/* ==========================================================================
   Book page — /rust-cli-mastery-book/
   Loaded only by that page. Every selector is prefixed .book- so nothing
   here can affect any other page. Colors, type and spacing all come from
   the site's existing design tokens (themes.css), so light/dark just work.
   ========================================================================== */

/* ---- Hero ---------------------------------------------------------------- */

.book-hero__grid {
  display: grid;
  gap: var(--space-xl);
  align-items: center;
}

@media (min-width: 900px) {
  .book-hero__grid {
    grid-template-columns: 1.15fr 0.85fr;
    gap: var(--space-2xl);
  }
}

.book-hero__eyebrow {
  font-family: var(--font-mono);
  font-size: var(--step--1);
  color: var(--color-signal);
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.book-hero__title {
  font-size: var(--step-5);
  letter-spacing: -0.02em;
  margin-bottom: var(--space-sm);
}
.book-hero__title span { color: var(--color-accent); }

.book-hero__subtitle {
  font-size: var(--step-2);
  font-weight: 600;
  line-height: var(--leading-snug);
  color: var(--color-text);
  margin-bottom: var(--space-md);
}

.book-hero__lead {
  font-size: var(--step-1);
  color: var(--color-text-muted);
  line-height: var(--leading-snug);
  max-width: 36rem;
  margin-bottom: var(--space-lg);
}

.book-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.btn--lg {
  padding: 0.95rem 1.6rem;
  font-size: var(--step-0);
}

.book-facts {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs) var(--space-lg);
  font-family: var(--font-mono);
  font-size: var(--step--1);
  color: var(--color-text-muted);
}
.book-facts li { display: inline-flex; align-items: baseline; gap: var(--space-2xs); }
.book-facts strong { color: var(--color-text); font-weight: 700; }

.book-cover-wrap {
  justify-self: center;
  width: 100%;
  max-width: 22rem;
  position: relative;
}

.book-cover {
  width: 100%;
  aspect-ratio: 2 / 3;
  object-fit: cover;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border-strong);
  box-shadow: var(--shadow-md), 0 24px 60px color-mix(in srgb, var(--color-accent) 18%, transparent);
  background: var(--color-code-bg);
}

.book-cover-tag {
  position: absolute;
  bottom: -0.75rem;
  right: -0.75rem;
  background: var(--color-accent);
  color: var(--color-accent-contrast);
  font-family: var(--font-mono);
  font-size: var(--step--1);
  font-weight: 700;
  padding: 0.4rem 0.7rem;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-sm);
}

@media (max-width: 899px) {
  .book-cover-wrap { order: -1; max-width: 16rem; }
}

/* ---- Description / prose -------------------------------------------------- */

.book-split {
  display: grid;
  gap: var(--space-xl);
}
@media (min-width: 900px) {
  .book-split { grid-template-columns: 1fr 1fr; gap: var(--space-2xl); align-items: start; }
}

.book-prose p {
  color: var(--color-text-muted);
  max-width: var(--measure);
  line-height: var(--leading-normal);
}
.book-prose p + p { margin-top: var(--space-sm); }
.book-prose strong { color: var(--color-text); font-weight: 600; }

.book-pull {
  margin-top: var(--space-lg);
  padding: var(--space-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--color-accent);
  border-radius: var(--radius-md);
}
.book-pull__label {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--step--1);
  font-weight: 700;
  color: var(--color-accent);
  margin-bottom: var(--space-2xs);
}
.book-pull p { color: var(--color-text-muted); }

/* ---- Cards (learn / capstones) ------------------------------------------- */

.book-grid {
  display: grid;
  gap: var(--space-md);
  grid-template-columns: 1fr;
}
@media (min-width: 640px) { .book-grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 980px) {
  .book-grid--3 { grid-template-columns: repeat(3, 1fr); }
  .book-grid--4 { grid-template-columns: repeat(4, 1fr); }
}

.book-card {
  padding: var(--space-lg) var(--space-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: border-color var(--duration-fast) var(--ease), transform var(--duration-fast) var(--ease);
}
.book-card:hover { border-color: var(--color-border-strong); transform: translateY(-2px); }

.book-card__tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-text-faint);
  letter-spacing: 0.02em;
  margin-bottom: var(--space-2xs);
}
.book-card__title { font-size: var(--step-1); margin-bottom: var(--space-xs); }
.book-card__title code {
  font-family: var(--font-mono);
  color: var(--color-accent);
}
.book-card__desc {
  color: var(--color-text-muted);
  font-size: var(--step--1);
  line-height: var(--leading-normal);
}
.book-card__crates {
  margin-top: var(--space-sm);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-signal);
}

