:root{
  --ink:#1B2A41;
  --flame:#E4572E;
  --sand:#D9A441;
  --sage:#7C9A92;
  --paper:#F6F1E7;
  --stone:#D9D2C3;
  --clay:#8C3B27;
  --forest:#2F4A46;
  --mist:#C7D0C9;
  --card:#FFFDF8;
  --line:rgba(27,42,65,.18);
  --line-soft:rgba(27,42,65,.10);
  --font-serif:"Noto Serif SC","Source Han Serif SC","Songti SC","SimSun",serif;
  --font-sans:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"IBM Plex Mono","JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --shell:1440px;
  --gutter:clamp(16px,3.2vw,44px);
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{
  margin:0;
  background-color:var(--paper);
  background-image:linear-gradient(to right,rgba(27,42,65,.035) 1px,transparent 1px);
  background-size:120px 100%;
  color:var(--ink);
  font-family:var(--font-sans);
  font-size:17px;
  line-height:1.75;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3,h4,h5,h6,p,figure,blockquote{margin:0}
ul,ol{margin:0;padding:0;list-style:none}
img,svg,video{display:block;max-width:100%}
a{color:inherit;text-decoration:none}
button{font:inherit;color:inherit;background:none;border:0;padding:0;cursor:pointer}
strong{font-weight:800}
[hidden]{display:none!important}
:focus-visible{outline:2px solid var(--flame);outline-offset:3px}
.site-header :focus-visible,.site-footer :focus-visible{outline-color:var(--sand)}

/* ---------- shell ---------- */
.shell{width:100%;max-width:var(--shell);margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-block:clamp(44px,6.5vw,92px)}
.section-head{display:flex;flex-direction:column;gap:12px;padding-top:22px;border-top:1px solid var(--line);margin-bottom:clamp(22px,3vw,36px)}
.eyebrow{display:inline-flex;align-items:center;gap:10px;font-family:var(--font-mono);font-size:11.5px;letter-spacing:.2em;color:var(--clay)}
.eyebrow::before{content:"";width:26px;height:1px;background:var(--sand)}
.lede{font-size:clamp(16.5px,1.5vw,19px);line-height:1.8;color:rgba(27,42,65,.82);max-width:52ch}
.rule-line{height:1px;border:0;background:var(--line);margin:0}

/* ---------- skip link ---------- */
.skip-link{
  position:fixed;left:14px;top:-140px;z-index:200;
  background:var(--sand);color:var(--ink);
  padding:10px 18px;font-size:13px;font-weight:800;letter-spacing:.08em;
  border-radius:1px;transition:top .18s ease;
}
.skip-link:focus,.skip-link:focus-visible{top:12px}

