:root {
  --bg: #faf8f5;
  --fg: #2a2a2a;
  --muted: #666;
  --light: #999;
  --border: #ddd;
  --accent: #c44;
  --accent-bg: #ffebee;
  --evidence: #48d;
  --evidence-bg: #e3f2fd;
  --verified: #2a7;
  --verified-bg: #e8f5e9;
  --warn: #da2;
  --warn-bg: #fff3e0;
  --max-content: 740px;
  --max-wide: 1100px;
  --focus-ring: #48d;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 3.5rem;
}

body {
  margin: 0;
  padding: 0;
  font-family: "Noto Serif SC", "Source Han Serif SC", "SimSun", "STSong", serif;
  font-size: 17px;
  line-height: 1.85;
  color: var(--fg);
  background: var(--bg);
  text-wrap: pretty;
}

/* Skip link */
.skip-link {
  position: absolute;
  top: -3rem;
  left: 1rem;
  z-index: 1000;
  background: var(--fg);
  color: #fff;
  padding: 0.5rem 1rem;
  border-radius: 0 0 6px 6px;
  font-family: "Noto Sans SC", sans-serif;
  font-size: 0.9em;
  text-decoration: none;
}

.skip-link:focus {
  top: 0;
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

/* Focus styles */
a:focus-visible,
button:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
  border-radius: 4px;
}

/* Typography */
h1, h2, h3, h4 {
  font-family: "Noto Sans SC", "Source Han Sans SC", "Microsoft YaHei", sans-serif;
  line-height: 1.35;
  margin-top: 2.5em;
  margin-bottom: 0.7em;
  text-wrap: balance;
}

h1 { font-size: 2em; }
h2 { font-size: 1.45em; border-bottom: 2px solid var(--border); padding-bottom: 0.3em; }
h3 { font-size: 1.15em; color: var(--muted); }

p { margin: 1.1em 0; }

a { color: var(--evidence); text-decoration: none; }
a:hover { text-decoration: underline; }

sup { font-size: 0.75em; color: var(--evidence); }

/* Layout */
.container {
  max-width: var(--max-content);
  margin: 0 auto;
  padding: 0 1.25rem;
}

.wide {
  max-width: var(--max-wide);
}

/* Header / Hero */
.hero {
  background: linear-gradient(180deg, #f0ece4 0%, var(--bg) 100%);
  padding: 3.5rem 0 2.5rem;
  text-align: center;
  border-bottom: 1px solid var(--border);
}

.hero h1 {
  font-size: 2.2em;
  margin: 0.3em 0;
  color: #1a1a1a;
  letter-spacing: 0.02em;
}

.hero .subtitle {
  font-size: 1.05em;
  color: var(--muted);
  max-width: 620px;
  margin: 0 auto;
  line-height: 1.65;
}

.hero-meta {
  margin-top: 1.8rem;
  font-size: 0.82em;
  color: var(--light);
  letter-spacing: 0.03em;
}

/* Navigation */
.toc {
  position: sticky;
  top: 0;
  background: rgba(250,248,245,0.96);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  z-index: 100;
  padding: 0.6rem 0;
  overflow-x: auto;
  scrollbar-width: thin;
}

.toc ul {
  list-style: none;
  display: flex;
  gap: 1.2rem;
  margin: 0;
  padding: 0;
  font-size: 0.85em;
  white-space: nowrap;
}

.toc a {
  color: var(--muted);
  padding: 0.3rem 0;
  display: inline-block;
}

.toc a:hover { color: var(--fg); }
.toc a.active { color: var(--fg); border-bottom: 2px solid var(--fg); font-weight: bold; }

/* Ethics banner */
.ethics-banner {
  background: var(--accent-bg);
  border-left: 4px solid var(--accent);
  padding: 1.2rem 1.5rem;
  margin: 2rem 0;
  border-radius: 0 6px 6px 0;
}

.ethics-banner h3 {
  margin-top: 0;
  color: var(--accent);
  font-size: 1.1em;
}

.ethics-banner ul {
  margin: 0.5em 0;
  padding-left: 1.2em;
}

.ethics-banner li {
  margin: 0.45em 0;
  font-size: 0.95em;
  line-height: 1.6;
}

/* Cards */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.2rem;
  margin: 1.5rem 0;
}

.card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.2rem;
  transition: box-shadow 0.2s;
}

