:root {
  --color-bg: #ffffff;
  --color-fg: #24292f;
  --color-muted: #57606a;
  --color-border: #d0d7de;
  --color-link: #0969da;
  --color-link-hover: #0550ae;
  --color-header-bg: #24292f;
  --color-header-fg: #ffffff;
  --color-code-bg: #f6f8fa;
  --color-sidebar-bg: #f6f8fa;
  --color-accent: #0969da;
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  --max-width: 1200px;
}

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

body {
  font-family: var(--font-body);
  color: var(--color-fg);
  background: var(--color-bg);
  line-height: 1.6;
  font-size: 16px;
}

/* Header */
header {
  background: var(--color-header-bg);
  color: var(--color-header-fg);
  padding: 1.5rem 2rem;
  border-bottom: 3px solid var(--color-accent);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

header h1 {
  font-size: 1.5rem;
  font-weight: 600;
}

header h1 a {
  color: var(--color-header-fg);
  text-decoration: none;
}

header h1 a:hover {
  opacity: 0.85;
}

.tagline {
  color: #8b949e;
  font-size: 0.9rem;
  margin-top: 0.25rem;
}

/* Layout */
.container {
  display: flex;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem;
  gap: 2rem;
}

/* Sidebar */
.sidebar {
  flex: 0 0 220px;
  position: sticky;
  top: 2rem;
  align-self: flex-start;
}

.sidebar ul {
  list-style: none;
}

.sidebar li {
  margin-bottom: 0.3rem;
}

.sidebar a {
  color: var(--color-fg);
  text-decoration: none;
  font-size: 0.9rem;
  padding: 0.25rem 0.5rem;
  display: block;
  border-radius: 4px;
}

.sidebar a:hover {
  background: var(--color-sidebar-bg);
  color: var(--color-link);
}

.sidebar hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 0.75rem 0;
}

/* Main content */
main {
  flex: 1;
  min-width: 0;
}

main h1 {
  font-size: 2rem;
  font-weight: 600;
  border-bottom: 1px solid var(--color-border);
  padding-bottom: 0.5rem;
  margin-bottom: 1rem;
}

main h2 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.3rem;
  border-bottom: 1px solid var(--color-border);
}

main h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

main h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-top: 1.25rem;
  margin-bottom: 0.5rem;
}

main p {
  margin-bottom: 1rem;
}

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

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

main ul, main ol {
  margin-bottom: 1rem;
  padding-left: 2rem;
}

main li {
  margin-bottom: 0.25rem;
}

main table {
  border-collapse: collapse;
  width: 100%;
  margin-bottom: 1rem;
}

main th, main td {
  border: 1px solid var(--color-border);
  padding: 0.5rem 0.75rem;
  text-align: left;
}

main th {
  background: var(--color-code-bg);
  font-weight: 600;
}

main code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--color-code-bg);
  padding: 0.15rem 0.35rem;
  border-radius: 3px;
}

main pre {
  background: var(--color-code-bg);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 1rem;
  overflow-x: auto;
  margin-bottom: 1rem;
}

main pre code {
  background: none;
  padding: 0;
  font-size: 0.85rem;
  line-height: 1.5;
}

main blockquote {
  border-left: 4px solid var(--color-accent);
  padding: 0.5rem 1rem;
  margin: 0 0 1rem 0;
  color: var(--color-muted);
  background: var(--color-code-bg);
  border-radius: 0 4px 4px 0;
}

main img {
  max-width: 100%;
}

/* Feature cards */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.feature-card {
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 1.25rem;
  background: var(--color-code-bg);
}

.feature-card h3 {
  margin-top: 0;
  margin-bottom: 0.5rem;
  font-size: 1rem;
}

.feature-card p {
  font-size: 0.9rem;
  color: var(--color-muted);
  margin-bottom: 0;
}

/* Footer */
footer {
  border-top: 1px solid var(--color-border);
  padding: 1.5rem 2rem;
  margin-top: 2rem;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  text-align: center;
  font-size: 0.85rem;
  color: var(--color-muted);
}

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

/* Responsive */
@media (max-width: 768px) {
  .container {
    flex-direction: column;
    padding: 1rem;
  }

  .sidebar {
    position: static;
    flex: none;
    border-bottom: 1px solid var(--color-border);
    padding-bottom: 1rem;
    margin-bottom: 1rem;
  }

  .sidebar ul {
    display: flex;
    flex-wrap: wrap;
    gap: 0.25rem;
  }

  .sidebar li {
    margin-bottom: 0;
  }

  .sidebar hr {
    display: none;
  }
}