/* ---------- header ---------- */
.site-header{
  position:sticky;top:0;z-index:70;
  background:var(--ink);
  color:var(--paper);
  border-bottom:1px solid rgba(217,164,65,.34);
}
.header-inner{
  position:relative;
  width:100%;max-width:var(--shell);margin-inline:auto;
  min-height:56px;padding-inline:var(--gutter);
  display:flex;align-items:stretch;gap:clamp(10px,2vw,26px);
}
.brand{display:flex;align-items:center;gap:10px;flex:0 0 auto;padding-block:8px;order:0}
.brand-stamp{
  width:34px;height:34px;display:grid;place-items:center;flex:0 0 auto;
  background:var(--flame);color:var(--ink);border-radius:1px;
  font-family:var(--font-serif);font-weight:900;font-size:17px;line-height:1;
}
.brand-text{display:flex;flex-direction:column;line-height:1.12}
.brand-name{font-size:15px;font-weight:900;letter-spacing:.08em;color:var(--paper)}
.brand-sub{font-family:var(--font-mono);font-size:10px;letter-spacing:.18em;color:var(--sand)}
.site-nav{flex:1 1 auto;min-width:0;display:flex;justify-content:center}
.nav-list{display:flex;align-items:stretch}
.nav-item{display:flex}
.nav-link{
  position:relative;display:flex;align-items:center;gap:6px;
  padding:0 clamp(7px,1.05vw,14px);
  font-size:13px;font-weight:700;letter-spacing:.03em;white-space:nowrap;
  color:rgba(246,241,231,.82);
  transition:color .16s ease,background-color .16s ease;
}
.nav-link::before{
  content:"";position:absolute;left:0;right:0;top:0;height:3px;
  background:var(--flame);transform:scaleX(0);transform-origin:left center;
  transition:transform .16s ease;
}
.nav-link:hover{color:var(--paper);background-color:rgba(246,241,231,.07)}
.nav-link:hover::before{transform:scaleX(1)}
.nav-num{font-family:var(--font-mono);font-size:10px;letter-spacing:.05em;color:var(--sand)}
.nav-label{display:inline-block}
.nav-link[aria-current="page"]{color:var(--paper);background-color:rgba(228,87,46,.14)}
.nav-link[aria-current="page"]::before{transform:scaleX(1)}
.nav-link[aria-current="page"] .nav-num{color:var(--flame)}
.header-tools{display:flex;align-items:center;gap:12px;flex:0 0 auto}
.tool-link{
  font-size:12.5px;font-weight:700;letter-spacing:.1em;
  color:rgba(246,241,231,.8);padding-block:4px;
  border-bottom:1px solid transparent;transition:color .16s ease,border-color .16s ease;
}
.tool-link:hover{color:var(--sand);border-bottom-color:var(--sand)}
.tool-cta{
  display:inline-flex;align-items:center;
  background:var(--flame);color:var(--ink);
  font-size:13px;font-weight:800;letter-spacing:.06em;
  padding:8px 14px;border-radius:1px;border:1px solid var(--flame);
  transition:background-color .16s ease,border-color .16s ease;
}
.tool-cta:hover{background:var(--sand);border-color:var(--sand)}
.nav-toggle{
  display:none;align-items:center;gap:8px;order:2;
  padding:8px 12px;border:1px solid rgba(246,241,231,.28);border-radius:1px;
  color:var(--paper);font-size:12px;font-weight:800;letter-spacing:.12em;
  transition:background-color .16s ease,color .16s ease,border-color .16s ease;
}
.nav-toggle-icon{display:flex;flex-direction:column;gap:3px;width:14px}
.nav-toggle-icon span{display:block;height:2px;width:100%;background:currentColor}
.nav-toggle[aria-expanded="true"]{background:var(--flame);color:var(--ink);border-color:var(--flame)}

/* ---------- footer ---------- */
.site-footer{
  background:var(--ink);
  color:var(--paper);
  border-top:3px solid var(--flame);
}
.footer-shell{
  width:100%;max-width:var(--shell);margin-inline:auto;
  padding:clamp(40px,6vw,72px) var(--gutter) clamp(26px,4vw,42px);
  display:grid;
  grid-template-columns:minmax(240px,1.5fr) repeat(3,minmax(0,1fr));
  gap:clamp(24px,3.4vw,48px);
}
.footer-lede{display:flex;flex-direction:column;align-items:flex-start;gap:14px}
.footer-kicker{font-family:var(--font-mono);font-size:11px;letter-spacing:.2em;color:var(--sand)}
.footer-title{
  font-family:var(--font-serif);font-weight:900;
  font-size:clamp(23px,2.5vw,31px);line-height:1.34;letter-spacing:-.01em;
  color:var(--paper);max-width:17ch;
}
.footer-title::after{content:"";display:block;width:56px;height:3px;background:var(--flame);margin-top:18px}
.footer-cta{margin-top:2px}
.footer-col{display:flex;flex-direction:column;gap:14px;min-width:0}
.footer-col-title{
  font-size:13px;font-weight:800;letter-spacing:.16em;color:var(--sand);
  padding-bottom:10px;border-bottom:1px solid rgba(246,241,231,.16);
}
.footer-list{display:flex;flex-direction:column;gap:10px}
.footer-link{
  display:inline-flex;align-items:center;gap:8px;
  font-size:14.5px;color:rgba(246,241,231,.82);transition:color .16s ease;
}
.footer-link::before{content:"";width:10px;height:1px;background:rgba(217,164,65,.55);transition:width .16s ease,background-color .16s ease}
.footer-link:hover{color:var(--paper)}
.footer-link:hover::before{width:20px;background:var(--flame)}
.footer-contact{display:flex;flex-direction:column;gap:10px}
.footer-contact-item{font-size:14px;line-height:1.68;color:rgba(246,241,231,.82);word-break:break-word}
.footer-bottom{
  width:100%;max-width:var(--shell);margin-inline:auto;
  padding:18px var(--gutter) 26px;
  border-top:1px solid rgba(246,241,231,.16);
  display:flex;flex-wrap:wrap;align-items:baseline;justify-content:space-between;gap:10px 28px;
}
.footer-legal{font-family:var(--font-mono);font-size:11.5px;letter-spacing:.08em;color:rgba(246,241,231,.62)}
.footer-note{font-size:12.5px;line-height:1.7;color:rgba(246,241,231,.6);max-width:62ch}

