:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f6f8fa;
  --bg-tertiary: #eef1f5;
  --text-primary: #24292e;
  --text-secondary: #586069;
  --border-color: #d1d5da;
  --accent-color: #2563eb;
  --link-color: #2563eb;
  --link-hover: #1d4ed8;
  --font-sans: system-ui, -apple-system, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, 'SF Mono', Menlo, Consolas, monospace;
}

body.dark {
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --bg-tertiary: #21262d;
  --text-primary: #e6edf3;
  --text-secondary: #8b949e;
  --border-color: #30363d;
  --accent-color: #58a6ff;
  --link-color: #58a6ff;
  --link-hover: #79c0ff;
}

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

body {
  font-family: var(--font-sans);
  color: var(--text-primary);
  background: var(--bg-primary);
  line-height: 1.6;
}

a {
  color: var(--link-color);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* ---- Header / Nav ---- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
}

.site-header nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
}

.nav-brand {
  font-weight: 600;
  font-size: 1.125rem;
  color: var(--text-primary);
  font-family: var(--font-mono);
}

.nav-brand:hover {
  color: var(--link-color);
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 16px;
  align-items: center;
}

.nav-links a {
  font-size: 14px;
  color: var(--text-secondary);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
  text-decoration: none;
}

.theme-toggle {
  background: none;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 4px 8px;
  cursor: pointer;
  font-size: 16px;
  line-height: 1;
}

/* ---- Main ---- */
main {
  max-width: 960px;
  margin: 0 auto;
  padding: 40px 24px;
}

section {
  margin-bottom: 48px;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
}

h2 {
  font-size: 1.5rem;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 8px;
}

h3 {
  font-size: 1.125rem;
  margin: 24px 0 8px;
}

p {
  margin-bottom: 12px;
  color: var(--text-secondary);
}

code {
  font-family: var(--font-mono);
  background: var(--bg-secondary);
  padding: 2px 6px;
  border-radius: 3px;
  font-size: 0.875rem;
}

kbd {
  font-family: var(--font-mono);
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 3px;
  padding: 1px 5px;
  font-size: 0.8rem;
}

/* ---- Hero ---- */
.hero {
  text-align: center;
  padding: 48px 0 32px;
}

.hero h1 {
  font-family: var(--font-mono);
}

.tagline {
  font-size: 1.25rem;
  max-width: 600px;
  margin: 0 auto 24px;
}

.hero-demo {
  margin: 32px 0;
  text-align: left;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  margin-top: 24px;
}

/* ---- Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  border-radius: 6px;
  font-size: 0.9rem;
  font-weight: 500;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: all 0.2s;
}

.btn.primary {
  background: var(--accent-color);
  color: #fff;
}

.btn.primary:hover {
  background: var(--link-hover);
  text-decoration: none;
}

.btn.secondary {
  background: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn.secondary:hover {
  background: var(--bg-tertiary);
  text-decoration: none;
}

/* ---- Feature grid ---- */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-top: 16px;
}

.feature-card {
  display: block;
  padding: 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  color: var(--text-secondary);
  transition: border-color 0.2s, background 0.2s;
}

.feature-card:hover {
  border-color: var(--accent-color);
  background: var(--bg-tertiary);
  text-decoration: none;
}

.feature-card h3 {
  margin: 0 0 4px;
  font-size: 1rem;
  color: var(--text-primary);
}

.feature-card p {
  font-size: 0.8125rem;
  margin: 0;
}

/* ---- Quick Start ---- */
.quick-start code-block {
  margin-bottom: 16px;
}

/* ---- Demo sections ---- */
.demo-section {
  margin-bottom: 48px;
}

.demo-description {
  margin-bottom: 16px;
}

.demo-section pdf-viewer {
  border-radius: 8px;
  margin-bottom: 12px;
}

.demo-code {
  margin-top: 12px;
}

/* ---- Browse controls ---- */
.browse-controls {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 12px;
}

.browse-status {
  font-size: 14px;
  color: var(--text-secondary);
}

.browse-status.error {
  color: #e53e3e;
}

/* ---- Related Components ---- */
.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}

.related-card {
  display: block;
  padding: 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  color: var(--text-secondary);
  transition: border-color 0.2s, background 0.2s;
}

.related-card:hover {
  border-color: var(--accent-color);
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  text-decoration: none;
}

.related-card:hover strong {
  color: var(--text-primary);
}

.related-card strong {
  display: block;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
}

/* ---- API tables ---- */
.api-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  margin-bottom: 24px;
}

.api-table th,
.api-table td {
  text-align: left;
  padding: 8px 12px;
  border: 1px solid var(--border-color);
}

.api-table th {
  background: var(--bg-secondary);
  font-weight: 600;
}

.api-table code {
  font-size: 0.75rem;
}

/* ---- Footer ---- */
.site-footer {
  text-align: center;
  padding: 24px;
  color: var(--text-secondary);
  font-size: 0.8125rem;
  border-top: 1px solid var(--border-color);
}

/* ---- Responsive ---- */
@media (max-width: 640px) {
  h1 {
    font-size: 2rem;
  }

  .tagline {
    font-size: 1rem;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .btn {
    justify-content: center;
  }

  .nav-links {
    gap: 10px;
  }
}