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

:root {
  --bg: #212121;
  --bg-surface: #2a2a2a;
  --bg-hover: #333;
  --text: #e8e8e8;
  --text-muted: #999;
  --text-dim: #666;
  --border: #373737;
  --accent: #e8e8e8;
  --link: #93b3e0;
  --code-bg: #1a1a1a;
  --panel-bg: #2a2a2a;
  --max-content: 720px;
  --sidebar-w: 56px;
  --panel-w: 340px;
}

/* ── Light mode ── */
[data-theme="light"] {
  --bg: #ffffff;
  --bg-surface: #f7f7f7;
  --bg-hover: #ebebeb;
  --text: #1a1a1a;
  --text-muted: #666;
  --text-dim: #999;
  --border: #e0e0e0;
  --accent: #1a1a1a;
  --link: #2563eb;
  --code-bg: #f4f4f4;
  --panel-bg: #f7f7f7;
}

/* ── Theme toggle icon visibility ── */
.theme-icon-light { display: none; }
.theme-icon-dark { display: flex; }
[data-theme="light"] .theme-icon-light { display: flex; }
[data-theme="light"] .theme-icon-dark { display: none; }

html { font-size: 16px; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

/* ── Layout ── */
.layout {
  display: flex;
  min-height: 100vh;
}

/* ── Left sidebar: back + TOC ── */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-w);
  height: 100vh;
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 16px 0;
  z-index: 10;
}

.sidebar-back {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  color: var(--text-muted);
  text-decoration: none;
  border-radius: 6px;
  transition: background 0.15s, color 0.15s;
}
.sidebar-back:hover { background: var(--bg-hover); color: var(--text); }
.sidebar-back svg { width: 18px; height: 18px; }

.toc {
  margin-top: 24px;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 2px;
  width: 100%;
  padding: 0 8px;
  overflow-y: auto;
  flex: 1;
  scrollbar-width: none;
}
.toc::-webkit-scrollbar { display: none; }

.toc li {
  position: relative;
}

.toc a {
  display: block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--text-dim);
  margin: 4px auto;
  transition: background 0.2s, transform 0.2s;
  text-decoration: none;
}
.toc a:hover,
.toc a.active {
  background: var(--text);
  transform: scale(1.5);
}

.toc-tooltip {
  position: absolute;
  left: 48px;
  top: 50%;
  transform: translateY(-50%);
  background: var(--bg-surface);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 4px 10px;
  border-radius: 6px;
  font-size: 0.75rem;
  white-space: nowrap;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.15s;
  z-index: 100;
}
.toc li:hover .toc-tooltip { opacity: 1; }

/* ── Main content ── */
.main {
  margin-left: var(--sidebar-w);
  flex: 1;
  display: flex;
  justify-content: center;
  padding: 60px 40px 120px;
}

.content {
  max-width: var(--max-content);
  width: 100%;
}

/* ── Toolbar (top right) ── */
.toolbar {
  position: fixed;
  top: 16px;
  right: 24px;
  display: flex;
  gap: 8px;
  z-index: 20;
}

.toolbar-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
  position: relative;
}
.toolbar-btn:hover { background: var(--bg-hover); color: var(--text); }
.toolbar-btn svg { width: 18px; height: 18px; }

/* ── Download dropdown ── */
.download-menu {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 4px;
  min-width: 180px;
  display: none;
  flex-direction: column;
  box-shadow: 0 8px 32px rgba(0,0,0,0.4);
}
.download-menu.open { display: flex; }

.download-menu button {
  background: none;
  border: none;
  color: var(--text);
  padding: 8px 12px;
  text-align: left;
  font-size: 0.875rem;
  border-radius: 6px;
  cursor: pointer;
  font-family: inherit;
}
.download-menu button:hover { background: var(--bg-hover); }

/* ── Sources panel ── */
.sources-panel {
  position: fixed;
  top: 0;
  right: 0;
  width: var(--panel-w);
  height: 100vh;
  background: var(--panel-bg);
  border-left: 1px solid var(--border);
  transform: translateX(100%);
  transition: transform 0.25s ease;
  z-index: 30;
  display: flex;
  flex-direction: column;
}
.sources-panel.open { transform: translateX(0); }

