*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--font-body);font-size:16.5px;line-height:1.7;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
img,svg,video{max-width:100%;height:auto}
ul,ol{margin:0;padding:0;list-style:none}
p{margin:0 0 1em}
button{font:inherit;color:inherit}
a{color:inherit}
:root{
  --ember:#F26B1F;
  --ember-deep:#C44E0E;
  --pitch:#0E2B22;
  --pitch-2:#17453A;
  --neon:#3BE0C4;
  --brick:#9B3B2A;
  --paper:#F4F1E8;
  --paper-grey:#D9D5C7;
  --midnight:#07110E;
  --turf:#6F8C7B;
  --turf-light:#A6BFB3;
  --ink:#15201B;
  --ink-soft:#31423A;
  --max:1240px;
  --gutter:24px;
  --gap:24px;
  --gap-lg:32px;
  --line:1px solid var(--paper-grey);
  --font-display:"Source Han Sans SC","Noto Sans CJK SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-body:system-ui,-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Source Han Sans SC",sans-serif;
  --font-mono:ui-monospace,"SFMono-Regular","IBM Plex Mono","Roboto Mono",Menlo,Consolas,"Noto Sans Mono CJK SC",monospace;
  --ease:cubic-bezier(.22,.61,.36,1);
}
h1,h2,h3,h4{font-family:var(--font-display);font-weight:800;line-height:1.06;letter-spacing:-.025em;margin:0 0 .55em;color:var(--pitch);text-wrap:balance}
h1{font-size:clamp(2rem,5.2vw,3.4rem)}
h2{font-size:clamp(1.55rem,3.4vw,2.25rem)}
h3{font-size:1.18rem;letter-spacing:-.012em;line-height:1.25}
h4{font-size:1rem;letter-spacing:0;line-height:1.35}
:focus-visible{outline:3px solid var(--ember-deep);outline-offset:3px;border-radius:2px}
.section--dark :focus-visible,.site-footer :focus-visible{outline-color:var(--neon)}
.skip-link{position:absolute;left:12px;top:-64px;z-index:200;background:var(--pitch);color:var(--paper);padding:10px 18px;font-weight:700;font-size:.9rem;text-decoration:none;border-radius:2px;transition:top .2s var(--ease)}
.skip-link:focus{top:12px}
.wrap{width:min(100% - 2 * var(--gutter),var(--max));margin-inline:auto}
.section{padding-block:clamp(48px,7vw,96px);position:relative}
.section--dark{background:var(--pitch);color:var(--paper)}
.section--dark::before{content:"";position:absolute;inset:0;pointer-events:none;background:radial-gradient(120% 90% at 88% 0%,rgba(242,107,31,.17),transparent 60%),radial-gradient(80% 60% at 0% 100%,rgba(59,224,196,.10),transparent 65%)}
.section--dark>*{position:relative}
.section--dark h1,.section--dark h2,.section--dark h3,.section--dark h4{color:var(--paper)}
.cut-tilt{clip-path:polygon(0 0,100% 0,100% calc(100% - 36px),0 100%)}
.grid{display:grid;grid-template-columns:repeat(12,1fr);gap:var(--gap)}
.grid--3{grid-template-columns:repeat(3,1fr)}
.grid--4{grid-template-columns:repeat(4,1fr)}
.grid--tight{gap:20px}
.grid--wide{gap:var(--gap-lg)}
.grid__span-5{grid-column:span 5}
.grid__span-7{grid-column:span 7}
.grid__span-6{grid-column:span 6}
.grid__span-4{grid-column:span 4}
.eyebrow{display:inline-flex;align-items:center;gap:8px;font-family:var(--font-mono);font-size:.72rem;font-weight:600;letter-spacing:.14em;color:var(--ember-deep);margin:0 0 12px}
.eyebrow::before{content:"";width:18px;height:1px;background:currentColor}
.section--dark .eyebrow{color:var(--neon)}
.lede{font-size:1.06rem;line-height:1.75;color:var(--ink-soft);max-width:36em}
.section--dark .lede{color:var(--turf-light)}
.rule{height:0;border:0;border-top:1px solid var(--paper-grey);margin:clamp(28px,4vw,48px) 0}
.section--dark .rule{border-top-color:rgba(244,241,232,.16)}
