:root {
  --sidebar-w: 260px;
  --bg: #f5f7fa;
  --panel: #fff;
  --border: #e4e7ed;
  --text: #303133;
  --muted: #606266;
  --accent: #1565c0;
  --accent-soft: #e3f2fd;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: "Segoe UI", "Microsoft YaHei", sans-serif;
  font-size: 14px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
}

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

.sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  background: var(--panel);
  border-right: 1px solid var(--border);
  padding: 20px 0 40px;
}

.sidebar-title {
  padding: 0 20px 12px;
  font-size: 15px;
  font-weight: 600;
  color: var(--accent);
  border-bottom: 1px solid var(--border);
  margin-bottom: 8px;
}

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

.toc a {
  display: block;
  padding: 6px 20px;
  color: var(--muted);
  text-decoration: none;
  font-size: 13px;
  border-left: 3px solid transparent;
}

.toc a:hover { background: var(--accent-soft); color: var(--accent); }

.toc a.active {
  color: var(--accent);
  font-weight: 600;
  border-left-color: var(--accent);
  background: var(--accent-soft);
}

.main {
  flex: 1;
  min-width: 0;
  padding: 32px 48px 80px;
  max-width: 920px;
  overflow-y: auto;
}

.content h1 { font-size: 26px; margin: 0 0 8px; color: var(--accent); }

.content .subtitle { color: var(--muted); margin-bottom: 32px; }

.content h2 {
  font-size: 20px;
  margin: 40px 0 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--accent-soft);
  scroll-margin-top: 16px;
}

.content h2:first-child { margin-top: 0; }

.content h3 { font-size: 16px; margin: 24px 0 10px; color: #1a1a1a; }

.content h4 { font-size: 14px; margin: 16px 0 8px; }

.content p { margin: 8px 0; }

.content ul, .content ol { margin: 8px 0; padding-left: 22px; }

.content li { margin: 4px 0; }

.content table {
  width: 100%;
  border-collapse: collapse;
  margin: 12px 0;
  font-size: 13px;
  background: var(--panel);
}

.content th, .content td {
  border: 1px solid var(--border);
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}

.content th { background: #fafafa; font-weight: 600; }

.content code {
  background: #f0f2f5;
  padding: 1px 5px;
  border-radius: 3px;
  font-size: 12px;
}

.content pre {
  background: #1e1e1e;
  color: #d4d4d4;
  padding: 14px 16px;
  border-radius: 6px;
  overflow-x: auto;
  font-size: 12px;
  line-height: 1.5;
  margin: 12px 0;
}

.content pre code { background: none; padding: 0; color: inherit; }

.content .note {
  background: #fff8e1;
  border-left: 4px solid #ffc107;
  padding: 10px 14px;
  margin: 12px 0;
  font-size: 13px;
}

.loading { color: #909399; padding: 24px 0; }

.error { color: #c62828; padding: 24px 0; }

@media (max-width: 768px) {
  .layout { flex-direction: column; }
  .sidebar { width: 100%; height: auto; position: relative; }
  .main { padding: 20px 16px 60px; }
}