*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:calc(var(--header-h) + 24px)}
body,h1,h2,h3,h4,h5,p,ul,ol,li,figure,blockquote,dl,dd{margin:0;padding:0}
ul,ol{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}

:root{
  --ink-900:#0B0E11;
  --ink-800:#151A20;
  --ink-700:#232B33;
  --tiger:#FF6A1A;
  --ember:#FF8F4D;
  --teal:#2FE3C4;
  --blue:#3B8CFF;
  --gold:#F2C46A;
  --paper-light:#F3F5F7;
  --mist:#A8B3BD;
  --paper:#EDE7DC;
  --paper-ink:#14181D;
  --header-h:56px;
  --rail-w:72px;
  --font-sans:"Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  --font-mono:"JetBrains Mono","IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --ease:cubic-bezier(.2,.7,.3,1);
  --dur:180ms;
}

body{
  background:var(--ink-900);
  color:var(--paper-light);
  font-family:var(--font-sans);
  font-size:16px;
  font-weight:400;
  line-height:1.8;
  min-height:100vh;
  -webkit-font-smoothing:antialiased;
}
body.no-scroll{overflow:hidden}
h1,h2,h3,h4{font-weight:800;line-height:1.15;letter-spacing:-.01em}
p{max-width:38em}
::selection{background:var(--tiger);color:#14181D}
:focus-visible{outline:2px solid var(--teal);outline-offset:2px;border-radius:2px}

.mono{font-family:var(--font-mono);letter-spacing:.08em;font-variant-numeric:tabular-nums}

/* ---------- skip link ---------- */
.skip-link{
  position:fixed;top:10px;left:10px;z-index:200;
  transform:translateY(-250%);
  background:var(--tiger);color:#14181D;
  padding:10px 18px;font-size:14px;font-weight:700;border-radius:2px;
  transition:transform var(--dur) var(--ease);
}
.skip-link:focus{transform:translateY(0)}

/* ---------- header ---------- */
.site-header{
  position:sticky;top:0;z-index:80;
  background:var(--ink-900);
  border-bottom:1px solid var(--ink-700);
  color:var(--paper-light);
}
.site-header__progress{
  position:absolute;left:0;right:0;top:0;height:2px;
  background:var(--ink-700);overflow:hidden;
}
.site-header__progress-fill{
  display:block;height:100%;width:0;
  background:linear-gradient(90deg,var(--blue) 0%,var(--teal) 38%,var(--tiger) 100%);
  transition:width .12s linear;
}
.site-header__inner{
  display:flex;align-items:center;gap:clamp(10px,2vw,26px);
  height:var(--header-h);
  padding:0 clamp(14px,2.2vw,26px);
}
.brand{display:flex;align-items:center;gap:10px;flex:0 0 auto}
.brand__mark{
  font-size:20px;font-weight:900;letter-spacing:.1em;color:var(--paper-light);
  display:inline-flex;align-items:center;
}
.brand__mark::before{
  content:"";width:8px;height:8px;background:var(--tiger);
  margin-right:9px;display:inline-block;
}
.brand__sub{
  font-size:11px;letter-spacing:.14em;color:var(--mist);
  padding-left:10px;border-left:1px solid var(--ink-700);white-space:nowrap;
}

.nav{flex:1 1 auto;display:flex;justify-content:center;min-width:0}
.nav__list{display:flex;align-items:center;gap:2px}
.nav__link{
  position:relative;display:block;
  padding:8px 12px;font-size:14px;font-weight:500;color:var(--mist);
  border-radius:2px;
  transition:color var(--dur) var(--ease),background var(--dur) var(--ease);
}
.nav__link:hover{color:var(--paper-light);background:var(--ink-800)}
.nav__link[aria-current="page"]{color:var(--paper-light);font-weight:700}
.nav__link[aria-current="page"]::after{
  content:"";position:absolute;left:12px;right:12px;bottom:2px;height:2px;
  background:var(--tiger);
}

.header-meta{display:flex;align-items:center;gap:clamp(8px,1.4vw,16px);flex:0 0 auto}
.header-meta__issue{
  display:inline-flex;align-items:center;gap:8px;
  font-size:12px;color:var(--mist);white-space:nowrap;
}
.header-meta__issue .mono{color:var(--gold);font-size:11px}