.num{font-family:var(--font-mono);font-weight:600;letter-spacing:.01em;font-variant-numeric:tabular-nums}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:.5em;padding:.78em 1.35em;border-radius:2px;border:1px solid transparent;background:transparent;font-family:var(--font-display);font-weight:700;font-size:.95rem;line-height:1.2;text-decoration:none;cursor:pointer;transition:background-color .2s var(--ease),color .2s var(--ease),border-color .2s var(--ease),transform .2s var(--ease)}
.btn:active{transform:translateY(1px)}
.btn--primary{background:var(--ember);color:#120804;border-color:var(--ember)}
.btn--primary:hover{background:var(--ember-deep);border-color:var(--ember-deep);color:var(--paper)}
.btn--ghost{color:var(--pitch);border-color:var(--paper-grey);background:rgba(255,255,255,.35)}
.btn--ghost:hover{border-color:var(--ember);color:var(--ember-deep)}
.section--dark .btn--ghost,.site-footer .btn--ghost{color:var(--paper);border-color:rgba(244,241,232,.3);background:transparent}
.section--dark .btn--ghost:hover{border-color:var(--neon);color:var(--neon)}
.btn--neon{color:var(--neon);border-color:rgba(59,224,196,.55);background:rgba(59,224,196,.07)}
.btn--neon:hover{background:rgba(59,224,196,.16);border-color:var(--neon)}
.btn--sm{font-size:.82rem;padding:.55em 1em}
.panel{background:#FBF9F3;border:1px solid var(--paper-grey);border-radius:2px;padding:clamp(18px,2.4vw,26px);box-shadow:0 1px 0 rgba(14,43,34,.04),0 12px 24px -22px rgba(14,43,34,.45)}
.panel--dark{background:var(--pitch-2);border-color:rgba(244,241,232,.14);color:var(--paper);box-shadow:0 14px 28px -24px rgba(0,0,0,.9)}
.chip{display:inline-flex;align-items:center;gap:6px;font-family:var(--font-mono);font-size:.7rem;font-weight:600;letter-spacing:.08em;padding:5px 9px;border-radius:2px;background:rgba(14,43,34,.07);color:var(--pitch-2);border:1px solid rgba(14,43,34,.12);white-space:nowrap}
.chip--brick{background:rgba(155,59,42,.12);border-color:rgba(155,59,42,.35);color:var(--brick)}
.chip--neon{background:rgba(59,224,196,.14);border-color:rgba(59,224,196,.45);color:#0B3B33}
.section--dark .chip{background:rgba(244,241,232,.08);border-color:rgba(244,241,232,.2);color:var(--turf-light)}
.section--dark .chip--neon{background:rgba(59,224,196,.12);border-color:rgba(59,224,196,.45);color:var(--neon)}
.stat{display:flex;flex-direction:column;gap:6px;padding:clamp(16px,2vw,22px);border:1px solid rgba(14,43,34,.14);border-radius:2px;background:rgba(255,255,255,.42)}
.stat__num{font-family:var(--font-mono);font-weight:600;font-size:clamp(1.55rem,3vw,2.15rem);line-height:1;letter-spacing:-.01em;color:var(--ember-deep);font-variant-numeric:tabular-nums}
.stat__label{font-size:.8rem;line-height:1.45;color:var(--turf);letter-spacing:.02em}
.stat--hero{border-color:rgba(14,43,34,.2);background:linear-gradient(155deg,rgba(242,107,31,.11),rgba(244,241,232,.6) 55%)}
.stat--hero .stat__num{font-size:clamp(2.6rem,7vw,4.4rem);color:var(--pitch)}
.section--dark .stat{border-color:rgba(244,241,232,.16);background:rgba(244,241,232,.05)}
.section--dark .stat__num{color:var(--neon)}
.section--dark .stat__label{color:var(--turf-light)}
.breadcrumbs{display:flex;flex-wrap:wrap;align-items:center;gap:10px;font-family:var(--font-mono);font-size:.74rem;letter-spacing:.06em;color:var(--turf);margin:0 0 20px}
.breadcrumbs li{display:flex;align-items:center;gap:10px}
.breadcrumbs li+li::before{content:"/";color:var(--paper-grey)}
.breadcrumbs__link{text-decoration:underline;text-underline-offset:3px;font-weight:600;color:var(--pitch)}
.breadcrumbs__link:hover{color:var(--ember-deep)}
.media{position:relative;overflow:hidden;border-radius:2px;background:linear-gradient(160deg,var(--pitch-2),var(--midnight));border:1px solid rgba(14,43,34,.16);isolation:isolate}
