/* ============ reset ============ */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body,h1,h2,h3,h4,h5,p,ul,ol,figure,blockquote,figure{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;padding:0;cursor:pointer}
a{color:inherit;text-decoration:none}
table{border-collapse:collapse;width:100%}

/* ============ tokens ============ */
:root{
  --ink:#101B3C;
  --ink-deep:#070C1C;
  --turq:#17B3A3;
  --rust:#B2462E;
  --gold:#E9B45C;
  --cyan:#5AE0CE;
  --amber:#F0A03C;
  --paper:#F6F2E9;
  --line:#2A3350;
  --mist:#C9CFDD;

  --rail-w:240px;
  --gutter:clamp(16px,3vw,40px);
  --maxw:1320px;

  --font-display:"PingFang SC","Hiragino Sans GB","Source Han Sans SC","Noto Sans SC","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  --font-serif:"Songti SC","Source Han Serif SC","Noto Serif SC",Georgia,"Times New Roman",serif;
  --font-mono:ui-monospace,"SF Mono","JetBrains Mono",Menlo,Consolas,"Liberation Mono",monospace;

  --t-12:12px;--t-14:14px;--t-16:16px;--t-18:18px;
  --t-22:22px;--t-28:28px;--t-40:40px;--t-64:64px;

  --flag-band:linear-gradient(to right,var(--turq) 0 22%,var(--gold) 22% 44%,var(--rust) 44% 62%,var(--cyan) 62% 82%,var(--mist) 82% 100%);
}

/* ============ base ============ */
body{
  font-family:var(--font-display);
  font-size:var(--t-16);
  line-height:1.75;
  color:var(--paper);
  background:var(--ink-deep);
  min-height:100vh;
}
@media (min-width:1024px){
  body{padding-left:var(--rail-w)}
}
#main-content{display:block;min-height:60vh}

::selection{background:var(--turq);color:var(--ink-deep)}

:focus-visible{
  outline:2px solid var(--gold);
  outline-offset:3px;
}

/* ============ skip link ============ */
.skip-link{
  position:absolute;left:14px;top:12px;z-index:200;
  background:var(--gold);color:var(--ink-deep);
  font-size:var(--t-14);font-weight:700;letter-spacing:.02em;
  padding:10px 16px;border:1px solid var(--ink-deep);
  transform:translateY(-220%);
  transition:transform .18s ease;
}
.skip-link:focus,.skip-link:focus-visible{transform:translateY(0)}

/* ============ side rail (header) ============ */
.rail{
  --scroll-progress:0;
  position:fixed;top:0;left:0;bottom:0;width:var(--rail-w);
  display:flex;flex-direction:column;gap:14px;
  padding:22px 18px 16px;
  background:var(--ink-deep);
  color:var(--paper);
  border-right:1px solid var(--line);
  overflow-y:auto;
  overscroll-behavior:contain;
  z-index:80;
}
.rail::before{
  content:"";position:absolute;top:0;left:0;right:0;height:3px;
  background:var(--flag-band);
  pointer-events:none;
}
.rail__progress{
  position:absolute;left:0;top:0;width:3px;height:100%;
  background:var(--gold);opacity:.85;
  transform:scaleY(var(--scroll-progress));transform-origin:top;
  pointer-events:none;
}

.rail__top{
  display:grid;grid-template-columns:minmax(0,1fr) auto;
  align-items:start;gap:8px;padding-top:8px;
}
.rail__brand{display:grid;gap:1px;min-width:0}
.rail__mark{
  font-family:var(--font-mono);font-size:var(--t-12);
  letter-spacing:.24em;color:var(--turq);
}
.rail__name{
  font-size:var(--t-22);font-weight:800;
  letter-spacing:-.01em;line-height:1.2;
}
.rail__sub{
  font-size:var(--t-12);letter-spacing:.16em;
  color:rgba(201,207,221,.72);
}
.rail__version{
  font-family:var(--font-mono);font-size:var(--t-12);
  background:var(--gold);color:var(--ink-deep);
  padding:2px 7px;letter-spacing:.06em;align-self:start;
}