.card:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.06);
}

.card-number {
  display: inline-block;
  width: 28px;
  height: 28px;
  line-height: 28px;
  text-align: center;
  background: var(--fg);
  color: #fff;
  border-radius: 50%;
  font-size: 0.85em;
  font-weight: bold;
  margin-bottom: 0.6rem;
}

.card h4 {
  margin: 0.5rem 0;
  font-size: 1.05em;
}

.card p {
  margin: 0.5rem 0;
  font-size: 0.95em;
  color: var(--muted);
}

/* Evidence level badges */
.badge {
  display: inline-block;
  padding: 0.2em 0.55em;
  border-radius: 4px;
  font-size: 0.72em;
  font-weight: bold;
  font-family: "Noto Sans SC", sans-serif;
  margin-left: 0.3em;
  letter-spacing: 0.02em;
  flex-shrink: 0;
}

.badge-A { background: var(--verified-bg); color: var(--verified); }
.badge-B { background: var(--evidence-bg); color: var(--evidence); }
.badge-C { background: var(--warn-bg); color: var(--warn); }
.badge-D { background: var(--accent-bg); color: var(--accent); }
.badge-E { background: #eee; color: #999; }

/* Figures */
figure {
  margin: 2.5rem 0;
  text-align: center;
}

figure img, figure svg {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 0 auto;
}

figcaption {
  font-size: 0.85em;
  color: var(--light);
  margin-top: 0.6rem;
  font-style: italic;
}

/* Tables */
.table-wrap {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin: 1.5rem 0;
  border: 1px solid var(--border);
  border-radius: 8px;
}

.table-wrap table {
  margin: 0;
  min-width: 600px;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.93em;
}

th, td {
  padding: 0.65rem 0.75rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

th {
  background: #f5f3f0;
  font-weight: bold;
  font-family: "Noto Sans SC", sans-serif;
  font-size: 0.88em;
  white-space: nowrap;
}

tr:last-child td { border-bottom: none; }
tr:hover { background: #fafafa; }

/* Blockquote */
blockquote {
  margin: 1.8rem 0;
  padding: 1rem 1.5rem;
  border-left: 4px solid var(--evidence);
  background: var(--evidence-bg);
  font-style: italic;
  color: var(--muted);
  border-radius: 0 6px 6px 0;
}

blockquote p { margin: 0.6em 0; }
blockquote p:first-child { margin-top: 0; }
blockquote p:last-child { margin-bottom: 0; }

/* Pull quote */
.pull-quote {
  font-size: 1.12em;
  font-style: italic;
  color: var(--muted);
  border-left: 4px solid var(--accent);
  padding: 1.1rem 1.6rem;
  margin: 1.8rem 0;
  background: var(--accent-bg);
  border-radius: 0 6px 6px 0;
  line-height: 1.7;
}

/* Evidence hint inline */
.evidence-hint {
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  padding: 0.6rem 0.9rem;
  background: #f5f3f0;
  border-radius: 6px;
  margin: 1.1rem 0;
  font-size: 0.88em;
  color: var(--muted);
  line-height: 1.5;
}

/* Interview sections */
.interview-category {
  margin: 1.5rem 0;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}

.interview-header {
  background: #f5f3f0;
  padding: 0.8rem 1.2rem;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.interview-header h4 {
  margin: 0;
  font-size: 1.05em;
}

.interview-content {
  padding: 1rem 1.2rem;
  display: none;
}

.interview-content.active {
  display: block;
}

.question-item {
  margin: 1rem 0;
  padding: 0.8rem;
  background: #fafafa;
  border-radius: 6px;
}

.question-item .q {
  font-weight: bold;
  color: var(--fg);
  margin-bottom: 0.3rem;
}

.question-item .meta {
  font-size: 0.85em;
  color: var(--light);
}

/* Question grid */
.question-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.question-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.2rem;
  position: relative;
  padding-left: 3rem;
  transition: box-shadow 0.2s;
}

.question-card:hover {
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}

.question-num {
  position: absolute;
  left: 1rem;
  top: 1.2rem;
  width: 28px;
  height: 28px;
  line-height: 28px;
  text-align: center;
  background: var(--fg);
  color: #fff;
  border-radius: 50%;
  font-size: 0.85em;
  font-weight: bold;
}

.question-card p {
  margin: 0;
  font-size: 0.95em;
  line-height: 1.6;
}

/* Source list */
.source-list {
  font-size: 0.9em;
  color: var(--muted);
  padding-left: 1.2em;
}

