:root {
  --primary: #2f6feb;
  --primary-hover: #2559c7;
  --bg: #ffffff;
  --sidebar-bg: #f6f8fa;
  --border: #d0d7de;
  --text: #24292f;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

.page-header {
  background: linear-gradient(120deg, #1f2937, #2f6feb);
  color: #fff;
  padding: 2rem 1.5rem 1rem;
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
}

.page-header h1 {
  margin: 0 0 0.25rem;
  font-size: 1.8rem;
}

.page-header h1 a {
  color: #fff;
  text-decoration: none;
}

.page-header p {
  margin: 0 0 1rem;
  opacity: 0.9;
}

.site-nav {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  border-top: 1px solid rgba(255,255,255,0.2);
  padding-top: 0.75rem;
}

.site-nav a {
  color: #e6edf3;
  text-decoration: none;
  font-size: 0.9rem;
  padding: 0.3rem 0.6rem;
  border-radius: 6px;
}

.site-nav a:hover,
.site-nav a.active {
  background: rgba(255,255,255,0.15);
  color: #fff;
}

.main-content-wrap {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  gap: 2rem;
  padding: 2rem 1.5rem;
  align-items: flex-start;
}

.sidebar-toc {
  flex: 0 0 220px;
  position: sticky;
  top: 1.5rem;
  background: var(--sidebar-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem 1.2rem;
}

.sidebar-toc strong {
  display: block;
  margin-bottom: 0.6rem;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #57606a;
}

.sidebar-toc ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.sidebar-toc li {
  margin-bottom: 0.5rem;
}

.sidebar-toc a {
  text-decoration: none;
  color: var(--primary);
  font-size: 0.92rem;
}

.sidebar-toc a:hover {
  text-decoration: underline;
}

.main-content {
  flex: 1;
  min-width: 0;
}

.main-content h1 {
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.5rem;
}

.main-content h2 {
  margin-top: 2rem;
}

.main-content pre {
  background: #f6f8fa;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem;
  overflow-x: auto;
}

.main-content code {
  background: #f6f8fa;
  border-radius: 4px;
  padding: 0.15rem 0.35rem;
  font-size: 0.9em;
}

.main-content pre code {
  background: none;
  padding: 0;
}

.main-content table {
  border-collapse: collapse;
  width: 100%;
  margin: 1rem 0;
}

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

.main-content th {
  background: var(--sidebar-bg);
}

.btn {
  display: inline-block;
  background: var(--primary);
  color: #fff !important;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  text-decoration: none;
  margin-right: 0.5rem;
  font-size: 0.9rem;
}

.btn:hover {
  background: var(--primary-hover);
}

.site-footer {
  text-align: center;
  padding: 1.5rem;
  border-top: 1px solid var(--border);
  color: #57606a;
  font-size: 0.85rem;
}

.site-footer a {
  color: var(--primary);
  text-decoration: none;
}

@media (max-width: 768px) {
  .main-content-wrap {
    flex-direction: column;
  }
  .sidebar-toc {
    position: static;
    width: 100%;
    flex: none;
  }
}