/* === Doc Viewer — Academic White === */

@import url('https://fonts.googleapis.com/css2?family=Newsreader:ital,opsz,wght@0,6..72,300..800;1,6..72,300..800&family=JetBrains+Mono:wght@400;500&family=DM+Sans:wght@400;500;600;700&display=swap');

:root {
  --fg: #1a1a1a;
  --fg-muted: #6b7280;
  --fg-light: #9ca3af;
  --bg: #ffffff;
  --bg-warm: #fafaf8;
  --bg-code: #f6f5f0;
  --accent: #2563eb;
  --accent-light: #dbeafe;
  --border: #e5e5e0;
  --border-light: #f0f0eb;
  --serif: 'Newsreader', 'Georgia', serif;
  --sans: 'DM Sans', -apple-system, sans-serif;
  --mono: 'JetBrains Mono', 'Menlo', monospace;
  --max-w: 760px;
  --toc-w: 240px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

body {
  font-family: var(--serif);
  color: var(--fg);
  background: var(--bg);
  line-height: 1.75;
  min-height: 100dvh;
}

/* === Index page === */
.index-page {
  max-width: 600px;
  margin: 0 auto;
  padding: 80px 24px 120px;
}

.index-header {
  margin-bottom: 56px;
}

.index-header h1 {
  font-family: var(--sans);
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 8px;
}

.index-header p {
  font-size: 0.9rem;
  color: var(--fg-muted);
  font-family: var(--sans);
}

.doc-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1px;
  background: var(--border-light);
  border-radius: 12px;
  overflow: hidden;
  border: 1px solid var(--border);
}

.doc-list li {
  background: var(--bg);
}

.doc-list a {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 20px 24px;
  text-decoration: none;
  color: var(--fg);
  transition: background 0.15s;
}

.doc-list a:hover {
  background: var(--bg-warm);
}

.doc-title {
  font-family: var(--sans);
  font-weight: 600;
  font-size: 1rem;
  color: var(--fg);
}

.doc-meta {
  font-family: var(--sans);
  font-size: 0.8rem;
  color: var(--fg-light);
}

/* === Viewer page === */
.viewer-layout {
  display: flex;
  min-height: 100dvh;
}

/* TOC sidebar */
.toc-sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--toc-w);
  height: 100dvh;
  overflow-y: auto;
  padding: 32px 16px 32px 24px;
  border-right: 1px solid var(--border-light);
  background: var(--bg-warm);
  z-index: 10;
}

.toc-sidebar .back-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-family: var(--sans);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--fg-muted);
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 24px;
  transition: color 0.15s;
}

.toc-sidebar .back-link:hover { color: var(--accent); }

.toc-sidebar nav { display: flex; flex-direction: column; gap: 2px; }

.toc-sidebar nav a {
  display: block;
  font-family: var(--sans);
  font-size: 0.78rem;
  line-height: 1.5;
  color: var(--fg-muted);
  text-decoration: none;
  padding: 4px 8px;
  border-radius: 6px;
  transition: all 0.15s;
  border-left: 2px solid transparent;
}

.toc-sidebar nav a:hover {
  color: var(--fg);
  background: rgba(0,0,0,0.03);
}

.toc-sidebar nav a.active {
  color: var(--accent);
  border-left-color: var(--accent);
  background: var(--accent-light);
}

.toc-sidebar nav a.toc-h3 { padding-left: 20px; font-size: 0.74rem; }
.toc-sidebar nav a.toc-h4 { padding-left: 32px; font-size: 0.72rem; }

/* Main content */
.content-area {
  margin-left: var(--toc-w);
  flex: 1;
  max-width: calc(var(--max-w) + 80px);
  padding: 48px 40px 120px;
}

/* Mobile TOC toggle */
.toc-toggle {
  display: none;
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 20;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--bg);
  box-shadow: 0 4px 20px rgba(0,0,0,0.1);
  font-size: 1.2rem;
  cursor: pointer;
  align-items: center;
  justify-content: center;
  font-family: var(--sans);
  color: var(--fg);
}

/* === Markdown content === */
.md-content h1 {
  font-family: var(--sans);
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.25;
  margin: 0 0 8px;
  padding-bottom: 16px;
  border-bottom: 2px solid var(--fg);
}

.md-content h2 {
  font-family: var(--sans);
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 48px 0 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

.md-content h3 {
  font-family: var(--sans);
  font-size: 1.1rem;
  font-weight: 600;
  margin: 36px 0 12px;
}

