/* The Human Factor Series — brand tokens derived from the book covers */
:root{
  --cream:#faf2e7;
  --cream-deep:#f2e9da;
  --ink:#111111;
  --ink-soft:#4a453d;
  --muted:#787064;
  --red:#ba1913;
  --rule:#ddd3c0;
  --measure:34rem;
  --pad:clamp(1.25rem,5vw,3rem);
  --gap:clamp(2.5rem,7vw,5.5rem);
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.001ms!important;animation-iteration-count:1!important;transition-duration:.001ms!important}
}
body{
  margin:0;background:var(--cream);color:var(--ink);
  font-family:"Inter",-apple-system,BlinkMacSystemFont,"Segoe UI",Helvetica,Arial,sans-serif;
  font-size:clamp(1rem,.96rem + .2vw,1.0625rem);line-height:1.65;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;height:auto;display:block}
a{color:inherit}
h1,h2,h3,.display{font-family:"Anton",Impact,"Arial Narrow Bold",sans-serif;font-weight:400;letter-spacing:.005em;line-height:.92;text-transform:uppercase;margin:0}
p{margin:0 0 1.1em}
.wrap{width:min(72rem,100% - var(--pad)*2);margin-inline:auto}
.narrow{max-width:var(--measure)}
.eyebrow{font-size:.75rem;letter-spacing:.18em;text-transform:uppercase;color:var(--muted);font-weight:600;margin:0 0 .9rem}
.rule{height:3px;background:var(--red);border:0;margin:1.5rem 0;width:clamp(3rem,10vw,7rem)}
.skip{position:absolute;left:-9999px}
.skip:focus{left:1rem;top:1rem;z-index:99;background:var(--ink);color:var(--cream);padding:.6rem 1rem}
:focus-visible{outline:3px solid var(--red);outline-offset:3px}

/* header */
.site-head{position:sticky;top:0;z-index:20;background:color-mix(in srgb,var(--cream) 92%,transparent);backdrop-filter:blur(8px);border-bottom:1px solid var(--rule)}
.site-head .wrap{display:flex;align-items:center;justify-content:space-between;gap:1rem;padding-block:.85rem}
.brand{font-family:"Anton",Impact,sans-serif;text-transform:uppercase;font-size:1rem;letter-spacing:.06em;text-decoration:none}
.brand span{color:var(--red)}
.nav{display:flex;gap:clamp(.9rem,3vw,1.75rem);flex-wrap:wrap}
.nav a{font-size:.8rem;letter-spacing:.1em;text-transform:uppercase;font-weight:600;text-decoration:none;color:var(--ink-soft);padding:.25rem 0;border-bottom:2px solid transparent}
.nav a:hover,.nav a[aria-current="page"]{color:var(--ink);border-bottom-color:var(--red)}

/* hero with the signature: cut strings */
.hero{position:relative;overflow:hidden;padding-block:clamp(3rem,9vw,6rem) var(--gap)}
.hero-grid{display:grid;gap:clamp(2rem,5vw,4rem);grid-template-columns:1fr;align-items:center}
@media(min-width:56rem){.hero-grid{grid-template-columns:1.05fr .95fr}}
.hero h1{font-size:clamp(3rem,12vw,7.5rem)}
.hero h1 .red{color:var(--red);display:block}
.hero .lede{font-size:clamp(1.05rem,1rem + .5vw,1.3rem);max-width:32ch;color:var(--ink-soft)}
.strings{position:absolute;inset-block-start:0;inset-inline-end:0;width:min(46%,26rem);height:100%;pointer-events:none;opacity:.9}
@media(max-width:56rem){.strings{display:none}}
.strings line.cord{stroke:var(--ink);stroke-width:2}
.strings line.cut{stroke:var(--red);stroke-width:4;stroke-linecap:round;opacity:0;animation:slash .5s ease forwards}
.strings line.cut:nth-of-type(1){animation-delay:.5s}
.strings line.cut:nth-of-type(2){animation-delay:.68s}
.strings line.cut:nth-of-type(3){animation-delay:.86s}
.strings line.cut:nth-of-type(4){animation-delay:1.04s}
@keyframes slash{from{opacity:0;transform:translateX(-6px)}to{opacity:1;transform:none}}

/* buttons */
.btn{display:inline-block;font-weight:700;font-size:.85rem;letter-spacing:.09em;text-transform:uppercase;text-decoration:none;padding:.95rem 1.6rem;border:2px solid var(--ink);background:var(--ink);color:var(--cream);transition:background .18s,color .18s,transform .18s}
.btn:hover{background:var(--red);border-color:var(--red);transform:translateY(-2px)}
.btn.ghost{background:transparent;color:var(--ink)}
.btn.ghost:hover{background:var(--ink);color:var(--cream);border-color:var(--ink)}
.btn-row{display:flex;flex-wrap:wrap;gap:.75rem;margin-top:1.5rem}

/* sections */
section{padding-block:var(--gap)}
.section-head{margin-bottom:clamp(1.75rem,4vw,3rem)}
.section-head h2{font-size:clamp(1.9rem,5vw,3.1rem)}