.nav-toggle{
  display:none;align-items:center;justify-content:center;
  width:44px;height:44px;flex:0 0 auto;
  border:1px solid var(--ink-700);border-radius:2px;cursor:pointer;
  transition:border-color var(--dur) var(--ease);
}
.nav-toggle:hover{border-color:var(--ember)}
.nav-toggle__bars{position:relative;display:block;width:18px;height:12px}
.nav-toggle__bars span{
  position:absolute;left:0;right:0;height:2px;background:var(--paper-light);
  transition:transform var(--dur) var(--ease),opacity var(--dur) var(--ease);
}
.nav-toggle__bars span:nth-child(1){top:0}
.nav-toggle__bars span:nth-child(2){top:5px}
.nav-toggle__bars span:nth-child(3){top:10px}
.site-header[data-open] .nav-toggle__bars span:nth-child(1){transform:translateY(5px) rotate(45deg)}
.site-header[data-open] .nav-toggle__bars span:nth-child(2){opacity:0}
.site-header[data-open] .nav-toggle__bars span:nth-child(3){transform:translateY(-5px) rotate(-45deg)}

/* ---------- left rail ---------- */
.rail{
  display:none;
  position:fixed;left:0;top:var(--header-h);bottom:0;width:var(--rail-w);
  flex-direction:column;align-items:center;
  padding:18px 0 22px;
  background:var(--ink-900);
  border-right:1px solid var(--ink-700);
  z-index:70;
}
.rail__readout{font-size:11px;color:var(--mist)}
.rail__track{
  position:relative;flex:1;width:2px;margin:18px 0;
  background:var(--ink-700);
}
.rail__fill{
  position:absolute;top:0;left:0;width:100%;height:0;
  background:linear-gradient(180deg,var(--blue) 0%,var(--teal) 45%,var(--tiger) 100%);
  transition:height .12s linear;
}
.rail__label{
  writing-mode:vertical-rl;font-family:var(--font-mono);
  font-size:10px;letter-spacing:.3em;color:#3A4753;
}

@media (min-width:1200px){
  body{padding-left:var(--rail-w)}
  .rail{display:flex}
}

/* ---------- layout helpers ---------- */
.container{width:100%;max-width:1280px;margin-inline:auto;padding-inline:clamp(16px,3vw,40px)}
.grid{display:grid;gap:clamp(14px,2vw,26px)}
.grid--12{grid-template-columns:repeat(12,minmax(0,1fr))}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
.span-3{grid-column:span 3}
.span-4{grid-column:span 4}
.span-6{grid-column:span 6}
.span-8{grid-column:span 8}
.span-9{grid-column:span 9}
.rule{height:1px;background:var(--ink-700);border:0;margin:0}

.section-head{
  display:flex;flex-wrap:wrap;align-items:baseline;gap:8px 16px;
  padding-bottom:14px;margin-bottom:clamp(20px,2.6vw,32px);
  border-bottom:1px solid var(--ink-700);
}
.section-head__index{font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;color:var(--tiger)}
.section-head__title{font-size:clamp(22px,3vw,30px);font-weight:800}
.section-head__note{margin-left:auto;font-size:13px;color:var(--mist);max-width:32em}

/* ---------- buttons / tags ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  min-height:44px;padding:0 20px;
  font-size:14px;font-weight:600;letter-spacing:.01em;
  border:1px solid transparent;border-radius:2px;cursor:pointer;
  transition:background var(--dur) var(--ease),color var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.btn--primary{background:var(--tiger);color:#14181D;border-color:var(--tiger)}
.btn--primary:hover{background:var(--ember);border-color:var(--ember)}
.btn--ghost{border-color:var(--ink-700);color:var(--paper-light)}
.btn--ghost:hover{border-color:var(--ember);color:var(--ember)}
.btn--sm{min-height:34px;padding:0 14px;font-size:13px}

.tag{
  display:inline-flex;align-items:center;gap:5px;
  padding:2px 8px;font-size:11.5px;font-weight:600;
  color:var(--gold);background:rgba(242,196,106,.1);
  border:1px solid rgba(242,196,106,.3);border-radius:2px;
}
.tag--teal{color:var(--teal);background:rgba(47,227,196,.1);border-color:rgba(47,227,196,.3)}
.tag--orange{color:var(--ember);background:rgba(255,106,26,.1);border-color:rgba(255,106,26,.32)}

/* ---------- card ---------- */
.card{
  position:relative;display:block;
  background:var(--ink-800);border:1px solid var(--ink-700);
  padding:clamp(16px,2vw,24px);
  transition:border-color var(--dur) var(--ease),background var(--dur) var(--ease);
}
.card:hover{border-color:#3A4855}
.card__tag{
  position:absolute;top:0;right:0;
  padding:2px 9px 3px;
  font-family:var(--font-mono);font-size:10px;letter-spacing:.1em;
  color:var(--mist);background:var(--ink-700);
  transition:background var(--dur) var(--ease),color var(--dur) var(--ease);
}
.card:hover .card__tag{background:var(--ember);color:#0B0E11}

