:root {
  --bookkit-accent: #3978c5;
  --bookkit-content-width: 760px;
  --bookkit-text: #27323c;
  --bookkit-muted: #6f7b86;
  --bookkit-border: rgba(23, 32, 42, 0.12);
  --bookkit-surface: #f8fafc;
  --bookkit-card: #fff;
  --bookkit-radius: 14px;
  --bookkit-shadow: 0 14px 36px rgba(23, 32, 42, 0.08);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body.bookkit-site {
  margin: 0;
  background: #fff;
  color: var(--bookkit-text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.65;
}

a { color: var(--bookkit-accent); }
img { max-width: 100%; height: auto; }

.bookkit-header,
.bookkit-footer { border-color: var(--bookkit-border); }
.bookkit-header { border-bottom: 1px solid var(--bookkit-border); }
.bookkit-footer { margin-top: 4rem; border-top: 1px solid var(--bookkit-border); }
.bookkit-header__inner,
.bookkit-footer__inner {
  width: min(1180px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 1rem 0;
}
.bookkit-header__inner { display: flex; align-items: center; justify-content: space-between; gap: 1.5rem; }
.bookkit-brand { color: var(--bookkit-text); font-weight: 850; text-decoration: none; letter-spacing: -0.02em; }
.bookkit-menu { display: flex; flex-wrap: wrap; gap: 1rem; }
.bookkit-menu a { color: var(--bookkit-muted); font-size: 0.9rem; font-weight: 700; text-decoration: none; }
.bookkit-menu a:hover { color: var(--bookkit-accent); }
.bookkit-footer { color: var(--bookkit-muted); font-size: 0.88rem; }

.bookkit-shell {
  width: min(1180px, calc(100% - 2rem));
  min-height: 70vh;
  margin: 0 auto;
  padding: 3rem 0;
}

.bookkit-page-header,
.bookkit-chapter,
.bookkit-chapters { width: min(var(--bookkit-content-width), 100%); margin-inline: auto; }
.bookkit-page-header { margin-bottom: 2rem; }
.bookkit-page-header h1,
.bookkit-book-hero h1,
.bookkit-chapter-header h1 { margin: 0.25rem 0 0.75rem; line-height: 1.08; letter-spacing: -0.035em; }
.bookkit-page-header h1,
.bookkit-book-hero h1 { font-size: clamp(2.2rem, 5vw, 4.5rem); }
.bookkit-chapter-header h1 { font-size: clamp(2rem, 4vw, 3.5rem); }
.bookkit-lede { max-width: 62ch; color: var(--bookkit-muted); font-size: 1.15rem; }
.bookkit-eyebrow {
  display: inline-block;
  color: var(--bookkit-accent);
  font-size: 0.76rem;
  font-weight: 850;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.bookkit-prose { width: 100%; font-size: 1.04rem; }
.bookkit-prose > :first-child { margin-top: 0; }
.bookkit-prose h2,
.bookkit-prose h3 { line-height: 1.2; letter-spacing: -0.02em; }
.bookkit-prose h2 { margin-top: 2.4rem; }
.bookkit-prose h3 { margin-top: 1.9rem; }
.bookkit-prose pre:not(.mermaid) {
  overflow-x: auto;
  padding: 1rem;
  border-radius: 10px;
  background: #111827;
  color: #f8fafc;
}
.bookkit-prose code:not(pre code) { padding: 0.15em 0.35em; border-radius: 5px; background: #f1f5f9; }
.bookkit-prose blockquote { margin-left: 0; padding-left: 1rem; border-left: 3px solid var(--bookkit-accent); color: var(--bookkit-muted); }

.bookkit-figure { margin: 2rem 0; }
.bookkit-figure img {
  display: block;
  width: 100%;
  border: 1px solid var(--bookkit-border);
  border-radius: 10px;
  background: #fff;
}
.bookkit-figure figcaption {
  margin-top: 0.7rem;
  font-size: 0.92rem;
  line-height: 1.55;
  color: var(--bookkit-muted);
}

.bookkit-book-grid { display: grid; gap: 1.25rem; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.bookkit-book-card {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 1rem;
  padding: 1rem;
  border: 1px solid var(--bookkit-border);
  border-radius: var(--bookkit-radius);
  background: var(--bookkit-card);
}
.bookkit-book-card h2 { margin: 0.4rem 0; font-size: 1.25rem; line-height: 1.2; }
.bookkit-book-card h2 a { color: var(--bookkit-text); text-decoration: none; }
.bookkit-book-card p { color: var(--bookkit-muted); font-size: 0.92rem; }
.bookkit-text-link { font-size: 0.9rem; font-weight: 800; text-decoration: none; }

.bookkit-book-hero {
  display: grid;
  grid-template-columns: minmax(220px, 320px) minmax(0, 1fr);
  gap: clamp(2rem, 5vw, 5rem);
  align-items: start;
}
.bookkit-book-hero--no-cover { display: block; width: min(var(--bookkit-content-width), 100%); margin-inline: auto; }
.bookkit-book-hero__content { min-width: 0; }
.bookkit-book-intro { margin-top: 1.5rem; }
.bookkit-cover { margin: 0; }
.bookkit-cover img { display: block; width: 100%; border-radius: 8px; box-shadow: var(--bookkit-shadow); }
.bookkit-cover--card img { box-shadow: 0 7px 18px rgba(23, 32, 42, 0.12); }

.bookkit-status {
  display: inline-block;
  margin: 0 0.4rem 0.6rem 0;
  padding: 0.28rem 0.55rem;
  border: 1px solid var(--bookkit-border);
  border-radius: 999px;
  background: var(--bookkit-surface);
  color: var(--bookkit-muted);
  font-size: 0.74rem;
  font-weight: 800;
}
.bookkit-status--published { border-color: rgba(22, 163, 74, 0.24); background: rgba(22, 163, 74, 0.08); color: #15803d; }

