:root{
  --ink:#05070A;
  --ink-2:#0A0E14;
  --ink-3:#111823;
  --line:rgba(255,255,255,.10);
  --line-2:rgba(255,255,255,.18);
  --fg:#EAF0F6;
  --fg-dim:#9FAEBE;
  --accent:#39C6EE;
  --accent-deep:#1E9BC4;
  --font-display:'Cabinet Grotesk','Satoshi',system-ui,sans-serif;
  --font-body:'Satoshi',system-ui,-apple-system,sans-serif;
  --wrap:1180px;
  --r:14px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;background:var(--ink);color:var(--fg);
  font-family:var(--font-body);font-size:17px;line-height:1.65;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block;height:auto}
a{color:inherit}
.wrap{width:100%;max-width:var(--wrap);margin:0 auto;padding:0 clamp(20px,5vw,40px)}
.skip{position:absolute;left:-9999px}
.skip:focus{left:16px;top:16px;z-index:99;background:var(--accent);color:#04121a;padding:10px 16px;border-radius:8px}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:4px}

/* typography */
h1,h2,h3{font-family:var(--font-display);font-weight:800;letter-spacing:-.02em;line-height:1.08;margin:0}
h1{font-size:clamp(38px,6.2vw,74px);text-transform:uppercase;letter-spacing:-.015em}
h2{font-size:clamp(27px,3.3vw,40px);line-height:1.14;letter-spacing:-.015em}
h3{font-size:19px;font-weight:700;letter-spacing:-.01em}
p{margin:0 0 1.05em}
.kicker{font-size:12px;letter-spacing:.16em;text-transform:uppercase;color:var(--fg-dim);font-weight:700;margin:0 0 14px}
.kicker.accent{color:var(--accent)}
.eyebrow{font-size:12px;letter-spacing:.14em;text-transform:uppercase;color:var(--accent);font-weight:700;margin:0 0 18px}

/* buttons */
.btn{
  display:inline-block;background:var(--accent);color:#03141c;text-decoration:none;
  font-weight:700;font-size:15px;padding:13px 26px;border-radius:999px;
  transition:transform .18s ease,background .18s ease,box-shadow .18s ease;
  box-shadow:0 8px 28px -14px rgba(57,198,238,.7);
}
.btn:hover{background:#5BD4F5;transform:translateY(-2px)}
.btn-ghost{background:transparent;color:var(--fg);border:1px solid var(--line-2);box-shadow:none}
.btn-ghost:hover{background:rgba(255,255,255,.06);border-color:var(--accent);color:var(--fg)}
.btn-sm{padding:9px 18px;font-size:14px}
.btn-full{display:block;text-align:center}

/* nav */
.nav{position:sticky;top:0;z-index:50;backdrop-filter:blur(12px);background:rgba(5,7,10,.62);border-bottom:1px solid transparent;transition:border-color .2s ease,background .2s ease}
.nav.is-stuck{border-bottom-color:var(--line);background:rgba(5,7,10,.88)}
.nav-inner{display:flex;align-items:center;gap:24px;min-height:66px}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--accent);flex:0 0 auto}
.mark{width:26px;height:26px}
.brand-txt{font-family:var(--font-display);font-weight:800;font-size:15px;letter-spacing:.01em;color:var(--fg)}
.links{display:flex;gap:22px;margin-left:auto;flex-wrap:wrap}
.links a{font-size:14px;text-decoration:none;color:var(--fg-dim);transition:color .16s ease}
.links a:hover{color:var(--fg)}