/* ---------- buttons ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:10px;
  padding:12px 20px;border:1px solid transparent;border-radius:1px;
  font-family:var(--font-sans);font-size:14.5px;font-weight:800;letter-spacing:.06em;line-height:1.2;
  transition:background-color .16s ease,color .16s ease,border-color .16s ease,transform .16s ease;
}
.btn:hover{transform:translateY(-1px)}
.btn--flame{background:var(--flame);border-color:var(--flame);color:var(--ink)}
.btn--flame:hover{background:var(--sand);border-color:var(--sand)}
.btn--ink{background:var(--ink);border-color:var(--ink);color:var(--paper)}
.btn--ink:hover{background:var(--clay);border-color:var(--clay)}
.btn--ghost{background:transparent;border-color:rgba(27,42,65,.34);color:var(--ink)}
.btn--ghost:hover{border-color:var(--clay);color:var(--clay)}

/* ---------- breadcrumbs & prose ---------- */
.crumbs{font-family:var(--font-mono);font-size:11.5px;letter-spacing:.1em;color:rgba(27,42,65,.6)}
.crumbs ol{display:flex;flex-wrap:wrap;align-items:center;gap:8px}
.crumbs li{display:flex;align-items:center;gap:8px}
.crumbs li+li::before{content:"/";color:var(--sand)}
.crumbs a{color:var(--clay);border-bottom:1px solid transparent;transition:border-color .16s ease}
.crumbs a:hover{border-bottom-color:var(--flame)}
.prose{max-width:68ch;font-size:17px;line-height:1.8;color:rgba(27,42,65,.9)}
.prose h2{font-size:clamp(23px,2.5vw,31px);font-weight:900;line-height:1.36;letter-spacing:-.01em;margin:1.7em 0 .55em}
.prose h3{font-size:20px;font-weight:800;line-height:1.45;margin:1.5em 0 .45em}
.prose p{margin:0 0 1.1em}
.prose ul{display:flex;flex-direction:column;gap:10px;margin:0 0 1.2em}
.prose ul li{position:relative;padding-left:22px}
.prose ul li::before{content:"";position:absolute;left:0;top:.62em;width:8px;height:8px;border:2px solid var(--flame);border-radius:1px}
.prose a{color:var(--clay);border-bottom:1px solid rgba(228,87,46,.5)}
.prose blockquote{margin:1.6em 0;padding:18px 22px;background:var(--forest);color:var(--paper);border-left:3px solid var(--sand);border-radius:1px}

/* ---------- grid ---------- */
.grid{display:grid;grid-template-columns:repeat(12,minmax(0,1fr));gap:clamp(18px,2.4vw,36px)}
.col-index{grid-column:span 3;min-width:0}
.col-main{grid-column:span 7;min-width:0}
.col-note{grid-column:span 2;min-width:0}

