:root{
  --page:#181c1f; --bar:#333333; --navy:#012458; --panel:#20262b; --rule:#2d343a;
  --text:#e9edf0; --dim:#9aa4ad; --steel:#c2c6ca; --steel-dk:#7f868c;
  --blue:#0793e6; --blue-lt:#4fb2ee; --blue-hover:#2aa3eb;
  --display:'Inter',system-ui,-apple-system,'Segoe UI',Arial,sans-serif;
  --body:'Source Sans 3','Segoe UI',system-ui,Arial,sans-serif;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:env(safe-area-inset-top,0px)}
body{margin:0;background:var(--page);color:var(--text);font-family:var(--body);font-size:19px;line-height:1.6;min-height:100vh;
  padding-bottom:env(safe-area-inset-bottom,0px)}
a{color:var(--blue-lt)}
a:focus-visible,button:focus-visible{outline:3px solid var(--blue);outline-offset:3px}
img{max-width:100%;display:block}

/* header bar, same charcoal as learnscada.com */
.masthead{background:var(--bar);padding-top:env(safe-area-inset-top,0px)}
.masthead-in{max-width:1180px;margin:0 auto;padding:.7rem 1.5rem;display:flex;justify-content:space-between;align-items:center;gap:1rem;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:.9rem;text-decoration:none;color:var(--text)}
.brand img{height:52px;width:auto;background:var(--page);padding:6px 8px;border-radius:3px}
.brand span{font-family:var(--display);font-size:.78rem;font-weight:600;letter-spacing:.22em;text-transform:uppercase;color:var(--steel)}
.topnav{display:flex;gap:1.8rem}
.topnav a{font-family:var(--display);font-size:.74rem;font-weight:500;letter-spacing:.2em;text-transform:uppercase;color:#cfd4d8;text-decoration:none}
.topnav a:hover{color:#fff}

/* navy hero band */
.hero{background:var(--navy);border-bottom:1px solid #0b3a7a}
.hero-in{max-width:1180px;margin:0 auto;padding:2.8rem 1.5rem 2.4rem}
.hero h1{font-family:var(--display);font-weight:700;font-size:clamp(2rem,5vw,3.2rem);line-height:1.1;margin:0 0 .8rem;color:#fff;max-width:42rem}
.hero p{margin:0;color:#b8c7dc;font-size:1.1rem;max-width:38rem}

.wrap,main.detail{max-width:1180px;margin:0 auto;padding:0 1.5rem 4rem}

.filters{display:flex;flex-wrap:wrap;gap:.55rem;padding:1.8rem 0 1.8rem;border-bottom:1px solid var(--rule);margin-bottom:2.5rem}
.chip{font-family:var(--display);font-size:.72rem;font-weight:500;letter-spacing:.14em;text-transform:uppercase;color:#cfd4d8;
  background:transparent;border:1px solid #4b545c;border-radius:3px;padding:.5rem .95rem;cursor:pointer}
.chip:hover{border-color:var(--blue);color:#fff}
.chip[aria-pressed="true"]{background:var(--blue);border-color:var(--blue);color:#fff}

/* the shelf: covers stand on a steel rail */
.shelf{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(170px,1fr));gap:2.8rem 2rem}
.book[hidden]{display:none}
.book a{display:flex;flex-direction:column;text-decoration:none;color:var(--text);height:100%}
.cover-wrap{position:relative;display:block}
.book .cover{aspect-ratio:2/3;width:100%;object-fit:contain;background:#0f1215;border-radius:2px 4px 4px 2px;
  box-shadow:0 14px 18px -10px rgba(0,0,0,.8);transform-origin:bottom center;transition:transform .25s ease}
.book a::after{content:"";display:block;height:6px;margin:-1px -.5rem 0;order:1;
  background:var(--steel);border-bottom:2px solid var(--steel-dk);box-shadow:0 6px 10px rgba(0,0,0,.45)}
.book .book-title{order:2;font-family:var(--display);font-weight:600;font-size:.98rem;line-height:1.3;margin-top:.9rem}
.book a:hover .cover,.book a:focus-visible .cover,.book a:hover .cover-blank{transform:translateY(-6px)}
.book a:hover .book-title{color:var(--blue-lt)}

.cover-blank{aspect-ratio:2/3;width:100%;background:var(--panel);border:1px solid #3a434b;
  display:flex;align-items:center;justify-content:center;padding:1rem;text-align:center}
.cover-blank span{font-family:var(--display);font-weight:700;font-size:1.1rem;color:var(--blue-lt);line-height:1.25}

