/* ============ 1. 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,li,figure,blockquote,dl,dd{margin:0}
ul,ol{padding:0;list-style:none}
img,svg{max-width:100%;display:block}
button{font:inherit;color:inherit;background:none;border:0}
input{font:inherit}
a{color:inherit}
[hidden]{display:none!important}

/* ============ 2. Tokens ============ */
:root{
  --ink:#0A1226;
  --ink-2:#101B36;
  --line:#1C2A47;
  --cyan:#2EE6D6;
  --blue:#4C7DFF;
  --amber:#F5B325;
  --muted:#7A8AA6;
  --body-text:#E6EDF7;
  --mist:#F2F5FA;
  --alert:#FF7A6B;
  --rail-w:220px;
  --bar-h:48px;
  --pad:32px;
  --maxw:1440px;
  --radius:2px;
  --font-head:"PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
  --font-body:system-ui,-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans SC",sans-serif;
  --font-mono:ui-monospace,SFMono-Regular,"SF Mono",Menlo,Consolas,"Liberation Mono","Courier New",monospace;
  --t-fast:120ms;
  --t-mid:240ms;
}
@media (max-width:719px){:root{--pad:20px}}

/* ============ 3. Base ============ */
body{
  margin:0;
  padding:var(--bar-h) 0 0;
  background:var(--ink);
  color:var(--body-text);
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.85;
  font-weight:400;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
@media (min-width:1080px){body{padding-left:var(--rail-w)}}
body::before{
  content:"";position:fixed;inset:0;z-index:0;pointer-events:none;
  background-image:
    linear-gradient(to right,rgba(28,42,71,.55) 1px,transparent 1px),
    linear-gradient(to bottom,rgba(28,42,71,.55) 1px,transparent 1px);
  background-size:80px 80px;
  opacity:.45;
  -webkit-mask-image:radial-gradient(circle at 50% 0%,#000 0%,transparent 76%);
  mask-image:radial-gradient(circle at 50% 0%,#000 0%,transparent 76%);
}
main{position:relative;z-index:1;display:block;scroll-margin-top:calc(var(--bar-h) + 16px)}
#main-content{outline:none}

h1,h2,h3,h4{font-family:var(--font-head);color:#fff;letter-spacing:-.01em;line-height:1.22}
h1{font-size:clamp(28px,4vw,40px);font-weight:800}
h2{font-size:clamp(20px,2.4vw,28px);font-weight:600}
h3{font-size:20px;font-weight:600}
h4{font-size:16px;font-weight:600}
p{margin:0 0 1em}
strong{color:#fff;font-weight:600}
a{color:var(--cyan)}
:focus-visible{outline:2px solid var(--cyan);outline-offset:3px}
::selection{background:rgba(46,230,214,.28);color:#fff}

.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums;letter-spacing:.02em}
.measure{max-width:68ch}
.visually-hidden{position:absolute!important;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);clip-path:inset(50%);white-space:nowrap;border:0}

/* ============ 4. Skip link ============ */
.skip-link{
  position:fixed;top:8px;left:8px;z-index:99;
  padding:10px 16px;background:var(--cyan);color:var(--ink);
  font-size:14px;font-weight:700;text-decoration:none;border-radius:var(--radius);
  transform:translateY(-180%);transition:transform var(--t-fast) linear;
}
.skip-link:focus{transform:none}

/* ============ 5. Header frame ============ */
.site-header{position:fixed;top:0;left:0;right:0;z-index:60}
.site-header__bar{
  position:relative;display:flex;align-items:center;
  height:var(--bar-h);
  background:rgba(10,18,38,.94);
  border-bottom:1px solid var(--line);
}
@supports ((backdrop-filter:blur(8px)) or (-webkit-backdrop-filter:blur(8px))){
  .site-header__bar{-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);background:rgba(10,18,38,.82)}
}
.brand{
  display:flex;align-items:center;gap:10px;flex:0 0 auto;
  width:var(--rail-w);height:100%;padding:0 16px;
  text-decoration:none;color:#fff;border-right:1px solid var(--line);
}
@media (max-width:1079px){.brand{width:auto;border-right:0;padding:0 12px 0 16px}}
.brand__mark{
  display:grid;place-items:center;width:26px;height:26px;
  background:var(--cyan);color:var(--ink);border-radius:var(--radius);
  font-size:12px;font-weight:700;letter-spacing:0;flex:0 0 auto;
}
.brand__text{font-family:var(--font-head);font-size:16px;font-weight:800;letter-spacing:.02em;white-space:nowrap}
.brand__tag{display:none;font-size:11px;color:var(--muted);letter-spacing:.14em;white-space:nowrap}
@media (min-width:1240px){.brand__tag{display:inline}}