.media__img{display:block;width:100%;height:100%;object-fit:cover}
.media--16x9{aspect-ratio:16/9}
.media--4x3{aspect-ratio:4/3}
.media--1x1{aspect-ratio:1/1}
.media--phone{aspect-ratio:9/19;max-width:280px}
.media--dark::after{content:"";position:absolute;inset:0;background:linear-gradient(180deg,rgba(7,17,14,.05),rgba(7,17,14,.72));pointer-events:none}
.media__tag{position:absolute;top:10px;left:10px;z-index:2;font-family:var(--font-mono);font-size:.68rem;letter-spacing:.1em;padding:4px 8px;border-radius:2px;background:rgba(7,17,14,.72);color:var(--neon);border:1px solid rgba(59,224,196,.4)}
.media__scan{position:absolute;inset:0;z-index:1;pointer-events:none;background-image:radial-gradient(rgba(7,17,14,.5) 1px,transparent 1.2px);background-size:4px 4px;opacity:.5;mix-blend-mode:multiply}
.media__caption{font-size:.86rem;color:var(--turf);margin:.7em 0 0;line-height:1.5}
[data-reveal]{transition:opacity .32s var(--ease),transform .32s var(--ease)}
.js-reveal [data-reveal]{opacity:0;transform:translateY(14px)}
.js-reveal [data-reveal].is-in{opacity:1;transform:none}
/* ===== header rail ===== */
.rail{position:sticky;top:0;z-index:80;background:var(--paper);border-top:1px solid var(--pitch);border-bottom:1px solid var(--paper-grey)}
.rail__inner{width:min(100% - 2 * var(--gutter),var(--max));margin-inline:auto;display:grid;grid-template-columns:auto 1fr auto;align-items:stretch;gap:clamp(14px,3vw,40px);min-height:76px}
.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--pitch);padding-block:12px;align-self:center}
.brand__mark{position:relative;flex:none;width:14px;height:14px;background:var(--ember);transform:rotate(45deg);transition:background-color .2s var(--ease)}
.brand__mark::after{content:"";position:absolute;inset:4px;background:var(--paper)}
.brand:hover .brand__mark{background:var(--ember-deep)}
.brand__text{display:block}
.brand__name{display:block;font-family:var(--font-display);font-weight:800;font-size:1.04rem;letter-spacing:-.015em;line-height:1.15;color:var(--pitch)}
.brand__line{display:block;font-family:var(--font-mono);font-size:.68rem;letter-spacing:.09em;color:var(--turf);line-height:1.5;margin-top:2px}
.rail-nav{align-self:stretch;display:flex;align-items:stretch;justify-content:center;border-top:1px solid var(--pitch);position:relative}
.rail-nav__list{display:flex;align-items:stretch;justify-content:center;gap:2px;width:100%}
.rail-nav__item{display:flex;align-items:stretch}
.rail-nav__link{position:relative;display:flex;align-items:center;padding:0 13px;text-decoration:none;font-family:var(--font-display);font-weight:700;font-size:.94rem;letter-spacing:.005em;color:var(--pitch);border-bottom:2px solid transparent;transition:color .2s var(--ease),background-color .2s var(--ease),border-color .2s var(--ease)}
.rail-nav__link::before{content:"";position:absolute;left:50%;top:0;width:1px;height:11px;background:var(--paper-grey);transform:translateX(-50%);transition:background-color .22s var(--ease),height .22s var(--ease),width .22s var(--ease)}
.rail-nav__link:hover{color:var(--ember-deep);background:rgba(242,107,31,.08)}
.rail-nav__link:hover::before{background:var(--ember);height:16px;width:2px}
.rail-nav__link[aria-current="page"]{color:var(--ink);border-bottom-color:var(--ember);background:rgba(242,107,31,.05)}
.rail-nav__link[aria-current="page"]::before{background:var(--ember);height:18px;width:2px}
.rail-meta{display:flex;align-items:center;gap:12px;justify-self:end;align-self:center;padding-block:10px}