/* hero */
.hero{position:relative;overflow:hidden;padding:clamp(56px,8vw,104px) 0 clamp(56px,7vw,96px)}
.hero-bg{position:absolute;inset:0;
  background:
    radial-gradient(900px 520px at 78% 18%,rgba(57,198,238,.20),transparent 68%),
    radial-gradient(700px 480px at 8% 78%,rgba(30,155,196,.14),transparent 70%),
    linear-gradient(180deg,#070B11 0%,#05070A 100%);
}
.hero-bg::after{content:"";position:absolute;inset:0;opacity:.35;
  background-image:linear-gradient(rgba(255,255,255,.035) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.035) 1px,transparent 1px);
  background-size:64px 64px;mask-image:radial-gradient(70% 60% at 50% 40%,#000,transparent)}
.hero-grid{position:relative;display:grid;grid-template-columns:1.05fr .95fr;gap:clamp(28px,5vw,64px);align-items:center}
.sub{font-family:var(--font-display);font-weight:700;font-size:clamp(18px,2.1vw,24px);color:var(--accent);margin:14px 0 20px}
.lede{font-size:18px;color:var(--fg);max-width:44ch;margin-bottom:28px}
.cta-row{display:flex;gap:14px;flex-wrap:wrap;margin-bottom:22px}
.byline{font-size:14px;color:var(--fg-dim);margin:0}
.hero-book img{filter:drop-shadow(0 40px 60px rgba(0,0,0,.65));border-radius:6px}

/* band quote */
.band{border-block:1px solid var(--line);background:var(--ink-2)}
.pull{margin:0;padding:clamp(34px,5vw,56px) 0;text-align:center}
.pull p{font-family:var(--font-display);font-weight:700;font-size:clamp(20px,2.6vw,30px);line-height:1.3;margin:0 auto 14px;max-width:24ch;color:var(--fg)}
.pull cite{font-style:normal;font-size:14px;color:var(--fg-dim)}

/* sections */
.sec{padding:clamp(60px,8vw,110px) 0}
.sec.tight{padding-top:0}
.sec-h{margin-bottom:34px}
.two-col{display:grid;grid-template-columns:.85fr 1.15fr;gap:clamp(28px,5vw,64px);align-items:start}
.col-head h2{max-width:22ch}
.prose p{color:#C6D2DE}
.prose p:last-child{margin-bottom:0}

.cards-3{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;margin-top:clamp(40px,5vw,64px)}
.card{background:var(--ink-2);border:1px solid var(--line);border-radius:var(--r);padding:28px 26px 26px;transition:border-color .2s ease,transform .2s ease}
.card:hover{border-color:var(--line-2);transform:translateY(-3px)}
.card .num{font-family:var(--font-display);font-weight:800;font-size:13px;letter-spacing:.1em;color:var(--accent)}
.card h3{margin:12px 0 10px}
.card p{font-size:15.5px;color:var(--fg-dim);margin:0}

/* frontier */
.frontier{position:relative;padding:clamp(64px,8vw,110px) 0;background:
  radial-gradient(700px 420px at 15% 0%,rgba(57,198,238,.16),transparent 70%),
  linear-gradient(180deg,#070C12,#060A0F);
  border-block:1px solid var(--line)}
.frontier-h{max-width:20ch;margin-bottom:18px}
.frontier-lede{max-width:62ch;color:#C6D2DE;font-size:18px;margin-bottom:clamp(34px,4vw,52px)}
.frontier-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:20px}
.fcard{background:rgba(255,255,255,.035);border:1px solid var(--line);border-left:2px solid var(--accent);border-radius:12px;padding:26px}
.fcard h3{margin-bottom:9px;color:var(--fg)}
.fcard p{margin:0;font-size:15.5px;color:var(--fg-dim)}
.fquote{margin:clamp(34px,4vw,52px) 0 0;padding-left:22px;border-left:2px solid var(--line-2);max-width:62ch}
.fquote p{font-family:var(--font-display);font-weight:700;font-size:clamp(18px,2vw,22px);line-height:1.35;margin-bottom:10px}
.fquote cite{font-style:normal;font-size:14px;color:var(--fg-dim)}

/* praise */
.praise-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:20px}
.praise-grid blockquote{margin:0;background:var(--ink-2);border:1px solid var(--line);border-radius:var(--r);padding:28px}
.praise-grid p{font-size:16px;color:#C6D2DE;margin-bottom:16px}
.praise-grid cite{font-style:normal;display:block;font-weight:700;font-size:15px;color:var(--fg)}
.praise-grid cite span{display:block;font-weight:400;font-size:13.5px;color:var(--fg-dim);margin-top:4px}

/* who */
.who{margin:0;padding:0;list-style:none;display:grid;gap:14px}
.who li{position:relative;padding-left:26px;font-size:16.5px;color:#C6D2DE}
.who li::before{content:"";position:absolute;left:0;top:11px;width:10px;height:10px;border-radius:50%;border:2px solid var(--accent)}
.who strong{color:var(--fg)}