.sources-header {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-shrink: 0;
}
.sources-header h3 {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text);
}
.sources-header .count {
  font-size: 0.75rem;
  color: var(--text-muted);
  background: var(--bg);
  padding: 2px 8px;
  border-radius: 10px;
}
.sources-close {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 4px;
  border-radius: 4px;
  display: flex;
}
.sources-close:hover { color: var(--text); }
.sources-close svg { width: 16px; height: 16px; }

.sources-list {
  flex: 1;
  overflow-y: auto;
  padding: 12px 16px;
}

.source-item {
  display: block;
  padding: 10px 12px;
  border-radius: 8px;
  text-decoration: none;
  color: var(--text);
  transition: background 0.15s;
  margin-bottom: 4px;
}
.source-item:hover { background: var(--bg-hover); }

.source-num {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-bottom: 2px;
}
.source-title {
  font-size: 0.85rem;
  font-weight: 500;
  line-height: 1.4;
  margin-bottom: 2px;
}
.source-url {
  font-size: 0.7rem;
  color: var(--text-dim);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ── Typography ── */
.content h1 {
  font-size: 1.75rem;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 8px;
}

.content-meta {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 40px;
}
.content-meta .model-badge {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.7rem;
  margin-left: 8px;
}

.content h2 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-top: 48px;
  margin-bottom: 16px;
  line-height: 1.35;
}

.content h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-top: 32px;
  margin-bottom: 12px;
}

.content p {
  margin-bottom: 16px;
  color: var(--text);
}

.content a {
  color: var(--link);
  text-decoration: none;
}
.content a:hover { text-decoration: underline; }

.content ul, .content ol {
  margin-bottom: 16px;
  padding-left: 24px;
}
.content li { margin-bottom: 6px; }

.content blockquote {
  border-left: 3px solid var(--border);
  padding-left: 16px;
  color: var(--text-muted);
  margin-bottom: 16px;
}

.content code {
  font-family: "SF Mono", "Fira Code", "Fira Mono", Menlo, monospace;
  font-size: 0.875em;
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 4px;
}

.content pre {
  background: var(--code-bg);
  border-radius: 8px;
  padding: 16px 20px;
  overflow-x: auto;
  margin-bottom: 16px;
  border: 1px solid var(--border);
}
.content pre code {
  background: none;
  padding: 0;
  font-size: 0.85rem;
  line-height: 1.6;
}

.content strong { font-weight: 600; }

/* ── Tables ── */
.content table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 20px;
  font-size: 0.9rem;
  line-height: 1.6;
}
.content thead {
  border-bottom: 2px solid var(--border);
}
.content th {
  text-align: left;
  font-weight: 600;
  padding: 10px 12px;
  color: var(--text);
  white-space: nowrap;
}
.content td {
  padding: 8px 12px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
.content tbody tr:last-child td {
  border-bottom: none;
}
.content tbody tr:hover {
  background: var(--code-bg);
}
.content table a {
  word-break: break-all;
}

/* ── Blockquotes (nested) ── */
.content blockquote blockquote {
  margin-top: 8px;
  border-left-color: var(--text-dim);
}

/* ── Definition lists ── */
.content dl {
  margin-bottom: 16px;
}
.content dt {
  font-weight: 600;
  margin-bottom: 4px;
}
.content dd {
  margin-left: 24px;
  margin-bottom: 12px;
  color: var(--text-muted);
}

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

/* ── Overflow wrapper for wide tables on mobile ── */
.content .table-wrap {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin-bottom: 20px;
}

.content hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 40px 0;
}

/* citation ref inline */
.cite-ref {
  font-size: 0.7rem;
  vertical-align: super;
  color: var(--link);
  cursor: pointer;
  margin-left: 1px;
}
.cite-ref:hover { text-decoration: underline; }

/* ── Index page ── */
.index-header {
  margin-bottom: 24px;
}
.index-header h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 8px;
}
.index-header p {
  color: var(--text-muted);
  font-size: 0.95rem;
}

.index-nav {
  margin-bottom: 24px;
  display: flex;
  gap: 20px;
}
.index-nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.85rem;
  transition: color 0.15s;
}
.index-nav a:hover { color: var(--text); }

