:root {
  --paper: #f4f1e9;
  --paper-strong: #fffdf8;
  --ink: #202824;
  --muted: #667069;
  --line: #d9d5ca;
  --green: #1f4b3f;
  --green-soft: #e4ece7;
  --rust: #a95f3f;
  --gold: #b68a3c;
  --shadow: 0 16px 40px rgba(45, 51, 46, 0.08);
  --radius: 20px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: ui-serif, "Songti SC", "STSong", "Noto Serif CJK SC", Georgia, serif;
  font-size: 17px;
  line-height: 1.78;
  -webkit-font-smoothing: antialiased;
}
button, input, summary { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
a { color: var(--green); }

#scroll-progress {
  position: fixed;
  z-index: 100;
  inset: 0 auto auto 0;
  width: 0;
  height: 3px;
  background: var(--rust);
  transition: width .08s linear;
}

.shell { width: min(1120px, calc(100% - 32px)); margin: 0 auto; }
.library-header { padding: 52px 0 28px; border-bottom: 1px solid var(--line); }
.eyebrow { margin: 0 0 10px; color: var(--rust); font: 700 13px/1.2 ui-sans-serif, system-ui, sans-serif; letter-spacing: .12em; text-transform: uppercase; }
h1, h2, h3, h4 { line-height: 1.3; }
.library-title { margin: 0; font-size: clamp(34px, 7vw, 62px); letter-spacing: -.04em; }
.library-intro { max-width: 680px; margin: 14px 0 0; color: var(--muted); font-size: 18px; }

.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; margin: 28px 0 0; background: var(--line); border: 1px solid var(--line); border-radius: 16px; overflow: hidden; }
.stat { padding: 16px 18px; background: rgba(255, 253, 248, .72); }
.stat strong { display: block; font: 700 24px/1.15 ui-sans-serif, system-ui, sans-serif; }
.stat span { color: var(--muted); font: 500 13px/1.4 ui-sans-serif, system-ui, sans-serif; }

.library-tools { position: sticky; z-index: 20; top: 0; padding: 16px 0 14px; background: color-mix(in srgb, var(--paper) 92%, transparent); backdrop-filter: blur(14px); }
.search-wrap { position: relative; }
.search-wrap svg { position: absolute; left: 16px; top: 50%; translate: 0 -50%; width: 20px; color: var(--muted); }
.search {
  width: 100%; min-height: 50px; padding: 0 16px 0 48px;
  border: 1px solid var(--line); border-radius: 14px;
  color: var(--ink); background: var(--paper-strong); outline: none;
  font-family: ui-sans-serif, system-ui, sans-serif; font-size: 16px;
}
.search:focus { border-color: var(--green); box-shadow: 0 0 0 3px rgba(31,75,63,.1); }
.filters { display: flex; gap: 8px; margin-top: 12px; overflow-x: auto; scrollbar-width: none; }
.filters::-webkit-scrollbar { display: none; }
.chip { flex: 0 0 auto; border: 1px solid var(--line); border-radius: 999px; padding: 7px 13px; color: var(--muted); background: transparent; cursor: pointer; font: 600 14px/1.2 ui-sans-serif, system-ui, sans-serif; }
.chip.active { color: #fff; border-color: var(--green); background: var(--green); }

.library-main { padding: 24px 0 70px; }
.results-head { display: flex; justify-content: space-between; align-items: baseline; margin-bottom: 14px; }
.results-head h2 { margin: 0; font-size: 22px; }
.results-count { color: var(--muted); font: 500 13px/1.4 ui-sans-serif, system-ui, sans-serif; }
.book-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; }
.book-card { display: flex; flex-direction: column; min-height: 285px; padding: 24px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--paper-strong); box-shadow: var(--shadow); }
.book-top { display: flex; justify-content: space-between; gap: 12px; }
.book-code { color: var(--rust); font: 700 13px/1.3 ui-sans-serif, system-ui, sans-serif; }
.book-status { color: var(--green); font: 600 12px/1.3 ui-sans-serif, system-ui, sans-serif; }
.book-card h3 { margin: 18px 0 6px; font-size: 27px; letter-spacing: -.025em; }
.book-byline { color: var(--muted); font: 500 14px/1.4 ui-sans-serif, system-ui, sans-serif; }
.book-summary { margin: 18px 0; color: #414a45; }
.book-meta { margin-top: auto; display: flex; justify-content: space-between; gap: 12px; color: var(--muted); font: 600 13px/1.4 ui-sans-serif, system-ui, sans-serif; }
.book-actions { display: grid; grid-template-columns: 1fr 1fr; gap: 9px; margin-top: 18px; }
.button { display: inline-flex; align-items: center; justify-content: center; min-height: 44px; padding: 0 14px; border: 1px solid var(--green); border-radius: 12px; color: var(--green); background: transparent; text-decoration: none; cursor: pointer; font: 700 14px/1.2 ui-sans-serif, system-ui, sans-serif; }
.button.primary { color: white; background: var(--green); }
.empty { padding: 60px 20px; text-align: center; color: var(--muted); }
.loading { padding: 80px 24px; text-align: center; color: var(--muted); }