/* author */
.author{padding:clamp(60px,8vw,104px) 0;background:var(--ink-2);border-block:1px solid var(--line)}
.author-grid{display:grid;grid-template-columns:260px 1fr;gap:clamp(28px,5vw,58px);align-items:start}
.portrait{margin:0}
.portrait img{width:100%;border-radius:var(--r);border:1px solid var(--line-2)}
.author p{color:#C6D2DE}
.author p:last-child{margin-bottom:0}

/* editions */
.editions{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.edition{background:var(--ink-2);border:1px solid var(--line);border-radius:var(--r);padding:24px;text-align:center;transition:border-color .2s ease,transform .2s ease}
.edition:hover{border-color:var(--line-2);transform:translateY(-3px)}
.edition img{height:200px;width:auto;margin:0 auto 20px;object-fit:contain;filter:drop-shadow(0 18px 26px rgba(0,0,0,.6))}
.edition h3{margin-bottom:6px}
.isbn{font-size:13px;color:var(--fg-dim);margin-bottom:18px}
.note{margin:26px 0 0;font-size:13.5px;color:var(--fg-dim);text-align:center}

/* footer */
.foot{border-top:1px solid var(--line);padding:38px 0;background:var(--ink)}
.foot-inner{display:flex;justify-content:space-between;gap:24px;flex-wrap:wrap;align-items:center}
.foot-brand{font-family:var(--font-display);font-weight:800;font-size:15px;margin:0 0 6px}
.foot-sm{font-size:13px;color:var(--fg-dim);margin:0}
.foot-links{display:flex;gap:20px;flex-wrap:wrap}
.foot-links a{font-size:13.5px;color:var(--fg-dim);text-decoration:none}
.foot-links a:hover{color:var(--fg)}

/* reveal */
.reveal{opacity:0;transform:translateY(14px);transition:opacity .6s ease,transform .6s ease}
.reveal.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){.reveal{opacity:1;transform:none;transition:none}html{scroll-behavior:auto}}

/* responsive */
@media (max-width:1000px){
  .links{display:none}
  .hero-grid,.two-col,.author-grid{grid-template-columns:1fr}
  .hero-book{order:-1;max-width:520px}
  .cards-3,.editions{grid-template-columns:1fr}
  .frontier-grid,.praise-grid{grid-template-columns:1fr}
  .author-grid .portrait{max-width:220px}
}
@media (max-width:560px){
  body{font-size:16px}
  .lede,.frontier-lede{font-size:17px}
  .cta-row .btn{width:100%;text-align:center}
}

/* cover panels — light wells so the product photography reads as intentional */
.hero-book{
  max-width:600px;margin-left:auto;padding:26px 22px;border-radius:18px;
  background:linear-gradient(165deg,#FFFFFF 0%,#EDF2F7 100%);
  border:1px solid rgba(255,255,255,.22);
  box-shadow:0 40px 80px -40px rgba(0,0,0,.9),0 0 0 1px rgba(57,198,238,.16);
}
.hero-book img{filter:none;border-radius:0;width:100%}
.edition .well{
  border-radius:12px;padding:18px;margin-bottom:20px;
  background:linear-gradient(165deg,#FFFFFF 0%,#EDF2F7 100%);
  display:flex;align-items:center;justify-content:center;height:236px;
}
.edition img{max-height:200px;width:auto;margin:0;filter:none}

/* ---- book figures (Figure E.1 / Table I.1) ---- */
.frontier-split{display:grid;grid-template-columns:.92fr 1.08fr;gap:clamp(26px,4vw,48px);align-items:start}
.frontier-split .frontier-grid{grid-template-columns:1fr;gap:18px}
.fig{margin:0}
.fig-well{
  background:linear-gradient(165deg,#FFFFFF 0%,#EEF3F8 100%);
  border-radius:16px;padding:16px;border:1px solid rgba(255,255,255,.2);
  box-shadow:0 34px 70px -38px rgba(0,0,0,.9),0 0 0 1px rgba(57,198,238,.14);
}
.fig-well a{display:block;transition:transform .25s ease}
.fig-well a:hover{transform:scale(1.012)}
.fig-well img{width:100%;border-radius:6px}
.fig figcaption{margin-top:14px;font-size:13.5px;line-height:1.55;color:var(--fg-dim);max-width:52ch}
.fig-tag{display:block;font-size:11.5px;letter-spacing:.14em;text-transform:uppercase;font-weight:700;color:var(--accent);margin-bottom:6px}