.detail{padding-top:1rem}
.back{display:inline-block;margin:1.4rem 0 2rem;font-size:1rem}
.back::before{content:"\2039\00a0"}
.detail-grid{display:grid;grid-template-columns:minmax(220px,340px) 1fr;gap:3.5rem;align-items:start}
.detail-cover{position:sticky;top:1.5rem}
.cover-lg{width:100%;border-radius:2px 5px 5px 2px;box-shadow:0 24px 30px -14px rgba(0,0,0,.85)}
.detail-text{max-width:40rem}
.detail h1{font-family:var(--display);font-weight:700;font-size:clamp(1.9rem,4.2vw,2.8rem);line-height:1.12;margin:0 0 .8rem}
.subtitle{font-family:var(--body);font-weight:400;font-size:1.25rem;line-height:1.4;color:var(--blue-lt);margin:0 0 1rem}
.byline{color:var(--dim);margin:0 0 2rem}
.buy{display:flex;flex-wrap:wrap;gap:.8rem;margin-bottom:2.5rem}
.btn{font-family:var(--display);font-size:.95rem;padding:.75rem 1.35rem;border:1px solid var(--blue);border-radius:3px;
  text-decoration:none;color:var(--blue-lt);font-weight:600}
.btn:hover{background:rgba(7,147,230,.12);color:#fff}
.btn-primary{background:var(--blue);color:#fff}
.btn-primary:hover{background:var(--blue-hover)}
.blurb p{margin:0 0 1.1rem}
.facts{display:grid;grid-template-columns:max-content 1fr;gap:.4rem 1.5rem;margin:2rem 0 0;padding-top:1.5rem;border-top:1px solid var(--rule);font-size:1rem}
.facts dt{color:var(--dim)}
.facts dd{margin:0}

.foot{max-width:1180px;margin:0 auto;padding:2rem 1.5rem 3rem;border-top:1px solid var(--rule);color:var(--dim);font-size:.95rem;
  display:flex;justify-content:space-between;flex-wrap:wrap;gap:1rem}
.foot p{margin:0}

/* coming soon */
.soon-badge{order:4;align-self:flex-start;margin-top:.45rem;background:var(--blue);color:#fff;font-family:var(--display);font-size:.68rem;
  font-weight:600;letter-spacing:.1em;text-transform:uppercase;padding:.2rem .55rem;border-radius:2px}
.is-soon .cover,.is-soon .cover-blank{filter:saturate(.8) brightness(.85)}
.book-meta{order:3;font-size:.88rem;color:var(--dim);margin-top:.15rem}
.soon{display:inline-block;border:1px dashed var(--blue);color:var(--blue-lt);border-radius:3px;padding:.55rem 1.1rem;margin:0;font-weight:600}

/* series page */
.series-h1{font-family:var(--display);font-weight:700;font-size:clamp(1.9rem,4.2vw,2.8rem);line-height:1.12;margin:0 0 .5rem}
.vols{list-style:none;margin:2rem 0 0;padding:0;display:grid;gap:2rem}
.vol{display:grid;grid-template-columns:120px 1fr;gap:1.5rem;align-items:start;padding-bottom:2rem;border-bottom:1px solid var(--rule)}
.cover-sm{width:100%;aspect-ratio:2/3;object-fit:contain;background:#0f1215;border-radius:2px 4px 4px 2px;box-shadow:0 12px 16px -10px rgba(0,0,0,.85)}
.vol-cover{text-decoration:none;display:block}
.vol-cover .cover-blank span{font-size:.8rem}
.vol h2{font-family:var(--display);font-weight:600;font-size:1.25rem;margin:0 0 .3rem}
.vol h2 a{color:var(--text);text-decoration:none}
.vol h2 a:hover{color:var(--blue-lt)}
.vol .subtitle{font-size:1.02rem;margin:0 0 .9rem}
.buy-compact{margin-bottom:0}
.buy-compact .btn{font-size:.85rem;padding:.5rem .95rem}

@media (max-width:720px){
  body{font-size:18px}
  .brand img{height:44px}
  .brand span{display:none}
  .masthead-in{flex-wrap:nowrap}
  .topnav{gap:1.1rem}
  .shelf{grid-template-columns:repeat(auto-fill,minmax(130px,1fr));gap:2.2rem 1.2rem}
  .detail-grid{grid-template-columns:1fr;gap:2rem}
  .detail-cover{position:static;max-width:260px}
  .vol{grid-template-columns:90px 1fr;gap:1rem}
}
@media (prefers-reduced-motion:reduce){.book .cover{transition:none}}