.reader-shell { width: min(900px, 100%); margin: 0 auto; }
.reader-topbar { position: sticky; z-index: 40; top: 0; display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 58px; padding: max(10px, env(safe-area-inset-top)) 18px 10px; border-bottom: 1px solid var(--line); background: color-mix(in srgb, var(--paper) 94%, transparent); backdrop-filter: blur(14px); }
.back-link { border: 0; padding: 8px 0; color: var(--green); background: transparent; cursor: pointer; font: 700 14px/1.2 ui-sans-serif, system-ui, sans-serif; }
.reader-top-title { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font: 700 14px/1.2 ui-sans-serif, system-ui, sans-serif; }
.reader-progress-label { min-width: 52px; text-align: right; color: var(--muted); font: 600 12px/1.2 ui-sans-serif, system-ui, sans-serif; }

.book-hero { padding: 42px 24px 30px; border-bottom: 1px solid var(--line); }
.book-hero h1 { margin: 8px 0 12px; font-size: clamp(32px, 8vw, 52px); letter-spacing: -.035em; }
.hero-summary { max-width: 700px; margin: 18px 0 0; color: var(--muted); }
.meta-row { display: flex; flex-wrap: wrap; gap: 8px; }
.meta-pill { border: 1px solid var(--line); border-radius: 999px; padding: 5px 10px; color: var(--muted); background: rgba(255,255,255,.35); font: 600 12px/1.3 ui-sans-serif, system-ui, sans-serif; }

.layer-nav { position: sticky; z-index: 30; top: 58px; display: grid; grid-template-columns: repeat(3, 1fr); border-bottom: 1px solid var(--line); background: color-mix(in srgb, var(--paper) 94%, transparent); backdrop-filter: blur(14px); }
.layer-step { position: relative; border: 0; padding: 12px 6px; color: var(--muted); background: transparent; cursor: pointer; font: 700 12px/1.25 ui-sans-serif, system-ui, sans-serif; }
.layer-step.active { color: var(--green); }
.layer-step.active::after { content: ""; position: absolute; inset: auto 18% -1px; height: 3px; border-radius: 3px 3px 0 0; background: var(--green); }
.layer-step.locked { opacity: .48; }

.reader-body { padding: 0 24px 80px; }
.layer { scroll-margin-top: 118px; }
.layer-head { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 30px 0 18px; }
.layer-kicker { color: var(--rust); font: 700 12px/1.2 ui-sans-serif, system-ui, sans-serif; letter-spacing: .1em; }
.layer-title { margin: 5px 0 0; font-size: 28px; }
.layer-time { flex: 0 0 auto; color: var(--muted); font: 600 13px/1.3 ui-sans-serif, system-ui, sans-serif; }
.layer-content { padding-bottom: 28px; }
.layer-content h2 { margin: 36px 0 14px; padding-top: 4px; font-size: 25px; scroll-margin-top: 126px; }
.layer-content h3 { margin: 28px 0 11px; font-size: 20px; scroll-margin-top: 126px; }
.layer-content h4 { margin: 22px 0 8px; font-size: 18px; }
.layer-content p { margin: 0 0 1.15em; }
.layer-content ul, .layer-content ol { margin: 0 0 1.2em; padding-left: 1.3em; }
.layer-content li { margin: .35em 0; }
.layer-content a, .layer-content li { overflow-wrap: anywhere; word-break: break-word; }
.layer-content blockquote { margin: 18px 0; padding: 13px 16px; border-left: 3px solid var(--rust); border-radius: 0 10px 10px 0; color: #4e574f; background: rgba(169,95,63,.07); }
.layer-content hr { border: 0; border-top: 1px solid var(--line); margin: 32px 0; }
.layer-content code { padding: 2px 5px; border-radius: 5px; background: #e8e4da; font-size: .9em; }