.bar__status{display:flex;align-items:center;gap:10px;flex:1 1 auto;min-width:0;padding:0 16px}
.bar__index{
  flex:0 0 auto;padding:1px 6px;border:1px solid rgba(46,230,214,.45);border-radius:var(--radius);
  color:var(--cyan);font-size:12px;letter-spacing:.08em;
}
.bar__label{
  font-size:12px;letter-spacing:.16em;color:var(--muted);
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
}
.bar__util{display:none;align-items:center;gap:4px;padding-right:6px}
@media (min-width:900px){.bar__util{display:flex}}
.util-btn{
  display:inline-flex;align-items:center;gap:8px;padding:6px 10px;
  font-size:12px;letter-spacing:.08em;color:var(--muted);
  border:1px solid var(--line);border-radius:var(--radius);cursor:pointer;
  transition:color var(--t-fast) linear,border-color var(--t-fast) linear;
}
.util-btn:hover,.util-btn[aria-expanded="true"]{color:var(--cyan);border-color:rgba(46,230,214,.5)}
.util-btn__icon{position:relative;width:10px;height:10px;border:2px solid currentColor;border-radius:50%;flex:0 0 auto}
.util-btn__icon::after{content:"";position:absolute;left:6px;top:7px;width:7px;height:2px;background:currentColor;transform:rotate(45deg)}
.util-link{
  display:inline-flex;align-items:center;gap:6px;padding:6px 10px;
  font-size:12px;letter-spacing:.06em;color:var(--body-text);text-decoration:none;
  border-bottom:1px solid transparent;
  transition:color var(--t-fast) linear,border-color var(--t-fast) linear;
}
.util-link:hover{color:var(--cyan);border-bottom-color:var(--cyan)}
.util-link__n{font-style:normal;font-size:11px;color:var(--amber)}

.nav-toggle{
  display:inline-flex;align-items:center;gap:8px;height:100%;
  padding:0 16px;margin-left:auto;cursor:pointer;
  color:var(--body-text);font-size:12px;letter-spacing:.16em;
  border-left:1px solid var(--line);
}
@media (min-width:1080px){.nav-toggle{display:none}}
.nav-toggle__bars{position:relative;width:16px;height:2px;background:currentColor;transition:background var(--t-fast) linear}
.nav-toggle__bars::before,.nav-toggle__bars::after{
  content:"";position:absolute;left:0;width:16px;height:2px;background:currentColor;
  transition:transform var(--t-fast) ease;
}
.nav-toggle__bars::before{top:-5px}
.nav-toggle__bars::after{top:5px}
.nav-toggle[data-open] .nav-toggle__bars{background:transparent}
.nav-toggle[data-open] .nav-toggle__bars::before{transform:translateY(5px) rotate(45deg)}
.nav-toggle[data-open] .nav-toggle__bars::after{transform:translateY(-5px) rotate(-45deg)}

.bar__progress{
  position:absolute;left:0;bottom:-1px;width:0;height:2px;
  background:linear-gradient(90deg,var(--cyan),var(--blue) 62%,var(--amber));
}

/* ============ 6. Filter panel ============ */
.site-filter{
  position:fixed;top:var(--bar-h);left:0;right:0;z-index:59;
  display:flex;flex-wrap:wrap;align-items:center;gap:12px;
  padding:12px var(--pad);
  background:var(--ink-2);border-bottom:1px solid var(--line);
}
@media (min-width:1080px){.site-filter{left:var(--rail-w)}}
.site-filter__input{
  flex:1 1 260px;min-width:0;padding:8px 12px;
  background:var(--ink);border:1px solid var(--line);border-radius:var(--radius);
  color:var(--body-text);font-size:14px;
}
.site-filter__input:focus{outline:none;border-color:var(--cyan);box-shadow:0 0 0 2px rgba(46,230,214,.25)}
.site-filter__hint{font-size:12px;color:var(--muted);margin:0}
.site-filter__hint .mono{color:var(--cyan)}

