:root{
  --paper:#EDEBE6;
  --field:#DAD8D3;
  --page:#FFFFFF;
  --ink:#0A0A0A;
  --muted:#6B6E70;
  --line:#E6E2DB;
  --rule:#D9D7D2;
  --blue:#2B4EA3;
  --radius:8px;
  --max:1160px;
  --sans:-apple-system,BlinkMacSystemFont,"Inter","Helvetica Neue",Helvetica,Arial,sans-serif;
  --mono:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;
  --serif:Georgia,"Times New Roman",serif;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
body{margin:0;font-family:var(--sans);color:var(--ink);background:var(--paper);line-height:1.5;-webkit-font-smoothing:antialiased}
a{color:inherit}
a:focus-visible,button:focus-visible{outline:2px solid var(--blue);outline-offset:2px}
img{display:block;max-width:100%}

.site-header{
  position:sticky;top:0;z-index:20;
  display:flex;align-items:center;gap:16px;
  padding:12px 18px;
  background:rgba(237,235,230,.94);
  backdrop-filter:blur(8px);
  border-bottom:1px solid var(--line);
}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;font-weight:650;letter-spacing:-.02em}
.brand span{opacity:.6;font-weight:400;margin-left:6px;font-size:12px;letter-spacing:.02em}
.toc{margin-left:auto;display:flex;gap:12px;flex-wrap:wrap}
.toc a{font-size:12px;letter-spacing:-.01em;color:var(--muted);text-decoration:none;padding:4px 0;border-bottom:2px solid transparent}
.toc a.is-active,.toc a:hover{color:var(--ink);border-color:var(--ink)}
.progress{position:absolute;left:0;right:0;bottom:-1px;height:2px}
.progress span{display:block;height:100%;width:0;background:var(--ink);transition:width .2s}

.slide{max-width:var(--max);margin:0 auto;padding:56px 18px 48px}
.slide.alt{background:var(--field);max-width:none;margin:0;padding-left:calc((100% - var(--max))/2 + 18px);padding-right:calc((100% - var(--max))/2 + 18px)}
@media (min-width: 1160px){
  .slide.alt{padding-left:calc((100% - var(--max))/2 + 18px);padding-right:calc((100% - var(--max))/2 + 18px)}
}
.section-head{max-width:680px;margin:0 0 24px}
.section-head h2{margin:0 0 8px;font-size:26px;line-height:1.15;letter-spacing:-.03em;font-weight:700}
.section-head p{margin:0;color:var(--muted);font-size:15px}

.cover .cover-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:28px;align-items:center}
.eyebrow{margin:0 0 8px;font-size:11px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
.cover h1{margin:0;font-size:46px;line-height:.92;letter-spacing:-.04em;font-weight:800}
.cover h1 span{font-weight:300;color:var(--muted);display:block;font-size:28px;margin-top:4px}
.lead{margin:10px 0 6px;font-size:17px}
.meta{margin:0;color:var(--muted);font-size:11px;font-family:var(--mono)}
.actions{margin-top:16px;display:flex;gap:10px;flex-wrap:wrap}
.btn{display:inline-flex;align-items:center;justify-content:center;padding:10px 16px;border-radius:999px;font-size:14px;font-weight:600;text-decoration:none;border:1px solid var(--line);background:#fff;color:var(--ink)}
.btn.primary{background:var(--ink);color:#fff;border-color:var(--ink)}
.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-top:16px}
.stats div{background:#fff;border:1px solid var(--line);border-radius:10px;padding:12px;text-align:center}
.stats strong{display:block;font-size:22px;line-height:1}
.stats span{color:var(--muted);font-size:11px}
.cover-card{margin:0;background:var(--page);border:1px solid var(--line);border-radius:4px;overflow:hidden;box-shadow:0 1px 0 rgba(0,0,0,.02)}
.cover-card img{width:100%;aspect-ratio:2000/1333;object-fit:cover}
.cover-card figcaption{padding:10px 12px;font-size:11px;color:var(--muted);border-top:1px solid var(--line);display:flex;justify-content:space-between;gap:12px}

.spread-view{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.spread{margin:0;background:var(--page);border:1px solid var(--line);border-radius:4px;overflow:hidden;box-shadow:0 1px 0 rgba(0,0,0,.03)}
.spread img{width:100%;aspect-ratio:2000/1333;object-fit:cover}
.spread figcaption{display:flex;justify-content:space-between;gap:12px;padding:10px 12px;font-size:11px;color:var(--muted);border-top:1px solid var(--line)}
.spread figcaption span:last-child{font-family:var(--mono);flex:none}
.spread.full{max-width:100%}
.spread.full img{aspect-ratio:4000/1333}

.detail-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin-top:16px}
.detail-grid.three{grid-template-columns:repeat(3,1fr)}
.detail{background:var(--page);border:1px solid var(--line);border-radius:8px;padding:16px}
.detail h3{margin:0 0 8px;font-size:13px;letter-spacing:-.02em}
.detail p{margin:0 0 8px;color:var(--muted);font-size:13px;line-height:1.5}
.detail ul{margin:0;padding-left:16px}
.detail li{font-size:12px;color:var(--muted);margin-bottom:4px}
.detail li::marker{color:var(--ink)}
.small{font-size:11px!important}
.detail code{font-family:var(--mono);font-size:11px;background:var(--paper);padding:1px 5px;border-radius:4px;border:1px solid var(--line)}

.system-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:12px}
.sys-card{background:var(--page);border:1px solid var(--line);border-radius:8px;padding:16px}
.sys-card h3{margin:0 0 6px;font-size:12px;letter-spacing:.06em;text-transform:uppercase;color:var(--muted)}
.sys-card p{margin:0;color:var(--muted);font-size:12px;line-height:1.5}
.sys-card code{display:block;margin-top:8px;font-family:var(--mono);font-size:11px;background:var(--paper);padding:6px 8px;border-radius:6px;border:1px solid var(--line)}

.video-note{margin-top:16px;background:var(--page);border:1px solid var(--line);border-radius:8px;padding:12px 16px;font-size:12px;color:var(--muted)}
.video-note strong{color:var(--ink)}
.video-note code{font-family:var(--mono);font-size:11px}

.site-footer{max-width:var(--max);margin:0 auto;padding:24px 18px 40px;display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap;color:var(--muted);font-size:11px;border-top:1px solid var(--line)}
.site-footer a{color:var(--ink)}
.site-footer code{font-family:var(--mono)}

@media (max-width: 900px){
  .cover .cover-grid,.spread-view,.detail-grid,.detail-grid.three,.system-grid{grid-template-columns:1fr}
  .cover h1{font-size:36px}
  .stats{grid-template-columns:1fr 1fr 1fr}
}
@media (max-width: 580px){
  .site-header{padding:10px 14px}
  .slide{padding:36px 14px 32px}
  .section-head h2{font-size:22px}
  .stats{grid-template-columns:1fr}
}