:root {
  --bg: #f8f6f1;
  --surface: #ffffff;
  --text: #1a1a1a;
  --muted: #5c5c5c;
  --accent: #2c5282;
  --accent-light: #ebf4ff;
  --border: #d4cfc4;
  --warning-bg: #fff8e6;
  --warning-border: #d4a017;
  --success-bg: #edf7ed;
  --success-border: #2d6a2d;
  --nav-width: 260px;
  --font-serif: Georgia, "Times New Roman", serif;
  --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
}

.layout {
  display: flex;
  min-height: 100vh;
}

nav.sidebar {
  width: var(--nav-width);
  min-width: var(--nav-width);
  background: #1e3a5f;
  color: #e8edf3;
  padding: 1.5rem 0;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
}

nav.sidebar h1 {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: normal;
  padding: 0 1.25rem 1rem;
  border-bottom: 1px solid rgba(255,255,255,0.15);
  margin-bottom: 0.75rem;
  line-height: 1.4;
}

nav.sidebar .subtitle {
  font-size: 0.75rem;
  color: #a8bdd4;
  display: block;
  margin-top: 0.35rem;
}

nav.sidebar ul { list-style: none; }

nav.sidebar li a {
  display: block;
  padding: 0.45rem 1.25rem;
  color: #c8d8ea;
  text-decoration: none;
  font-size: 0.88rem;
  border-left: 3px solid transparent;
  transition: background 0.15s, color 0.15s;
}

nav.sidebar li a:hover,
nav.sidebar li a.active {
  background: rgba(255,255,255,0.08);
  color: #fff;
  border-left-color: #63b3ed;
}

main.content {
  flex: 1;
  padding: 2rem 2.5rem 4rem;
  max-width: 900px;
}

h1.page-title {
  font-family: var(--font-serif);
  font-size: 1.85rem;
  font-weight: normal;
  margin-bottom: 0.35rem;
  color: #1e3a5f;
}

.page-meta {
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 1.75rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
}

h2 {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: normal;
  margin: 2rem 0 0.75rem;
  color: #2c5282;
}

h3 {
  font-size: 1.05rem;
  margin: 1.5rem 0 0.5rem;
  color: #333;
}

p { margin-bottom: 0.85rem; }

ul, ol { margin: 0.5rem 0 1rem 1.5rem; }
li { margin-bottom: 0.35rem; }

a { color: var(--accent); }
a:hover { text-decoration: underline; }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1.25rem 1.5rem;
  margin: 1rem 0;
}

.card h3 { margin-top: 0; }

.alert {
  border-radius: 6px;
  padding: 1rem 1.25rem;
  margin: 1rem 0;
  border-left: 4px solid;
}

.alert-warning {
  background: var(--warning-bg);
  border-color: var(--warning-border);
}

.alert-success {
  background: var(--success-bg);
  border-color: var(--success-border);
}

.alert-info {
  background: var(--accent-light);
  border-color: var(--accent);
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.9rem;
  background: var(--surface);
}

th, td {
  border: 1px solid var(--border);
  padding: 0.55rem 0.75rem;
  text-align: left;
  vertical-align: top;
}

th {
  background: #eef2f7;
  font-weight: 600;
}

tr:nth-child(even) td { background: #fafafa; }

.source-link {
  word-break: break-all;
  font-size: 0.85rem;
}

.tag {
  display: inline-block;
  font-size: 0.72rem;
  padding: 0.15rem 0.5rem;
  border-radius: 3px;
  background: #e2e8f0;
  color: #2d3748;
  margin-right: 0.35rem;
  vertical-align: middle;
}

.tag-verified { background: #c6f6d5; color: #22543d; }
.tag-unverified { background: #fed7d7; color: #742a2a; }
.tag-new { background: #bee3f8; color: #2a4365; }

blockquote {
  border-left: 3px solid var(--accent);
  padding: 0.5rem 0 0.5rem 1rem;
  margin: 1rem 0;
  font-style: italic;
  color: var(--muted);
  background: var(--accent-light);
  border-radius: 0 4px 4px 0;
}

.diagram {
  font-family: "Consolas", "Courier New", monospace;
  font-size: 0.8rem;
  background: #f0f0f0;
  padding: 1rem;
  border-radius: 4px;
  overflow-x: auto;
  white-space: pre;
  line-height: 1.4;
  margin: 1rem 0;
}

.link-grid {
  display: grid;
  gap: 0.5rem;
  margin: 1rem 0;
}

.link-grid a {
  display: block;
  padding: 0.5rem 0.75rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  text-decoration: none;
  font-size: 0.88rem;
}

.link-grid a:hover {
  background: var(--accent-light);
  border-color: var(--accent);
}

footer.page-footer {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  font-size: 0.8rem;
  color: var(--muted);
}

@media (max-width: 768px) {
  .layout { flex-direction: column; }
  nav.sidebar {
    width: 100%;
    height: auto;
    position: relative;
  }
  main.content { padding: 1.25rem; }
}