:root {
  color-scheme: light;
  --bg: #f7f8f6;
  --bg-strong: #f0f2ef;
  --surface: rgba(255, 255, 255, .94);
  --surface-solid: #ffffff;
  --surface-soft: #f2f4f1;
  --ink: #252c29;
  --ink-soft: #4d5753;
  --muted: #818a86;
  --line: #e0e4e1;
  --accent: #27a487;
  --accent-dark: #18785f;
  --accent-soft: #e6f4ef;
  --shadow: 0 12px 36px rgba(35, 47, 42, .065);
  --serif: Georgia, "Songti SC", "Noto Serif CJK SC", "Source Han Serif SC", STSong, SimSun, serif;
  --sans: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  --reading: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  text-rendering: optimizeLegibility;
}
button, input { font: inherit; }
button { color: inherit; }
button:focus-visible, input:focus-visible, a:focus-visible, summary:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--accent) 44%, transparent);
  outline-offset: 2px;
}
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }
.ambient { display: none; }

.topbar {
  position: sticky;
  top: 0;
  z-index: 30;
  height: 76px;
  display: flex;
  align-items: center;
  padding: 0 24px;
  border-bottom: 1px solid color-mix(in srgb, var(--line) 82%, transparent);
  background: rgba(255, 255, 255, .88);
  backdrop-filter: blur(18px);
}
.brand { display: inline-flex; align-items: center; gap: 12px; color: inherit; text-decoration: none; }
.brand-mark { display: grid; place-items: center; width: 42px; height: 42px; border-radius: 13px 13px 13px 4px; color: white; background: var(--accent); font: 600 1.45rem/1 var(--serif); box-shadow: 0 7px 18px color-mix(in srgb, var(--accent) 20%, transparent); }
.brand strong { display: block; font: 600 1.12rem/1.2 var(--serif); letter-spacing: .08em; }
.brand small { display: block; margin-top: 3px; color: var(--muted); font-size: .73rem; letter-spacing: .04em; }
.icon-button { border: 1px solid var(--line); background: var(--surface); cursor: pointer; transition: .18s ease; }
.icon-button:hover { border-color: var(--accent); background: var(--accent-soft); }
.icon-button { width: 40px; height: 40px; display: grid; place-items: center; border-radius: 12px; }
.icon-button svg { width: 19px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; }
.menu-button { display: none; margin-right: 12px; }

.app-shell { width: min(1600px, 100%); margin: 0 auto; display: grid; grid-template-columns: 236px minmax(0, 1fr); gap: 24px; padding: 24px 28px 72px; }
.sidebar { position: sticky; top: 100px; height: calc(100vh - 120px); display: flex; flex-direction: column; padding: 18px; border: 1px solid var(--line); border-radius: 18px; background: var(--surface-solid); box-shadow: var(--shadow); overflow: hidden; }
.sidebar-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 16px; }
.sidebar-head strong { display: block; margin-top: 3px; font: 600 1.24rem/1.2 var(--serif); }
.sidebar-close { display: none; }
.eyebrow { display: block; color: var(--accent); font-size: .73rem; font-weight: 700; letter-spacing: .13em; text-transform: uppercase; }
.search-box { display: flex; align-items: center; gap: 8px; height: 42px; padding: 0 12px; border: 1px solid var(--line); border-radius: 11px; background: #fbfcfb; }
.search-box:focus-within { border-color: var(--accent); box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 12%, transparent); }
.search-box svg { width: 17px; fill: none; stroke: var(--muted); stroke-width: 1.8; }
.search-box input { width: 100%; border: 0; outline: 0; color: var(--ink); background: transparent; font-size: .84rem; }
.search-box input::placeholder { color: var(--muted); }
.search-status { min-height: 18px; margin: 8px 2px 4px; color: var(--muted); font-size: .73rem; }
.chapter-grid { flex: 1; min-height: 0; padding: 2px 4px 14px 2px; overflow-y: auto; scrollbar-width: thin; scrollbar-color: var(--line) transparent; }
.chapter-section + .chapter-section { margin-top: 20px; padding-top: 18px; border-top: 1px solid var(--line); }
.chapter-section-head { display: flex; align-items: baseline; justify-content: space-between; margin: 0 3px 9px; }
.chapter-section-head strong { color: var(--accent-dark); font: 600 .9rem/1.2 var(--serif); letter-spacing: .08em; }
.chapter-section-head span { color: var(--muted); font-size: .67rem; }
.chapter-grid-inner { display: grid; grid-template-columns: repeat(5, 1fr); gap: 7px; }
.chapter-grid button { aspect-ratio: 1; border: 1px solid transparent; border-radius: 11px; background: transparent; cursor: pointer; font-size: .81rem; transition: .15s ease; }
.chapter-grid button:hover { color: var(--accent-dark); background: var(--accent-soft); }
.chapter-grid button.active { color: white; background: var(--accent); box-shadow: 0 5px 13px color-mix(in srgb, var(--accent) 20%, transparent); }
.chapter-grid button.match { border-color: color-mix(in srgb, var(--accent) 40%, var(--line)); }
.source-note { flex: none; padding-top: 14px; border-top: 1px solid var(--line); color: var(--muted); font-size: .68rem; line-height: 1.7; }
.source-note span { margin-right: 5px; color: var(--accent); font-weight: 700; }

