/* Self-hosted Manrope — latin-ext subset */
@font-face {
  font-family: 'Manrope';
  font-style: normal;
  font-weight: 400 800;
  font-display: swap;
  src: url('../fonts/manrope-latin-ext.woff2') format('woff2');
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
/* Self-hosted Manrope — latin subset */
@font-face {
  font-family: 'Manrope';
  font-style: normal;
  font-weight: 400 800;
  font-display: swap;
  src: url('../fonts/manrope-latin.woff2') format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

:root {
  --void-980: #03060f;
  --void-950: #050813;
  --void-925: #09101d;
  --void-900: #0b1020;
  --void-850: #12192b;
  --void-800: #172033;

  --paper-050: #f7f4ee;
  --paper-075: #f3f4f7;
  --paper-100: #eef3fb;
  --paper-200: #dce5f2;

  --ink-050: #f6fbff;
  --ink-100: #dfe8f6;
  --ink-200: #c8d4e8;
  --ink-300: #a9b8d0;
  --ink-700: #32415b;
  --ink-900: #121a2a;

  --book-1: #8fb6ff;
  --book-2: #b08cff;
  --book-3: #86efff;
  --book-4: #95f3a1;
  --book-5: #ffb24d;
  --book-6: #ff6156;
  --book-7: #f6fbff;

  --gradient-spectral: linear-gradient(135deg,
    #7fb3ff 0%,
    #b28fff 18%,
    #80ebff 38%,
    #8ff0b0 58%,
    #ffbd58 78%,
    #ff6b62 100%);

  --gradient-void:
    radial-gradient(circle at 20% 20%, rgba(127, 179, 255, 0.16), transparent 26%),
    radial-gradient(circle at 80% 30%, rgba(178, 143, 255, 0.14), transparent 22%),
    radial-gradient(circle at 60% 75%, rgba(255, 107, 98, 0.09), transparent 24%),
    linear-gradient(180deg, #060914 0%, #0b1020 55%, #12192b 100%);

  --gradient-paper: linear-gradient(180deg, #f8f6f1 0%, #eef3fb 100%);

  --radius-panel: 32px;
  --radius-card: 24px;
  --radius-pill: 999px;

  --shadow-soft: 0 14px 40px rgba(0, 0, 0, 0.24);
  --shadow-glow: 0 0 0 1px rgba(255,255,255,.05), 0 10px 30px rgba(0,0,0,.25), 0 0 48px rgba(127,179,255,.14);
  --shadow-paper: 0 12px 28px rgba(18, 26, 42, 0.08);

  --max: 1440px;
  --content: 1180px;

  --ease-out: cubic-bezier(.22, 1, .36, 1);
  --transition-fast: 140ms var(--ease-out);
  --transition-base: 240ms var(--ease-out);
  --transition-slow: 420ms var(--ease-out);

  --font-mark: system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-display: "Manrope", system-ui, sans-serif;

  --gradient-glass: linear-gradient(135deg, rgba(255,255,255,.06), rgba(255,255,255,.03));

  --accent: #b28fff;
  --accent-soft: rgba(178, 143, 255, 0.18);
  --hero-cover: linear-gradient(180deg, #16335f, #0b1020);
}

[data-theme="foundations"] { --accent: var(--book-1); --accent-soft: rgba(143,182,255,.22); --hero-cover: linear-gradient(180deg, #16335f, #0b1020); }
[data-theme="holomorphy"] { --accent: var(--book-2); --accent-soft: rgba(176,140,255,.22); --hero-cover: linear-gradient(180deg, #312069, #0b1020); }
[data-theme="spectrum"] { --accent: var(--book-3); --accent-soft: rgba(134,239,255,.22); --hero-cover: linear-gradient(180deg, #0a4a65, #0b1020); }
[data-theme="microcosm"] { --accent: var(--book-4); --accent-soft: rgba(149,243,161,.22); --hero-cover: linear-gradient(180deg, #0f5237, #0b1020); }
[data-theme="macrocosm"] { --accent: var(--book-5); --accent-soft: rgba(255,178,77,.22); --hero-cover: linear-gradient(180deg, #74410d, #0b1020); }
[data-theme="life"] { --accent: var(--book-6); --accent-soft: rgba(255,97,86,.22); --hero-cover: linear-gradient(180deg, #77211d, #0b1020); }
[data-theme="metaphysics"] { --accent: var(--book-7); --accent-soft: rgba(127,179,255,.22); --hero-cover: linear-gradient(180deg, #39456c, #0b1020), var(--gradient-spectral); }

