:root {
  color-scheme: light dark;
  --bg: #f8f4ec;
  --paper: #fffaf1;
  --card: #ffffff;
  --fg: #1f2933;
  --muted: #667085;
  --line: #e4ded2;
  --accent: #7c3aed;
  --accent-2: #b45309;
  --shadow: 0 18px 50px rgba(31, 41, 51, .08);
  --radius: 24px;
  --sans: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --serif: ui-serif, Georgia, Cambria, "Times New Roman", serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111827;
    --paper: #151f2f;
    --card: #1f2937;
    --fg: #f9fafb;
    --muted: #b6c0cc;
    --line: #374151;
    --shadow: 0 18px 50px rgba(0, 0, 0, .24);
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: var(--serif);
  background: radial-gradient(circle at top left, rgba(124, 58, 237, .12), transparent 34rem), var(--bg);
  color: var(--fg);
  line-height: 1.68;
}

a { color: inherit; }

.container { width: min(1120px, calc(100% - 40px)); margin: 0 auto; }
.site-header { padding: 26px 0 0; font-family: var(--sans); }
.nav { display: flex; align-items: center; justify-content: space-between; gap: 18px; }
.brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; text-decoration: none; letter-spacing: -.03em; }
.brand-mark { width: 36px; height: 36px; display: grid; place-items: center; border-radius: 12px; background: var(--fg); color: var(--bg); }
.nav-links { display: flex; gap: 16px; flex-wrap: wrap; color: var(--muted); font-size: 14px; }
.nav-links a { text-decoration: none; }
.nav-links a:hover { color: var(--fg); }

.hero { padding: 80px 0 54px; }
.eyebrow { color: var(--accent); font: 800 13px/1.2 var(--sans); text-transform: uppercase; letter-spacing: .12em; }
h1, h2, h3 { line-height: 1.05; }
h1 { max-width: 880px; font-size: clamp(44px, 8vw, 88px); margin: 18px 0 22px; letter-spacing: -.065em; }
.lead { max-width: 760px; font-size: clamp(20px, 2.3vw, 27px); color: var(--muted); margin: 0; }

.hero-actions { margin-top: 32px; display: flex; gap: 14px; flex-wrap: wrap; font-family: var(--sans); }
.button, .mode-button { display: inline-flex; align-items: center; justify-content: center; min-height: 44px; padding: 10px 18px; border-radius: 999px; border: 1px solid var(--line); background: var(--card); color: var(--fg); text-decoration: none; font: 750 14px/1 var(--sans); box-shadow: var(--shadow); cursor: pointer; }
.button.primary, .mode-button.active { background: var(--fg); color: var(--bg); border-color: var(--fg); }
.section { padding: 30px 0; }
.section-head { display: flex; justify-content: space-between; align-items: end; gap: 20px; margin-bottom: 18px; }
.section-head h2 { margin: 0; font-size: clamp(30px, 4vw, 48px); letter-spacing: -.04em; }
.section-head p { margin: 8px 0 0; color: var(--muted); font-family: var(--sans); }
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 18px; }
.card, .book-card, .note-card { background: color-mix(in srgb, var(--card) 92%, transparent); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; box-shadow: var(--shadow); }
.card h3, .book-card h3, .note-card h3 { margin: 0 0 8px; font-size: 22px; }
.card p, .book-card p, .note-card p { color: var(--muted); margin: 0; font-family: var(--sans); font-size: 15px; }
.book-card { display: flex; flex-direction: column; gap: 14px; }
.book-meta { color: var(--muted); font: 14px/1.4 var(--sans); }
.book-card a.title-link { text-decoration: none; }
.book-card a.title-link:hover { text-decoration: underline; }
.badges { display: flex; gap: 8px; flex-wrap: wrap; }
.badge { display: inline-flex; align-items: center; border: 1px solid var(--line); border-radius: 999px; padding: 5px 9px; font: 12px/1 var(--sans); color: var(--muted); background: var(--paper); }
.page-title { padding: 58px 0 24px; }
.page-title h1 { font-size: clamp(42px, 7vw, 76px); }
.content-grid { display: grid; grid-template-columns: minmax(0, 1.5fr) minmax(260px, .7fr); gap: 22px; align-items: start; }
.prose { background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); padding: clamp(22px, 4vw, 38px); box-shadow: var(--shadow); }
.prose h2 { font-size: 30px; margin-top: 0; }
.prose p { font-size: 18px; }
.prose .muted { color: var(--muted); font-family: var(--sans); font-size: 15px; }
.chapter-list { display: grid; gap: 12px; margin-top: 18px; }
.chapter-link { display: flex; align-items: center; justify-content: space-between; gap: 18px; padding: 16px 18px; border: 1px solid var(--line); border-radius: 18px; background: var(--card); text-decoration: none; font-family: var(--sans); }
.chapter-link strong { font-family: var(--serif); }
.chapter-link span { color: var(--muted); font-size: 14px; }
.mode-bar { position: sticky; top: 0; z-index: 5; margin: 12px 0 8px; padding: 12px; border: 1px solid var(--line); border-radius: 999px; background: color-mix(in srgb, var(--bg) 88%, transparent); backdrop-filter: blur(10px); display: flex; gap: 10px; flex-wrap: wrap; align-items: center; font-family: var(--sans); }
.mode-label { color: var(--muted); font-size: 13px; margin-right: 4px; }
.bilingual-reader { display: grid; gap: 18px; }
.bilingual-paragraph { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 18px; background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); padding: clamp(18px, 3vw, 28px); box-shadow: var(--shadow); }
.text-col h3, .single-language-card h3 { margin: 0 0 10px; color: var(--muted); font: 800 12px/1 var(--sans); letter-spacing: .12em; text-transform: uppercase; }
.text-col p { margin: 0; font-size: clamp(18px, 2vw, 21px); }
.text-col.zh p { font-family: var(--serif); }
.paragraph-notes { grid-column: 1 / -1; border-top: 1px solid var(--line); padding-top: 12px; color: var(--muted); font: 14px/1.55 var(--sans); }
.single-language-card { display: none; background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); padding: clamp(24px, 4vw, 44px); box-shadow: var(--shadow); }
.single-language-card p { margin: 0 0 1.15em; font-size: clamp(19px, 2vw, 23px); line-height: 1.85; }
.single-language-card p:last-child { margin-bottom: 0; }
.reader-page[data-mode="en"] .bilingual-paragraph,
.reader-page[data-mode="zh"] .bilingual-paragraph { display: none; }
.reader-page[data-mode="en"] .single-language-card.en-full,
.reader-page[data-mode="zh"] .single-language-card.zh-full { display: block; }
.reader-guide { background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); padding: clamp(22px, 4vw, 36px); box-shadow: var(--shadow); font-family: var(--sans); color: var(--muted); }
.reader-guide h2, .reader-guide h3 { font-family: var(--serif); color: var(--fg); }
.footer { margin-top: 58px; padding: 36px 0 54px; color: var(--muted); font: 14px/1.6 var(--sans); border-top: 1px solid var(--line); }
.footer a { color: var(--fg); }

@media (max-width: 820px) {
  .content-grid, .bilingual-paragraph { grid-template-columns: 1fr; }
  .hero { padding-top: 56px; }
  .section-head { align-items: start; flex-direction: column; }
  .mode-bar { border-radius: 24px; }
  .chapter-link { align-items: start; flex-direction: column; }
}