:root{
  --ink:#0B1B2B;
  --ink-panel:#122A3F;
  --ink-line:#24445C;
  --paper:#F4EFE4;
  --text:#EAF1F6;
  --text-dim:#A8BAC7;
  --signal:#FF6A2A;
  --celadon:#3FC7A8;
  --electric:#2ED9D0;
  --silver:#C3CBD3;
  --violet:#8B7CF6;
  --on-light:#08131F;

  --font-head:"Noto Sans SC","Source Han Sans SC","PingFang SC","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  --font-body:"Noto Sans SC","PingFang SC","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  --font-mono:"IBM Plex Mono","JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;

  --shell-w:1180px;
  --shell-pad:1.4rem;
  --ease:cubic-bezier(.2,.7,.3,1);
  --dur:160ms;
  --line:1px solid var(--ink-line);
}

*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{
  margin:0;
  background:var(--ink);
  color:var(--text);
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.8;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
h1,h2,h3,h4,h5,p,ul,ol,dl,dd,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,video{display:block;max-width:100%;height:auto}
table{border-collapse:collapse;width:100%}
:focus-visible{outline:2px solid var(--electric);outline-offset:3px;border-radius:2px}
::selection{background:var(--signal);color:var(--on-light)}

h1,h2,h3,h4{font-family:var(--font-head);font-weight:900;line-height:1.14;letter-spacing:-.01em;color:var(--paper)}
h1{font-size:clamp(2.4rem,6vw,5rem)}
h2{font-size:clamp(1.6rem,3vw,2.6rem)}
h3{font-size:clamp(1.15rem,1.6vw,1.35rem);font-weight:800}

.visually-hidden{
  position:absolute;width:1px;height:1px;padding:0;margin:-1px;
  overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0;
}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums;letter-spacing:.02em}

/* ---------- shell / layout helpers ---------- */
.shell{width:min(var(--shell-w),100% - (var(--shell-pad) * 2));margin-inline:auto}
.stack > * + *{margin-top:1.4rem}
.grid{display:grid;gap:clamp(1rem,2.4vw,1.8rem)}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
.split{display:grid;grid-template-columns:minmax(0,.9fr) minmax(0,1.35fr);gap:clamp(1.2rem,3vw,2.8rem)}

/* ---------- panels / paper language ---------- */
.panel{
  position:relative;
  background:var(--ink-panel);
  border:var(--line);
  padding:clamp(1.2rem,3vw,2.2rem);
}
.panel--paper{background:var(--paper);color:var(--on-light);border-color:var(--ink-line)}
.panel--paper h2,.panel--paper h3{color:var(--on-light)}
.rule{border:0;height:1px;background:var(--ink-line);margin:0}
.section-label{
  display:inline-flex;align-items:center;gap:.5rem;
  font-family:var(--font-mono);font-size:11.5px;font-weight:700;letter-spacing:.18em;
  color:var(--electric);border:1px solid var(--ink-line);background:rgba(46,217,208,.07);
  padding:.34rem .62rem;
}
.coord{
  font-family:var(--font-mono);font-size:12px;letter-spacing:.16em;
  color:var(--text-dim);writing-mode:vertical-rl;text-orientation:mixed;
}
.tag{
  display:inline-block;font-family:var(--font-mono);font-size:11px;font-weight:700;
  letter-spacing:.12em;padding:.2rem .45rem;border:1px solid var(--silver);
  color:var(--silver);background:rgba(195,203,211,.08);
}
.tag[data-tone="signal"]{color:var(--signal);border-color:var(--signal);background:rgba(255,106,42,.1)}
.tag[data-tone="celadon"]{color:var(--celadon);border-color:var(--celadon);background:rgba(63,199,168,.1)}
.tag[data-tone="electric"]{color:var(--electric);border-color:var(--electric);background:rgba(46,217,208,.1)}
.stamp{
  display:inline-block;font-family:var(--font-mono);font-size:12px;font-weight:700;
  letter-spacing:.14em;color:var(--signal);border:2px solid var(--signal);
  padding:.3rem .6rem;transform:rotate(-5deg);
}
.route-legend{display:flex;flex-wrap:wrap;gap:.6rem 1.2rem;font-size:12.5px;color:var(--text-dim)}
.legend-item{display:inline-flex;align-items:center;gap:.45rem}
.legend-dot{width:9px;height:9px;display:inline-block;border-radius:50%;background:var(--silver);flex:0 0 auto}
.legend-dot[data-tone="signal"]{background:var(--signal)}
.legend-dot[data-tone="celadon"]{background:var(--celadon)}
.legend-dot[data-tone="electric"]{background:var(--electric)}
.legend-dot[data-tone="violet"]{background:var(--violet)}