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  font-family: "Manrope", system-ui, sans-serif;
  line-height: 1.5;
  letter-spacing: -0.01em;
  color: var(--ink-050);
  background: var(--gradient-void);
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image: radial-gradient(circle at 1px 1px, rgba(255,255,255,.08) 1px, transparent 0);
  background-size: 28px 28px;
  opacity: .22;
  mask-image: linear-gradient(180deg, rgba(0,0,0,.9), rgba(0,0,0,.15));
}
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }
button,input,textarea,select { font: inherit; }

.container { width: min(calc(100% - 40px), var(--max)); margin: 0 auto; }
.content { width: min(calc(100% - 40px), var(--content)); margin: 0 auto; }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 10px 16px;
  border-radius: var(--radius-pill);
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(255,255,255,.08);
  color: var(--ink-100);
  font-size: 12px;
  letter-spacing: .14em;
  text-transform: uppercase;
  backdrop-filter: blur(20px);
}
.eyebrow::before {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 20px var(--accent);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  backdrop-filter: blur(22px);
  background: linear-gradient(180deg, rgba(3,6,15,.78), rgba(3,6,15,.48));
  border-bottom: 1px solid rgba(255,255,255,.06);
  transition: background var(--transition-base), border-color var(--transition-base);
}
.site-header.is-condensed {
  background: linear-gradient(180deg, rgba(3,6,15,.92), rgba(3,6,15,.74));
  border-bottom-color: rgba(255,255,255,.1);
}
.site-header__inner {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 14px;
  font-weight: 800;
  font-size: 13px;
  letter-spacing: .16em;
}
.brand__text {
  text-transform: uppercase;
}
.brand__mark {
  width: 40px;
  height: 40px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 35%, rgba(255,255,255,.22), rgba(255,255,255,.04));
  border: 1px solid rgba(255,255,255,.08);
  box-shadow: 0 0 32px rgba(127,179,255,.18);
  font-family: var(--font-mark);
  font-size: 22px;
  text-transform: none;
}
.nav-toggle {
  display: none;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  border: 1px solid rgba(255,255,255,.08);
  background: rgba(255,255,255,.04);
  color: white;
}
.site-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: flex-end;
}
.site-nav a {
  padding: 10px 14px;
  border-radius: 999px;
  color: var(--ink-200);
  font-size: 14px;
  transition: background var(--transition-fast), color var(--transition-fast), transform var(--transition-fast);
}
.site-nav a:hover,
.site-nav a[aria-current="page"] {
  background: rgba(255,255,255,.08);
  color: white;
  transform: translateY(-1px);
}

