/* AI Delivery Discipline — Visual Style Guide v2.1: charcoal #1A1A1A, gold #C9A84C, white */
:root{
  --charcoal:#1A1A1A; --surface:#212121; --surface2:#262626;
  --gold:#C9A84C; --gold-dim:#A38A42;
  --text:#EDEAE3; --muted:#A29D93; --faint:#6E6A62;
  --line:#333330; --maxw:1080px; --readw:700px;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{background:var(--charcoal);color:var(--text);font-family:'Fira Sans',-apple-system,'Segoe UI',sans-serif;font-weight:300;line-height:1.7;font-size:17px;-webkit-font-smoothing:antialiased}
a{color:var(--gold);text-decoration:none}
a:hover{color:#DCC06A}
a:focus-visible{outline:2px solid var(--gold);outline-offset:3px}
img{max-width:100%;height:auto}
::selection{background:var(--gold);color:var(--charcoal)}

/* The signature: a single gold horizon line */
.horizon{height:1px;border:0;background:linear-gradient(90deg,transparent,var(--gold) 18%,var(--gold) 82%,transparent);box-shadow:0 0 18px rgba(201,168,76,.35);margin:0}
.horizon--quiet{box-shadow:none;background:linear-gradient(90deg,transparent,var(--gold-dim),transparent);opacity:.6}

/* Nav */
header.site{position:sticky;top:0;z-index:50;background:rgba(26,26,26,.92);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.nav{max-width:var(--maxw);margin:0 auto;padding:14px 24px;display:flex;align-items:center;gap:28px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:11px;color:var(--text)}
.brand img{height:17px;width:auto}
.brand span{font-size:.86rem;font-weight:600;letter-spacing:.14em;text-transform:uppercase;color:var(--text)}
.brand:hover span{color:var(--gold)}
nav.links{margin-left:auto;display:flex;gap:22px;flex-wrap:wrap}
nav.links a{color:var(--muted);font-size:.9rem;font-weight:400;letter-spacing:.02em}
nav.links a:hover,nav.links a[aria-current]{color:var(--gold)}

/* Layout */
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 24px}
.read{max-width:var(--readw);margin:0 auto;padding:0 24px}
section{padding:64px 0}
.eyebrow{font-size:.74rem;font-weight:600;letter-spacing:.22em;text-transform:uppercase;color:var(--gold);margin-bottom:14px}
h1{font-size:clamp(1.9rem,4.6vw,3.1rem);font-weight:300;line-height:1.18;letter-spacing:-.01em}
h1 strong,h2 strong{font-weight:600}
h2{font-size:1.5rem;font-weight:400;line-height:1.3;margin:2.2em 0 .7em}
h3{font-size:1.12rem;font-weight:600;margin:1.8em 0 .5em}
.lead{font-size:1.16rem;color:var(--muted);line-height:1.75;margin-top:22px}
p{margin:0 0 1.15em}
.btn{display:inline-block;padding:12px 26px;border:1px solid var(--gold);color:var(--gold);font-size:.92rem;font-weight:400;letter-spacing:.05em;transition:all .18s}
.btn:hover{background:var(--gold);color:var(--charcoal)}
.btn--solid{background:var(--gold);color:var(--charcoal);font-weight:600}
.btn--solid:hover{background:#DCC06A;color:var(--charcoal)}

/* Hero */
.hero{padding:96px 0 72px;position:relative}
.hero .wrap{max-width:880px}
.hero h1{margin-top:10px}
.hero .horizon{margin:44px 0}
.hero-def{font-size:1.05rem;color:var(--text)}
.hero-def b{color:var(--gold);font-weight:600}

/* Cards & index rows */
.doors{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:22px;margin-top:36px}
.door{background:var(--surface);border:1px solid var(--line);padding:30px 28px;display:block;color:var(--text);transition:border-color .18s}
.door:hover{border-color:var(--gold);color:var(--text)}
.door h3{margin:0 0 10px;color:var(--gold);font-weight:600;font-size:1.02rem;letter-spacing:.06em;text-transform:uppercase}
.door p{color:var(--muted);font-size:.95rem;margin:0}
.rows{margin-top:8px}
.row{display:block;padding:30px 4px;border-bottom:1px solid var(--line);color:var(--text)}
.row:hover .row-t{color:var(--gold)}
.row-k{font-size:.74rem;letter-spacing:.18em;text-transform:uppercase;color:var(--faint);margin-bottom:8px}
.row-t{font-size:1.3rem;font-weight:400;line-height:1.3;transition:color .15s}
.row-d{color:var(--muted);margin-top:8px;font-size:.98rem;max-width:760px}