/* ---------- breadcrumb / prose ---------- */
.breadcrumb{font-family:var(--font-mono);font-size:12px;color:var(--text-dim)}
.breadcrumb-list{display:flex;flex-wrap:wrap;align-items:center;gap:.5rem}
.breadcrumb-item{display:inline-flex;align-items:center;gap:.5rem}
.breadcrumb-item + .breadcrumb-item::before{content:"/";color:var(--ink-line)}
.breadcrumb-link{color:var(--text-dim);text-decoration:underline;text-underline-offset:3px;text-decoration-color:var(--ink-line)}
.breadcrumb-link:hover{color:var(--electric);text-decoration-color:var(--electric)}
.prose{max-width:68ch;color:var(--text)}
.prose p + p{margin-top:1rem}
.prose ul{margin-top:1rem;display:grid;gap:.4rem}
.prose li{position:relative;padding-left:1.1rem}
.prose li::before{content:"";position:absolute;left:0;top:.72em;width:.5rem;height:1px;background:var(--electric)}
.prose a{color:var(--electric);text-decoration:underline;text-underline-offset:3px}

/* ---------- figures ---------- */
.figure-frame{
  position:relative;isolation:isolate;margin:0;
  background:var(--ink-panel);border:1px solid var(--ink-line);
}
.figure-frame::after{
  content:"";position:absolute;inset:10px -10px -10px 10px;
  border:1px solid var(--ink-line);z-index:-1;pointer-events:none;
}
.figure-frame img,.figure-frame svg{display:block;width:100%;height:auto;aspect-ratio:16/10;object-fit:cover}
.figure-frame--wide img,.figure-frame--wide svg{aspect-ratio:21/9}
.figure-frame--tall img,.figure-frame--tall svg{aspect-ratio:3/4}
.figure-frame--square img,.figure-frame--square svg{aspect-ratio:1/1}
.figure-frame figcaption{
  font-family:var(--font-mono);font-size:11.5px;line-height:1.6;letter-spacing:.04em;
  color:var(--text-dim);background:rgba(11,27,43,.85);
  border-top:1px solid var(--ink-line);padding:.55rem .75rem;
}
.figure-placeholder{
  position:relative;aspect-ratio:16/10;display:grid;place-items:center;
  background-color:var(--ink-panel);
  background-image:
    linear-gradient(rgba(36,68,92,.5) 1px,transparent 1px),
    linear-gradient(90deg,rgba(36,68,92,.5) 1px,transparent 1px);
  background-size:28px 28px;
}
.figure-placeholder::before{
  content:attr(data-label);
  font-family:var(--font-mono);font-size:11.5px;letter-spacing:.16em;
  color:var(--silver);border:1px dashed var(--silver);
  padding:.35rem .6rem;background:rgba(11,27,43,.75);
  text-align:center;max-width:80%;
}

