:root{
  --bg:#f7f8fa; --surface:#fff; --ink:#0f172a; --ink-soft:#475569; --ink-faint:#94a3b8;
  --accent:#2563eb; --accent-dk:#1e40af; --gold:#b88a1b; --line:#e2e8f0; --navy:#0f172a;
  --maxw:720px; --radius:16px; --shadow:0 10px 30px rgba(15,23,42,.07);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);
  font:18px/1.7 "Inter","Segoe UI",system-ui,-apple-system,sans-serif}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 24px}
a{color:var(--accent);text-decoration:none}
a:hover{color:var(--accent-dk)}

header.site{position:sticky;top:0;z-index:10;background:rgba(247,248,250,.85);
  backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
header.site .wrap{max-width:1080px;display:flex;align-items:center;justify-content:space-between;height:64px}
.brand{font-weight:700;font-size:18px;color:var(--ink)}
.brand span{color:var(--accent)}
.back{font:600 13px/1 "Inter",system-ui,sans-serif;color:var(--accent)}

main.article{padding:3.5rem 24px 2rem}
.article .eyebrow{font-size:12px;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:var(--accent);margin:0}
.article h1{font-size:clamp(2rem,5vw,2.8rem);line-height:1.12;letter-spacing:-.02em;margin:.6rem 0 .8rem}
.article .subtitle{font-size:1.2rem;color:var(--ink-soft);margin:0 0 1rem;font-style:italic}
.article .byline{font-size:.9rem;color:var(--ink-faint);border-bottom:1px solid var(--line);padding-bottom:1.5rem;margin-bottom:2rem}
.article blockquote{margin:1.8rem 0;padding:.4rem 0 .4rem 1.4rem;border-left:3px solid var(--accent);color:var(--ink-soft);font-style:italic}
.article blockquote p{margin:.4rem 0}
.article blockquote p:first-child{margin-top:0}
.article blockquote p:last-child{margin-bottom:0}

article h2{font-size:1.05rem;font-family:"Inter",system-ui,sans-serif;text-transform:uppercase;
  letter-spacing:.08em;color:var(--ink-faint);margin:2.8rem 0 1rem;font-weight:700}
article h3{font-size:1.3rem;margin:2rem 0 .8rem;letter-spacing:-.01em}
article p{margin:0 0 1.2rem}
article ul{margin:0 0 1.2rem;padding-left:1.4rem}
article li{margin:0 0 .5rem;line-height:1.65}
article strong{color:var(--ink)}
article em{color:var(--ink-soft)}
article hr{border:0;border-top:1px solid var(--line);margin:2.5rem 0}
article a{border-bottom:1px solid rgba(37,99,235,.25)}

.article-cta{margin:3.5rem 0 1rem;padding-top:2rem;border-top:1px solid var(--line);text-align:center}
.article-cta .formula-mini{color:var(--ink-soft);font-weight:600;margin-bottom:1.2rem;font-size:.95rem}
.btn{display:inline-block;padding:.6rem 1.1rem;border-radius:10px;font-weight:600;font-size:14px;
  background:var(--accent);color:#fff !important;margin:.25rem;border-bottom:none !important}
.btn:hover{background:var(--accent-dk)}
.btn-ghost{background:transparent;color:var(--ink) !important;border:1.5px solid var(--line)}
.btn-ghost:hover{border-color:var(--accent);color:var(--accent) !important}

footer{padding:3rem 0;border-top:1px solid var(--line);text-align:center;color:var(--ink-faint);font-size:14px;margin-top:2rem}