.toc { margin: 2px 0 26px; border: 1px solid var(--line); border-radius: 14px; background: rgba(255,253,248,.58); }
.toc summary { padding: 13px 16px; cursor: pointer; color: var(--green); font: 700 14px/1.4 ui-sans-serif, system-ui, sans-serif; }
.toc-links { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 6px 14px; padding: 0 16px 16px; }
.toc-links a { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; color: var(--muted); text-decoration: none; font: 500 13px/1.5 ui-sans-serif, system-ui, sans-serif; }

.table-wrap { margin: 18px 0 25px; overflow-x: auto; border: 1px solid var(--line); border-radius: 14px; background: var(--paper-strong); }
table { width: 100%; border-collapse: collapse; font-size: 15px; line-height: 1.55; }
th, td { padding: 12px 13px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
th { color: var(--green); background: var(--green-soft); font: 700 13px/1.4 ui-sans-serif, system-ui, sans-serif; }
tr:last-child td { border-bottom: 0; }

.content-card { margin: 18px 0; padding: 18px 18px 4px; border: 1px solid var(--line); border-radius: 16px; background: var(--paper-strong); box-shadow: 0 8px 24px rgba(45,51,46,.05); }
.content-card h3 { margin-top: 0; color: var(--green); }
.content-card.story { border-left: 4px solid var(--rust); }
.content-card.event { border-left: 4px solid var(--gold); }
.content-card.concept { border-left: 4px solid var(--green); }
.timeline-table tbody tr td:first-child { color: var(--rust); font-weight: 800; white-space: nowrap; }
.person-table tbody tr td:first-child, .concept-table tbody tr td:first-child { color: var(--green); font-weight: 800; }

.layer-cta { display: flex; gap: 10px; padding: 24px 0 34px; border-top: 1px solid var(--line); }
.layer-cta .button { flex: 1; }
.reader-footer { padding: 28px 24px calc(32px + env(safe-area-inset-bottom)); border-top: 1px solid var(--line); text-align: center; }

@media (max-width: 640px) {
  .shell { width: min(100% - 24px, 560px); }
  .library-header { padding-top: 34px; }
  .stats { grid-template-columns: 1fr 1fr 1fr; }
  .stat { padding: 13px 10px; }
  .stat strong { font-size: 20px; }
  .book-grid { grid-template-columns: 1fr; }
  .book-card { min-height: 0; padding: 20px; }
  .book-card h3 { font-size: 25px; }
  .book-hero { padding: 30px 18px 24px; }
  .reader-body { padding-inline: 18px; }
  .layer-head { align-items: flex-end; }
  .layer-title { font-size: 25px; }
  .layer-content h2 { font-size: 23px; }
  .toc-links { grid-template-columns: 1fr; }
  .layer-cta { flex-direction: column-reverse; }
  .book-actions { grid-template-columns: 1fr 1.25fr; }

  .table-wrap { overflow: visible; border: 0; background: transparent; }
  table, thead, tbody, tr, th, td { display: block; }
  thead { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
  tbody { display: grid; gap: 10px; }
  tr { overflow: hidden; border: 1px solid var(--line); border-radius: 13px; background: var(--paper-strong); }
  td { display: grid; grid-template-columns: minmax(90px, .42fr) 1fr; gap: 12px; padding: 10px 12px; border-bottom: 1px solid var(--line); }
  td::before { content: attr(data-label); color: var(--muted); font: 700 12px/1.5 ui-sans-serif, system-ui, sans-serif; }
  tr:last-child td, td:last-child { border-bottom: 0; }
  .timeline-table tbody tr td:first-child { background: rgba(169,95,63,.06); }
}

@media (min-width: 900px) {
  .reader-shell { display: grid; grid-template-columns: 1fr; }
  .book-hero, .reader-body { padding-inline: 54px; }
}

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