:root {
  color-scheme: light;
  --canvas: #f2efe8;
  --paper: #fffdf8;
  --ink: #243036;
  --muted: #68747a;
  --line: #ddd8cc;
  --accent: #a8442b;
  --accent-2: #315b62;
  --accent-soft: #f3e2da;
  --code: #f2eee5;
  --shadow: 0 18px 55px rgba(63, 49, 35, .09);
  --reading-size: 18px;
}

html[data-theme="dark"] {
  color-scheme: dark;
  --canvas: #182024;
  --paper: #202a2f;
  --ink: #e8e3d8;
  --muted: #aeb8bb;
  --line: #3a464a;
  --accent: #ed967d;
  --accent-2: #89b8bd;
  --accent-soft: #442e2a;
  --code: #182125;
  --shadow: 0 18px 55px rgba(0, 0, 0, .22);
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--canvas);
  color: var(--ink);
  font-family: ui-serif, "Noto Serif SC", "Source Han Serif SC", "Songti SC", SimSun, serif;
  font-size: 17px;
  line-height: 1.9;
  text-rendering: optimizeLegibility;
}
a { color: var(--accent); text-underline-offset: .18em; }
a:hover { text-decoration-thickness: 2px; }
button, input { font: inherit; }
button:disabled { cursor: default; opacity: .45; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }
.skip-link { position: absolute; z-index: 80; top: 8px; left: 16px; padding: 10px 18px; background: var(--paper); transform: translateY(-160%); }
.skip-link:focus { transform: translateY(0); }

.site-header {
  position: static;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  align-items: center;
  justify-content: space-between;
  min-height: 62px;
  padding: 10px max(20px, calc((100% - 1280px) / 2));
  border-bottom: 1px solid var(--line);
  background: var(--canvas);
}
.brand {
  color: var(--ink);
  font: 800 15px/1.5 ui-sans-serif, system-ui, sans-serif;
  letter-spacing: .06em;
  text-decoration: none;
}
.header-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 16px; }
.quiet-link { display: inline-flex; align-items: center; min-height: 44px; color: var(--muted); font: 13px/1.5 ui-sans-serif, system-ui, sans-serif; text-decoration: none; }
.icon-button {
  min-width: 44px;
  min-height: 44px;
  padding: 9px 13px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--paper);
  color: var(--ink);
  cursor: pointer;
  font: 13px/1 ui-sans-serif, system-ui, sans-serif;
}

.home { max-width: 1180px; margin: 0 auto; padding: 82px 24px 90px; }
.hero { max-width: 900px; margin-bottom: 58px; }
.eyebrow {
  margin: 0 0 16px;
  color: var(--accent);
  font: 800 12px/1.4 ui-sans-serif, system-ui, sans-serif;
  letter-spacing: .18em;
  text-transform: uppercase;
}
.hero h1 {
  margin: 0;
  font-size: clamp(48px, 8vw, 92px);
  line-height: 1.05;
  letter-spacing: -.055em;
  text-wrap: balance;
}
.hero-copy { max-width: 740px; margin: 28px 0; color: var(--muted); font-size: clamp(18px, 2vw, 23px); }
.stats { display: flex; flex-wrap: wrap; gap: 22px; margin-top: 34px; }
.stat { min-width: 105px; padding-left: 13px; border-left: 3px solid var(--accent); }
.stat strong { display: block; font: 800 26px/1.15 ui-sans-serif, system-ui, sans-serif; }
.stat span { color: var(--muted); font: 12px/1.3 ui-sans-serif, system-ui, sans-serif; }

.controls { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin: 0 0 28px; }
.search {
  flex: 1 1 280px;
  min-height: 44px;
  padding: 0 15px;
  border: 1px solid var(--line);
  border-radius: 8px;
  outline: none;
  background: var(--paper);
  color: var(--ink);
  font-family: ui-sans-serif, system-ui, sans-serif;
}
.search:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.filter {
  min-height: 40px;
