:root {
  --bg-color: #ffffff;
  --text-color: #333333;
  --sidebar-bg: #f3f3f3;
  --sidebar-width: 240px;
}
[data-theme="dark"] {
  --bg-color: #222222;
  --text-color: #eeeeee;
  --sidebar-bg: #333333;
}
body {
  margin: 0;
  background: var(--bg-color);
  color: var(--text-color);
  font-family: Arial, sans-serif;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}
.header {
  display: flex;
  align-items: center;
  padding: 0.5rem 1rem;
  background: var(--sidebar-bg);
  position: sticky;
  top: 0;
  z-index: 1100;
}
.search-input {
  margin-left: auto;
  padding: 0.25rem;
}
.search-results {
  display: none;
  position: absolute;
  right: 1rem;
  top: 100%;
  background: var(--bg-color);
  border: 1px solid #ccc;
  width: 250px;
  max-height: 200px;
  overflow-y: auto;
  z-index: 100;
}
.search-results a {
  display: block;
  padding: 0.25rem;
  color: var(--text-color);
  text-decoration: none;
}
.search-results a:hover {
  background: var(--sidebar-bg);
}
.search-results .no-results {
  padding: 0.25rem;
}
.logo { text-decoration: none; color: var(--text-color); font-weight: bold; }
.sidebar-toggle,
.theme-toggle { background: none; border: none; font-size: 1.2rem; margin-right: 1rem; cursor: pointer; }
.container { display: flex; flex: 1; }
.sidebar {
  width: var(--sidebar-width);
  background: var(--sidebar-bg);
  padding: 1rem;
  box-sizing: border-box;
}
.sidebar ul { list-style: none; padding: 0; margin: 0; }
.sidebar li { margin: 0.25rem 0; }
.sidebar a { text-decoration: none; color: var(--text-color); display: block; padding: 0.25rem 0; }
.sidebar nav { font-size: 0.9rem; }
.nav-link:hover { text-decoration: underline; }
.nav-link.active { font-weight: bold; }
.nav-section summary {
  list-style: none;
  cursor: pointer;
  position: relative;
  display: flex;
  align-items: center;
}
.nav-section summary::-webkit-details-marker { display: none; }
.nav-section summary::before {
  content: '▸';
  display: inline-block;
  margin-right: 0.25rem;
  transition: transform 0.2s ease;
}
.nav-section[open] > summary::before { transform: rotate(90deg); }
.nav-level { padding-left: 1rem; margin-left: 0.5rem; border-left: 2px solid #ccc; }
.sidebar ul ul { padding-left: 1rem; margin-left: 0.5rem; border-left: 2px solid #ccc; }
main {
  flex: 1;
  padding: 2rem;
}
.breadcrumbs a { color: var(--text-color); text-decoration: none; }
.footer {
  text-align: center;
  padding: 1rem;
  background: var(--sidebar-bg);
  position: relative;
}
.footer-links {
  margin-bottom: 0.5rem;
}
.footer-links a {
  margin: 0 0.5rem;
  text-decoration: none;
  color: var(--text-color);
}
.footer-permanent-links {
  position: absolute;
  right: 0.5rem;
  bottom: 0.25rem;
  font-size: 0.8rem;
  opacity: 0.7;
}
.footer-permanent-links a {
  margin-left: 0.5rem;
  text-decoration: none;
  color: var(--text-color);
}

.sidebar-overlay {
  display: none;
}
@media (max-width: 768px) {
  body.sidebar-open .sidebar-overlay {
    display: block;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.3);
    z-index: 999;
  }
}
@media (max-width: 768px) {
  .sidebar {
    position: fixed;
    left: -100%;
    top: 0;
    height: 100%;
    overflow-y: auto;
    transition: none;
    z-index: 1000;
  }
  body.sidebar-open .sidebar { left: 0; }
}

@media (min-width: 769px) {
  .sidebar {
    transition: width 0.2s ease;
  }
  body:not(.sidebar-open) .sidebar {
    width: 0;
    padding: 0;
    overflow: hidden;
  }
}