/* article hero image */
.article-hero{margin:1.5rem 0 2.5rem}
.article-hero img{width:100%;height:auto;display:block;border-radius:12px;border:1px solid var(--line);box-shadow:0 10px 30px rgba(15,23,42,.07)}
.article-hero figcaption{font-size:.85rem;color:var(--ink-faint);margin-top:.7rem;text-align:center;line-height:1.5}
.article-related{margin:3rem 0 0;padding:1.5rem 0 0;border-top:1px solid var(--line)}
.article-related h2{font-size:1.05rem;letter-spacing:.02em;text-transform:uppercase;color:var(--ink-faint);margin:0 0 .8rem}
.article-related h3{font-size:.95rem;margin:1rem 0 .4rem;color:var(--ink)}
.article-related ul{margin:0 0 .5rem;padding-left:1.1rem}
.article-related li{margin:.25rem 0}
.article-related a{color:var(--accent);text-decoration:none}
.article-related a:hover{text-decoration:underline}

/* markdown tables (GFM) — responsive, scrolls on overflow, on-brand */
.table-wrap{margin:2rem 0;overflow-x:auto;-webkit-overflow-scrolling:touch}
.article table{border-collapse:collapse;width:100%;font-size:.95rem;line-height:1.5}
.article table th,.article table td{padding:.6rem .9rem;text-align:left;vertical-align:top;border-bottom:1px solid var(--line)}
.article table thead th{border-bottom:2px solid var(--ink);font-weight:700;color:var(--ink)}
.article table tbody tr:last-child td{border-bottom:none}

/* inline article figure (in-body, shortcode) */
.article-fig{margin:2.5rem 0}
.article-fig img{width:100%;height:auto;display:block;border-radius:12px;border:1px solid var(--line);box-shadow:0 10px 30px rgba(15,23,42,.07)}
.article-fig figcaption{font-size:.85rem;color:var(--ink-faint);margin-top:.7rem;text-align:center;line-height:1.5}

/* code — inline spans and fenced blocks (ASCII diagrams, CLI output) */
article code{font-family:ui-monospace,SFMono-Regular,"SF Mono",Menlo,Consolas,monospace;
  font-size:.88em;background:#eef1f6;color:var(--ink);padding:.12em .38em;border-radius:5px;
  border:1px solid var(--line)}
article pre{background:#0f172a;color:#e2e8f0;border:1px solid var(--line);border-radius:12px;
  padding:1.1rem 1.25rem;margin:2rem 0;overflow-x:auto;line-height:1.55;
  box-shadow:0 10px 30px rgba(15,23,42,.07)}
article pre code{font-family:ui-monospace,SFMono-Regular,"SF Mono",Menlo,Consolas,monospace;
  font-size:.85rem;background:none;color:inherit;padding:0;border:0;border-radius:0;
  white-space:pre;display:block}

/* --- Book reference pages (ADR-068 references-layer) --- */
.book-cover{margin:1.25rem 0 0;max-width:200px}
.book-cover img{width:100%;border-radius:8px;box-shadow:0 10px 30px rgba(15,23,42,.14)}
.book-rating{color:var(--gold);letter-spacing:3px;font-size:1.15rem}
.ai-note{margin-top:2.5rem;padding-top:1rem;border-top:1px solid var(--line);
  font-size:.82rem;color:var(--ink-faint)}

/* --- Series navigation (ADR-067) + in-page TOC (added 2026-07-31) --- */
/* Series banner under the byline: series title + "Part X of N". */
.series-banner{display:flex;flex-wrap:wrap;align-items:center;gap:.6rem;
  margin:0 0 1.6rem;padding:.6rem .9rem;background:var(--surface);
  border:1px solid var(--line);border-left:3px solid var(--accent);border-radius:10px;
  font-size:.9rem}
.series-banner a{font-weight:700;color:var(--ink)}
.series-banner a:hover{color:var(--accent)}
.series-progress{color:var(--ink-faint);font-weight:600}
.series-progress::before{content:"·";margin-right:.6rem;color:var(--line)}