  padding: 0 13px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font: 13px/1 ui-sans-serif, system-ui, sans-serif;
}
.filter.active { border-color: var(--accent); background: var(--accent-soft); color: var(--accent); }
.books-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; }
.book-card {
  position: relative;
  display: flex;
  min-height: 300px;
  flex-direction: column;
  padding: 27px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--paper);
  box-shadow: 0 8px 28px rgba(63, 49, 35, .04);
  transition: transform .18s ease, box-shadow .18s ease;
}
.book-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.book-card::after {
  content: attr(data-number);
  position: absolute;
  right: -7px;
  bottom: -31px;
  color: var(--accent-soft);
  font: 900 116px/1 ui-sans-serif, system-ui, sans-serif;
  pointer-events: none;
}
.card-meta { display: flex; justify-content: space-between; gap: 8px; color: var(--muted); font: 12px/1.4 ui-sans-serif, system-ui, sans-serif; }
.status { color: var(--accent); }
.book-card h2 { position: relative; z-index: 1; margin: 32px 0 10px; font-size: 25px; line-height: 1.34; letter-spacing: -.02em; }
.book-card .author { margin: 0 0 16px; color: var(--accent-2); font: 13px/1.5 ui-sans-serif, system-ui, sans-serif; }
.book-card .summary { position: relative; z-index: 1; margin: 0; color: var(--muted); font-size: 15px; line-height: 1.75; }
.card-link { position: relative; z-index: 2; margin-top: auto; padding-top: 20px; color: var(--ink); font: 700 14px/1.4 ui-sans-serif, system-ui, sans-serif; text-decoration: none; }
.method {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 40px;
  margin-top: 82px;
  padding-top: 48px;
  border-top: 1px solid var(--line);
}
.method h2 { margin: 0; font-size: 30px; line-height: 1.25; }
.method p { margin-top: 0; color: var(--muted); }
.site-footer { max-width: 1180px; margin: 0 auto; padding: 30px 24px 55px; border-top: 1px solid var(--line); color: var(--muted); font: 13px/1.7 ui-sans-serif, system-ui, sans-serif; }

#progress { position: fixed; z-index: 70; inset: 0 auto auto 0; width: 0; height: 2px; background: var(--accent); pointer-events: none; }
.reader-shell {
  display: grid;
  grid-template-columns: minmax(210px, 250px) minmax(0, 1fr);
  align-items: start;
  gap: clamp(24px, 3vw, 48px);
  max-width: 1328px;
  margin: 0 auto;
  padding: 24px 24px 64px;
}
.reader-sidebar {
  position: sticky;
  top: 16px;
  min-width: 0;
  max-height: calc(100vh - 32px);
  max-height: calc(100dvh - 32px);
}
.reader-toc { min-width: 0; scroll-margin-top: 16px; }
.reader-toc > summary {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 48px;
  padding: 10px 12px;
  color: var(--ink);
  font: 700 15px/1.5 ui-sans-serif, system-ui, sans-serif;
  list-style: none;
  cursor: pointer;
}
.reader-toc > summary::-webkit-details-marker { display: none; }
.reader-toc > summary::after { content: "+"; margin-left: auto; font-size: 21px; font-weight: 400; }
.reader-toc[open] > summary::after { content: "−"; }
.toc-count { color: var(--muted); font-size: 12px; font-weight: 400; white-space: nowrap; }
.toc-content {
  max-height: calc(100vh - 84px);
  max-height: calc(100dvh - 84px);
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-gutter: stable;
  padding: 12px 4px 16px 0;
}
.sidebar-label { overflow-wrap: anywhere; margin: 0 12px 18px; color: var(--accent); font: 700 11px/1.6 ui-sans-serif, system-ui, sans-serif; letter-spacing: .1em; text-transform: uppercase; }