.rail__toggle{
  display:none;align-items:center;gap:9px;
  border:1px solid var(--line);
  padding:8px 12px;
  font-size:var(--t-14);letter-spacing:.08em;color:var(--mist);
  transition:border-color .2s,color .2s;
}
.rail__toggle:hover{border-color:var(--gold);color:var(--gold)}
.rail__bars{position:relative;display:block;width:18px;height:12px}
.rail__bars::before,.rail__bars::after{
  content:"";position:absolute;left:0;width:100%;height:2px;
  background:currentColor;transition:transform .2s ease;
}
.rail__bars::before{top:0;box-shadow:0 5px 0 currentColor}
.rail__bars::after{top:10px}
.rail[data-open="true"] .rail__bars::before{transform:translateY(5px) rotate(45deg);box-shadow:none}
.rail[data-open="true"] .rail__bars::after{transform:translateY(-5px) rotate(-45deg)}
.rail__toggle-text{font-family:var(--font-mono)}

.rail__nav{display:flex;flex-direction:column;gap:16px;margin-top:4px}
.rail__list{counter-reset:rail;border-top:1px solid var(--line)}
.rail__list li{counter-increment:rail}
.rail__link{
  display:flex;align-items:baseline;gap:10px;
  padding:11px 8px 11px 12px;
  border-left:3px solid transparent;
  font-size:var(--t-16);
  color:var(--mist);
  transition:color .2s,border-color .2s,background .2s;
}
.rail__link::before{
  content:counter(rail,decimal-leading-zero);
  font-family:var(--font-mono);font-size:var(--t-12);
  color:var(--line);flex:0 0 auto;
}
.rail__link:hover{
  color:var(--paper);border-left-color:var(--gold);
  background:rgba(233,180,92,.07);
}
.rail__link[aria-current="page"]{
  color:var(--paper);border-left-color:var(--turq);
  background:rgba(23,179,163,.13);
}
.rail__link[aria-current="page"]::before{color:var(--turq)}

.rail__actions{display:grid;gap:8px;padding-top:14px;border-top:1px solid var(--line)}

.rail__foot{
  margin-top:auto;display:grid;gap:8px;
  padding-top:14px;border-top:1px solid var(--line);
  font-size:var(--t-12);line-height:1.5;
}
.rail__legacy{
  justify-self:start;
  font-family:var(--font-mono);font-size:var(--t-12);
  letter-spacing:.08em;color:var(--gold);
  border-bottom:1px solid transparent;
  transition:border-color .2s,color .2s;
}
.rail__legacy:hover{color:var(--paper);border-bottom-color:var(--paper)}
.rail__meta{color:rgba(201,207,221,.62);font-family:var(--font-mono);letter-spacing:.02em}

/* ============ footer ============ */
.foot{
  position:relative;
  background:var(--ink);
  color:var(--paper);
  border-top:1px solid var(--line);
  padding:clamp(38px,6vw,72px) var(--gutter) clamp(22px,3vw,30px);
}
.foot::before{
  content:"";position:absolute;top:0;left:0;right:0;height:3px;
  background:var(--flag-band);
}
.foot__inner{
  max-width:var(--maxw);margin-inline:auto;
  display:grid;gap:clamp(24px,4vw,44px);
}
.foot__top{
  display:flex;flex-wrap:wrap;align-items:flex-end;
  justify-content:space-between;gap:18px 32px;
  padding-bottom:22px;border-bottom:1px solid var(--line);
}
.foot__brand{display:grid;gap:6px;min-width:0}
.foot__mark{
  font-size:var(--t-28);font-weight:800;
  letter-spacing:-.02em;line-height:1.15;
}
.foot__tagline{
  font-family:var(--font-serif);font-size:var(--t-16);
  color:var(--mist);max-width:34ch;line-height:1.7;
}
.foot__legacy{
  font-family:var(--font-mono);font-size:var(--t-14);
  letter-spacing:.04em;color:var(--gold);
  border:1px solid rgba(233,180,92,.55);
  padding:9px 14px;
  transition:background .2s,color .2s,border-color .2s;
}
.foot__legacy:hover{background:var(--gold);color:var(--ink-deep);border-color:var(--gold)}

