/* Layout: a single reading column per chapter; the rotatable model is each chapter's hero, evidence and lessons follow. */
:root{
  --bg:#f2f3f4; --panel:#ffffff; --ink:#1d2329; --muted:#5b6670; --rule:#d5dadf;
  --brass:#9a6b12; --brass-soft:#f3e7cf; --good:#2f6b3f; --bad:#a23b2a;
  --display:"Archivo Narrow","Arial Narrow",Arial,sans-serif;
  --body:"Archivo",system-ui,-apple-system,"Segoe UI",sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,Consolas,monospace;
  color-scheme:light;
}
@media (prefers-color-scheme: dark){:root{
  --bg:#15191d; --panel:#1d2227; --ink:#e6e9ec; --muted:#9aa5ae; --rule:#323a42;
  --brass:#d9a441; --brass-soft:#3a2f1a; --good:#7fc08e; --bad:#e58a77; color-scheme:dark}}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.6 var(--body);padding:24px 16px 64px}
.wrap{max-width:1080px;margin:0 auto;display:grid;gap:44px}
h1,h2{font-family:var(--display);text-wrap:balance;margin:0;letter-spacing:.005em}
h1{font-size:clamp(32px,5.4vw,52px);line-height:1.04}
h2{font-size:27px;line-height:1.15}
h3{margin:0;font:600 17px/1.3 var(--body)}
p{margin:0;max-width:68ch}
a{color:var(--brass)}
.eyebrow{font:500 12px/1 var(--mono);letter-spacing:.12em;text-transform:uppercase;color:var(--brass)}
.lede{color:var(--muted);font-size:18px}
.small{color:var(--muted);font-size:15px}
header{display:grid;gap:14px}

/* site navigation: the chapter strip */
.topnav{display:flex;flex-wrap:wrap;gap:6px 18px;align-items:center;font-size:14px;border-bottom:1px solid var(--rule);padding-bottom:14px}
.topnav .brand{font:700 18px/1 var(--display);color:var(--ink);text-decoration:none;margin-right:auto}
.topnav a{color:var(--muted);text-decoration:none}
.topnav a:hover{color:var(--ink)}
.topnav a[aria-current="page"]{color:var(--brass);font-weight:600}

.stats{display:flex;flex-wrap:wrap;gap:12px 32px;margin-top:6px}
.stat{display:grid;gap:2px}
.stat b{font:500 20px/1.2 var(--mono);font-variant-numeric:tabular-nums}
.stat span{font-size:13px;color:var(--muted)}

.viewer{border:1px solid var(--rule);border-radius:8px;overflow:hidden;background:#5d646a}
.stage{position:relative;height:min(68vh,620px);background:radial-gradient(ellipse 70% 75% at 50% 45%,#a2a9af 0%,#848b91 45%,#5d646a 100%);touch-action:none}
.stage canvas{display:block;width:100%;height:100%;cursor:grab}.stage canvas:active{cursor:grabbing}
.status{position:absolute;left:0;right:0;bottom:14px;text-align:center;font-size:13px;color:#eef1f3;pointer-events:none;margin:0;max-width:none}
.bar{display:flex;flex-wrap:wrap;gap:8px;align-items:center;padding:12px 14px;background:var(--panel);border-top:1px solid var(--rule)}
button{font:500 14px/1 var(--body);padding:9px 13px;border:1px solid var(--rule);border-radius:4px;background:var(--panel);color:var(--ink);cursor:pointer}
button:hover{border-color:var(--brass)}
button[aria-pressed="true"]{background:var(--brass);border-color:var(--brass);color:var(--panel)}
button:focus-visible,a:focus-visible{outline:2px solid var(--brass);outline-offset:2px}
.hint{margin-left:auto;font-size:13px;color:var(--muted)}

section{display:grid;gap:16px}
figure{margin:0;display:grid;gap:8px}
figure img{width:100%;height:auto;border:1px solid var(--rule);border-radius:6px;background:#5d646a}
figcaption{font-size:14px;color:var(--muted);max-width:80ch}
.photos{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}
.photos img{background:#fff}

ol.steps{margin:0;padding:0;list-style:none;display:grid;gap:16px;counter-reset:s}
ol.steps li{display:grid;grid-template-columns:34px 1fr;gap:12px;counter-increment:s}
ol.steps li::before{content:counter(s);font:500 14px/30px var(--mono);text-align:center;width:30px;height:30px;border:1px solid var(--brass);color:var(--brass);border-radius:50%}
ol.steps b{display:block}
ol.steps span{color:var(--muted);font-size:15px}

.tablewrap{overflow-x:auto;border:1px solid var(--rule);border-radius:6px;background:var(--panel)}
table{border-collapse:collapse;width:100%;font-size:14px;min-width:620px}
th,td{text-align:left;padding:9px 12px;border-bottom:1px solid var(--rule);vertical-align:top}
th{font:500 12px/1.2 var(--mono);letter-spacing:.06em;text-transform:uppercase;color:var(--muted)}
td.num{font-family:var(--mono);font-variant-numeric:tabular-nums;white-space:nowrap}
tr.here td{background:var(--brass-soft);font-weight:600}

.cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:18px 28px}
.cols div{display:grid;gap:6px;min-width:0}
.cols p{color:var(--muted);font-size:15px}
ul.plain{margin:0;padding-left:20px;display:grid;gap:8px;max-width:75ch}
ul.plain li{color:var(--muted)}
ul.plain b{color:var(--ink)}

/* the lesson box carried from one chapter into the next */
.lesson{border-left:3px solid var(--brass);background:var(--panel);padding:16px 18px;border-radius:0 6px 6px 0;display:grid;gap:8px}
.lesson .eyebrow{margin-bottom:2px}

/* landing: three chapter cards */
.cards{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}
.card{display:grid;grid-template-rows:auto 1fr;border:1px solid var(--rule);border-radius:8px;overflow:hidden;background:var(--panel);text-decoration:none;color:var(--ink)}
.card:hover{border-color:var(--brass)}
.card img{width:100%;height:auto;max-width:100%;aspect-ratio:1/1;object-fit:cover;display:block;background:#5d646a;border:0;border-radius:0}
.card .body{padding:14px 16px;display:grid;gap:6px;align-content:start}
.card .num{font:500 12px/1 var(--mono);letter-spacing:.1em;color:var(--brass)}
.card h3{font:700 22px/1.15 var(--display)}
.card p{color:var(--muted);font-size:14px}
.card .score{font:500 13px/1.3 var(--mono);color:var(--ink)}

/* previous / next */
.pager{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.pager a{display:grid;gap:4px;border:1px solid var(--rule);border-radius:6px;padding:14px 16px;text-decoration:none;color:var(--ink);background:var(--panel)}
.pager a:hover{border-color:var(--brass)}
.pager a span{font:500 12px/1 var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
.pager a b{font:700 19px/1.2 var(--display)}
.pager .next{text-align:right;grid-column:2}

footer{color:var(--muted);font-size:13px;border-top:1px solid var(--rule);padding-top:18px}
@media (max-width:760px){.cards{grid-template-columns:1fr}}
@media (max-width:520px){.topnav .brand{flex-basis:100%}}
@media (max-width:640px){.hint{margin-left:0;width:100%}.photos{grid-template-columns:1fr}.pager{grid-template-columns:1fr}.pager .next{grid-column:1;text-align:left}}
@media (prefers-reduced-motion: reduce){*{transition:none!important}}