
  transition:transform .22s ease,opacity .22s ease;
}
.site-header[data-open] .nav-toggle-bars i:nth-child(1){transform:translateY(6px) rotate(45deg);}
.site-header[data-open] .nav-toggle-bars i:nth-child(2){opacity:0;}
.site-header[data-open] .nav-toggle-bars i:nth-child(3){transform:translateY(-6px) rotate(-45deg);}

.primary-nav{
  display:flex;
  align-items:center;
  justify-content:flex-end;
  gap:clamp(16px,2.4vw,44px);
  flex:1 1 auto;
  min-width:0;
}
.nav-list{
  display:flex;
  align-items:center;
  gap:clamp(8px,1.5vw,26px);
}
.nav-list a{
  position:relative;
  display:inline-flex;
  align-items:baseline;
  gap:6px;
  padding:9px 2px;
  font-size:.86rem;
  font-weight:700;
  letter-spacing:.03em;
  color:var(--ink);
  white-space:nowrap;
}
.nav-list a::after{
  content:"";
  position:absolute;
  left:0;
  right:100%;
  bottom:3px;
  height:3px;
  background:var(--cyan);
  transition:right .26s ease;
}
.nav-list a:hover::after,
.nav-list a:focus-visible::after{right:0;}
.nav-list a[aria-current="page"]{color:var(--ochre);}
.nav-list a[aria-current="page"]::after{right:0;background:var(--ochre);}
.nav-list a[aria-current="page"] .nav-idx{color:var(--cyan);}
.nav-idx{
  font-family:var(--font-mono);
  font-size:.6rem;
  font-weight:500;
  letter-spacing:.1em;
  color:var(--gobi);
}
.nav-actions{
  display:flex;
  align-items:center;
  gap:10px;
  flex:0 0 auto;
}
.nav-actions .btn{padding:10px 16px;font-size:.8rem;}

/* ---------- buttons ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:12px 20px;
  border:2px solid var(--ink);
  background:var(--ink);
  color:var(--bone);
  font-family:var(--font-body);
  font-weight:700;
  font-size:.86rem;
  line-height:1.2;
  letter-spacing:.06em;
  text-align:center;
  cursor:pointer;
  transition:transform .18s ease,box-shadow .18s ease,background-color .18s ease,color .18s ease,border-color .18s ease;
}
.btn:hover{transform:translate(-2px,-2px);box-shadow:4px 4px 0 var(--gobi);}
.btn:active{transform:translate(0,0);box-shadow:none;}
.btn-solid{background:var(--ochre);border-color:var(--ink);color:var(--bone);}
.btn-solid:hover{box-shadow:4px 4px 0 var(--ink);}
.btn-ghost{background:transparent;border-color:var(--ink);color:var(--ink);}
.btn-ghost:hover{background:var(--sand);box-shadow:4px 4px 0 var(--ink);}
.btn-lime{background:var(--lime);border-color:var(--ink);color:var(--ink);}

/* ---------- layout utilities ---------- */
.wrap{
  width:100%;
  max-width:var(--wrap);
  margin-inline:auto;
  padding-inline:var(--gutter);
}
.wrap--narrow{max-width:860px;}

.grid{
  display:grid;
  grid-template-columns:repeat(6,minmax(0,1fr));
  gap:clamp(14px,2vw,26px);
}
.col-2,.col-3,.col-4,.col-6,.col-8,.col-12{grid-column:span 6;}

@media (min-width:760px){
  .col-2,.col-3{grid-column:span 3;}
  .col-4{grid-column:span 6;}
}
@media (min-width:1080px){
  .grid{grid-template-columns:repeat(12,minmax(0,1fr));}
  .col-2{grid-column:span 2;}
  .col-3{grid-column:span 3;}
  .col-4{grid-column:span 4;}
  .col-6{grid-column:span 6;}
  .col-8{grid-column:span 8;}
  .col-12{grid-column:span 12;}
}

/* ---------- breadcrumbs ---------- */
.crumbs{padding-top:clamp(16px,2.4vw,26px);}
.crumbs ol{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  font-family:var(--font-mono);
  font-size:.68rem;
  letter-spacing:.12em;
  color:var(--muted);
}
.crumbs li{display:flex;align-items:center;gap:8px;}
.crumbs li+li::before{content:"/";color:var(--gobi);}
.crumbs a{color:var(--ink);border-bottom:1px solid var(--rule);}
.crumbs a:hover{color:var(--cyan);border-bottom-color:var(--cyan);}
.crumbs [aria-current="page"]{color:var(--ochre);}

