/* ==========================================================================
   Inner — Books (shared visual system for the book pages)

   One grammar, many covers. The structure below is book-agnostic: a hero that
   holds the cover, an editorial reading column, a vertical I–V sequence, a
   quiet closing, a ghost-pill CTA, and the standard footer. A book supplies
   only its atmosphere: a handful of custom properties on <html>.

     <html class="books books--auditory-ascension">
     <body class="book">

   Atmosphere should read as light escaping from the cover, not as a new
   site-wide brand colour: deep midnight / near-black dominates, the accent is
   used for hairlines, numerals and one closing line, and Inner violet stays
   for secondary interactive states.

   The canvas is a genuine full-document gradient on <body> (scroll-attached,
   never `fixed`), over an <html> floor colour, so it renders identically in
   normal scrolling, tall or full-page captures, print and mobile browsers.

   Depends on tokens.css, fonts.css, base.css, shell.css. Does not alter any
   shared selector outside `.books` / `.book`.
   ========================================================================== */

/* ---------- Atmosphere (per-book custom properties) ---------- */

html.books {
  /* canvas: four near-continuous tones, deepest at the floor */
  --book-field-0: #0a0b17;
  --book-field-1: #09080f;
  --book-field-2: #07060b;
  --book-field-3: #050407;
  --book-floor: var(--book-field-3);

  /* light escaping from the cover (rgb triplet, composed with alpha at use) */
  --book-accent: 217, 165, 102;
  --book-glow-rgb: var(--book-accent); /* the glow behind the cover may differ from the line accent */
  --book-glow: 0.12;
  --book-line: 0.2;

  /* restrained Inner violet: secondary interactive states only */
  --book-violet: 161, 140, 255;

  /* type colours */
  --book-ink-strong: #f6f3ee;
  --book-ink: rgba(238, 235, 230, 0.88);
  --book-ink-soft: rgba(214, 210, 204, 0.74);

  background-color: var(--book-floor);
}

/* Auditory Ascension: ring-and-door amber on warm black */
html.books--auditory-ascension {
  --book-field-0: #0a0b17;
  --book-field-1: #09080f;
  --book-field-2: #07060b;
  --book-field-3: #050407;
  --book-accent: 217, 165, 102;
  --book-glow: 0.12;
}

/* ---------- Canvas and base ---------- */

body.book {
  margin: 0;
  min-height: 100vh;
  background-color: var(--book-floor);
  background-image: linear-gradient(
    180deg,
    var(--book-field-0) 0%,
    var(--book-field-1) 24%,
    var(--book-field-2) 60%,
    var(--book-field-3) 100%
  );
  background-repeat: no-repeat;
  background-size: 100% 100%;
  color: var(--book-ink);
  font-family: var(--font-body);
  font-weight: 300;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.book .topbar a,
.book .brand-link {
  font-family: var(--font-heading);
  font-weight: 600;
  letter-spacing: 0.03em;
}

:where(.book) h1,
:where(.book) h2,
:where(.book) h3,
:where(.book) h4,
:where(.book) p,
:where(.book) ol {
  margin: 0;
  padding: 0;
}

.book-main {
  display: block;
  overflow-x: clip;
  padding-top: calc(var(--topbar-height, 58px) + clamp(40px, 8vh, 88px));
}

@media (max-width: 560px) {
  :root { --topbar-height: 64px; }
}

/* ---------- Hero: the cover is the object ---------- */

.book-hero {
  position: relative;
  isolation: isolate;
  padding: 0 22px clamp(36px, 7vh, 72px) 22px;
  text-align: center;
}

/* a very faint warm light behind the cover; no imagery */
.book-hero::before {
  content: '';
  position: absolute;
  z-index: -1;
  top: -40px;
  left: 50%;
  width: min(1000px, 130vw);
  height: 820px;
  transform: translateX(-50%);
  background: radial-gradient(
    ellipse 40% 44% at 50% 36%,
    rgba(var(--book-glow-rgb), var(--book-glow)) 0%,
    rgba(var(--book-glow-rgb), calc(var(--book-glow) * 0.34)) 46%,
    transparent 74%
  );
  pointer-events: none;
}

.book-cover {
  display: block;
  width: clamp(190px, 21vw, 270px);
  height: auto;
  aspect-ratio: 25 / 37;
  margin: 0 auto;
  border-radius: 4px;
  background: #0b0a0e;
  box-shadow:
    0 24px 64px rgba(0, 0, 0, 0.7),
    0 0 90px rgba(var(--book-glow-rgb), calc(var(--book-glow) * 0.8));
}