/* ---------- media / glow ---------- */
.media{
  position:relative;overflow:hidden;
  border:1px solid var(--ink-700);
  background:linear-gradient(150deg,var(--ink-800) 0%,var(--ink-900) 65%);
  aspect-ratio:16/9;
}
.media--wide{aspect-ratio:21/9}
.media--square{aspect-ratio:1/1}
.media--tall{aspect-ratio:4/5}
.media img{width:100%;height:100%;object-fit:cover}
.media__caption{
  position:absolute;left:0;right:0;bottom:0;
  padding:10px 14px;font-size:12px;color:var(--mist);
  background:linear-gradient(180deg,rgba(11,14,17,0) 0%,rgba(11,14,17,.86) 100%);
}
.glow{
  position:absolute;pointer-events:none;border-radius:50%;
  width:var(--glow-size,480px);height:var(--glow-size,480px);
  background:radial-gradient(circle at center,rgba(47,227,196,.30) 0%,rgba(59,140,255,.16) 42%,rgba(11,14,17,0) 72%);
  opacity:.35;
  transition:opacity .22s var(--ease);
}
.glow--warm{
  background:radial-gradient(circle at center,rgba(255,106,26,.28) 0%,rgba(242,196,106,.12) 45%,rgba(11,14,17,0) 72%);
}
.glow:hover{opacity:.5}

/* ---------- breadcrumb ---------- */
.breadcrumb{
  display:flex;flex-wrap:wrap;align-items:center;gap:8px;
  font-family:var(--font-mono);font-size:11.5px;letter-spacing:.06em;color:var(--mist);
}
.breadcrumb a{transition:color var(--dur) var(--ease)}
.breadcrumb a:hover{color:var(--tiger)}
.breadcrumb__sep{color:var(--ink-700)}

/* ---------- prose (paper) ---------- */
.prose{
  background:var(--paper);color:var(--paper-ink);
  border:1px solid #D6CDBE;
  padding:clamp(22px,3.6vw,48px);
  box-shadow:10px 10px 0 rgba(35,43,51,.5);
}
.prose > * + *{margin-top:1.15em}
.prose p,.prose li{font-size:16.5px;line-height:1.9;max-width:68ch}
.prose h2{font-size:clamp(20px,2.6vw,26px);line-height:1.35;color:#0F1317}
.prose h3{font-size:18px;color:#0F1317}
.prose ul,.prose ol{list-style:square;padding-left:1.3em}
.prose ol{list-style:decimal}
.prose a{color:#A83A00;text-decoration:underline;text-underline-offset:3px}
.prose .mono{color:#6A5B45}

/* ---------- accordion ---------- */
.accordion{border:1px solid var(--ink-700);background:var(--ink-800)}
.accordion__item + .accordion__item{border-top:1px solid var(--ink-700)}
.accordion__trigger{
  display:flex;align-items:baseline;gap:12px;width:100%;
  padding:16px 18px;text-align:left;cursor:pointer;
  font-size:15.5px;font-weight:600;color:var(--paper-light);
  transition:color var(--dur) var(--ease);
}
.accordion__trigger:hover{color:var(--ember)}
.accordion__trigger[aria-expanded="true"]{color:var(--paper-light)}
.accordion__chev{
  margin-left:auto;flex:0 0 auto;color:var(--tiger);font-size:12px;
  transition:transform var(--dur) var(--ease);
}
.accordion__trigger[aria-expanded="true"] .accordion__chev{transform:rotate(90deg)}
.accordion__panel{
  display:grid;grid-template-rows:0fr;visibility:hidden;
  transition:grid-template-rows var(--dur) var(--ease),visibility var(--dur);
}
.accordion__trigger[aria-expanded="true"] + .accordion__panel{
  grid-template-rows:1fr;visibility:visible;
}
.accordion__body{overflow:hidden;padding:0 18px}
.accordion__body > *:first-child{padding-top:2px}
.accordion__body > *:last-child{padding-bottom:18px}
.accordion__body p{font-size:15px;line-height:1.85;color:var(--mist);max-width:60ch}

/* ---------- section link state ---------- */
[data-section-link]{
  display:block;
  transition:color var(--dur) var(--ease),padding-left var(--dur) var(--ease);
}
[data-section-link].is-active{color:var(--tiger);padding-left:4px}

/* ---------- tiger band ---------- */
.tiger-band{
  height:6px;
  background-image:repeating-linear-gradient(45deg,var(--tiger) 0 8px,rgba(11,14,17,0) 8px 20px);
  opacity:.9;
}