/* Article body */
.article-head{padding:76px 0 40px}
.article-head .lead{margin-top:16px}
.meta{color:var(--faint);font-size:.88rem;margin-top:18px}
.body{padding:14px 0 80px}
.body p{margin-bottom:1.3em}
.body h2{color:var(--text);font-weight:400;font-size:1.45rem}
.body h3{color:var(--gold)}
.body strong{font-weight:600;color:var(--text)}
.body em{color:var(--muted)}
.body blockquote{border-left:2px solid var(--gold);padding:4px 0 4px 22px;margin:1.6em 0;color:var(--muted)}
.body ul,.body ol{margin:0 0 1.3em 1.3em}
.body li{margin-bottom:.5em}
.body hr{border:0;border-top:1px solid var(--line);margin:2.4em auto;width:38%}
.body img{margin:1.6em 0;background:#fff;padding:10px}
.body table{border-collapse:collapse;margin:1.6em 0;width:100%;font-size:.92rem}
.body td,.body th{border:1px solid var(--line);padding:9px 12px;text-align:left}
.body th{color:var(--gold);font-weight:600}

/* Paper landing */
.paper-grid{display:grid;grid-template-columns:1fr 300px;gap:48px;align-items:start}
.paper-side{background:var(--surface);border:1px solid var(--line);padding:28px;position:sticky;top:90px}
.paper-side .btn{width:100%;text-align:center;margin-top:6px}
.kv{font-size:.88rem;color:var(--muted);margin-bottom:14px}
.kv b{color:var(--text);font-weight:600;display:block;font-size:.74rem;letter-spacing:.16em;text-transform:uppercase;color:var(--faint);margin-bottom:2px}
.cite{background:var(--surface);border-left:2px solid var(--gold);padding:18px 22px;font-size:.88rem;color:var(--muted);margin-top:34px;word-break:break-word}
.cite b{color:var(--gold);font-weight:600;display:block;margin-bottom:6px;font-size:.74rem;letter-spacing:.18em;text-transform:uppercase}

/* Concepts */
.concept{padding:38px 4px;border-bottom:1px solid var(--line)}
.concept h2{margin:0 0 12px;font-size:1.45rem;font-weight:400;color:var(--gold)}
.concept .def{max-width:760px}
.concept .src{font-size:.88rem;color:var(--faint);margin-top:10px}
.concept .src a{color:var(--muted)}
.concept .src a:hover{color:var(--gold)}
.concept:target{background:linear-gradient(90deg,rgba(201,168,76,.06),transparent);border-left:2px solid var(--gold);padding-left:22px}

/* Author block / about */
.author{display:grid;grid-template-columns:220px 1fr;gap:44px;align-items:start}
.author img{width:100%;border:1px solid var(--line)}
.badges{margin-top:26px;padding-top:22px;border-top:1px solid var(--line);color:var(--faint);font-size:.9rem}
.badges b{color:var(--muted);font-weight:400}

/* Books */
.book{display:grid;grid-template-columns:1fr;gap:10px;padding:38px 4px;border-bottom:1px solid var(--line)}
.book h2{margin:0;font-size:1.5rem;font-weight:400}
.book .sub{color:var(--gold);font-size:1rem}
.book p{color:var(--muted);max-width:760px}
.book .btn{margin-top:8px}

/* Subscribe band */
.subscribe{background:var(--surface);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.subscribe .wrap{display:flex;gap:30px;align-items:center;justify-content:space-between;flex-wrap:wrap}
.subscribe h2{margin:0;font-weight:300;font-size:1.5rem}
.subscribe p{margin:6px 0 0;color:var(--muted)}

/* Footer */
footer.site{border-top:1px solid var(--line);padding:44px 0 60px;margin-top:20px}
footer.site .wrap{display:flex;justify-content:space-between;gap:24px;flex-wrap:wrap;color:var(--faint);font-size:.88rem}
footer.site a{color:var(--muted)}
footer.site a:hover{color:var(--gold)}
footer.site nav{display:flex;gap:20px;flex-wrap:wrap}

@media(max-width:820px){
  .paper-grid{grid-template-columns:1fr}
  .paper-side{position:static}
  .author{grid-template-columns:1fr}
  .author img{max-width:260px}
  section{padding:48px 0}
  .hero{padding:64px 0 48px}
}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}

/* Book covers */
.book{grid-template-columns:170px 1fr;gap:34px;align-items:start}
.book .cover{width:170px;border:1px solid var(--line);display:block}
.book .cover:hover{border-color:var(--gold)}
.covers-mini{display:flex;gap:14px;margin-top:22px}
.covers-mini img{height:120px;border:1px solid var(--line);transition:border-color .18s}
.covers-mini a:hover img{border-color:var(--gold)}
@media(max-width:820px){.book{grid-template-columns:120px 1fr;gap:20px}.book .cover{width:120px}}
.book--plain{grid-template-columns:1fr}