.bookkit-stores { display: flex; flex-wrap: wrap; gap: 0.55rem; margin: 1rem 0; }
.bookkit-store {
  display: inline-flex;
  align-items: center;
  min-height: 2.35rem;
  padding: 0.45rem 0.75rem;
  border: 1px solid var(--bookkit-border);
  border-radius: 8px;
  background: #fff;
  color: var(--bookkit-text);
  font-size: 0.84rem;
  font-weight: 800;
  text-decoration: none;
}
.bookkit-store:hover { border-color: var(--bookkit-accent); color: var(--bookkit-accent); }

.bookkit-reader {
  margin: 1.25rem 0 1.6rem;
  padding: 1rem;
  border: 1px solid var(--bookkit-border);
  border-radius: var(--bookkit-radius);
  background: var(--bookkit-surface);
}
.bookkit-resume {
  display: grid;
  gap: 0.5rem;
  margin-bottom: 1rem;
  padding: 0.9rem 1rem;
  border: 1px solid color-mix(in srgb, var(--bookkit-accent) 18%, transparent);
  border-radius: 11px;
  background: #fff;
}
.bookkit-resume__kicker { color: var(--bookkit-muted); font-size: 0.76rem; font-weight: 850; letter-spacing: 0.08em; text-transform: uppercase; }
.bookkit-resume__link { display: flex; align-items: baseline; justify-content: space-between; gap: 1rem; color: var(--bookkit-text); text-decoration: none; }
.bookkit-resume__link:hover { color: var(--bookkit-accent); }
.bookkit-resume__link span { flex: 0 0 auto; color: var(--bookkit-accent); font-size: 0.86rem; font-weight: 800; }
.bookkit-resume.has-progress { border-color: var(--bookkit-accent); box-shadow: 0 8px 22px color-mix(in srgb, var(--bookkit-accent) 10%, transparent); }
.bookkit-reader__context,
.bookkit-reader__header { display: flex; align-items: baseline; justify-content: space-between; gap: 1rem; }
.bookkit-reader__context { margin-bottom: 0.8rem; font-size: 0.84rem; }
.bookkit-reader__context a { font-weight: 800; text-decoration: none; }
.bookkit-reader__context span,
.bookkit-reader__count { color: var(--bookkit-muted); font-size: 0.8rem; font-weight: 700; }
.bookkit-reader__header { margin-bottom: 0.6rem; }
.bookkit-reader__chapters { display: flex; gap: 0.45rem; overflow-x: auto; padding: 0.15rem 0 0.35rem; scrollbar-width: thin; }
.bookkit-reader__chapter {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  justify-content: center;
  min-width: 2.35rem;
  height: 2.35rem;
  padding: 0 0.55rem;
  border: 1px solid var(--bookkit-border);
  border-radius: 8px;
  background: #fff;
  color: var(--bookkit-text);
  font-size: 0.82rem;
  font-weight: 850;
  text-decoration: none;
}
.bookkit-reader__chapter:hover { border-color: var(--bookkit-accent); color: var(--bookkit-accent); }
.bookkit-reader__chapter.is-current { border-color: var(--bookkit-accent); background: var(--bookkit-accent); color: #fff; }
.bookkit-reader__chapter.is-last-read:not(.is-current) { border-color: var(--bookkit-accent); background: color-mix(in srgb, var(--bookkit-accent) 8%, white); color: var(--bookkit-accent); }

.bookkit-chapters { margin-top: 4rem; }
.bookkit-chapter-list { display: grid; gap: 0.75rem; }
.bookkit-chapter-card {
  display: grid;
  grid-template-columns: 3rem 1fr;
  gap: 1rem;
  padding: 1rem 0;
  border-top: 1px solid var(--bookkit-border);
}
.bookkit-chapter-card__number { color: var(--bookkit-muted); font-size: 0.82rem; font-weight: 850; }
.bookkit-chapter-card h3 { margin: 0; line-height: 1.25; }
.bookkit-chapter-card h3 a { color: var(--bookkit-text); text-decoration: none; }
.bookkit-chapter-card p { margin-bottom: 0; color: var(--bookkit-muted); }

.bookkit-chapter-header { margin-bottom: 1.4rem; }
.bookkit-backlink { display: inline-block; margin-bottom: 1rem; color: var(--bookkit-muted); font-size: 0.88rem; font-weight: 750; text-decoration: none; }
.bookkit-prev-next {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--bookkit-border);
}
.bookkit-prev-next > div { min-width: 0; }
.bookkit-prev-next__next { text-align: right; }
.bookkit-prev-next__label { display: block; margin-bottom: 0.25rem; color: var(--bookkit-muted); font-size: 0.72rem; font-weight: 850; letter-spacing: 0.08em; text-transform: uppercase; }
.bookkit-prev-next a { font-weight: 800; text-decoration: none; }

.mermaid { overflow-x: auto; padding: 1rem; text-align: center; }

@media (max-width: 760px) {
  .bookkit-shell { padding-top: 2rem; }
  .bookkit-header__inner { align-items: flex-start; flex-direction: column; }
  .bookkit-book-hero { grid-template-columns: 1fr; }
  .bookkit-book-hero__cover { width: min(260px, 72vw); }
  .bookkit-book-card { grid-template-columns: 80px 1fr; }
  .bookkit-resume__link,
  .bookkit-reader__context,
  .bookkit-reader__header { align-items: flex-start; flex-direction: column; gap: 0.35rem; }
  .bookkit-prev-next { grid-template-columns: 1fr; }
  .bookkit-prev-next__next { text-align: left; }
}