.hero,
.page-hero {
  position: relative;
  overflow: clip;
}
.hero {
  padding: 86px 0 58px;
}
.hero__grid,
.page-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.1fr .9fr;
  gap: 36px;
  align-items: center;
}
.hero__orb {
  position: absolute;
  right: -80px;
  top: -30px;
  width: 560px;
  height: 560px;
  border-radius: 50%;
  background:
    radial-gradient(circle at 50% 50%, rgba(255,255,255,.22), rgba(255,255,255,.05) 18%, transparent 34%),
    radial-gradient(circle at 40% 40%, rgba(127,179,255,.22), transparent 30%),
    radial-gradient(circle at 58% 58%, rgba(178,143,255,.18), transparent 28%),
    radial-gradient(circle at 68% 48%, rgba(255,107,98,.16), transparent 24%);
  filter: blur(8px);
  opacity: .9;
  animation: breathe 8s ease-in-out infinite;
}
.hero__orb::after {
  content: "πρ";
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  font-family: var(--font-mark);
  font-size: clamp(7rem, 12vw, 10rem);
  color: rgba(255,255,255,.92);
  text-shadow: 0 0 60px rgba(127,179,255,.45);
  letter-spacing: -.08em;
}
@keyframes breathe {
  0%,100% { transform: scale(1) translate3d(0,0,0); }
  50% { transform: scale(1.04) translate3d(-8px,6px,0); }
}
.hero__title {
  margin: 20px 0 18px;
  font-size: clamp(3rem, 7vw, 6rem);
  line-height: .92;
  letter-spacing: -.05em;
  text-transform: uppercase;
  max-width: 9ch;
}
.page-hero {
  padding: 72px 0 34px;
}
.page-hero::after {
  content: "";
  position: absolute;
  inset: auto -120px -140px auto;
  width: 420px;
  height: 420px;
  border-radius: 50%;
  background: radial-gradient(circle, var(--accent-soft), transparent 66%);
  filter: blur(2px);
}
.page-hero__panel { position: relative; z-index: 1; padding: 30px; }
.page-hero__title {
  margin: 14px 0 10px;
  font-size: clamp(2.1rem, 4vw, 3.4rem);
  line-height: .94;
  letter-spacing: -.045em;
  text-transform: uppercase;
  max-width: 11ch;
}
.hero__copy,
.page-hero__copy,
.lead {
  margin: 0;
  max-width: 62ch;
  color: var(--ink-200);
  font-size: clamp(1rem, 1.4vw, 1.14rem);
}
.hero__actions,
.actions-row,
.chip-row,
.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.hero-card,
.panel {
  background: rgba(255,255,255,.04);
  border: 1px solid rgba(255,255,255,.08);
  border-radius: var(--radius-panel);
  box-shadow: var(--shadow-glow);
  backdrop-filter: blur(22px);
}
.hero-card { padding: 26px; }
.panel--paper {
  background: var(--gradient-paper);
  border: 1px solid rgba(18,26,42,.08);
  box-shadow: var(--shadow-paper);
  color: var(--ink-900);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 52px;
  padding: 0 22px;
  border-radius: 999px;
  border: 1px solid transparent;
  font-weight: 700;
  font-size: 14px;
  transition: transform var(--transition-fast), box-shadow var(--transition-base), border-color var(--transition-fast), background var(--transition-fast);
}
.button:hover { transform: translateY(-3px); }
.button--primary {
  background: var(--gradient-spectral);
  color: #08101c;
  box-shadow: 0 10px 32px rgba(127,179,255,.18);
}
.button--secondary {
  background: rgba(255,255,255,.04);
  border-color: rgba(255,255,255,.08);
  color: white;
  backdrop-filter: blur(18px);
}
.button--ghost {
  background: transparent;
  border-color: rgba(255,255,255,.08);
  color: var(--ink-100);
}

.section { padding: 30px 0 72px; }
.section__intro {
  margin-bottom: 24px;
  display: flex;
  align-items: end;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 20px;
}
.section__intro h2 {
  margin: 0;
  font-size: clamp(1.8rem, 4vw, 3rem);
  line-height: 1;
  letter-spacing: -.04em;
}
.section__intro p {
  margin: 0;
  color: var(--ink-200);
  max-width: 56ch;
}

.section-grid {
  display: grid;
  gap: 20px;
}
.section-grid--2 { grid-template-columns: repeat(2, minmax(0,1fr)); }
.section-grid--3 { grid-template-columns: repeat(3, minmax(0,1fr)); }

.card,
.resource-item,
.link-item {
  padding: 24px;
  border-radius: var(--radius-card);
  background: rgba(255,255,255,.045);
  border: 1px solid rgba(255,255,255,.08);
  box-shadow: var(--shadow-soft);
  transition: transform var(--transition-fast), box-shadow var(--transition-base), border-color var(--transition-fast);
}
.card:hover,
.resource-item:hover,
.link-item:hover {
  transform: translateY(-4px);
  border-color: rgba(255,255,255,.14);
  box-shadow: var(--shadow-glow);
}
.card h3,
.card h4,
.resource-item h3,
.resource-item h4,
.link-item h3,
.link-item h4 {
  margin: 0 0 10px;
  letter-spacing: -.03em;
}
.card p,
.resource-item p,
.link-item p { margin: 0; color: var(--ink-200); }