/* ============ 7. Nav rail ============ */
.nav-rail{
  position:fixed;top:var(--bar-h);left:0;z-index:58;
  width:var(--rail-w);
  height:calc(100vh - var(--bar-h));
  height:calc(100dvh - var(--bar-h));
  display:flex;flex-direction:column;
  background:var(--ink);border-right:1px solid var(--line);
  overflow-y:auto;overscroll-behavior:contain;
}
.rail__head{
  padding:18px 18px 14px;
  font-size:11px;letter-spacing:.2em;color:var(--muted);text-transform:uppercase;
}
.rail__list{display:flex;flex-direction:column}
.rail__link{
  position:relative;display:grid;grid-template-columns:26px 1fr auto;align-items:center;gap:6px;
  padding:11px 16px 11px 18px;
  color:var(--body-text);text-decoration:none;font-size:14px;
  transition:background var(--t-fast) linear,color var(--t-fast) linear;
}
.rail__link::before{
  content:"";position:absolute;left:0;top:6px;bottom:6px;width:2px;
  background:var(--cyan);transform:scaleY(0);transform-origin:50% 50%;
  transition:transform var(--t-fast) ease;
}
.rail__link:hover{background:rgba(46,230,214,.06);color:#fff}
.rail__link:hover::before,.rail__link:focus-visible::before{transform:scaleY(1)}
.rail__link[aria-current="page"]{background:var(--ink-2);color:#fff}
.rail__link[aria-current="page"]::before{transform:scaleY(1)}
.rail__num{font-size:11px;color:var(--muted);letter-spacing:.08em}
.rail__label{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.rail__count{font-size:11px;color:var(--muted)}
.rail__link[aria-current="page"] .rail__num{color:var(--cyan)}
.rail__link[aria-current="page"] .rail__count{color:var(--amber)}
.rail__foot{
  margin-top:auto;display:grid;gap:10px;
  padding:16px 18px 20px;border-top:1px solid var(--line);
}
.rail__foot-line{font-size:11px;color:var(--muted);letter-spacing:.06em;margin:0}
.rail__cta{
  display:inline-flex;align-items:center;justify-content:center;
  min-height:36px;padding:0 12px;
  background:var(--cyan);color:var(--ink);border-radius:var(--radius);
  font-size:12px;font-weight:600;letter-spacing:.04em;text-decoration:none;
  transition:background var(--t-fast) linear;
}
.rail__cta:hover{background:#57F0E3;color:var(--ink)}

@media (max-width:1079px){
  .nav-rail{
    top:var(--bar-h);left:0;right:0;width:auto;height:auto;
    max-height:calc(100dvh - var(--bar-h));
    border-right:0;border-bottom:1px solid var(--line);
    transform:translateY(-10px);opacity:0;visibility:hidden;pointer-events:none;
    transition:transform var(--t-mid) ease,opacity var(--t-mid) ease,visibility var(--t-mid) linear;
  }
  .nav-rail[data-open]{
    transform:none;opacity:1;visibility:visible;pointer-events:auto;
  }
  .rail__link{padding:14px 20px;font-size:15px}
  .rail__foot{margin-top:8px;padding:16px 20px 20px}
}

/* ============ 8. Layout helpers ============ */
.wrap{width:100%;max-width:var(--maxw);margin:0 auto;padding:0 var(--pad)}
.band{padding:56px 0;position:relative;z-index:1}
.band--panel{background:var(--ink-2);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.band--light{background:var(--mist);color:var(--ink)}
.band--light h2,.band--light h3,.band--light h4{color:var(--ink)}
.band--light .eyebrow{color:var(--blue)}
.band--light .chapter{border-top-color:#D6DEEB}
.band--light .chapter__note,.band--light .prose{color:#26334C}
.grid{display:grid;gap:24px;grid-template-columns:1fr}
.grid--tight{gap:12px}
@media (min-width:720px){
  .grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
  .grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
}
@media (min-width:1080px){
  .grid--12{grid-template-columns:repeat(12,minmax(0,1fr))}
  .span-4{grid-column:span 4}
  .span-6{grid-column:span 6}
  .span-8{grid-column:span 8}
  .span-12{grid-column:span 12}
}
.panel{background:var(--ink-2);border:1px solid var(--line);border-radius:var(--radius);padding:20px}
.panel--light{background:var(--mist);border-color:#D6DEEB;color:var(--ink)}

