/* The ebook has its own visual layer and does not alter the blog theme. */
:root {
  --paper: #f6f4ef;
  --paper-strong: #fffdf8;
  --ink: #27312d;
  --muted: #77817a;
  --line: #d9ddd5;
  --accent: #587563;
  --accent-soft: #e4ece4;
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
  --serif: var(--font-family);
  --sans: var(--font-family);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--paper); font-family: var(--serif); line-height: 1.95; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.world-shell { width: min(100% - 40px, 1040px); margin: 0 auto; }
.world-header { display: flex; justify-content: space-between; align-items: center; padding: 24px 0; border-bottom: 1px solid var(--line); font-family: var(--sans); font-size: 13px; }
.world-header nav { display: flex; gap: 18px; }
.brand { color: var(--ink); font-weight: 700; letter-spacing: .08em; }
main { padding: 56px 0 72px; }
.hero { max-width: 720px; padding: 46px 0 72px; }
.kicker, .chapter-number { margin: 0 0 12px; color: var(--accent); font: 600 12px/1.4 var(--sans); letter-spacing: .16em; }
h1, h2, h3 { color: var(--ink); line-height: 1.28; font-weight: 600; }
h1 { margin: 0 0 24px; font-size: clamp(38px, 7vw, 66px); letter-spacing: -.04em; }
h2 { margin: 36px 0 16px; font-size: clamp(25px, 4vw, 36px); }
h3 { margin: 28px 0 10px; font-size: 22px; }
.lead { max-width: 680px; margin: 0 0 30px; color: #59645d; font-size: clamp(18px, 2.5vw, 23px); line-height: 1.8; }
.primary-action { display: inline-flex; gap: 12px; padding: 11px 18px; border: 1px solid var(--accent); border-radius: 999px; background: var(--accent); color: #fff; font-family: var(--sans); font-size: 14px; }
.primary-action:hover { background: #466451; text-decoration: none; }
.reading-note, .book-heading { max-width: 760px; }
.reading-note { padding: 28px 0; border-top: 1px solid var(--line); }
.reading-note p { margin: 0 0 16px; }
.reading-note ul, .reading-note ol { padding-left: 1.4em; }
.section-heading { margin: 60px 0 22px; }
.section-heading h2 { margin-top: 0; }
.volume-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.volume-card { display: block; padding: 26px; border: 1px solid var(--line); border-radius: 14px; background: var(--paper-strong); transition: transform .2s ease, border-color .2s ease; }
.volume-card:hover { border-color: var(--accent); transform: translateY(-2px); text-decoration: none; }
.volume-card span { color: var(--muted); font: 600 12px var(--sans); letter-spacing: .12em; }
.volume-card h2 { margin: 12px 0 4px; font-size: 25px; }
.volume-card p { margin: 0; color: var(--muted); font-family: var(--sans); font-size: 13px; }
.book-heading { margin-bottom: 34px; }
.book-heading > h1 { margin-bottom: 18px; font-size: clamp(35px, 6vw, 58px); }
.chapter-list { border-top: 1px solid var(--line); }
.chapter-row { display: grid; grid-template-columns: 58px 1fr 24px; gap: 16px; align-items: center; padding: 17px 0; border-bottom: 1px solid var(--line); color: var(--ink); font-family: var(--sans); }
.chapter-row span:first-child { color: var(--muted); font-size: 12px; letter-spacing: .1em; }
.chapter-row strong { font-family: var(--serif); font-size: 18px; font-weight: 500; }
.chapter-row .arrow { color: var(--accent); text-align: right; }
.back-links { margin-top: 30px; font-family: var(--sans); font-size: 13px; }
.chapter { max-width: 780px; margin: 0 auto; }
.breadcrumb { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 50px; color: var(--muted); font: 13px var(--sans); }
.breadcrumb span { color: var(--line); }
.chapter-number { margin-bottom: 8px; font-size: 14px; }
.chapter h1 { margin-bottom: 48px; font-size: clamp(38px, 7vw, 62px); }
.chapter-content { font-size: 18px; }
.chapter-content h2 { margin-top: 54px; padding-top: 22px; border-top: 1px solid var(--line); }
.chapter-content h3 { margin-top: 34px; font-size: 23px; }
.chapter-content p { margin: 0 0 20px; }
.chapter-content ul, .chapter-content ol { padding-left: 1.5em; margin: 0 0 24px; }
.chapter-content li { padding-left: 4px; margin: 3px 0; }
.chapter-content blockquote { margin: 28px 0; padding: 4px 0 4px 22px; border-left: 3px solid var(--accent); color: #59645d; font-size: 20px; }
.chapter-content code { padding: 2px 5px; border-radius: 4px; background: var(--accent-soft); font: .86em ui-monospace, SFMono-Regular, Menlo, monospace; }
.chapter-content pre { overflow-x: auto; padding: 18px; border-radius: 10px; background: #25302b; color: #eef3ed; font-size: 14px; line-height: 1.6; }
.chapter-content pre code { padding: 0; background: transparent; color: inherit; }
.chapter-content hr { border: 0; border-top: 1px solid var(--line); margin: 38px 0; }
.chapter-nav { display: grid; grid-template-columns: 1fr auto 1fr; gap: 18px; align-items: center; max-width: 900px; margin: 72px auto 0; padding-top: 24px; border-top: 1px solid var(--line); font: 13px var(--sans); }
.chapter-nav > :last-child { text-align: right; }
.toc-link { padding: 7px 12px; border: 1px solid var(--line); border-radius: 999px; background: var(--paper-strong); }
.muted { color: var(--muted); }
.world-footer { padding: 24px 0 42px; border-top: 1px solid var(--line); color: var(--muted); font: 12px/1.6 var(--sans); }
@media (max-width: 640px) {
  .world-shell { width: min(100% - 28px, 1040px); }
  .world-header { align-items: flex-start; gap: 18px; }
  .world-header nav { flex-direction: column; gap: 2px; text-align: right; }
  main { padding-top: 34px; }
  .hero { padding: 22px 0 48px; }
  .volume-grid { grid-template-columns: 1fr; }
  .chapter-content { font-size: 17px; }
  .chapter-nav { grid-template-columns: 1fr 1fr; }
  .chapter-nav .toc-link { grid-column: 1 / -1; grid-row: 1; justify-self: start; }
  .chapter-nav > :last-child { text-align: right; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .volume-card { transition: none; }
}