.paper-block {
  padding: 22px;
  border-radius: 22px;
  background: var(--gradient-paper);
  color: var(--ink-900);
  box-shadow: var(--shadow-paper);
}
.paper-block h1,
.paper-block h2,
.paper-block h3,
.paper-block h4 { color: var(--ink-900); letter-spacing: -.03em; }
.paper-block p,
.paper-block li {
  font-family: Georgia, "Times New Roman", serif;
  line-height: 1.72;
  color: #1b2538;
}
.paper-block strong { color: var(--ink-900); }

.chip,
.filter-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 34px;
  padding: 0 14px;
  border-radius: var(--radius-pill);
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(255,255,255,.08);
  color: var(--ink-100);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
}
.filter-chip { cursor: pointer; }
.filter-chip.is-active,
.chip--solid {
  background: var(--accent);
  color: #0b1020;
  border-color: transparent;
}

.stat-grid,
.path-grid,
.related-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0,1fr));
  gap: 14px;
}
.stat {
  padding: 18px;
  border-radius: 20px;
  background: rgba(255,255,255,.045);
  border: 1px solid rgba(255,255,255,.08);
}
.stat strong {
  display: block;
  margin-bottom: 8px;
  font-size: .78rem;
  text-transform: uppercase;
  letter-spacing: .12em;
  color: var(--ink-300);
}
.stat span {
  display: block;
  font-size: 1.2rem;
  line-height: 1.15;
  letter-spacing: -.03em;
}

.book-grid {
  display: grid;
  grid-template-columns: repeat(7, minmax(0,1fr));
  gap: 14px;
}
.book-link { display: block; }
.book-link.is-hidden { display: none; }
.book-card {
  position: relative;
  overflow: hidden;
  aspect-ratio: 5 / 8;
  border-radius: 4px;
  padding: 18px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  background:
    radial-gradient(circle at 50% 32%, rgba(255,255,255,.2), transparent 20%),
    linear-gradient(180deg, rgba(255,255,255,.08), rgba(255,255,255,.02)),
    var(--cover, linear-gradient(180deg, #10192d, #0b1020));
  border: 1px solid rgba(255,255,255,.1);
  box-shadow: 0 20px 40px rgba(0,0,0,.22), inset 0 1px 0 rgba(255,255,255,.08);
  transition: transform var(--transition-base), box-shadow var(--transition-base), filter var(--transition-base), opacity var(--transition-base);
}
.book-card:hover {
  transform: translateY(-6px) scale(1.015);
  box-shadow: 0 30px 48px rgba(0,0,0,.26), 0 0 40px rgba(127,179,255,.16);
  filter: saturate(1.06);
}
.book-card__top,
.book-card__meta {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: rgba(255,255,255,.82);
}
.book-card__title {
  font-size: 1.26rem;
  line-height: .94;
  letter-spacing: -.04em;
  text-transform: uppercase;
  font-weight: 800;
  max-width: 7ch;
}
.book-card__mark {
  align-self: end;
  font-family: var(--font-mark);
  font-size: 2rem;
  text-shadow: 0 0 20px rgba(255,255,255,.24);
}
.book-card__meta {
  display: flex;
  justify-content: space-between;
  gap: 10px;
}
.book-card__cover {
  position: absolute;
  inset: 0;
  z-index: 0;
  border-radius: inherit;
  overflow: hidden;
}
.book-card__cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow);
}
.book-card:hover .book-card__cover img {
  transform: scale(1.04);
}
.book-card__top,
.book-card__title,
.book-card__mark,
.book-card__meta {
  position: relative;
  z-index: 1;
}
/* Hide overlay text when cover image is present — covers are self-contained */
.book-card:has(.book-card__cover) .book-card__top,
.book-card:has(.book-card__cover) .book-card__title,
.book-card:has(.book-card__cover) .book-card__mark,
.book-card:has(.book-card__cover) .book-card__meta {
  display: none;
}