#toc { font: 13px/1.65 ui-sans-serif, system-ui, sans-serif; }
#toc ol { margin: 0; padding: 0; list-style: none; }
#toc a { display: block; min-height: 38px; padding: 8px 12px; overflow-wrap: anywhere; border-left: 2px solid transparent; color: var(--muted); text-decoration: none; }
#toc a:hover, #toc a.active { border-color: var(--accent); color: var(--accent); background: var(--accent-soft); }
#toc a.level-3 { padding-left: 26px; font-size: 12px; }
.reader-main { min-width: 0; }
.reader-toolbar { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 4px 16px; max-width: 880px; min-height: 48px; margin: 0 auto 14px; }
.reading-settings { display: flex; align-items: center; gap: 6px; }
.reading-settings .icon-button { padding: 8px; border-radius: 8px; font-size: 15px; }
.font-size-label { min-width: 28px; text-align: center; color: var(--muted); font: 12px/1.5 ui-sans-serif, system-ui, sans-serif; }
.paper { min-width: 0; max-width: 880px; margin: 0 auto; padding: clamp(28px, 3.5vw, 56px); border: 1px solid var(--line); border-radius: 8px; background: var(--paper); box-shadow: var(--shadow); font-size: var(--reading-size); line-height: 1.95; overflow-wrap: anywhere; }
.paper .book-summary { margin: 0 0 28px; padding: 16px 18px; border-left: 3px solid var(--accent); background: var(--accent-soft); color: var(--ink); font-size: .94em; line-height: 1.85; }
.book-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 22px; }
.book-tag { padding: 5px 9px; border: 1px solid var(--line); border-radius: 999px; color: var(--muted); font: 12px/1.2 ui-sans-serif, system-ui, sans-serif; }
.paper h1, .paper h2, .paper h3, .paper h4 { line-height: 1.5; text-wrap: pretty; scroll-margin-top: 24px; }
.paper h1 { margin: 0 0 26px; padding-bottom: 24px; border-bottom: 1px solid var(--line); font-size: clamp(28px, 3.5vw, 42px); font-weight: 800; letter-spacing: -.025em; }
.paper h2 { margin: 2.6em 0 1em; padding-top: 8px; font-size: 1.55em; letter-spacing: -.02em; }
.paper h2::after { content: ""; display: block; width: 44px; margin-top: 13px; border-bottom: 3px solid var(--accent); }
.paper h3 { margin: 1.8em 0 .65em; font-size: 1.18em; }
.paper h4 { margin: 1.6em 0 .5em; font-size: 1.05em; }
.section-toc { display: none; }
.paper p { margin: 1em 0; }
.paper strong { color: color-mix(in srgb, var(--ink) 82%, var(--accent)); }
.paper ul, .paper ol { padding-left: 1.4em; }
.paper li { margin: .42em 0; padding-left: .22em; }
.paper li::marker { color: var(--accent); }
.paper code { padding: .12em .36em; border-radius: 4px; background: var(--code); font: .88em/1.5 ui-monospace, SFMono-Regular, Consolas, monospace; }
.paper pre { max-width: 100%; padding: 18px; overflow-x: auto; border: 1px solid var(--line); border-radius: 6px; background: var(--code); font-size: .88em; line-height: 1.65; white-space: pre; overflow-wrap: normal; tab-size: 4; }
.paper pre code { padding: 0; font-size: 1em; background: transparent; }
.paper img, .paper video, .paper svg { max-width: 100%; height: auto; }
.paper blockquote { margin: 1.5em 0; padding: 4px 0 4px 18px; border-left: 3px solid var(--line); color: var(--muted); }
.table-scroll { width: 100%; max-width: 100%; margin: 28px 0; overflow-x: auto; border: 1px solid var(--line); border-radius: 6px; scrollbar-width: thin; }
.paper table { width: 100%; margin: 0; border-collapse: collapse; font-family: ui-sans-serif, system-ui, sans-serif; font-size: .82em; line-height: 1.7; }