.foot__grid{
  display:grid;gap:clamp(22px,3vw,40px);
  grid-template-columns:repeat(3,minmax(0,1fr));
}
.foot__col-title{
  font-family:var(--font-serif);font-size:var(--t-14);font-weight:400;
  letter-spacing:.22em;color:var(--turq);
  padding-bottom:10px;margin-bottom:12px;
  border-bottom:1px solid var(--line);
}
.foot__links{display:grid;gap:9px}
.foot__link{
  justify-self:start;
  font-size:var(--t-16);color:var(--mist);
  border-bottom:1px solid transparent;
  transition:color .2s,border-color .2s;
}
.foot__link:hover{color:var(--paper);border-bottom-color:var(--turq)}
.foot__contact{display:grid;gap:9px;font-size:var(--t-14);color:var(--mist);line-height:1.7}
.foot__line{display:grid;gap:2px}
.foot__label{
  font-family:var(--font-mono);font-size:var(--t-12);
  letter-spacing:.14em;color:rgba(201,207,221,.6);
}
.foot__note{
  font-size:var(--t-12);line-height:1.65;
  color:rgba(201,207,221,.6);
  padding-left:10px;border-left:1px solid var(--rust);
  max-width:34ch;
}
.foot__base{
  display:flex;flex-wrap:wrap;justify-content:space-between;
  gap:10px 24px;padding-top:18px;
  border-top:1px solid var(--line);
  font-family:var(--font-mono);font-size:var(--t-12);
  letter-spacing:.05em;color:rgba(201,207,221,.62);
}
.foot__copy{font-variant-numeric:tabular-nums}

/* ============ layout helpers ============ */
.container{
  width:100%;max-width:var(--maxw);
  margin-inline:auto;padding-inline:var(--gutter);
}
.section{padding-block:clamp(32px,6vw,72px)}
.section__head{display:grid;gap:10px;max-width:60ch;margin-bottom:clamp(20px,3vw,32px)}
.eyebrow{
  font-family:var(--font-mono);font-size:var(--t-12);
  letter-spacing:.2em;text-transform:uppercase;color:var(--turq);
}
.lede{
  font-family:var(--font-serif);font-size:var(--t-22);
  line-height:1.6;color:var(--paper);max-width:44ch;
}
.prose{max-width:66ch;font-size:var(--t-18);line-height:1.85;color:var(--mist)}
.prose p + p{margin-top:1.1em}
.prose h2,.prose h3{color:var(--paper);line-height:1.3;letter-spacing:-.01em}
.prose h2{font-size:var(--t-28);margin-top:1.6em}
.prose h3{font-size:var(--t-22);margin-top:1.4em}
.prose strong{color:var(--paper)}
.prose a{color:var(--gold);border-bottom:1px solid rgba(233,180,92,.5)}

.grid{display:grid;gap:clamp(14px,2vw,28px)}
.grid--12{grid-template-columns:repeat(12,minmax(0,1fr))}
.span-3{grid-column:span 3}
.span-4{grid-column:span 4}
.span-5{grid-column:span 5}
.span-6{grid-column:span 6}
.span-7{grid-column:span 7}
.span-8{grid-column:span 8}
.span-12{grid-column:span 12}
@media (max-width:900px){
  .grid--12 > [class*="span-"]{grid-column:span 12}
}

.rule{
  display:flex;align-items:center;gap:14px;
  margin-block:clamp(26px,5vw,54px);
}
.rule::before,.rule::after{
  content:"";flex:1;height:1px;
  background:repeating-linear-gradient(to right,var(--line) 0 9px,transparent 9px 15px);
}
.serif-index{
  font-family:var(--font-serif);font-size:var(--t-18);
  letter-spacing:.24em;color:var(--gold);white-space:nowrap;
}

/* ============ breadcrumb ============ */
.breadcrumb{
  display:flex;flex-wrap:wrap;align-items:center;gap:8px;
  font-family:var(--font-mono);font-size:var(--t-12);
  letter-spacing:.05em;color:rgba(201,207,221,.7);
}
.breadcrumb__item{display:inline-flex;align-items:center;gap:8px}
.breadcrumb__item a{transition:color .2s}
.breadcrumb__item a:hover{color:var(--gold)}
.breadcrumb__sep{color:var(--line)}
.breadcrumb [aria-current="page"]{color:var(--gold)}