/* ---- Audience + chapter shape -------------------------------------------- */

.book-checks li {
  position: relative;
  padding-left: 1.75rem;
  color: var(--color-text-muted);
  line-height: var(--leading-normal);
  max-width: var(--measure);
}
.book-checks li + li { margin-top: var(--space-sm); }
.book-checks li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.45em;
  width: 0.9rem;
  height: 0.5rem;
  border-left: 2.5px solid var(--color-signal);
  border-bottom: 2.5px solid var(--color-signal);
  transform: rotate(-45deg) scale(0.85);
}
.book-checks strong { color: var(--color-text); font-weight: 600; }

.book-subhead {
  font-size: var(--step-1);
  margin-bottom: var(--space-md);
}

/* ---- Table of contents ---------------------------------------------------- */

.book-toc {
  display: grid;
  gap: var(--space-md);
  grid-template-columns: 1fr;
}
@media (min-width: 900px) { .book-toc { grid-template-columns: repeat(2, 1fr); } }

.book-part {
  padding: var(--space-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
}

.book-part__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-sm);
  padding-bottom: var(--space-xs);
  margin-bottom: var(--space-xs);
  border-bottom: 1px solid var(--color-border);
}
.book-part__title {
  font-size: var(--step-0);
  display: flex;
  align-items: baseline;
  gap: var(--space-xs);
}
.book-part__num {
  font-family: var(--font-mono);
  font-size: var(--step--1);
  font-weight: 700;
  color: var(--color-accent);
}
.book-part__pg {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-text-faint);
  white-space: nowrap;
}

.book-chapters li {
  display: flex;
  align-items: baseline;
  gap: var(--space-xs);
  padding-block: 0.35rem;
  font-size: var(--step--1);
  line-height: var(--leading-snug);
}
.book-chapters .n {
  flex: none;
  width: 1.6rem;
  font-family: var(--font-mono);
  font-weight: 600;
  color: var(--color-text-faint);
}
.book-chapters .t { color: var(--color-text); }
.book-chapters .t code {
  font-family: var(--font-mono);
  font-size: 0.92em;
  color: var(--color-accent);
}
.book-chapters .dots {
  flex: 1;
  min-width: 0.75rem;
  align-self: end;
  margin-bottom: 0.35em;
  border-bottom: 1px dotted var(--color-border-strong);
}
.book-chapters .p {
  flex: none;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-text-faint);
}

.book-part--wide { grid-column: 1 / -1; }
@media (min-width: 900px) {
  .book-part--wide .book-chapters { columns: 3; column-gap: var(--space-lg); }
  .book-part--wide .book-chapters li { break-inside: avoid; }
}

/* ---- Author --------------------------------------------------------------- */

.book-author {
  display: grid;
  gap: var(--space-xl);
}
@media (min-width: 900px) {
  .book-author { grid-template-columns: 15rem 1fr; gap: var(--space-2xl); }
}

.book-author__links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: var(--space-lg);
}

/* ---- Closing call to action ---------------------------------------------- */

.book-cta {
  display: grid;
  gap: var(--space-lg);
  padding: var(--space-xl) var(--space-lg);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  position: relative;
  overflow: hidden;
}
.book-cta::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(120deg, color-mix(in srgb, var(--color-accent) 9%, transparent), transparent 60%);
  pointer-events: none;
}
.book-cta > * { position: relative; }
@media (min-width: 780px) {
  .book-cta { grid-template-columns: 1fr auto; align-items: center; padding: var(--space-xl); }
}
.book-cta__title { font-size: var(--step-3); letter-spacing: -0.01em; margin-bottom: var(--space-xs); }
.book-cta__text { color: var(--color-text-muted); font-size: var(--step-1); line-height: var(--leading-snug); max-width: 38rem; }
.book-cta__note {
  margin-top: var(--space-xs);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-text-faint);
  text-align: center;
}

/* ---- Home page promo (the "ebook" section on /) --------------------------- */

.book-promo {
  display: grid;
  gap: var(--space-lg);
  align-items: center;
  padding: var(--space-lg);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  position: relative;
  overflow: hidden;
}
.book-promo::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(120deg, color-mix(in srgb, var(--color-accent) 8%, transparent), transparent 60%);
  pointer-events: none;
}
.book-promo > * { position: relative; }
@media (min-width: 700px) {
  .book-promo { grid-template-columns: 11rem 1fr; gap: var(--space-xl); padding: var(--space-xl); }
}
.book-promo__cover { display: block; max-width: 11rem; }
.book-promo__cover img {
  width: 100%;
  aspect-ratio: 2 / 3;
  object-fit: cover;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border-strong);
  box-shadow: var(--shadow-md);
}
.book-promo__actions { margin-top: var(--space-md); }

/* ---- Inline code + small typographic fixes ------------------------------- */

.book-hero__lead code,
.book-prose code,
.book-card__desc code,
.book-promo .section__lead code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  padding: 0.1em 0.35em;
  border-radius: var(--radius-sm);
  background: color-mix(in srgb, var(--color-accent) 12%, transparent);
  color: var(--color-text);
}
.book-hero__subtitle,
.book-hero__lead,
.book-cta__text { text-wrap: balance; }