/* ---------- buttons ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.4rem;
  padding:.74rem 1.1rem;font-family:var(--font-body);font-size:14px;font-weight:700;
  line-height:1;letter-spacing:.02em;border:1px solid transparent;border-radius:2px;
  cursor:pointer;
  transition:transform var(--dur) var(--ease),background-color var(--dur) var(--ease),
    border-color var(--dur) var(--ease),color var(--dur) var(--ease),box-shadow var(--dur) var(--ease);
}
.btn:hover{transform:translateY(-1px)}
.btn:active{transform:translateY(0)}
.btn--compact{padding:.58rem .8rem;font-size:13px}
.btn--signal{background:var(--signal);border-color:var(--signal);color:var(--on-light)}
.btn--signal:hover{background:#ff8347;border-color:#ff8347;box-shadow:0 3px 0 0 rgba(255,106,42,.35)}
.btn--celadon{background:var(--celadon);border-color:var(--celadon);color:var(--on-light)}
.btn--celadon:hover{background:#57d9bd;border-color:#57d9bd;box-shadow:0 3px 0 0 rgba(63,199,168,.32)}
.btn--ghost{background:transparent;border-color:var(--ink-line);color:var(--text)}
.btn--ghost:hover{border-color:var(--silver);color:var(--paper);background:rgba(195,203,211,.08)}

/* ---------- header ---------- */
.skip-link{
  position:fixed;top:.6rem;left:.6rem;z-index:120;
  transform:translateY(-180%);
  background:var(--paper);color:var(--on-light);
  font-size:14px;font-weight:700;padding:.7rem 1.1rem;
  border:2px solid var(--on-light);border-radius:2px;
  transition:transform var(--dur) var(--ease);
}
.skip-link:focus{transform:none}

.site-header{
  position:sticky;top:0;z-index:60;
  background:var(--ink);
  border-bottom:1px solid var(--ink-line);
  box-shadow:0 10px 24px -18px rgba(0,0,0,.9);
}
.header-inner{
  position:relative;z-index:2;
  width:min(var(--shell-w),100% - (var(--shell-pad) * 2));
  margin-inline:auto;
  display:flex;align-items:center;justify-content:space-between;
  gap:1rem;min-height:74px;padding-block:.55rem;
  background:var(--ink);
}
.brand{display:inline-flex;align-items:center;gap:.6rem;flex:0 0 auto}
.brand-name{
  font-family:var(--font-head);font-weight:900;
  font-size:clamp(1rem,1.5vw,1.18rem);letter-spacing:.02em;
  color:var(--paper);white-space:nowrap;
}
.brand-rule{display:block;width:1px;height:1.05rem;background:var(--ink-line)}
.brand-stamp{
  font-family:var(--font-mono);font-size:11px;font-weight:700;line-height:1.2;
  letter-spacing:.14em;color:var(--signal);
  border:1px solid var(--signal);border-radius:1px;
  padding:.14rem .38rem;background:rgba(255,106,42,.09);
  transform:rotate(-4deg);
  transition:transform var(--dur) var(--ease);
}
.brand:hover .brand-stamp{transform:rotate(0deg)}

.header-tools{display:flex;align-items:center;gap:clamp(.5rem,1.4vw,1.1rem);min-width:0}
.header-actions{display:flex;align-items:center;gap:.5rem;flex:0 0 auto}

.site-nav{display:flex;align-items:center}
.nav-caption{display:none}
.nav-list{display:flex;align-items:center;gap:clamp(.15rem,.9vw,.55rem)}
.nav-item{display:block}
.nav-link{
  position:relative;display:inline-flex;align-items:center;gap:.35rem;
  padding:.55rem .6rem;font-size:14px;font-weight:600;color:var(--text-dim);
  border-radius:2px;
  transition:color var(--dur) var(--ease),background-color var(--dur) var(--ease);
}
.nav-link::after{
  content:"";position:absolute;left:.6rem;right:.6rem;bottom:.28rem;height:2px;
  background:var(--electric);transform:scaleX(0);transform-origin:0 50%;
  transition:transform var(--dur) var(--ease);
}
.nav-link:hover{color:var(--paper);background:rgba(46,217,208,.08)}
.nav-link:hover::after{transform:scaleX(1)}
.nav-link[aria-current="page"]{color:var(--paper)}
.nav-link[aria-current="page"]::after{transform:scaleX(1);background:var(--signal)}
.nav-index{
  font-family:var(--font-mono);font-size:10px;font-weight:600;
  letter-spacing:.08em;color:var(--silver);opacity:.55;
}
.nav-link[aria-current="page"] .nav-index{color:var(--signal);opacity:1}
.nav-extra{display:none}