/* ---------- footer ---------- */
.site-footer{
  margin-top:clamp(48px,8vw,96px);
  background:var(--ink-900);
  border-top:1px solid var(--ink-700);
}
.site-footer__inner{
  max-width:1280px;margin-inline:auto;
  padding:clamp(32px,4vw,56px) clamp(16px,3vw,40px) clamp(24px,3.2vw,40px);
  display:grid;grid-template-columns:1.5fr 1fr 1.5fr 1fr;
  gap:clamp(24px,3vw,44px);
}
.footer-brand__mark{
  display:inline-flex;align-items:center;
  font-size:26px;font-weight:900;letter-spacing:.12em;color:var(--paper-light);
}
.footer-brand__mark::before{
  content:"";width:10px;height:10px;background:var(--tiger);
  margin-right:10px;display:inline-block;
}
.footer-brand__desc{margin-top:14px;font-size:14px;line-height:1.75;color:var(--mist);max-width:30ch}
.footer-brand__meta{margin-top:16px;font-size:10.5px;letter-spacing:.16em;color:#4C5A66}
.footer-col__title{
  display:flex;align-items:center;gap:8px;
  margin-bottom:16px;font-size:12px;font-weight:600;letter-spacing:.16em;color:var(--tiger);
}
.footer-col__title::before{content:"";width:14px;height:1px;background:var(--tiger);display:inline-block}
.footer-nav{display:block}
.footer-nav__list{display:flex;flex-direction:column;gap:9px}
.footer-link{
  font-size:14px;color:var(--mist);
  border-bottom:1px solid transparent;
  transition:color var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.footer-link:hover{color:var(--ember);border-bottom-color:var(--ember)}
.footer-contact{display:block}
.footer-contact__list{display:flex;flex-direction:column;gap:14px}
.footer-contact__item{display:block}
.footer-contact__label{display:block;font-size:10px;letter-spacing:.16em;color:#5A6874;margin-bottom:3px}
.footer-contact__row{display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.footer-contact__value{font-size:13.5px;color:var(--paper-light);word-break:break-all}
.footer-legal{display:block}
.copy{
  flex:0 0 auto;padding:1px 7px;
  font-family:var(--font-mono);font-size:10px;letter-spacing:.08em;
  color:var(--mist);border:1px solid var(--ink-700);border-radius:2px;cursor:pointer;
  transition:color var(--dur) var(--ease),border-color var(--dur) var(--ease),background var(--dur) var(--ease);
}
.copy:hover{color:var(--ember);border-color:var(--ember)}
.copy[data-copied]{color:#0B0E11;background:var(--teal);border-color:var(--teal)}
.site-footer__base{
  max-width:1280px;margin-inline:auto;
  padding:16px clamp(16px,3vw,40px) 28px;
  border-top:1px solid var(--ink-700);
  display:flex;flex-direction:column;align-items:center;gap:6px;
  text-align:center;font-size:12px;color:#5A6874;
}
.site-footer__copy,.site-footer__icp{max-width:none}
.site-footer__icp{font-family:var(--font-mono);letter-spacing:.06em;color:#4C5A66}

/* ---------- responsive ---------- */
@media (max-width:960px){
  .site-header__inner{position:relative}
  .header-meta__issue{display:none}
  .nav{
    position:absolute;top:100%;left:0;right:0;
    display:block;flex:none;
    background:var(--ink-800);
    border-bottom:1px solid var(--ink-700);
    max-height:0;overflow:hidden;visibility:hidden;
    box-shadow:0 18px 30px rgba(0,0,0,.5);
    transition:max-height .22s var(--ease),visibility .22s;
  }
  .site-header[data-open] .nav{
    max-height:75vh;overflow-y:auto;visibility:visible;
  }
  .nav__list{flex-direction:column;align-items:stretch;gap:0;padding:6px 16px 14px}
  .nav__item + .nav__item{border-top:1px solid var(--ink-700)}
  .nav__link{padding:15px 4px;font-size:15.5px;border-radius:0}
  .nav__link[aria-current="page"]{color:var(--tiger)}
  .nav__link[aria-current="page"]::after{left:4px;right:auto;width:18px;bottom:10px}
  .nav-toggle{display:inline-flex}

  .grid--12{grid-template-columns:repeat(6,minmax(0,1fr))}
  .span-3{grid-column:span 6}
  .span-4{grid-column:span 6}
  .span-6{grid-column:span 6}
  .span-8{grid-column:span 6}
  .span-9{grid-column:span 6}
  .grid--3{grid-template-columns:repeat(2,minmax(0,1fr))}

  .site-footer__inner{grid-template-columns:1fr 1fr}
  .footer-brand{grid-column:1 / -1}
  .section-head__note{margin-left:0;width:100%}
}

@media (max-width:640px){
  html{scroll-padding-top:calc(var(--header-h) + 12px)}
  .brand__sub{display:none}
  .header-meta__cta{display:none}
  .grid--12,.grid--2,.grid--3{grid-template-columns:1fr}
  .span-3,.span-4,.span-6,.span-8,.span-9{grid-column:1 / -1}
  .site-footer__inner{grid-template-columns:1fr}
  .footer-brand{grid-column:auto}
  .prose{box-shadow:6px 6px 0 rgba(35,43,51,.5)}
  .prose p,.prose li{font-size:16px}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    transition-delay:0ms !important;
  }
}