.rail-chapter{font-family:var(--font-mono);font-size:.68rem;letter-spacing:.12em;color:var(--turf);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-width:12ch}
.rail-chapter:empty{display:none}
.version-chip{display:inline-flex;align-items:center;gap:7px;font-family:var(--font-mono);font-size:.72rem;font-weight:600;letter-spacing:.03em;color:var(--pitch-2);background:rgba(59,224,196,.16);border:1px solid rgba(23,69,58,.24);padding:6px 10px;border-radius:2px;white-space:nowrap}
.version-chip__dot{width:6px;height:6px;border-radius:50%;background:#2BB49C;box-shadow:0 0 0 3px rgba(59,224,196,.24);flex:none}
.nav-toggle{display:none;align-items:center;justify-content:center;flex-direction:column;gap:5px;width:44px;height:44px;padding:0;border:1px solid var(--paper-grey);background:rgba(255,255,255,.5);border-radius:2px;cursor:pointer;transition:border-color .2s var(--ease),background-color .2s var(--ease)}
.nav-toggle:hover{border-color:var(--ember);background:rgba(242,107,31,.1)}
.nav-toggle__bar{display:block;width:18px;height:2px;background:var(--pitch);transition:transform .24s var(--ease),opacity .18s var(--ease)}
.rail[data-open="true"] .nav-toggle__bar:nth-child(1){transform:translateY(7px) rotate(45deg)}
.rail[data-open="true"] .nav-toggle__bar:nth-child(2){opacity:0}
.rail[data-open="true"] .nav-toggle__bar:nth-child(3){transform:translateY(-7px) rotate(-45deg)}
.rail-progress{position:absolute;left:0;right:0;bottom:-1px;height:2px;background:rgba(14,43,34,.08);pointer-events:none;z-index:3}
.rail-progress__bar{display:block;width:0;height:100%;background:linear-gradient(90deg,var(--ember) 0%,var(--ember) 52%,var(--neon) 100%)}
.thumb-bar{display:none}
/* ===== footer ===== */
.site-footer{background:var(--midnight);color:var(--paper);position:relative;overflow:hidden}
.site-footer::before{content:"";display:block;height:clamp(26px,4.5vw,52px);background:var(--pitch);clip-path:polygon(0 0,100% 0,100% 26%,0 100%)}
.site-footer::after{content:"";position:absolute;left:0;right:0;top:clamp(26px,4.5vw,52px);height:1px;background:rgba(59,224,196,.22);pointer-events:none}
.footer-top{width:min(100% - 2 * var(--gutter),var(--max));margin-inline:auto;display:grid;grid-template-columns:minmax(220px,1fr) minmax(0,2.15fr);gap:clamp(28px,4vw,64px);padding-block:clamp(36px,5vw,72px) clamp(28px,3.5vw,44px)}
.footer-brand__link{display:inline-block;font-family:var(--font-display);font-weight:800;font-size:clamp(1.5rem,3.2vw,2.3rem);line-height:1.05;letter-spacing:-.03em;color:var(--paper);text-decoration:none;border-bottom:2px solid transparent;transition:color .2s var(--ease),border-color .2s var(--ease)}
.footer-brand__link:hover{color:var(--ember);border-bottom-color:var(--ember)}
.footer-brand__summary{margin:16px 0 0;font-size:.94rem;line-height:1.7;color:var(--turf-light);max-width:26em}
.footer-brand__stamp{margin:16px 0 0;display:inline-flex;font-family:var(--font-mono);font-size:.7rem;letter-spacing:.1em;color:var(--neon);border:1px solid rgba(59,224,196,.34);background:rgba(59,224,196,.08);padding:5px 9px;border-radius:2px}
.footer-cols{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:clamp(18px,2.5vw,32px)}
.footer-col{min-width:0}
.footer-col__title{margin:0 0 14px;font-family:var(--font-mono);font-weight:700;font-size:.72rem;letter-spacing:.14em;color:var(--neon);text-transform:uppercase}
.footer-col__list{display:flex;flex-direction:column;gap:9px}
.footer-col__link{display:inline-block;font-size:.88rem;line-height:1.5;color:var(--paper);text-decoration:none;border-bottom:1px solid transparent;transition:color .2s var(--ease),border-color .2s var(--ease)}