.nav-toggle{
  display:none;align-items:center;gap:.45rem;
  border:1px solid var(--ink-line);border-radius:2px;
  padding:.5rem .6rem;font-size:13px;font-weight:700;color:var(--text);
  transition:border-color var(--dur) var(--ease),background-color var(--dur) var(--ease);
}
.nav-toggle:hover{border-color:var(--electric);background:rgba(46,217,208,.08)}
.nav-toggle-bars{display:inline-flex;flex-direction:column;justify-content:space-between;width:16px;height:12px}
.nav-toggle-bars span{
  display:block;height:2px;width:100%;background:var(--electric);
  transition:transform var(--dur) var(--ease),opacity var(--dur) var(--ease);
}
.nav-toggle-text{white-space:nowrap}

.scroll-progress{
  position:absolute;left:0;right:0;bottom:0;height:2px;z-index:3;
  background:rgba(36,68,92,.5);pointer-events:none;
}
.scroll-progress-bar{
  display:block;height:100%;width:100%;
  background:linear-gradient(90deg,var(--electric),var(--celadon));
  transform:scaleX(0);transform-origin:0 50%;
}

/* ---------- export dialog ---------- */
html.has-dialog{overflow:hidden}
.export-dialog{
  position:fixed;inset:0;z-index:90;
  display:grid;place-items:center;padding:1.2rem;
  background:rgba(8,19,31,.82);
}
.export-dialog[hidden]{display:none}
.export-panel{
  position:relative;width:min(560px,100%);max-height:88vh;overflow-y:auto;
  background:var(--paper);color:var(--on-light);border:1px solid var(--ink-line);
  padding:clamp(1.2rem,3vw,1.9rem);
  box-shadow:10px 10px 0 -1px rgba(46,217,208,.28),0 0 0 1px rgba(8,19,31,.12);
}
.export-panel::after{
  content:"V4";position:absolute;right:1.1rem;top:1.1rem;
  font-family:var(--font-mono);font-size:11px;font-weight:700;letter-spacing:.14em;
  color:var(--signal);border:1px solid var(--signal);padding:.12rem .36rem;
  transform:rotate(-4deg);
}
.export-kicker{font-family:var(--font-mono);font-size:11px;letter-spacing:.18em;color:#4a6374}
.export-title{font-family:var(--font-head);font-size:1.35rem;font-weight:900;color:var(--on-light);margin-top:.2rem}
.export-text{font-size:14px;line-height:1.7;color:#2b3d4c;margin-top:.5rem;max-width:46ch}
.export-list{margin-top:1rem;border-top:1px solid rgba(8,19,31,.16)}
.export-item{
  display:grid;grid-template-columns:5.4rem 1fr;gap:.8rem;
  padding:.5rem 0;border-bottom:1px solid rgba(8,19,31,.12);font-size:13px;
}
.export-key{color:#4a6374;font-weight:600}
.export-val{color:var(--on-light)}
.export-actions{display:flex;flex-wrap:wrap;gap:.6rem;margin-top:1.1rem}
.export-actions .btn--ghost{border-color:rgba(8,19,31,.28);color:var(--on-light)}
.export-actions .btn--ghost:hover{background:rgba(8,19,31,.08);color:var(--on-light);border-color:var(--on-light)}