.compare{padding:clamp(60px,8vw,104px) 0;background:var(--ink-2);border-block:1px solid var(--line)}
.compare-grid{display:grid;grid-template-columns:1fr .9fr;gap:clamp(30px,5vw,60px);align-items:center}
.compare-grid h2{max-width:24ch;margin-bottom:20px}
.compare-lede{color:#C6D2DE;max-width:52ch}
.compare .btn-ghost{margin-top:10px}
.compare .fig-well{max-width:520px;margin-left:auto}
.compare figcaption{margin-left:auto;text-align:right;max-width:520px}

@media (max-width:1000px){
  .frontier-split,.compare-grid{grid-template-columns:1fr}
  .frontier-split .frontier-grid{grid-template-columns:1fr}
  .fig-well{max-width:560px;margin-inline:auto}
  .compare .fig-well{margin-inline:auto}
  .compare figcaption{text-align:left;margin-inline:auto}
}

/* ---- editions: badges + disabled buttons ---- */
.edition{position:relative}
.badge{
  position:absolute;top:14px;left:14px;font-size:11px;letter-spacing:.1em;text-transform:uppercase;
  font-weight:700;padding:5px 10px;border-radius:999px;background:var(--accent);color:#03141c;z-index:2;
}
.badge-soon{background:rgba(255,255,255,.10);color:var(--fg-dim);border:1px solid var(--line-2)}
.edition.featured{border-color:rgba(57,198,238,.45);box-shadow:0 0 0 1px rgba(57,198,238,.18)}
.btn-disabled{
  background:rgba(255,255,255,.06);color:var(--fg-dim);box-shadow:none;
  border:1px solid var(--line-2);cursor:not-allowed;pointer-events:none;
}

/* ---- mailing list ---- */
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.signup{padding:clamp(48px,6vw,76px) 0;background:
  radial-gradient(600px 300px at 80% 20%,rgba(57,198,238,.13),transparent 70%),var(--ink-2);
  border-top:1px solid var(--line)}
.signup-inner{display:grid;grid-template-columns:1.05fr .95fr;gap:clamp(26px,4vw,52px);align-items:center}
.signup-copy h2{font-size:clamp(23px,2.5vw,31px);margin-bottom:12px;max-width:26ch}
.signup-copy p{color:var(--fg-dim);font-size:15.5px;max-width:48ch;margin:0}
.signup-form{display:flex;gap:12px;flex-wrap:wrap;align-items:center}
.signup-form input{
  flex:1 1 240px;min-width:0;background:rgba(255,255,255,.05);border:1px solid var(--line-2);
  border-radius:999px;padding:13px 20px;color:var(--fg);font:inherit;font-size:15px;
}
.signup-form input::placeholder{color:#7C8B9C}
.signup-form input:focus{outline:none;border-color:var(--accent);background:rgba(57,198,238,.07)}
.signup-form input:disabled{opacity:.6}
.signup-form button{border:0;cursor:pointer;font-family:inherit}
.signup-form button:disabled{opacity:.55;cursor:default}
.signup-msg{flex:1 1 100%;margin:2px 0 0;font-size:13.5px;min-height:1.2em}
.signup-msg.ok{color:var(--accent)}
.signup-msg.err{color:#FF9B8A}
@media (max-width:1000px){.signup-inner{grid-template-columns:1fr}}

/* badge legibility + spacing */
.edition{padding-top:56px}
.badge{top:18px;left:50%;transform:translateX(-50%);background:var(--accent);color:#03141c;white-space:nowrap}
.badge-soon{background:#1A222D;color:#AFC0D0;border:1px solid var(--line-2)}

.signup-msg a{color:var(--accent)}
.foot-sm a{color:var(--fg-dim);text-decoration:none;border-bottom:1px solid var(--line-2)}
.foot-sm a:hover{color:var(--accent);border-color:var(--accent)}