/* ---------- type ---------- */
.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:10px;
  font-family:var(--font-mono);
  font-size:.66rem;
  letter-spacing:.24em;
  text-transform:uppercase;
  color:var(--ochre);
}
.eyebrow::before{
  content:"";
  flex:0 0 auto;
  width:28px;
  height:3px;
  background:var(--gobi);
}
.h-display{
  font-family:var(--font-display);
  font-weight:900;
  font-size:clamp(2.4rem,5vw,4.8rem);
  line-height:.98;
  letter-spacing:-.025em;
}
.h-section{
  font-family:var(--font-display);
  font-weight:900;
  font-size:clamp(1.5rem,2.6vw,2.2rem);
  line-height:1.12;
  letter-spacing:-.015em;
}
.h-sub{
  font-family:var(--font-body);
  font-weight:700;
  font-size:clamp(1.05rem,1.4vw,1.2rem);
  line-height:1.4;
}

/* ---------- panels / data / tags ---------- */
.panel{
  position:relative;
  background:var(--card);
  border:3px solid var(--ink);
  box-shadow:var(--shadow-hard);
  padding:clamp(18px,2.4vw,30px);
}
.panel--soft{border-width:2px;box-shadow:var(--shadow-soft);}
.panel--veil{background-image:linear-gradient(180deg,var(--veil),transparent 65%);}

.num{
  font-family:var(--font-mono);
  font-variant-numeric:tabular-nums;
  letter-spacing:-.02em;
}
.tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:4px 10px;
  border:2px solid var(--ink);
  background:var(--sand);
  color:var(--ink);
  font-family:var(--font-mono);
  font-size:.64rem;
  line-height:1.4;
  letter-spacing:.14em;
  text-transform:uppercase;
}
.tag--live{background:var(--lime);}
.tag--cyan{background:var(--cyan);color:var(--bone);}

/* ---------- image containers ---------- */
.figure{
  position:relative;
  display:block;
  margin:0;
  border:3px solid var(--ink);
  background:linear-gradient(135deg,var(--sand),#BFA063);
  box-shadow:var(--shadow-soft);
  overflow:hidden;
}
.figure img{
  display:block;
  width:100%;
  height:100%;
  object-fit:cover;
}
.figure figcaption{
  position:absolute;
  left:0;
  bottom:0;
  max-width:100%;
  padding:7px 12px;
  background:var(--ink);
  color:var(--sand);
  font-family:var(--font-mono);
  font-size:.64rem;
  letter-spacing:.1em;
}
.figure--wide{aspect-ratio:16/9;}
.figure--square{aspect-ratio:1/1;}
.figure--tall{aspect-ratio:3/4;}
.figure--band{aspect-ratio:21/9;}
.img-pair{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(160px,1fr));
  gap:clamp(10px,1.6vw,18px);
}

/* ---------- scroll chapter highlight ---------- */
[data-chapter]{
  border-left:4px solid transparent;
  padding-left:clamp(12px,1.6vw,20px);
  transition:border-color .3s ease;
}
[data-chapter].is-current{border-left-color:var(--cyan);}

/* ---------- reading progress (injected) ---------- */
.read-progress{
  position:fixed;
  top:0;
  left:0;
  height:3px;
  width:0;
  z-index:190;
  background:linear-gradient(90deg,var(--gobi),var(--lime));
  pointer-events:none;
  transition:width .12s linear;
}