.source-list li {
  margin: 0.8rem 0;
  line-height: 1.6;
  padding-left: 0.5em;
}

/* Filters */
.filter-bar {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin: 1rem 0;
}

.filter-btn {
  padding: 0.4rem 0.9rem;
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 20px;
  cursor: pointer;
  font-size: 0.85em;
  font-family: inherit;
  min-height: 36px;
  min-width: 48px;
  transition: background 0.15s, border-color 0.15s;
}

.filter-btn:hover {
  background: #f5f3f0;
}

.filter-btn.active {
  background: var(--fg);
  color: #fff;
  border-color: var(--fg);
}

/* Timeline interactive */
.timeline-node {
  cursor: pointer;
  transition: opacity 0.2s;
}

.timeline-detail {
  display: none;
  padding: 1rem;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 6px;
  margin-top: 0.5rem;
}

.timeline-detail.active {
  display: block;
}

/* Footer */
.page-footer {
  margin-top: 4rem;
  padding: 2.5rem 0;
  border-top: 2px solid var(--border);
  text-align: center;
  color: var(--light);
  font-size: 0.9em;
}

.page-footer p { margin: 0.5em 0; }

/* Responsive */
@media (max-width: 768px) {
  body { font-size: 16px; line-height: 1.8; }
  .hero { padding: 2.5rem 0 2rem; }
  .hero h1 { font-size: 1.7em; }
  .hero .subtitle { font-size: 0.95em; }
  .toc ul { gap: 0.8rem; padding: 0 0.5rem; }
  .toc a { font-size: 0.9em; }
  .cards { grid-template-columns: 1fr; }
  .question-grid { grid-template-columns: 1fr; }
  table { font-size: 0.85em; }
  th, td { padding: 0.5rem; }
  .pull-quote { font-size: 1.05em; padding: 0.9rem 1.2rem; }
  .container { padding: 0 1rem; }
  h2 { font-size: 1.3em; }
}

@media (max-width: 480px) {
  .hero h1 { font-size: 1.45em; }
  .hero .subtitle { font-size: 0.88em; }
  .toc a { font-size: 0.82em; }
  .question-card { padding-left: 2.6rem; }
  .question-num { left: 0.8rem; top: 1rem; width: 24px; height: 24px; line-height: 24px; font-size: 0.78em; }
}

/* Print styles */
@media print {
  body {
    font-size: 11pt;
    line-height: 1.6;
    background: #fff;
    color: #000;
  }

  .toc,
  .filter-bar,
  .interview-header,
  button,
  .skip-link {
    display: none !important;
  }

  .hero {
    background: none;
    border-bottom: 2pt solid #ccc;
    padding: 1rem 0;
  }

  .hero h1 { font-size: 18pt; }
  .hero .subtitle { font-size: 11pt; color: #333; }
  .hero-meta { font-size: 9pt; color: #666; }

  h2 { font-size: 14pt; border-bottom: 1pt solid #ccc; }
  h3 { font-size: 12pt; }

  .container {
    max-width: 100%;
    padding: 0;
  }

  .ethics-banner,
  blockquote,
  .pull-quote {
    border-left-width: 3pt;
    page-break-inside: avoid;
  }

  figure {
    page-break-inside: avoid;
    max-width: 100%;
  }

  figure img {
    max-height: 60vh;
  }

  .table-wrap {
    border: 1pt solid #ccc;
  }

  table {
    font-size: 9pt;
  }

  th, td {
    padding: 0.4rem 0.5rem;
    border-bottom: 0.5pt solid #ccc;
  }

  .question-grid {
    grid-template-columns: 1fr;
    gap: 0.6rem;
  }

  .question-card {
    border: 1pt solid #ccc;
    page-break-inside: avoid;
  }

  .page-footer {
    border-top: 1pt solid #ccc;
    margin-top: 2rem;
    font-size: 9pt;
  }

  a {
    color: #000;
    text-decoration: underline;
  }

  a[href]::after {
    content: " (" attr(href) ")";
    font-size: 8pt;
    color: #666;
    word-break: break-all;
  }

  a[href^="#"]::after {
    content: "";
  }
}

/* Utility */
.text-center { text-align: center; }
.mt-2 { margin-top: 2rem; }
.mb-2 { margin-bottom: 2rem; }
.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;
}