.footer-col__link:hover{color:var(--ember);border-bottom-color:var(--ember)}
.footer-col__text{font-size:.88rem;line-height:1.55;color:var(--turf-light);word-break:break-word}
.footer-base{width:min(100% - 2 * var(--gutter),var(--max));margin-inline:auto;display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:14px 24px;padding-block:20px 26px;border-top:1px solid rgba(244,241,232,.14)}
.footer-legal{margin:0;font-family:var(--font-mono);font-size:.74rem;letter-spacing:.04em;color:var(--turf)}
.footer-legal__links{display:flex;flex-wrap:wrap;gap:8px 20px}
.footer-legal__links a{font-size:.78rem;font-weight:600;color:var(--paper);text-decoration:underline;text-underline-offset:3px;text-decoration-color:rgba(244,241,232,.35);transition:color .2s var(--ease),text-decoration-color .2s var(--ease)}
.footer-legal__links a:hover{color:var(--neon);text-decoration-color:var(--neon)}
/* ===== responsive ===== */
@media (max-width:1080px){
  .grid--4{grid-template-columns:repeat(2,1fr)}
  .footer-top{grid-template-columns:1fr}
  .footer-cols{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (max-width:940px){
  .rail__inner{grid-template-columns:1fr auto;min-height:64px;gap:12px}
  .rail-nav{grid-column:1 / -1;display:none;border-top:1px solid var(--paper-grey);margin-inline:calc(var(--gutter) * -1);padding-inline:var(--gutter);background:var(--paper)}
  .rail[data-open="true"] .rail-nav{display:block}
  .rail-nav__list{flex-direction:column;gap:0;width:100%}
  .rail-nav__item{display:block}
  .rail-nav__link{padding:15px 14px;border-bottom:1px solid rgba(14,43,34,.12);border-left:3px solid transparent;justify-content:flex-start}
  .rail-nav__link::before{display:none}
  .rail-nav__link:hover{background:rgba(242,107,31,.08);border-left-color:var(--ember)}
  .rail-nav__link[aria-current="page"]{border-bottom-color:rgba(14,43,34,.12);border-left-color:var(--ember);background:rgba(242,107,31,.08)}
  .rail-meta{padding-block:8px;gap:8px}
  .rail-chapter{display:none}
  .version-chip{display:none}
  .nav-toggle{display:inline-flex}
  .rail-meta .btn--sm{align-self:center}
  .grid{gap:20px}
  .grid--3{grid-template-columns:repeat(2,1fr)}
  .grid__span-5,.grid__span-7,.grid__span-6,.grid__span-4{grid-column:span 12}
}
@media (max-width:720px){
  :root{--gutter:20px;--gap:18px}
  body{font-size:16px;padding-bottom:calc(58px + env(safe-area-inset-bottom,0px))}
  h1{font-size:clamp(1.85rem,7.5vw,2.5rem)}
  .rail-meta .btn--sm{display:none}
  .grid--4,.grid--3{grid-template-columns:1fr}
  .footer-cols{grid-template-columns:1fr;gap:24px}
  .footer-base{flex-direction:column;align-items:flex-start}
  .thumb-bar{display:grid;grid-template-columns:repeat(3,1fr);position:fixed;left:0;right:0;bottom:0;z-index:70;background:rgba(244,241,232,.97);border-top:1px solid var(--paper-grey);padding-bottom:env(safe-area-inset-bottom,0px);backdrop-filter:blur(8px)}
  .thumb-bar__item{display:flex;align-items:center;justify-content:center;min-height:58px;font-family:var(--font-display);font-size:.84rem;font-weight:700;text-decoration:none;color:var(--pitch);border-right:1px solid var(--paper-grey);transition:color .2s var(--ease),background-color .2s var(--ease)}
  .thumb-bar__item:last-child{border-right:0}
  .thumb-bar__item:hover{color:var(--ember-deep);background:rgba(242,107,31,.09)}
  .media--phone{max-width:100%}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.001ms!important;animation-iteration-count:1!important;transition-duration:.001ms!important}
  .js-reveal [data-reveal]{opacity:1;transform:none}
}