.book-detail-grid {
  display: grid;
  grid-template-columns: 1.15fr .85fr;
  gap: 20px;
}
.cover-preview {
  position: relative;
  min-height: 430px;
  border-radius: 28px;
  padding: 22px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  background:
    radial-gradient(circle at 50% 30%, rgba(255,255,255,.22), transparent 18%),
    linear-gradient(180deg, rgba(255,255,255,.08), rgba(255,255,255,.02)),
    var(--hero-cover);
  border: 1px solid rgba(255,255,255,.1);
  box-shadow: 0 24px 48px rgba(0,0,0,.24), inset 0 1px 0 rgba(255,255,255,.08);
}
.cover-preview__meta {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: end;
  color: rgba(255,255,255,.84);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .12em;
}
.cover-preview__title {
  font-size: clamp(1.9rem, 4vw, 2.9rem);
  line-height: .92;
  letter-spacing: -.04em;
  text-transform: uppercase;
  font-weight: 800;
  max-width: 8ch;
}
.cover-preview__mark {
  align-self: end;
  font-family: var(--font-mark);
  font-size: 3rem;
  text-shadow: 0 0 32px rgba(255,255,255,.24);
}
.cover-preview__image {
  position: absolute;
  inset: 0;
  z-index: 0;
  border-radius: inherit;
  overflow: hidden;
}
.cover-preview__image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.cover-preview__meta,
.cover-preview__title,
.cover-preview__mark {
  position: relative;
  z-index: 1;
}
/* Hide overlay text when cover image is present */
.cover-preview:has(.cover-preview__image) .cover-preview__meta,
.cover-preview:has(.cover-preview__image) .cover-preview__title,
.cover-preview:has(.cover-preview__image) .cover-preview__mark {
  display: none;
}

.meta-panel {
  padding: 20px;
  border-radius: 22px;
  background: rgba(18,26,42,.05);
  border: 1px solid rgba(18,26,42,.08);
  box-shadow: var(--shadow-paper);
  color: var(--ink-900);
}
.meta-panel h3,
.meta-panel h4 { color: var(--ink-900); letter-spacing: -.03em; }
.meta-row {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 11px 0;
  border-top: 1px solid rgba(18,26,42,.08);
  color: #25334c;
  font-size: 14px;
}
.meta-row:first-of-type { border-top: 0; padding-top: 0; }
.meta-label { color: #31405b; }

.faq-list {
  display: grid;
  gap: 14px;
}
.faq-item {
  border-radius: 22px;
  background: rgba(255,255,255,.045);
  border: 1px solid rgba(255,255,255,.08);
  box-shadow: var(--shadow-soft);
  overflow: hidden;
  transition: background var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
}
.faq-item:hover {
  border-color: rgba(255,255,255,.14);
  background: rgba(255,255,255,.06);
}
.faq-item[open] {
  background: rgba(255,255,255,.06);
  border-color: rgba(255,255,255,.10);
}
.faq-item summary {
  list-style: none;
  cursor: pointer;
  padding: 18px 20px;
  font-weight: 700;
  letter-spacing: -.02em;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item > div {
  padding: 0 20px 20px;
  color: var(--ink-200);
}
.faq-item p,
.faq-item li {
  color: var(--ink-200);
}

.post-grid {
  display: grid;
  gap: 20px;
  grid-template-columns: repeat(2, minmax(0,1fr));
}

.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}
.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.footer { padding: 84px 0 40px; }
.footer__panel {
  padding: 26px;
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: center;
  flex-wrap: wrap;
}
.footer .brand { margin-bottom: 8px; }
.footer .brand__mark { width: 34px; height: 34px; font-size: 18px; }
.footer__copy { max-width: 60ch; color: var(--ink-200); }
.footer-links a {
  padding: 8px 12px;
  border-radius: 999px;
  background: rgba(255,255,255,.04);
  border: 1px solid rgba(255,255,255,.06);
}

/* Utility classes */
.chip-row--spaced { margin-top: 16px; }
.chip-row--tight  { margin-top: 12px; }
.mb-20 { margin-bottom: 20px; }
.hero-card__tagline { margin: 18px 0 12px; font-size: 1.6rem; letter-spacing: -.04em; }
.spectrum-bar { margin-top: 22px; height: 6px; border-radius: 999px; background: var(--gradient-spectral); }
.hero__actions { margin-top: 24px; }
.paper-block .eyebrow + h1 { margin-top: 18px; }
.card .eyebrow + h3 { margin-top: 14px; }