/* ---------- footer ---------- */
.site-footer{
  position:relative;
  margin-top:clamp(3rem,7vw,5.5rem);
  background-color:var(--ink-panel);
  border-top:2px solid var(--ink-line);
  color:var(--text-dim);
  background-image:
    linear-gradient(rgba(36,68,92,.22) 1px,transparent 1px),
    linear-gradient(90deg,rgba(36,68,92,.22) 1px,transparent 1px);
  background-size:100% 64px,64px 100%;
}
.site-footer::before{
  content:"";position:absolute;left:0;top:-2px;
  width:clamp(80px,14vw,180px);height:2px;background:var(--electric);
}
.footer-inner{
  width:min(var(--shell-w),100% - (var(--shell-pad) * 2));
  margin-inline:auto;
  padding:clamp(2rem,4vw,3.2rem) 0 clamp(1.4rem,3vw,2rem);
  display:grid;grid-template-columns:1.6fr 1fr 1fr 1.5fr;
  gap:clamp(1.4rem,3vw,2.6rem);
}
.footer-col{min-width:0}
.footer-brand{display:flex;flex-direction:column;align-items:flex-start}
.footer-name{font-family:var(--font-head);font-weight:900;font-size:1.3rem;letter-spacing:.02em;color:var(--paper)}
.footer-seal{
  display:inline-block;margin-top:.7rem;
  font-family:var(--font-mono);font-size:11px;font-weight:700;letter-spacing:.14em;
  color:var(--silver);border:1px solid var(--silver);padding:.2rem .45rem;
  transform:rotate(-3deg);
}
.footer-note{margin-top:.8rem;font-size:13px;line-height:1.7;color:var(--text-dim);max-width:26ch}
.footer-heading{
  font-family:var(--font-mono);font-size:11px;font-weight:700;letter-spacing:.2em;
  color:var(--silver);padding-bottom:.7rem;margin-bottom:.8rem;
  border-bottom:1px dashed var(--ink-line);
}
.footer-col[data-tone="signal"] .footer-heading{color:var(--signal)}
.footer-col[data-tone="celadon"] .footer-heading{color:var(--celadon)}
.footer-col[data-tone="electric"] .footer-heading{color:var(--electric)}
.footer-list{display:grid;gap:.35rem}
.footer-link{
  display:inline-block;font-size:13.5px;font-weight:500;color:var(--text-dim);
  padding:.16rem 0;
  transition:color var(--dur) var(--ease),transform var(--dur) var(--ease);
}
.footer-link:hover{color:var(--paper);transform:translateX(3px)}
.footer-hint{margin-top:.7rem;font-size:12px;line-height:1.6;color:var(--silver)}
.contact-list{display:grid;grid-template-columns:auto 1fr;gap:.45rem .7rem;align-items:baseline;font-size:13.5px}
.contact-key{font-family:var(--font-mono);font-size:10.5px;letter-spacing:.14em;color:var(--silver);opacity:.85}
.contact-val{color:var(--text);word-break:break-word}
.footer-bar{
  width:min(var(--shell-w),100% - (var(--shell-pad) * 2));
  margin-inline:auto;
  border-top:1px solid var(--ink-line);
  padding:1rem 0 1.4rem;
  display:flex;flex-wrap:wrap;align-items:center;gap:.5rem 1.1rem;
  font-size:12px;color:var(--text-dim);
}
.footer-meta{font-size:12px}
.footer-tools{display:inline-flex;align-items:center;flex-wrap:wrap;gap:.5rem;margin-left:auto}
.link-button{
  font:inherit;font-size:12px;font-weight:600;color:var(--electric);
  background:none;border:0;padding:0;text-decoration:underline;
  text-underline-offset:3px;cursor:pointer;
  transition:color var(--dur) var(--ease);
}
.link-button:hover{color:var(--paper)}
.footer-sep{color:var(--ink-line)}