.book-kicker {
  margin-top: 40px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.72rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(214, 210, 204, 0.78);
}

.book-title {
  margin-top: 16px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: clamp(2.4rem, 6vw, 3.9rem);
  line-height: 1.05;
  letter-spacing: 0.005em;
  color: #fff;
  text-wrap: balance;
}

.book-subtitle {
  margin-top: 12px;
  font-weight: 300;
  font-style: italic;
  font-size: 1rem;
  letter-spacing: 0.02em;
  color: rgba(var(--book-accent), 0.9);
}

.book-lede {
  max-width: 34rem;
  margin: 26px auto 0 auto;
  font-size: 1.125rem;
  line-height: 1.72;
  color: var(--book-ink);
  text-wrap: pretty;
}

.book-actions {
  margin-top: 34px;
  display: flex;
  justify-content: center;
}

/* ---------- Button: ghost pill, the site's grammar ---------- */

.book-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  min-width: 176px;
  padding: 11px 28px;
  box-sizing: border-box;
  border: 1px solid rgba(var(--book-accent), 0.5);
  border-radius: 999px;
  background: rgba(var(--book-accent), 0.05);
  color: var(--book-ink-strong);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.78rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  text-decoration: none;
  cursor: pointer;
  transition: border-color 0.3s ease, color 0.3s ease, background-color 0.3s ease;
}
.book-btn:hover {
  border-color: rgba(var(--book-accent), 0.85);
  background: rgba(var(--book-accent), 0.1);
  color: #fff;
}

/* ---------- Sections ---------- */

.book-section {
  max-width: 46rem;
  margin: 0 auto;
  padding: clamp(72px, 12vh, 128px) 22px 0 22px;
}

.book-label {
  text-align: center;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.72rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(214, 210, 204, 0.78);
}

.book-h2 {
  margin-top: 18px;
  text-align: center;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: clamp(1.7rem, 3.6vw, 2.3rem);
  line-height: 1.15;
  color: #fff;
  text-wrap: balance;
}

.book-intro {
  max-width: 34rem;
  margin: 20px auto 0 auto;
  text-align: center;
  font-size: 1.0625rem;
  line-height: 1.7;
  color: var(--book-ink-soft);
  text-wrap: pretty;
}

/* ---------- Editorial reading column ---------- */

.book-prose {
  max-width: 36rem;
  margin: clamp(36px, 6vh, 56px) auto 0 auto;
  text-align: left;
}
.book-prose p {
  margin-top: 1.3em;
  font-size: 1.125rem;
  line-height: 1.8;
  color: var(--book-ink);
  text-wrap: pretty;
}
.book-prose p:first-child { margin-top: 0; }

/* the one sentence the page leans on: larger, with a thin amber rule */
.book-prose p.book-emphasis {
  margin: 1.9em 0;
  padding: 2px 0 2px 22px;
  border-left: 1px solid rgba(var(--book-accent), 0.6);
  font-size: 1.34rem;
  line-height: 1.5;
  color: var(--book-ink-strong);
}

/* the page's strongest, still restrained, warm accent */
.book-prose p.book-final-line {
  margin-top: 2em;
  font-style: italic;
  font-size: 1.3rem;
  line-height: 1.6;
  color: rgb(236, 192, 138);
}

/* ---------- Vertical I–V sequence (no cards) ---------- */

.book-sequence {
  list-style: none;
  max-width: 44rem;
  margin: clamp(40px, 7vh, 64px) auto 0 auto;
}
.book-sequence-item {
  display: grid;
  grid-template-columns: 7.5rem minmax(0, 1fr);
  column-gap: 32px;
  padding: 34px 0 38px 0;
  border-top: 1px solid rgba(var(--book-accent), var(--book-line));
}
.book-sequence-item:last-child {
  border-bottom: 1px solid rgba(var(--book-accent), var(--book-line));
}

.book-numeral {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 4px;
  padding-top: 4px;
}
.book-numeral-word {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.66rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--book-ink-soft);
}
.book-numeral-roman {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 1.9rem;
  line-height: 1;
  color: rgba(var(--book-accent), 0.92);
}

.book-sequence-title {
  text-align: left;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 1.25rem;
  line-height: 1.3;
  color: #fff;
}
.book-sequence-text {
  margin-top: 12px;
  font-size: 1.0625rem;
  line-height: 1.75;
  color: var(--book-ink);
  text-wrap: pretty;
}