/* 3D book mockup — solid cuboid with real cover images */
.book-mockup {
  --book-depth: 40px;
  perspective: 1200px;
  display: flex;
  justify-content: center;
  align-items: center;
}
.book-mockup__body {
  --book-w: 280px;
  position: relative;
  width: var(--book-w);
  transform-style: preserve-3d;
  transform: rotateY(-25deg);
  transition: transform var(--transition-slow);
}
.book-mockup:hover .book-mockup__body {
  transform: rotateY(25deg);
}
/* Front face — position: relative drives body height from image */
.book-mockup__front {
  position: relative;
  width: 100%;
  overflow: hidden;
  border-radius: 0 4px 4px 0;
  transform: translateZ(calc(var(--book-depth) / 2));
  box-shadow:
    6px 6px 18px rgba(0,0,0,.35),
    0 0 48px rgba(127,179,255,.10);
}
.book-mockup__front img {
  display: block;
  width: 100%;
  height: auto;
}
/* Light reflection overlay on front cover */
.book-mockup__front::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    115deg,
    rgba(255,255,255,.12) 0%,
    transparent 40%,
    transparent 60%,
    rgba(255,255,255,.04) 100%
  );
  pointer-events: none;
  border-radius: inherit;
}
/* Back face — real back cover image */
.book-mockup__back {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  border-radius: 4px 0 0 4px;
  background: var(--void-950);
  font-size: 0;
  color: transparent;
  transform: rotateY(180deg) translateZ(calc(var(--book-depth) / 2));
}
.book-mockup__back img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
/* Spine face — real spine cover image */
.book-mockup__spine {
  position: absolute;
  top: 0;
  left: calc(50% - var(--book-depth) / 2);
  width: var(--book-depth);
  height: 100%;
  overflow: hidden;
  background: var(--void-950);
  font-size: 0;
  color: transparent;
  transform: rotateY(-90deg) translateZ(calc(var(--book-w) / 2));
}
.book-mockup__spine img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
/* Page edge (right side) — cream paper texture, CSS-only */
.book-mockup__body::after {
  content: "";
  position: absolute;
  top: 2px;
  left: calc(50% - var(--book-depth) / 2);
  width: var(--book-depth);
  height: calc(100% - 4px);
  background: linear-gradient(90deg, #e8e4dc, #f5f2ec, #e8e4dc);
  transform: rotateY(90deg) translateZ(calc(var(--book-w) / 2));
  border-radius: 0 2px 2px 0;
}
/* Top edge removed — the 3D transform caused a visible gap above the cover */

/* Volume navigation */
.book-nav { padding: 30px 0 72px; }
.book-nav__row {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 14px;
  align-items: center;
}
.book-nav__link {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 18px 22px;
  border-radius: var(--radius-card);
  background: rgba(255,255,255,.045);
  border: 1px solid rgba(255,255,255,.08);
  box-shadow: var(--shadow-soft);
  transition: transform var(--transition-fast), box-shadow var(--transition-base), border-color var(--transition-fast);
}
.book-nav__link:hover {
  transform: translateY(-3px);
  border-color: rgba(255,255,255,.14);
  box-shadow: var(--shadow-glow);
}
.book-nav__link--prev { text-align: left; }
.book-nav__link--next { text-align: right; }
.book-nav__link--index {
  padding: 12px 20px;
  border-radius: var(--radius-pill);
  font-weight: 700;
  font-size: 13px;
  letter-spacing: .1em;
  text-transform: uppercase;
}
.book-nav__link--disabled { visibility: hidden; }
.book-nav__label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--ink-300);
}
.book-nav__title {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: -.02em;
  color: var(--ink-050);
}

/* Meta-panel links */
.meta-panel a {
  color: var(--ink-900);
  text-decoration: underline;
  text-decoration-color: rgba(18,26,42,.22);
  text-underline-offset: 3px;
}
.meta-panel a:hover {
  text-decoration-color: var(--ink-900);
}

/* Accordion summary chips */
.faq-item summary .chip {
  margin-right: 10px;
  pointer-events: none;
  vertical-align: middle;
}