.reader { width: min(1220px, 100%); min-height: 75vh; margin: 0 auto; outline: none; }
.loading-card, .reading-card { border: 1px solid var(--line); border-radius: 18px; background: var(--surface-solid); box-shadow: var(--shadow); }
.loading-card { padding: 72px; color: var(--muted); text-align: center; }
.reading-card { padding: clamp(26px, 5vw, 54px); }
.reading-card + .reading-card { margin-top: 18px; }
.classical-text { margin: 0; font: 400 1.08rem/2 var(--reading); letter-spacing: .025em; text-align: justify; text-justify: inter-ideograph; }
.classical-text + .classical-text { margin-top: 1rem; }
.annotated-segment { border-radius: .2em; text-decoration: underline; text-decoration-color: color-mix(in srgb, var(--accent) 40%, transparent); text-decoration-style: dotted; text-decoration-thickness: 1px; text-underline-offset: .22em; cursor: help; transition: color .15s ease, background .15s ease; }
.annotated-segment:hover, .annotated-segment:focus, .annotated-segment.note-pinned { color: var(--accent-dark); background: color-mix(in srgb, var(--accent-soft) 72%, transparent); outline: none; }
.annotated-segment.note-pinned { box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 22%, transparent); }
.footnote-marker { display: inline; margin: 0 .08em; color: color-mix(in srgb, var(--muted) 58%, transparent); font-family: var(--sans); font-size: .62em; font-weight: 500; letter-spacing: 0; vertical-align: .38em; text-decoration: none; }
.footnote-marker.annotated-segment { text-decoration: none; }
.global-annotation { position: absolute; z-index: 100; width: min(650px, calc(100vw - 48px)); max-height: min(60vh, 620px); padding: 16px 18px; border: 1px solid color-mix(in srgb, var(--accent) 45%, var(--line)); border-radius: 7px 16px 16px 16px; color: var(--ink); background: rgba(255, 255, 255, .985); box-shadow: 0 18px 48px rgba(35, 47, 42, .14); font: 400 .95rem/1.82 var(--reading); letter-spacing: .01em; overflow-y: auto; overscroll-behavior: contain; pointer-events: auto; transform: translateX(-50%); scrollbar-width: thin; scrollbar-color: var(--line) transparent; }
.global-annotation.chen-annotation { width: min(860px, calc(100vw - 48px)); }
.global-annotation[hidden] { display: none; }
.note-line { margin: 0; padding: 5px 2px; border-radius: 0; background: transparent; }
.note-line + .note-line { margin-top: 3px; }
.note-line-odd { color: var(--ink); font-weight: 500; }
.note-line-even { color: #77817d; font-weight: 400; }
.reference-card { background: #fbfcfb; }
.translation-text { margin: 0; color: #66736e; font: 400 .95rem/1.9 var(--reading); letter-spacing: .01em; }
.discussion-text { margin: 0; color: var(--ink-soft); font: 400 .98rem/1.95 var(--reading); letter-spacing: .008em; text-align: justify; text-justify: inter-ideograph; }
.translation-text + .translation-text, .discussion-text + .discussion-text { margin-top: .9rem; }
.compare-grid { display: grid; grid-template-columns: 1.04fr 1fr; gap: 18px; align-items: stretch; }
.compare-grid .reading-card { padding: clamp(24px, 3.5vw, 40px); }
.compare-grid .reading-card + .reading-card { margin-top: 0; }
.compare-pane { height: min(820px, calc(100vh - 124px)); min-height: 500px; overflow-y: auto; overscroll-behavior: contain; scrollbar-width: thin; scrollbar-color: var(--line) transparent; }
.compare-column { display: flex; flex-direction: column; gap: 16px; padding-right: 4px; }
.compare-column .reading-card + .reading-card { margin-top: 0; }
.wang-reading { flex: none; }
.translation-card { flex: none; border-color: var(--line); background: #f4f6f3; box-shadow: 0 10px 30px rgba(35, 47, 42, .045); }
.translation-heading { margin: 0 0 18px; color: var(--muted); font: 600 .78rem/1.4 var(--sans); letter-spacing: .14em; }
.chen-panel { position: relative; padding-top: 24px !important; }
.chen-panel-toolbar { position: sticky; top: -24px; z-index: 4; display: flex; justify-content: flex-end; margin: -24px -16px 18px; padding: 12px 16px 10px; background: rgba(251, 252, 251, .94); backdrop-filter: blur(12px); }
.chen-mode-switch { display: inline-flex; gap: 3px; padding: 3px; border: 1px solid var(--line); border-radius: 11px; background: var(--surface-solid); }
.chen-mode-switch button { padding: 7px 11px; border: 0; border-radius: 9px; color: var(--muted); background: transparent; cursor: pointer; font-size: .76rem; transition: .15s ease; }
.chen-mode-switch button:hover { color: var(--accent-dark); }
.chen-mode-switch button.active { color: white; background: var(--accent); }
.discussion-reading { max-width: 46em; margin: 0 auto; }
.empty-state { padding: 60px 30px; border: 1px dashed var(--line); border-radius: 20px; color: var(--muted); text-align: center; }
.page-arrow { position: fixed; top: 52%; z-index: 8; width: 48px; height: 72px; display: grid; place-items: center; border: 1px solid var(--line); background: var(--surface); border-radius: 16px; box-shadow: 0 10px 30px rgba(29, 73, 76, .09); cursor: pointer; backdrop-filter: blur(14px); transition: .18s ease; }
.page-arrow:hover { color: white; border-color: var(--accent); background: var(--accent); transform: translateY(-2px); }
.page-arrow svg { width: 23px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.page-prev { left: max(268px, calc((100vw - 1600px) / 2 + 268px)); }
.page-next { right: max(12px, calc((100vw - 1600px) / 2 + 12px)); }
.page-arrow:disabled { opacity: 0; pointer-events: none; }
.scrim { display: none; }