/* ---------- media ---------- */
.media{
  position:relative;display:block;overflow:hidden;
  aspect-ratio:16/10;
  background:var(--stone);
  border:1px solid rgba(27,42,65,.18);border-radius:1px;
}
.media::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  background-image:repeating-linear-gradient(45deg,rgba(27,42,65,.06) 0 1px,transparent 1px 7px);
  opacity:.45;
}
.media img,.media svg,.media video{width:100%;height:100%;object-fit:cover}
.media--wide{aspect-ratio:21/9}
.media--tall{aspect-ratio:3/4}
.media--square{aspect-ratio:1/1}
.media-frame{display:flex;flex-direction:column;gap:10px;margin:0;min-width:0}
.media-caption{font-size:13px;line-height:1.64;color:rgba(27,42,65,.66);border-left:1px solid var(--sand);padding-left:10px}

/* ---------- panel & tags ---------- */
.panel{
  position:relative;background:var(--card);border:1px solid var(--line);
  padding:clamp(18px,2.2vw,26px);border-radius:1px;
}
.panel::before{content:"";position:absolute;top:-1px;left:-1px;width:38px;height:3px;background:var(--flame)}
.panel-title{font-size:14px;font-weight:800;letter-spacing:.1em;color:var(--ink);margin-bottom:12px}
.tag{
  display:inline-flex;align-items:center;gap:6px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;line-height:1.5;
  padding:3px 8px;border:1px solid rgba(27,42,65,.24);border-radius:1px;
  background:var(--mist);color:var(--ink);
}
.tag--flame{background:var(--flame);border-color:var(--flame);color:var(--ink)}
.tag--sage{background:var(--sage);border-color:var(--sage);color:var(--ink)}
.tag--sand{background:var(--sand);border-color:var(--sand);color:var(--ink)}

/* ---------- steps ---------- */
.steps{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(190px,1fr));gap:1px;
  background:var(--line);border:1px solid var(--line);
}
.step{position:relative;display:flex;flex-direction:column;gap:10px;background:var(--card);padding:clamp(16px,2vw,22px)}
.step::before{content:"";position:absolute;left:0;right:0;top:0;height:3px;background:var(--sand);transition:background-color .16s ease}
.step:hover::before,.step[data-current]::before{background:var(--flame)}
.step-num{font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;color:var(--clay)}
.step-title{font-size:16px;font-weight:800;line-height:1.45;color:var(--ink)}
.step-body{font-size:14.5px;line-height:1.7;color:rgba(27,42,65,.85)}

/* ---------- timeline ---------- */
.timeline{display:flex;flex-direction:column;border-left:1px solid rgba(27,42,65,.22);margin-left:6px}
.tl-item{
  position:relative;display:grid;grid-template-columns:112px minmax(0,1fr);
  gap:clamp(12px,2vw,24px);
  padding:18px 0 18px 22px;
  border-bottom:1px dashed rgba(27,42,65,.16);
}
.tl-item::before{
  content:"";position:absolute;left:-6px;top:24px;width:11px;height:11px;
  background:var(--sand);border:1px solid var(--ink);border-radius:1px;
}
.tl-month{font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;color:var(--clay);padding-top:2px}
.tl-body{font-size:15px;line-height:1.72;color:rgba(27,42,65,.86);min-width:0}
.tl-body h3{font-size:17px;font-weight:800;line-height:1.5;margin-bottom:6px}

/* ---------- compare ---------- */
.compare{
  display:grid;grid-template-columns:1fr 1px 1fr;
  border:1px solid var(--line);background:var(--card);
}
.compare-side{display:flex;flex-direction:column;gap:12px;padding:clamp(16px,2vw,24px);min-width:0}
.compare-mid{background:repeating-linear-gradient(180deg,var(--flame) 0 6px,transparent 6px 12px);opacity:.75}
.compare-row{
  display:flex;align-items:baseline;justify-content:space-between;gap:12px;
  padding-bottom:8px;border-bottom:1px dashed rgba(27,42,65,.16);
  font-size:14.5px;line-height:1.65;
}