/* --- TOC grid (book detail page) --- */
.toc-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--void-800);
  border: 1px solid var(--void-800);
  border-radius: var(--radius-card);
  overflow: hidden;
}
.toc-entry {
  display: flex;
  gap: 12px;
  padding: 20px 24px;
  background: var(--void-925);
}
.toc-entry__number {
  font-family: var(--font-display);
  font-weight: 700;
  color: var(--accent, var(--ink-050));
  white-space: nowrap;
  min-width: 36px;
}
.toc-entry__title {
  font-family: var(--font-display);
  font-weight: 600;
  color: var(--ink-050);
  margin: 0 0 4px;
  font-size: 0.95rem;
}
.toc-entry__desc {
  color: var(--ink-200);
  font-size: 0.85rem;
  line-height: 1.5;
  margin: 0;
}

/* --- Preview panel (book detail page) --- */
.preview-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 32px 40px;
  background: var(--gradient-glass);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: var(--radius-panel);
  backdrop-filter: blur(22px);
}
.preview-panel h3 {
  margin: 0 0 4px;
  color: var(--ink-050);
}
.preview-panel p {
  margin: 0;
  color: var(--ink-200);
}

/* --- Q&A page styles --- */
.qa-epigraph {
  font-style: italic;
  color: var(--ink-200);
  border-left: 2px solid var(--accent, var(--ink-300));
  padding-left: 16px;
  margin: 12px 0 20px;
  font-size: 0.95rem;
  line-height: 1.6;
}
.qa-epigraph cite {
  display: block;
  font-style: normal;
  font-size: 0.85rem;
  color: var(--ink-300);
  margin-top: 6px;
}

.qa-nav-bar { padding-top: 0; padding-bottom: 0; }
.qa-nav-bar .chip-row {
  overflow-x: auto;
  flex-wrap: nowrap;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
  padding-bottom: 4px;
}
.qa-nav-bar .chip-row::-webkit-scrollbar { display: none; }
.qa-nav-bar .chip { white-space: nowrap; flex-shrink: 0; }
.qa-nav-bar .content { position: relative; }
.qa-nav-bar .content::after {
  content: "";
  position: absolute;
  right: 0; top: 0; bottom: 0;
  width: 48px;
  background: linear-gradient(90deg, transparent, var(--void-900));
  pointer-events: none;
  border-radius: 0 var(--radius-pill) var(--radius-pill) 0;
}

.qa-item summary {
  display: flex;
  align-items: baseline;
  gap: 0;
}
.qa-number {
  font-family: var(--font-display);
  font-weight: 700;
  color: var(--accent, var(--ink-050));
  margin-right: 8px;
  min-width: 28px;
  flex-shrink: 0;
}
.qa-ref {
  font-size: 0.78rem;
  color: var(--ink-300);
  font-weight: 400;
  margin-left: auto;
  padding-left: 12px;
  white-space: nowrap;
  flex-shrink: 0;
}

.qa-section + .qa-section { padding-top: 12px; }

.qa-closing {
  text-align: center;
  max-width: 640px;
  margin: 0 auto;
  padding: 32px 40px;
  color: var(--ink-200);
  font-style: italic;
  line-height: 1.7;
  border-radius: var(--radius-card);
  background: rgba(255,255,255,.04);
  border: 1px solid rgba(255,255,255,.06);
}
.qa-closing__attr {
  font-style: normal;
  font-weight: 700;
  color: var(--ink-050);
  margin-top: 16px;
}