/* ============ 9. Text components ============ */
.eyebrow{
  display:block;margin:0 0 12px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.22em;
  text-transform:uppercase;color:var(--cyan);
}
.chapter{margin-top:56px;padding-top:24px;border-top:1px solid var(--line)}
.chapter:first-child{margin-top:0;padding-top:0;border-top:0}
.chapter__index{display:block;margin-bottom:10px;font-family:var(--font-mono);font-size:11px;letter-spacing:.24em;color:var(--cyan)}
.chapter__title{margin:0 0 8px;font-size:clamp(20px,2.4vw,28px);font-weight:600;color:#fff}
.chapter__note{margin:0;max-width:62ch;font-size:14px;color:var(--muted);line-height:1.8}
.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:2px 8px;border:1px solid var(--line);border-radius:var(--radius);
  font-family:var(--font-mono);font-size:12px;color:var(--muted);
}
.tag--accent{color:var(--cyan);border-color:rgba(46,230,214,.45)}
.tag--warn{color:var(--alert);border-color:rgba(255,122,107,.5)}
.stat{display:block}
.stat__value{display:block;font-family:var(--font-mono);font-size:28px;font-weight:600;line-height:1.1;color:var(--amber)}
.stat__label{display:block;margin-top:6px;font-size:12px;letter-spacing:.1em;color:var(--muted)}
.prose{max-width:68ch;font-size:16px;line-height:1.85}
.prose h2{margin:2em 0 .6em}
.prose h3{margin:1.6em 0 .5em}
.prose p{margin:0 0 1.1em}
.prose ul,.prose ol{margin:0 0 1.2em;padding-left:1.25em}
.prose ul{list-style:none}
.prose li{position:relative;margin-bottom:.5em}
.prose ul li::before{content:"▸";position:absolute;left:-1.15em;color:var(--cyan)}
.prose a{color:var(--cyan);text-decoration:none;border-bottom:1px solid rgba(46,230,214,.45)}
.prose a:hover{border-bottom-color:var(--cyan)}
.prose code{
  font-family:var(--font-mono);font-size:.9em;color:var(--cyan);
  background:rgba(46,230,214,.08);border-radius:var(--radius);padding:1px 5px;
}

/* ============ 10. Buttons ============ */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  min-height:44px;padding:0 20px;border-radius:var(--radius);
  font-family:var(--font-body);font-size:14px;font-weight:600;letter-spacing:.04em;
  text-decoration:none;cursor:pointer;
  background:var(--cyan);border:1px solid var(--cyan);color:var(--ink);
  transition:background var(--t-fast) linear,color var(--t-fast) linear,border-color var(--t-fast) linear,transform var(--t-fast) ease;
}
.btn:hover{background:#fff;border-color:#fff;transform:translateY(-1px)}
.btn--ghost{background:transparent;color:var(--cyan);border-color:rgba(46,230,214,.45)}
.btn--ghost:hover{background:rgba(46,230,214,.1);color:var(--cyan);border-color:var(--cyan)}
.btn--quiet{background:transparent;color:var(--amber);border-color:rgba(245,179,37,.5)}
.btn--quiet:hover{background:rgba(245,179,37,.12);color:var(--amber);border-color:var(--amber)}
.btn--block{width:100%}

/* ============ 11. Breadcrumbs ============ */
.crumbs{
  display:flex;flex-wrap:wrap;align-items:center;
  margin:0 0 22px;font-family:var(--font-mono);font-size:12px;color:var(--muted);
}
.crumbs li{display:flex;align-items:center}
.crumbs li+li::before{content:"/";margin:0 8px;color:var(--line)}
.crumbs a{color:var(--muted);text-decoration:none;transition:color var(--t-fast) linear}
.crumbs a:hover{color:var(--cyan)}
.crumbs [aria-current="page"]{color:var(--body-text)}

/* ============ 12. Data table ============ */
.data-table{width:100%;border-collapse:collapse;font-size:14px;line-height:1.7}
.data-table th,.data-table td{padding:12px 14px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
.data-table thead th{
  font-family:var(--font-mono);font-size:11px;font-weight:500;
  letter-spacing:.14em;text-transform:uppercase;color:var(--muted);white-space:nowrap;
}
.data-table tbody tr{transition:background var(--t-fast) linear}
.data-table tbody tr:hover{background:rgba(46,230,214,.05)}
.data-table td .mono{color:var(--amber)}