/* book showcase */
.book-feature{display:grid;gap:clamp(1.75rem,5vw,3.5rem);grid-template-columns:1fr;align-items:start}
@media(min-width:48rem){.book-feature{grid-template-columns:minmax(0,15rem) 1fr}}
.cover{border:1px solid var(--rule);box-shadow:0 18px 40px -22px rgba(17,17,17,.5)}
.checks{list-style:none;margin:0 0 1.5rem;padding:0}
.checks li{position:relative;padding-left:1.6rem;margin-bottom:.65rem}
.checks li::before{content:"";position:absolute;left:0;top:.62em;width:.55rem;height:.55rem;background:var(--red)}

/* series ladder — numbering is real sequence info */
.ladder{list-style:none;margin:0;padding:0;border-top:1px solid var(--rule)}
.ladder li{border-bottom:1px solid var(--rule)}
.ladder a,.ladder .row{display:grid;grid-template-columns:2.75rem 1fr;gap:1rem;padding:1.35rem 0;text-decoration:none;align-items:baseline}
@media(min-width:48rem){.ladder a,.ladder .row{grid-template-columns:3.5rem 1fr auto;gap:1.5rem}}
.ladder .num{font-family:"Anton",Impact,sans-serif;font-size:1.5rem;color:var(--red);line-height:1}
.ladder h3{font-size:clamp(1.15rem,3vw,1.6rem)}
.ladder p{margin:.35rem 0 0;color:var(--muted);font-size:.95rem;max-width:52ch}
.ladder .status{font-size:.7rem;letter-spacing:.14em;text-transform:uppercase;font-weight:700;color:var(--muted);white-space:nowrap;align-self:center}
.ladder a:hover h3{color:var(--red)}
.ladder .soon{opacity:.62}

/* pull quote */
.pull{border-left:4px solid var(--red);padding-left:clamp(1rem,3vw,2rem);margin:0}
.pull p{font-family:"Anton",Impact,sans-serif;text-transform:uppercase;font-size:clamp(1.4rem,4vw,2.4rem);line-height:1.05;margin:0}

/* faq */
.faq{border-top:1px solid var(--rule)}
.faq details{border-bottom:1px solid var(--rule)}
.faq summary{cursor:pointer;list-style:none;padding:1.15rem 0;font-weight:700;display:flex;justify-content:space-between;gap:1rem;align-items:center}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";font-family:"Anton",sans-serif;color:var(--red);font-size:1.35rem;line-height:1}
.faq details[open] summary::after{content:"–"}
.faq details > div{padding-bottom:1.15rem;max-width:var(--measure);color:var(--ink-soft)}

/* about strip */
.about-grid{display:grid;gap:clamp(1.5rem,4vw,3rem);grid-template-columns:1fr}
@media(min-width:48rem){.about-grid{grid-template-columns:1fr 1.4fr}}

/* footer */
.site-foot{border-top:1px solid var(--rule);padding-block:clamp(2rem,5vw,3.5rem);font-size:.875rem;color:var(--muted)}
.site-foot .wrap{display:flex;flex-wrap:wrap;gap:1rem 2rem;justify-content:space-between;align-items:center}
.site-foot a{text-decoration:none;border-bottom:1px solid var(--rule)}
.site-foot a:hover{color:var(--ink);border-bottom-color:var(--red)}
.disclosure{max-width:46rem;margin-top:1rem;font-size:.8rem;line-height:1.55}

/* ---- SERIES: four books, each with its own identity ---- */
.arc{max-width:52rem;margin-bottom:clamp(2rem,5vw,3.5rem)}
.arc p{font-size:clamp(1.05rem,1rem + .4vw,1.25rem);color:var(--ink-soft)}
.arc strong{color:var(--ink)}

.books{display:grid;gap:1.25rem;grid-template-columns:1fr;list-style:none;margin:0;padding:0}
@media(min-width:40rem){.books{grid-template-columns:repeat(2,1fr)}}
@media(min-width:68rem){.books{grid-template-columns:repeat(4,1fr)}}

.book-card{position:relative;display:flex;flex-direction:column;height:100%;background:var(--cream);
  border:1px solid var(--rule);padding:1.5rem 1.35rem 1.35rem;text-decoration:none;
  transition:transform .2s ease,box-shadow .2s ease,border-color .2s ease}
.book-card::before{content:"";position:absolute;inset-inline:0;inset-block-start:0;height:5px;background:var(--accent)}
a.book-card:hover{transform:translateY(-4px);box-shadow:0 16px 32px -20px rgba(17,17,17,.45);border-color:var(--accent)}
.book-card .mark{width:44px;height:44px;margin-bottom:1rem;color:var(--accent);flex:none}
.book-card .n{font-family:"Anton",Impact,sans-serif;font-size:.8rem;letter-spacing:.14em;color:var(--accent);margin-bottom:.35rem}
.book-card h3{font-size:1.3rem;line-height:1;margin-bottom:.6rem}
.book-card .promise{font-size:.95rem;color:var(--ink-soft);margin:0 0 1rem;flex:1}
.book-card .teaches{font-size:.8rem;color:var(--muted);margin:0 0 1rem;line-height:1.5}
.book-card .tag{font-size:.68rem;letter-spacing:.14em;text-transform:uppercase;font-weight:700;
  color:var(--accent);border:1.5px solid var(--accent);padding:.3rem .6rem;align-self:flex-start}
.book-card.is-live .tag{background:var(--accent);color:var(--cream)}
.book-card.is-next{border-style:dashed}

@media(min-width:68rem){section .books:has(li:nth-child(3):last-child){grid-template-columns:repeat(3,1fr)}}