/* ============ buttons ============ */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.55em;
  font-size:var(--t-14);font-weight:600;letter-spacing:.03em;
  padding:.72em 1.15em;
  border:1px solid var(--line);
  color:var(--paper);background:transparent;
  transition:background .2s,color .2s,border-color .2s,transform .2s;
}
.btn:hover{transform:translateY(-2px)}
.btn--primary{background:var(--turq);border-color:var(--turq);color:var(--ink-deep)}
.btn--primary:hover{background:var(--cyan);border-color:var(--cyan)}
.btn--ghost{border-color:var(--gold);color:var(--gold)}
.btn--ghost:hover{background:var(--gold);color:var(--ink-deep)}
.btn--quiet{border-color:var(--line);color:var(--mist)}
.btn--quiet:hover{border-color:var(--turq);color:var(--paper)}
.btn--block{width:100%}

/* ============ tags / chips / numbers ============ */
.tag{
  display:inline-block;
  font-family:var(--font-mono);font-size:var(--t-12);
  letter-spacing:.1em;
  padding:2px 8px;
  background:var(--rust);color:var(--paper);
}
.tag--turq{background:var(--turq);color:var(--ink-deep)}
.tag--gold{background:var(--gold);color:var(--ink-deep)}
.tag--outline{background:transparent;border:1px solid var(--line);color:var(--mist)}

.chip{
  display:inline-flex;align-items:center;gap:8px;
  padding:5px 13px;
  border:1px solid var(--line);
  background:rgba(16,27,60,.85);
  font-size:var(--t-14);color:var(--mist);
  transition:background .2s,color .2s,border-color .2s;
}
.chip:hover{border-color:var(--turq);color:var(--paper)}
.chip[aria-pressed="true"]{background:var(--turq);border-color:var(--turq);color:var(--ink-deep)}
.chip .num{font-size:var(--t-12);opacity:.8}

.num{
  font-family:var(--font-mono);
  font-variant-numeric:tabular-nums;
  font-feature-settings:"tnum" 1;
  letter-spacing:.01em;
}

/* ============ paper panel ============ */
.panel{
  position:relative;
  background:var(--paper);color:var(--ink);
  border:1px solid var(--line);
  padding:20px 20px 22px;
  box-shadow:6px 6px 0 rgba(42,51,80,.55);
  transition:box-shadow .2s,transform .2s,border-color .2s;
}
.panel::before{
  content:"";position:absolute;top:0;right:0;
  width:0;height:0;
  border-top:18px solid var(--gold);
  border-left:18px solid transparent;
}
.panel:hover{
  transform:translateY(-2px);
  border-color:var(--gold);
  box-shadow:6px 8px 0 rgba(233,180,92,.35);
}
.panel__head{
  display:flex;align-items:center;justify-content:space-between;
  gap:12px;margin-bottom:14px;
}
.panel__tag{
  font-family:var(--font-mono);font-size:var(--t-12);
  letter-spacing:.1em;padding:2px 8px;
  background:var(--rust);color:var(--paper);
}
.panel__tag--turq{background:var(--turq);color:var(--ink-deep)}
.panel__tag--gold{background:var(--gold);color:var(--ink-deep)}
.panel__num{
  font-family:var(--font-mono);font-size:var(--t-12);
  letter-spacing:.08em;color:rgba(16,27,60,.55);
}
.panel p{font-size:var(--t-16);line-height:1.75;color:#25304d}
.panel h3{font-size:var(--t-22);line-height:1.3;letter-spacing:-.01em;color:var(--ink)}

/* ============ stats & bars ============ */
.stat{display:grid;gap:2px}
.stat__value{
  font-family:var(--font-mono);font-variant-numeric:tabular-nums;
  font-size:var(--t-40);line-height:1.05;letter-spacing:-.02em;
  color:var(--cyan);
}
.stat__label{
  font-size:var(--t-12);letter-spacing:.14em;
  color:rgba(201,207,221,.7);
}
.bar{
  position:relative;height:8px;width:100%;
  background:rgba(42,51,80,.85);
  overflow:hidden;
}
.bar__fill{
  display:block;height:100%;width:var(--bar,50%);
  background:var(--cyan);
  transition:width .4s ease;
}
.bar--amber .bar__fill{background:var(--amber)}

/* ============ media frame ============ */
.media-frame{
  position:relative;display:block;overflow:hidden;
  aspect-ratio:16/9;
  background:var(--line);
  border:1px solid var(--line);
}
.media-frame--wide{aspect-ratio:21/9}
.media-frame--tall{aspect-ratio:3/4}
.media-frame--square{aspect-ratio:1/1}
.media-frame > img,
.media-frame > picture > img{
  width:100%;height:100%;object-fit:cover;
}
.media-frame__caption{
  position:absolute;left:0;bottom:0;right:0;
  padding:10px 12px;
  font-family:var(--font-mono);font-size:var(--t-12);
  letter-spacing:.06em;
  color:var(--paper);
  background:rgba(7,12,28,.82);
  border-top:1px solid var(--line);
}