/* ============ 13. Image containers ============ */
.figure{display:block;margin:0}
.figure__frame{
  position:relative;width:100%;aspect-ratio:16/9;overflow:hidden;
  background:var(--ink-2);border:1px solid var(--line);border-radius:var(--radius);
  background-image:
    linear-gradient(to right,rgba(46,230,214,.12) 1px,transparent 1px),
    linear-gradient(to bottom,rgba(46,230,214,.12) 1px,transparent 1px);
  background-size:48px 48px;
}
.figure__frame img,.figure__frame svg,.figure__frame video{
  width:100%;height:100%;object-fit:cover;display:block;
}
.figure__frame--wide{aspect-ratio:21/9}
.figure__frame--square{aspect-ratio:1/1}
.figure__frame--tall{aspect-ratio:4/5}
.figure__caption{
  margin-top:10px;font-family:var(--font-mono);font-size:12px;line-height:1.6;color:var(--muted);
}

/* ============ 14. Reveal ============ */
[data-reveal]{opacity:0;transform:translateY(12px);transition:opacity .5s ease,transform .5s ease}
[data-reveal].is-in{opacity:1;transform:none}

/* ============ 15. Footer ============ */
.site-footer{
  position:relative;z-index:1;margin-top:72px;
  padding:56px 0 24px;
  background:var(--ink-2);border-top:1px solid var(--line);color:var(--body-text);
}
.footer__grid{display:grid;gap:32px;grid-template-columns:1fr}
@media (min-width:720px){.footer__grid{grid-template-columns:1.4fr 1fr 1fr;gap:40px}}
@media (min-width:1080px){.footer__grid{grid-template-columns:1.5fr .9fr .9fr 1.3fr}}
.footer__col{min-width:0}
.footer__brand{display:grid;gap:14px;align-content:start}
.brand--footer{width:auto;height:auto;padding:0;border-right:0}
.footer__note{margin:0;max-width:34ch;font-size:14px;line-height:1.8;color:var(--muted)}
.footer__meta-line{font-size:12px;letter-spacing:.08em;color:var(--cyan)}
.footer__title{
  margin:0 0 14px;font-family:var(--font-mono);font-size:11px;font-weight:500;
  letter-spacing:.2em;text-transform:uppercase;color:var(--muted);
}
.footer__list{display:grid;gap:10px;font-size:14px}
.footer__list a{
  width:fit-content;color:var(--body-text);text-decoration:none;
  border-bottom:1px solid transparent;
  transition:color var(--t-fast) linear,border-color var(--t-fast) linear;
}
.footer__list a:hover{color:var(--cyan);border-bottom-color:var(--cyan)}
.footer__list--plain{font-size:13px;line-height:1.75;color:var(--muted)}
.footer__list--plain .mono{color:var(--body-text)}
.footer__hours{color:var(--amber);font-size:12px}
.footer__bottom{
  display:flex;flex-wrap:wrap;gap:12px 24px;justify-content:space-between;
  margin-top:40px;padding-top:20px;border-top:1px solid var(--line);
}
.footer__legal{margin:0;font-size:11px;letter-spacing:.08em;color:var(--muted)}

/* ============ 16. Help dock ============ */
.help-dock{
  position:fixed;right:20px;bottom:20px;z-index:50;
  display:inline-flex;align-items:center;gap:8px;
  padding:10px 14px;border-radius:var(--radius);
  background:var(--ink-2);border:1px solid rgba(46,230,214,.5);
  color:var(--cyan);font-size:12px;letter-spacing:.06em;text-decoration:none;
  box-shadow:0 6px 24px rgba(0,0,0,.45);
  transition:transform var(--t-fast) ease,background var(--t-fast) linear,border-color var(--t-fast) linear;
}
.help-dock:hover{background:var(--ink);border-color:var(--cyan);transform:translateY(-2px)}
.help-dock__dot{width:6px;height:6px;border-radius:50%;background:var(--cyan);box-shadow:0 0 0 3px rgba(46,230,214,.18);flex:0 0 auto}
.help-dock__text{white-space:nowrap}
@media (max-width:600px){
  .help-dock{right:12px;bottom:12px;padding:8px 10px;font-size:11px}
  .help-dock__text{max-width:9em;overflow:hidden;text-overflow:ellipsis}
  .site-footer{padding-bottom:76px}
}

/* ============ 17. 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;
  }
  [data-reveal]{opacity:1;transform:none}
  .nav-rail{transition:none}
}