.paper th, .paper td { min-width: 130px; padding: 12px 14px; border: 1px solid var(--line); text-align: left; vertical-align: top; }
.paper td code { overflow-wrap: anywhere; }
.paper th { background: var(--accent-soft); }
.reader-end { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 8px 20px; margin-top: 48px; padding-top: 16px; border-top: 1px solid var(--line); font: 14px/1.6 ui-sans-serif, system-ui, sans-serif; }
.reader-end a { display: inline-flex; align-items: center; min-height: 44px; }
.discussion-link { display: inline-block; margin-top: 48px; padding: 12px 17px; border: 1px solid var(--accent); border-radius: 6px; text-decoration: none; font: 700 14px/1.4 ui-sans-serif, system-ui, sans-serif; }
.empty { grid-column: 1 / -1; padding: 50px 0; color: var(--muted); text-align: center; }

@media (max-width: 1023px) {
  .books-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .reader-shell { grid-template-columns: minmax(0, 1fr); max-width: 928px; gap: 12px; padding: 20px 24px 48px; }
  .reader-sidebar { position: static; max-height: none; }
  .reader-toc { border: 1px solid var(--line); border-radius: 8px; background: var(--paper); }
  .reader-toc > summary { padding: 12px 16px; }
  .toc-content { max-height: 50vh; max-height: 50dvh; padding: 12px 8px 16px; border-top: 1px solid var(--line); }
  #toc a { min-height: 44px; }
  .reader-toolbar { margin-bottom: 12px; }
  .section-toc { display: table; min-height: 44px; margin: -12px 0 4px auto; padding: 10px 0 10px 16px; color: var(--muted); font: 12px/2 ui-sans-serif, system-ui, sans-serif; text-decoration: none; }
}
@media (max-width: 660px) {
  body { font-size: 16px; }
  .home { padding-top: 55px; }
  .books-grid { grid-template-columns: 1fr; }
  .method { grid-template-columns: 1fr; gap: 12px; }
  .site-header { padding: 10px 20px; gap: 0 12px; }
  .header-actions { gap: 4px 12px; }
  .header-actions .quiet-link { display: none; }
  .reader-shell { padding: 16px 0 32px; gap: 8px; }
  .reader-sidebar, .reader-toolbar { margin-left: 20px; margin-right: 20px; }
  .paper { padding: 28px 20px 36px; border-width: 1px 0; border-radius: 0; box-shadow: none; }
  .paper h1 { font-size: 1.65em; line-height: 1.55; }
  .paper h2 { font-size: 1.4em; }
  .paper th, .paper td { min-width: 120px; padding: 10px 12px; }
  .book-tags { gap: 6px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
}
@media print {
  :root, html[data-theme="dark"] { color-scheme: light; --paper: #fff; --ink: #111; --muted: #444; --line: #ccc; --accent: #333; --accent-soft: #eee; --code: #f5f5f5; }
  body { background: #fff; font-size: 11pt; }
  .site-header, .reader-sidebar, .reader-toolbar, .reader-end, .section-toc, .skip-link, #progress { display: none; }
  .reader-shell { display: block; max-width: none; padding: 0; }
  .reader-main { padding: 0; }
  .paper { max-width: none; padding: 0; border: 0; box-shadow: none; font-size: 11pt; }
  .paper h1 { font-size: 30pt; }
  .paper h2, .paper h3 { break-after: avoid; }
  .table-scroll, .paper pre { overflow: visible; }
  .paper pre { white-space: pre-wrap; overflow-wrap: anywhere; }
  .paper table { table-layout: fixed; font-size: 9pt; }
  .paper th, .paper td { min-width: 0; padding: 6px; }
  .paper tr { break-inside: avoid; }
  .paper a { color: inherit; }
  .paper a[href^="http"]::after { content: " (" attr(href) ")"; font-size: 8pt; word-break: break-all; }
}