/* Bottom prev · series-home · next control. */
.series-nav{display:grid;grid-template-columns:1fr auto 1fr;gap:.8rem;align-items:stretch;
  margin:3rem 0 0;padding-top:1.6rem;border-top:1px solid var(--line)}
.series-link{display:flex;flex-direction:column;gap:.2rem;padding:.7rem .9rem;
  border:1px solid var(--line);border-radius:12px;background:var(--surface);
  color:var(--ink);transition:border-color .15s,transform .15s}
.series-link:hover{border-color:var(--accent);transform:translateY(-1px);color:var(--ink)}
.series-link.next{text-align:right}
.series-link.home{text-align:center;justify-content:center;background:transparent}
.series-link.disabled{visibility:hidden;border:0}
.series-dir{font-size:.72rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--accent)}
.series-name{font-size:.95rem;font-weight:600;line-height:1.3}

/* Two-column article layout: sticky TOC rail + article. Widens past the 720
   body only when a TOC is present, so non-TOC articles keep the narrow measure. */
.article-layout{display:block}
.article-toc{display:none}
.article-toc .toc-title{font-size:.72rem;font-weight:700;letter-spacing:.08em;
  text-transform:uppercase;color:var(--ink-faint);margin:0 0 .6rem}
.article-toc ul{list-style:none;margin:0;padding:0;border-left:2px solid var(--line)}
.article-toc li{margin:0}
.article-toc a{display:block;padding:.28rem 0 .28rem .9rem;margin-left:-2px;
  font-size:.9rem;line-height:1.35;color:var(--ink-soft);
  border-left:2px solid transparent}
.article-toc a:hover{color:var(--accent);border-left-color:var(--accent)}
.article-toc .toc-h3 a{padding-left:1.7rem;font-size:.85rem;color:var(--ink-faint)}

/* On wide screens: TOC becomes a sticky left rail beside the article. */
@media (min-width:1100px){
  main.article:has(.article-toc){max-width:1040px}
  .article-layout:has(.article-toc){display:grid;
    grid-template-columns:230px minmax(0,720px);gap:48px;align-items:start;
    justify-content:center}
  .article-toc{display:block;position:sticky;top:88px;align-self:start;
    max-height:calc(100vh - 110px);overflow:auto}
}
/* Fallback for browsers without :has() — show TOC inline as a boxed summary. */
@supports not (selector(:has(*))){
  .article-toc{display:block;margin:0 0 2rem;padding:1rem 1.2rem;
    background:var(--surface);border:1px solid var(--line);border-radius:12px}
}

/* Series-overview page: ordered list of parts (the kapstok landing). */
.series-list{list-style:none;margin:2rem 0 0;padding:0;counter-reset:none}
.series-list li{margin:0 0 .8rem}
.series-list a,.series-list li.pending{display:flex;align-items:center;gap:1rem;
  padding:1rem 1.2rem;border:1px solid var(--line);border-radius:12px;
  background:var(--surface);transition:border-color .15s,transform .15s}
.series-list a:hover{border-color:var(--accent);transform:translateY(-1px)}
.series-list li.pending{opacity:.6}
.series-list-n{flex:0 0 2rem;height:2rem;display:flex;align-items:center;justify-content:center;
  border-radius:50%;background:var(--accent);color:#fff;font-weight:700;font-size:.9rem}
.series-list li.pending .series-list-n{background:var(--ink-faint)}
.series-list-t{font-weight:600;color:var(--ink);line-height:1.35}
.series-list-t em{color:var(--ink-faint);font-weight:500;font-style:normal;font-size:.85rem}

/* Brand mark in the header (12 Oct 2026) — same pattern as buildingyourown.ai. */
a.brand{display:inline-flex;align-items:center}
a.brand svg{width:24px;height:24px;flex:0 0 auto;display:block;margin-right:10px}
/* Flex would turn the "Magic" span into its own item and the gap would split the
   wordmark; spacing lives on the mark only. The space before Magic must be   (a plain space collapses at the end of a flex item). */
header.site .wrap > a.brand,a.brand{gap:0}