/* ============ accordion ============ */
.acc{display:grid;border-top:1px solid var(--line)}
.acc__item{border-bottom:1px solid var(--line)}
.acc__trigger{
  display:flex;align-items:center;gap:14px;width:100%;
  padding:16px 2px;text-align:left;
  font-size:var(--t-18);font-weight:600;letter-spacing:-.01em;
  color:var(--paper);
  transition:color .2s;
}
.acc__trigger:hover{color:var(--gold)}
.acc__sign{
  position:relative;flex:0 0 16px;height:16px;
  border:1px solid var(--turq);
  transition:border-color .2s,background .2s;
}
.acc__sign::before,.acc__sign::after{
  content:"";position:absolute;background:var(--turq);
  transition:transform .24s ease,background .24s ease;
}
.acc__sign::before{left:3px;right:3px;top:6px;height:1px}
.acc__sign::after{top:3px;bottom:3px;left:6px;width:1px}
.acc__item[data-open="true"] .acc__sign{border-color:var(--rust);background:rgba(178,70,46,.2)}
.acc__item[data-open="true"] .acc__sign::after{transform:scaleY(0)}
.acc__item[data-open="true"] .acc__sign::before{background:var(--rust)}
.acc__panel{
  display:grid;grid-template-rows:0fr;
  transition:grid-template-rows .24s ease;
}
.acc__item[data-open="true"] .acc__panel{grid-template-rows:1fr}
.acc__inner{overflow:hidden;font-size:var(--t-16);line-height:1.8;color:var(--mist)}
.acc__inner > *{margin-bottom:16px}

/* ============ reveal ============ */
.js [data-reveal]{
  opacity:0;transform:translateY(12px);
  transition:opacity .5s ease var(--reveal-delay,0ms),transform .5s ease var(--reveal-delay,0ms);
}
.js [data-reveal].is-visible{opacity:1;transform:none}

/* ============ responsive: rail becomes top bar ============ */
@media (max-width:1023px){
  .rail{
    position:sticky;top:0;left:auto;bottom:auto;
    width:100%;height:auto;
    flex-direction:row;flex-wrap:wrap;align-items:center;
    gap:8px 12px;
    padding:10px 16px 12px;
    border-right:0;border-bottom:1px solid var(--line);
    overflow:visible;
  }
  .rail::before{top:auto;bottom:0;height:2px}
  .rail__progress{
    top:auto;bottom:0;left:0;width:100%;height:2px;
    transform:scaleX(var(--scroll-progress));
    transform-origin:left;
  }
  .rail__top{
    flex:1 1 auto;grid-template-columns:auto auto;
    align-items:center;gap:10px;padding-top:0;min-width:0;
  }
  .rail__brand{display:flex;align-items:baseline;gap:8px;min-width:0}
  .rail__name{font-size:var(--t-18);white-space:nowrap}
  .rail__sub{display:none}
  .rail__version{font-size:11px;padding:1px 6px}
  .rail__toggle{display:inline-flex;flex:0 0 auto}
  .rail__nav{
    display:none;
    flex-basis:100%;width:100%;
    max-height:68vh;overflow-y:auto;
    padding-top:6px;
    border-top:1px solid var(--line);
  }
  .rail[data-open="true"] .rail__nav{display:flex}
  .rail__foot{
    display:none;flex-basis:100%;width:100%;
    margin-top:0;padding-top:12px;
  }
  .rail[data-open="true"] .rail__foot{display:grid}
  .rail__list{border-top:0}
  .rail__link{padding:12px 8px 12px 10px;font-size:var(--t-18)}
  .foot__grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .foot__top{align-items:flex-start}
}

@media (max-width:640px){
  .foot__grid{grid-template-columns:1fr}
  .foot__mark{font-size:var(--t-22)}
  .foot__base{flex-direction:column;align-items:flex-start}
  .stat__value{font-size:var(--t-28)}
  .panel{padding:16px 16px 18px;box-shadow:4px 4px 0 rgba(42,51,80,.55)}
}

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