.md-content h4 {
  font-family: var(--sans);
  font-size: 0.95rem;
  font-weight: 600;
  margin: 28px 0 8px;
  color: var(--fg-muted);
}

.md-content p { margin: 0 0 16px; }

.md-content a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 2px;
  text-decoration-color: rgba(37, 99, 235, 0.3);
  transition: text-decoration-color 0.15s;
}
.md-content a:hover { text-decoration-color: var(--accent); }

.md-content blockquote {
  margin: 20px 0;
  padding: 16px 20px;
  border-left: 3px solid var(--accent);
  background: var(--bg-warm);
  border-radius: 0 8px 8px 0;
  color: var(--fg-muted);
  font-style: italic;
}
.md-content blockquote p:last-child { margin-bottom: 0; }

.md-content ul, .md-content ol {
  margin: 0 0 16px;
  padding-left: 24px;
}

.md-content li { margin-bottom: 6px; }
.md-content li > ul, .md-content li > ol { margin-top: 6px; margin-bottom: 0; }

.md-content hr {
  border: none;
  height: 1px;
  background: var(--border);
  margin: 40px 0;
}

/* Code */
.md-content code {
  font-family: var(--mono);
  font-size: 0.85em;
  background: var(--bg-code);
  padding: 2px 6px;
  border-radius: 4px;
  color: #c7254e;
}

.md-content pre {
  margin: 20px 0;
  border-radius: 10px;
  overflow: hidden;
  border: 1px solid var(--border);
}

.md-content pre code {
  display: block;
  padding: 20px 24px;
  background: var(--bg-code);
  color: var(--fg);
  font-size: 0.82rem;
  line-height: 1.7;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

/* Tables */
.md-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  font-size: 0.88rem;
  font-family: var(--sans);
  overflow-x: auto;
  display: block;
}

.md-content thead th {
  background: var(--bg-warm);
  font-weight: 600;
  text-align: left;
  padding: 12px 16px;
  border-bottom: 2px solid var(--border);
  white-space: nowrap;
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--fg-muted);
}

.md-content tbody td {
  padding: 10px 16px;
  border-bottom: 1px solid var(--border-light);
  vertical-align: top;
}

.md-content tbody tr:hover { background: var(--bg-warm); }

/* Strong / Em */
.md-content strong { font-weight: 700; }
.md-content em { font-style: italic; }

/* Images */
.md-content img {
  max-width: 100%;
  border-radius: 8px;
  margin: 16px 0;
}

/* === Responsive === */
@media (max-width: 900px) {
  .toc-sidebar {
    transform: translateX(-100%);
    transition: transform 0.25s ease;
    width: 280px;
    box-shadow: 4px 0 24px rgba(0,0,0,0.1);
  }

  .toc-sidebar.open { transform: translateX(0); }

  .toc-toggle { display: flex; }

  .content-area {
    margin-left: 0;
    padding: 32px 20px 100px;
  }

  .md-content h1 { font-size: 1.5rem; }
  .md-content h2 { font-size: 1.15rem; }
  .md-content h3 { font-size: 1rem; }

  .md-content pre code {
    padding: 16px;
    font-size: 0.78rem;
  }

  .md-content table { font-size: 0.82rem; }
  .md-content thead th { padding: 8px 12px; }
  .md-content tbody td { padding: 8px 12px; }
}

@media (max-width: 480px) {
  .index-page { padding: 48px 16px 80px; }
  .doc-list a { padding: 16px 18px; }
  .content-area { padding: 24px 16px 80px; }
}

/* TOC overlay backdrop */
.toc-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.2);
  z-index: 9;
}
.toc-backdrop.open { display: block; }

/* Scroll progress bar */
.progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  background: var(--accent);
  z-index: 100;
  transition: width 0.1s;
  width: 0%;
}

/* Logout button */
.logout-btn {
  display: inline-block;
  font-family: var(--sans);
  font-size: 0.75rem;
  color: var(--fg-light);
  background: none;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 4px 12px;
  cursor: pointer;
  transition: all 0.15s;
  margin-top: 8px;
}
.logout-btn:hover {
  color: var(--fg-muted);
  border-color: var(--fg-light);
}

/* Print */
@media print {
  .toc-sidebar, .toc-toggle, .progress-bar { display: none !important; }
  .content-area { margin-left: 0; padding: 0; }
}