/* ── Page theme toggle (top right on non-slug pages) ── */
.page-theme-btn {
  position: fixed;
  top: 16px;
  right: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
  z-index: 20;
}
.page-theme-btn:hover { background: var(--bg-hover); color: var(--text); }
.page-theme-btn svg { width: 18px; height: 18px; }

/* ── Epigraph ── */
.epigraph {
  margin-bottom: 32px;
  padding: 0;
}
.epigraph blockquote {
  border-left: 2px solid var(--border);
  padding-left: 16px;
  margin: 0 0 8px;
  color: var(--text-muted);
  font-style: italic;
  line-height: 1.7;
  font-size: 0.9rem;
}
.epigraph cite {
  display: block;
  font-size: 0.8rem;
  color: var(--text-dim);
  font-style: normal;
  padding-left: 16px;
}

.entry-list {
  list-style: none;
}

.entry-item {
  border-bottom: 1px solid var(--border);
}

.entry-item a {
  display: block;
  padding: 20px 0;
  text-decoration: none;
  color: var(--text);
  transition: color 0.15s;
}
.entry-item a:hover { color: var(--text-muted); }

.entry-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.entry-excerpt {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.5;
  margin-bottom: 6px;
}

.entry-meta {
  font-size: 0.75rem;
  color: var(--text-dim);
  display: flex;
  gap: 12px;
}

/* ── Static pages (about, faq) ── */
.page-container {
  max-width: 640px;
  margin: 80px auto;
  padding: 0 24px;
}
.page-container h1 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 32px;
}
.page-container h2 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-top: 36px;
  margin-bottom: 12px;
}
.page-container p, .page-container li {
  color: var(--text);
  line-height: 1.75;
  margin-bottom: 12px;
}
.page-container a { color: var(--text-muted); text-decoration: none; transition: color 0.15s; }
.page-container a:hover { color: var(--text); }
.page-nav {
  margin-bottom: 48px;
}
.page-nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.85rem;
  transition: color 0.15s;
}
.page-nav a:hover { color: var(--text); }

/* ── FAQ page ── */
.faq-container {
  max-width: 640px;
  margin: 60px auto;
  padding: 0 24px;
}

.faq-header {
  margin-bottom: 32px;
}
.faq-header h1 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 8px;
}
.faq-meta {
  display: flex;
  gap: 20px;
  font-size: 0.75rem;
  color: var(--text-dim);
}

.faq-toc {
  margin-bottom: 40px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
}
.faq-toc h2 {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 10px;
}
.faq-toc ol {
  list-style: none;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.faq-toc li a {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.15s;
  line-height: 1.6;
}
.faq-toc li a:hover { color: var(--text); }

.faq-body h2 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-top: 36px;
  margin-bottom: 10px;
  color: var(--text);
}
.faq-body p {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.75;
  margin-bottom: 12px;
}

/* ── Graph modal ── */
.graph-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 50;
  align-items: center;
  justify-content: center;
}
.graph-backdrop.open { display: flex; }

.graph-modal {
  width: 80vw;
  height: 80vh;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  position: relative;
  overflow: hidden;
}
.graph-modal svg { width: 100%; height: 100%; }

.graph-modal-tooltip {
  position: absolute;
  top: 12px;
  left: 12px;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 4px 10px;
  border-radius: 8px;
  font-size: 0.75rem;
  font-family: monospace;
  white-space: nowrap;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.15s;
  z-index: 51;
  box-shadow: 0 2px 8px rgba(0,0,0,0.2);
}
.graph-modal-tooltip.visible { opacity: 1; }

/* ── Responsive ── */
@media (max-width: 768px) {
  .sidebar { display: none; }
  .main { margin-left: 0; padding: 40px 20px 80px; }
  .sources-panel { width: 100%; }
  .toolbar { right: 16px; top: 12px; }
  .content table { font-size: 0.8rem; }
  .content th, .content td { padding: 6px 8px; }
}

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-dim); }

/* ── Print ── */
@media print {
  .sidebar, .toolbar, .sources-panel { display: none !important; }
  .main { margin-left: 0; padding: 0; }
  body { background: #fff; color: #000; }
  .content a { color: #000; }
  .content pre { border-color: #ccc; }
}