/* ---------- accordion ---------- */
.accordion{border-top:1px solid rgba(27,42,65,.2)}
.accordion-item{border-bottom:1px solid rgba(27,42,65,.2)}
.accordion-trigger{
  display:flex;align-items:center;gap:14px;width:100%;
  padding:18px 0;text-align:left;
  font-size:16px;font-weight:800;line-height:1.5;color:var(--ink);
  transition:color .16s ease;
}
.accordion-trigger:hover{color:var(--clay)}
.accordion-trigger::after{content:"+";margin-left:auto;font-family:var(--font-mono);font-size:18px;color:var(--flame)}
.accordion-item[data-open] .accordion-trigger::after{content:"–"}
.accordion-panel{padding:0 0 20px;font-size:15px;line-height:1.78;color:rgba(27,42,65,.85)}

/* ---------- filter ---------- */
.filter-bar{display:flex;flex-wrap:wrap;align-items:center;gap:8px}
.filter-btn{
  font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;
  padding:7px 12px;border:1px solid rgba(27,42,65,.24);border-radius:1px;
  background:transparent;color:rgba(27,42,65,.8);
  transition:background-color .16s ease,color .16s ease,border-color .16s ease;
}
.filter-btn:hover{border-color:var(--clay);color:var(--clay)}
.filter-btn[aria-pressed="true"]{background:var(--ink);border-color:var(--ink);color:var(--paper)}

/* ---------- progress & reveal ---------- */
.scroll-progress{
  position:fixed;left:0;right:0;top:0;height:3px;z-index:90;
  background:rgba(27,42,65,.14);pointer-events:none;
}
.scroll-progress span{display:block;height:100%;width:100%;background:var(--flame);transform:scaleX(0);transform-origin:left center}
.js [data-reveal]{opacity:0;transform:translateY(12px);transition:opacity .38s ease,transform .38s ease}
.js [data-reveal].is-visible{opacity:1;transform:none}

/* ---------- responsive ---------- */
@media (max-width:1080px){
  .footer-shell{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-lede{grid-column:1 / -1}
}
@media (max-width:1000px){
  .grid{grid-template-columns:1fr}
  .col-index,.col-main,.col-note{grid-column:1 / -1}
}
@media (max-width:980px){
  .header-inner{min-height:54px;flex-wrap:nowrap}
  .nav-toggle{display:inline-flex;margin-left:0}
  .header-tools{order:1;margin-left:auto;gap:8px}
  .tool-link{display:none}
  .site-nav{
    position:absolute;left:0;right:0;top:100%;
    display:none;flex-direction:column;justify-content:flex-start;
    background:#16233a;
    border-bottom:1px solid rgba(217,164,65,.34);
    padding:10px var(--gutter) 20px;
    box-shadow:0 18px 32px rgba(0,0,0,.3);
  }
  .site-nav[data-open]{display:flex}
  .nav-list{flex-direction:column;width:100%}
  .nav-item{width:100%;border-bottom:1px solid rgba(246,241,231,.12)}
  .nav-item:last-child{border-bottom:0}
  .nav-link{width:100%;gap:10px;padding:14px 6px;font-size:15px}
  .nav-link::before{left:0;right:auto;top:0;bottom:0;width:3px;height:auto;transform:scaleY(0);transform-origin:top center}
  .nav-link:hover::before,.nav-link[aria-current="page"]::before{transform:scaleY(1)}
  .nav-link[aria-current="page"]{background-color:rgba(228,87,46,.16)}
}
@media (max-width:760px){
  .compare{grid-template-columns:1fr}
  .compare-mid{height:3px;background:var(--flame);opacity:1}
  .tl-item{grid-template-columns:1fr;gap:6px;padding-left:20px}
}
@media (max-width:600px){
  .footer-shell{grid-template-columns:1fr}
  .footer-bottom{flex-direction:column;align-items:flex-start}
  .brand-sub{font-size:9px;letter-spacing:.14em}
  .tool-cta{padding:7px 11px;font-size:12px}
  .nav-toggle{padding:7px 10px;font-size:11px}
}
@media (max-width:400px){
  .brand-stamp{width:30px;height:30px;font-size:15px}
  .brand-name{font-size:14px}
}
@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 [data-reveal]{opacity:1;transform:none}
  .btn:hover{transform:none}
}