/* TOC page styles */
.toc-nav-bar { padding-top: 0; padding-bottom: 0; }
.toc-nav-bar .chip-row {
  padding: 12px 0;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: none;
  flex-wrap: nowrap;
}
.toc-nav-bar .chip-row::-webkit-scrollbar { display: none; }
.toc-nav-bar .chip { white-space: nowrap; flex-shrink: 0; }
.toc-nav-bar .content { position: relative; }
.toc-nav-bar .content::after {
  content: "";
  position: absolute;
  right: 0; top: 0; bottom: 0;
  width: 48px;
  background: linear-gradient(90deg, transparent, var(--void-900));
  pointer-events: none;
  border-radius: 0 var(--radius-pill) var(--radius-pill) 0;
}
.toc-part-section + .toc-part-section { padding-top: 12px; }
.toc-part-abstract {
  font-family: Georgia, "Times New Roman", serif;
  font-style: italic;
  color: var(--ink-200);
  line-height: 1.75;
  padding: 20px 28px;
  margin-bottom: 24px;
  border-radius: var(--radius-card);
  background: var(--gradient-glass);
  border: 1px solid rgba(255,255,255,.06);
}
.toc-part-abstract p { margin: 0; }
.toc-part-abstract p + p { margin-top: 12px; }
.toc-chapter-number {
  font-family: var(--font-display);
  font-weight: 700;
  color: var(--accent);
  min-width: 2.5em;
  display: inline-block;
}

@media (max-width: 1100px) {
  .hero__grid,
  .page-hero__grid,
  .book-detail-grid,
  .section-grid--2,
  .section-grid--3,
  .stat-grid,
  .path-grid,
  .related-grid,
  .post-grid {
    grid-template-columns: 1fr;
  }
  .book-grid { grid-template-columns: repeat(4, minmax(0,1fr)); }
  .book-nav__row { grid-template-columns: 1fr; }
  .book-nav__link--next { text-align: left; }
  .book-nav__link--index { justify-self: center; }
  .book-nav__link--disabled { display: none; }
  .book-mockup__body { --book-w: 220px; width: var(--book-w); }
  .book-mockup { --book-depth: 32px; }
}
@media (max-width: 820px) {
  .site-nav {
    display: none;
    width: 100%;
    flex-direction: column;
    align-items: stretch;
    padding-bottom: 14px;
  }
  .site-nav.is-open {
    display: flex;
    min-height: calc(100vh - 72px);
    min-height: calc(100dvh - 72px);
    background: var(--void-950);
    overflow-y: auto;
    padding-bottom: 32px;
  }
  .site-nav a { background: rgba(255,255,255,.04); }
  .nav-toggle {
    display: inline-grid;
    place-items: center;
  }
  .site-header__inner {
    min-height: 72px;
    flex-wrap: wrap;
    align-items: center;
  }
  .hero { padding-top: 58px; }
  .hero__orb {
    width: 360px;
    height: 360px;
    right: -120px;
    top: 10px;
    opacity: .7;
  }
  .book-grid { grid-template-columns: repeat(2, minmax(0,1fr)); }
  .book-grid > :last-child:nth-child(odd) { grid-column: 1 / -1; }
  .toc-grid { grid-template-columns: 1fr; }
  .preview-panel {
    flex-direction: column;
    text-align: center;
    padding: 24px;
  }
  .qa-nav-bar .chip { font-size: 0.78rem; padding: 6px 12px; }
  .qa-nav-bar .content::after { width: 32px; }
  .qa-ref { display: none; }
  .qa-closing { padding: 24px; }
  .toc-nav-bar .chip { font-size: 0.78rem; padding: 6px 12px; }
  .toc-nav-bar .content::after { width: 32px; }
  .toc-part-abstract { padding: 16px 20px; font-size: 0.92rem; }
}
/* Stretched link — make entire post card clickable */
.post-grid .card { position: relative; }
.post-grid .card h3 a::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
}

/* Orphaned last card in 2-column grids — span full width */
.section-grid--2 > :last-child:nth-child(odd) { grid-column: 1 / -1; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation: none !important;
    transition: none !important;
  }
}

/* Accessibility */
.skip-link {
  position: absolute;
  top: -100px;
  left: 16px;
  z-index: 100;
  padding: 12px 20px;
  background: var(--accent);
  color: #0b1020;
  border-radius: var(--radius-pill);
  font-weight: 700;
  font-size: 14px;
  text-decoration: none;
}
.skip-link:focus { top: 16px; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}
.button:focus-visible,
.chip:focus-visible,
.filter-chip:focus-visible,
.site-nav a:focus-visible,
.footer-links a:focus-visible,
.brand:focus-visible {
  outline-offset: 4px;
  border-radius: var(--radius-pill);
}
.faq-item summary:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
  border-radius: var(--radius-card);
}