/* ---------- Closing call ---------- */

.book-cta {
  text-align: center;
  padding-bottom: 0;
}
.book-cta-title {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: clamp(1.6rem, 3.2vw, 2.1rem);
  line-height: 1.15;
  color: #fff;
}
.book-cta-sub {
  margin-top: 10px;
  font-style: italic;
  font-size: 0.98rem;
  color: rgba(var(--book-accent), 0.9);
}
.book-cta .book-actions { margin-top: 30px; }

/* ---------- Link and modal (scoped to the book pages) ---------- */

.book .modal-backdrop {
  background: rgba(4, 4, 8, 0.84);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}
.book .modal-card {
  background: #0b0a10;
  border: 1px solid rgba(var(--book-accent), 0.24);
  border-radius: 14px;
  box-shadow: 0 28px 70px rgba(0, 0, 0, 0.6);
}
.book .modal-book-title {
  font-weight: 600;
  color: #fff;
}
.book .modal-book-sub {
  color: rgba(var(--book-accent), 0.9);
}
.book .modal-retailer-btn {
  border-radius: 999px;
  border: 1px solid rgba(var(--book-accent), 0.5);
  background: rgba(var(--book-accent), 0.05);
  color: var(--book-ink-strong);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.78rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
.book .modal-retailer-btn:hover {
  border-color: rgba(var(--book-accent), 0.85);
  background: rgba(var(--book-accent), 0.1);
  box-shadow: none;
  transform: none;
}
.book .modal-coming-soon {
  color: rgba(214, 210, 204, 0.66) !important;
}

/* ---------- Footer on the book pages ---------- */

.book .site-footer {
  max-width: 880px;
  margin: 0 auto;
  padding: clamp(88px, 14vh, 140px) 24px 52px 24px;
}

/* ---------- Responsive ---------- */

@media (max-width: 720px) {
  .book-prose p { font-size: 1.0625rem; }
  .book-prose p.book-emphasis { font-size: 1.22rem; }
  .book-prose p.book-final-line { font-size: 1.2rem; }
  .book-lede { font-size: 1.0625rem; }
  .book-sequence-item {
    grid-template-columns: minmax(0, 1fr);
    row-gap: 12px;
    padding: 28px 0 32px 0;
  }
  .book-numeral {
    flex-direction: row;
    align-items: baseline;
    gap: 10px;
    padding-top: 0;
  }
  .book-numeral-roman { font-size: 1.5rem; }
  .book-sequence-text { margin-top: 8px; }
}
@media (max-width: 380px) {
  .book-btn { min-width: 0; width: 100%; }
}

/* ---------- Reduced motion ---------- */

@media (prefers-reduced-motion: reduce) {
  .book-btn { transition: none; }
}


/* ==========================================================================
   Additive components (first used by Guardians)
   ========================================================================== */

/* Guardians: midnight / sapphire atmosphere with gold from the cover */
html.books--guardians {
  --book-field-0: #070a14;
  --book-field-1: #06080f;
  --book-field-2: #05060b;
  --book-field-3: #040408;
  --book-accent: 239, 176, 107;
  --book-glow-rgb: 136, 202, 254;
  --book-glow: 0.13;
  --book-ink-strong: #f3f5ff;
  --book-ink: rgba(232, 236, 248, 0.88);
  --book-ink-soft: rgba(206, 212, 230, 0.76);
}

/* a quiet footnote: availability, rest-first, framework status */
.book-note {
  max-width: 34rem;
  margin: 22px auto 0 auto;
  text-align: center;
  font-size: 0.92rem;
  line-height: 1.65;
  color: var(--book-ink-soft);
  text-wrap: pretty;
}
.book-note strong {
  font-weight: 500;
  color: var(--book-ink-strong);
}

/* more than one action: wrap, centred */
.book-actions--pair {
  flex-wrap: wrap;
  gap: 14px;
}

/* product / app action: restrained Inner violet, book action stays gold */
.book-btn--secondary {
  border-color: rgba(var(--book-violet), 0.5);
  background: rgba(var(--book-violet), 0.06);
}
.book-btn--secondary:hover {
  border-color: rgba(var(--book-violet), 0.85);
  background: rgba(var(--book-violet), 0.12);
}

/* sequence with a label instead of a numeral (phases, not an order) */
.book-sequence--labels .book-track {
  padding-top: 6px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: rgba(var(--book-accent), 0.92);
}
@media (max-width: 720px) {
  .book-sequence--labels .book-track { padding-top: 0; }
}