/* ---------- footer ---------- */
.site-footer{
  position:relative;
  margin-top:clamp(56px,8vw,120px);
  background:var(--night);
  color:var(--sand);
  border-top:8px solid var(--ochre);
  overflow:hidden;
}
.site-footer::before{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  background-image:
    repeating-linear-gradient(90deg,rgba(227,197,139,.10) 0 1px,transparent 1px 96px),
    repeating-linear-gradient(180deg,rgba(227,197,139,.07) 0 1px,transparent 1px 96px);
}
.footer-inner{
  position:relative;
  z-index:1;
  max-width:var(--wrap);
  margin:0 auto;
  padding:clamp(40px,6vw,76px) var(--gutter) clamp(30px,4vw,48px);
  display:grid;
  grid-template-columns:1.5fr .8fr .8fr 1.3fr;
  gap:clamp(24px,4vw,56px);
}
.footer-brand-line{
  font-family:var(--font-display);
  font-weight:900;
  font-size:clamp(1.1rem,1.8vw,1.45rem);
  line-height:1.2;
  letter-spacing:-.01em;
  color:var(--bone);
}
.footer-tagline{
  margin-top:12px;
  max-width:20em;
  font-size:.92rem;
  line-height:1.7;
  color:rgba(227,197,139,.9);
}
.footer-coord{
  display:inline-block;
  margin-top:20px;
  padding-top:12px;
  border-top:1px solid var(--rule-dark);
  font-family:var(--font-mono);
  font-size:.66rem;
  letter-spacing:.18em;
  color:var(--lime);
}
.footer-col-title{
  display:flex;
  align-items:center;
  gap:10px;
  margin:0 0 16px;
  font-family:var(--font-mono);
  font-size:.66rem;
  font-weight:600;
  letter-spacing:.24em;
  text-transform:uppercase;
  color:var(--gobi);
}
.footer-col-title::after{
  content:"";
  flex:1 1 auto;
  height:1px;
  background:var(--rule-dark);
}
.footer-col ul li+li{margin-top:10px;}
.footer-col a{
  display:inline-block;
  padding-bottom:2px;
  border-bottom:1px solid transparent;
  font-size:.9rem;
  color:var(--sand);
  transition:color .18s ease,border-color .18s ease,transform .18s ease;
}
.footer-col a:hover{
  color:var(--lime);
  border-bottom-color:var(--lime);
  transform:translateX(3px);
}
.footer-address{
  display:grid;
  grid-template-columns:auto 1fr;
  gap:10px 14px;
  font-size:.86rem;
  line-height:1.6;
}
.footer-key{
  padding-top:.3em;
  font-family:var(--font-mono);
  font-size:.62rem;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--gobi);
}
.footer-val{color:var(--sand);word-break:break-word;}
.footer-base{
  position:relative;
  z-index:1;
  border-top:1px solid var(--rule-dark);
  background:rgba(23,19,16,.28);
}
.footer-base-inner{
  max-width:var(--wrap);
  margin:0 auto;
  padding:18px var(--gutter) 26px;
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:10px 26px;
  font-family:var(--font-mono);
  font-size:.68rem;
  letter-spacing:.1em;
  color:rgba(227,197,139,.66);
}
.footer-copy{color:rgba(227,197,139,.82);}
.footer-icp{color:var(--gobi);}
.footer-note{
  flex:1 1 240px;
  font-family:var(--font-body);
  font-size:.72rem;
  letter-spacing:.02em;
  color:rgba(227,197,139,.58);
}

/* ---------- responsive: header ---------- */
@media (max-width:1080px){
  .nav-toggle{display:inline-flex;}
  .primary-nav{
    position:absolute;
    top:100%;
    left:0;
    right:0;
    display:none;
    flex-direction:column;
    align-items:stretch;
    gap:0;
    padding:16px var(--gutter) 22px;
    background:var(--bone);
    border-bottom:3px solid var(--ink);
    box-shadow:0 20px 40px rgba(23,19,16,.22);
    max-height:calc(100vh - var(--header-h));
    overflow-y:auto;
  }
  .primary-nav[data-open]{display:flex;}
  .nav-list{flex-direction:column;align-items:stretch;gap:0;}
  .nav-list li+li{border-top:1px solid var(--rule);}
  .nav-list a{display:flex;padding:14px 2px;font-size:1rem;}
  .nav-list a::after{display:none;}
  .nav-list a[aria-current="page"]{
    background-image:linear-gradient(90deg,var(--veil),rgba(201,150,63,0));
  }
  .nav-actions{
    flex-direction:column;
    align-items:stretch;
    gap:10px;
    margin-top:18px;
  }
  .nav-actions .btn{width:100%;padding:14px 18px;font-size:.9rem;}
}

@media (max-width:820px){
  .site-header{--header-h:98px;}
  .header-coord{height:30px;font-size:.6rem;letter-spacing:.12em;}
  .coord-id{display:none;}
  .brand-sub{display:none;}
  .header-bar{min-height:64px;}
  .brand{padding:10px 0;}
  .brand-mark{height:38px;}
}

@media (max-width:620px){
  .coord-note{display:none;}
}

/* ---------- responsive: footer ---------- */
@media (max-width:920px){
  .footer-inner{
    grid-template-columns:1fr 1fr;
    gap:32px 28px;
  }
  .footer-brand{grid-column:1/-1;}
  .footer-contact{grid-column:1/-1;}
}
@media (max-width:560px){
  .footer-inner{grid-template-columns:1fr;}
  .footer-base-inner{font-size:.64rem;letter-spacing:.06em;}
}

/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion:reduce){
  *,
  *::before,
  *::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  html{scroll-behavior:auto;}
  .btn:hover{transform:none;}
  .footer-col a:hover{transform:none;}
  .read-progress{transition:none;}
}