@media (max-width: 1140px) {
  .app-shell { gap: 26px; padding-right: 24px; padding-left: 24px; }
  .page-prev { left: 8px; }
  .page-next { right: 8px; }
}

@media (max-width: 820px) {
  .topbar { height: 68px; padding: 0 14px; }
  .menu-button, .sidebar-close { display: grid; }
  .brand small { display: none; }
  .brand-mark { width: 38px; height: 38px; border-radius: 12px 12px 12px 4px; }
  .reading-tools .text-button { padding: 0 9px; }
  .app-shell { display: block; padding: 24px 16px 64px; }
  .sidebar { position: fixed; z-index: 50; top: 0; bottom: 0; left: 0; width: min(88vw, 330px); height: 100vh; border-radius: 0 24px 24px 0; transform: translateX(-105%); transition: transform .25s ease; }
  body.menu-open { overflow: hidden; }
  body.menu-open .sidebar { transform: translateX(0); }
  .scrim { position: fixed; z-index: 45; inset: 0; width: 100%; height: 100%; border: 0; background: rgba(4, 25, 26, .35); backdrop-filter: blur(3px); }
  body.menu-open .scrim { display: block; }
  .chapter-grid { max-height: none; }
  .compare-grid { grid-template-columns: 1fr; }
  .reading-card { border-radius: 20px; }
  .compare-grid .reading-card + .reading-card { margin-top: 0; }
  .compare-pane { height: 62vh; min-height: 380px; }
  .global-annotation, .global-annotation.chen-annotation { width: calc(100vw - 24px); max-height: 56vh; padding: 16px 17px; }
}

@media (max-width: 480px) {
  .brand strong { font-size: 1rem; }
  .reading-card { padding: 26px 22px; }
  .classical-text { line-height: 1.95; text-align: left; }
  .page-arrow { width: 38px; height: 56px; border-radius: 13px; opacity: .88; }
  .page-arrow svg { width: 19px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .01ms !important; animation-duration: .01ms !important; }
}