/* ---------- reveal ---------- */
[data-reveal]{
  opacity:0;transform:translateY(14px);
  transition:opacity 380ms var(--ease),transform 380ms var(--ease);
}
[data-reveal].is-visible{opacity:1;transform:none}

/* ---------- responsive ---------- */
@media (min-width:901px) and (max-width:1120px){
  .nav-link{font-size:13px;padding:.5rem .42rem;gap:.25rem}
  .nav-index{display:none}
  .header-actions .btn--compact{padding:.52rem .62rem;font-size:12.5px}
}

@media (max-width:900px){
  :root{--shell-pad:1.1rem}
  .header-inner{min-height:62px;padding-block:.45rem}
  .nav-toggle{display:inline-flex}
  .header-actions .btn--ghost{display:none}

  .site-nav{
    position:fixed;top:0;right:0;bottom:0;left:auto;z-index:1;
    display:block;
    width:min(340px,86vw);
    background:var(--ink-panel);
    border-left:1px solid var(--ink-line);
    padding:calc(62px + 2rem) 1.3rem 2rem;
    overflow-y:auto;
    transform:translateX(101%);
    visibility:hidden;
    box-shadow:-18px 0 40px -22px rgba(0,0,0,.85);
    transition:transform 220ms var(--ease),visibility 220ms linear;
  }
  .site-header[data-open="true"] .site-nav{transform:translateX(0);visibility:visible}
  .site-header::before{
    content:"";position:fixed;inset:0;z-index:0;
    background:rgba(8,19,31,.74);opacity:0;pointer-events:none;
    transition:opacity 200ms var(--ease);
  }
  .site-header[data-open="true"]::before{opacity:1;pointer-events:auto}
  .site-header[data-open="true"] .nav-toggle-bars span:nth-child(1){transform:translateY(5px) rotate(45deg)}
  .site-header[data-open="true"] .nav-toggle-bars span:nth-child(2){opacity:0}
  .site-header[data-open="true"] .nav-toggle-bars span:nth-child(3){transform:translateY(-5px) rotate(-45deg)}

  .nav-caption{
    display:block;font-family:var(--font-mono);font-size:11px;font-weight:700;
    letter-spacing:.2em;color:var(--electric);
    margin-bottom:1rem;padding-bottom:.6rem;border-bottom:1px dashed var(--ink-line);
  }
  .nav-list{flex-direction:column;align-items:stretch;gap:0}
  .nav-link{
    display:flex;width:100%;padding:.95rem .2rem;
    font-size:1rem;color:var(--text);border-bottom:1px solid var(--ink-line);
    border-radius:0;
  }
  .nav-link::after{left:0;right:auto;bottom:0;width:100%;height:2px}
  .nav-index{font-size:11px;width:1.8rem;opacity:.7}
  .nav-extra{display:block;margin-top:1.3rem}
  .nav-extra .btn{width:100%}

  .split{grid-template-columns:minmax(0,1fr)}
  .footer-inner{grid-template-columns:1fr 1fr}
}

@media (max-width:860px){
  .grid--2,.grid--3{grid-template-columns:minmax(0,1fr)}
}

@media (max-width:640px){
  :root{--shell-pad:.9rem}
  .nav-toggle-text{display:none}
  .nav-toggle{padding:.55rem}
  .header-actions .btn--signal{padding:.55rem .62rem;font-size:12.5px}
  .brand-name{font-size:1rem}
  .grid--3{grid-template-columns:minmax(0,1fr)}
  .footer-inner{grid-template-columns:minmax(0,1fr)}
  .footer-tools{margin-left:0}
  .export-item{grid-template-columns:1fr;gap:.1rem}
}

@media (max-width:620px){
  .footer-inner{grid-template-columns:minmax(0,1fr)}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  [data-reveal]{opacity:1;transform:none}
  .btn:hover,.footer-link:hover{transform:none}
  .site-nav{transition:none}
}