:root {
  color-scheme: light;
  --bg: #f4f6fb;
  --surface: #ffffff;
  --muted: #6b7280;
  --text: #111827;
  --accent: #3366ff;
  --accent-dark: #1d4ed8;
  --border: #e5e7eb;
  --sidebar-bg: #ffffff;
  --sidebar-border: #d1d5db;
}

* {
  box-sizing: border-box;
}

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

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

a:hover,
a:focus {
  text-decoration: underline;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 32px;
  background: linear-gradient(90deg, #1f2937 0%, #111827 100%);
  color: #fff;
  box-shadow: 0 10px 30px rgba(17, 24, 39, 0.35);
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-pill {
  display: inline-flex;
  align-items: center;
  padding: 6px 12px;
  border-radius: 999px;
  background: rgba(59, 130, 246, 0.2);
  color: #bfdbfe;
  font-size: 13px;
  letter-spacing: 0.2px;
  text-transform: uppercase;
  font-weight: 600;
}

.brand-title {
  font-size: 20px;
  font-weight: 600;
}

.mode-switcher {
  display: inline-flex;
  gap: 10px;
  align-items: center;
}

.mode-btn {
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.08);
  color: #fff;
  font-size: 14px;
  padding: 8px 18px;
  border-radius: 999px;
  cursor: pointer;
  transition: all 0.2s ease-in-out;
}

.mode-btn:hover,
.mode-btn:focus {
  background: rgba(255, 255, 255, 0.18);
  border-color: rgba(255, 255, 255, 0.35);
  outline: none;
}

.mode-btn.active {
  background: #fff;
  color: var(--accent-dark);
  border-color: #fff;
  box-shadow: 0 8px 20px rgba(255, 255, 255, 0.35);
}

.layout {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 24px;
  padding: 28px 32px 60px;
}

.sidebar {
  position: sticky;
  top: 90px;
  align-self: start;
  padding: 24px;
  border-radius: 18px;
  background: var(--sidebar-bg);
  border: 1px solid var(--sidebar-border);
  box-shadow: 0 12px 28px rgba(15, 23, 42, 0.08);
  max-height: calc(100vh - 120px);
  overflow-y: auto;
}

.sidebar::-webkit-scrollbar {
  width: 6px;
}

.sidebar::-webkit-scrollbar-thumb {
  background: rgba(107, 114, 128, 0.35);
  border-radius: 999px;
}

.sidebar-section {
  display: block;
}

.sidebar-section.hidden {
  display: none;
}

.sidebar-title {
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 16px;
}

.sidebar nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 10px;
}

.sidebar nav a {
  display: block;
  font-size: 15px;
  color: var(--muted);
  padding: 6px 10px;
  border-radius: 8px;
  transition: background 0.2s ease-in-out, color 0.2s;
}

.sidebar nav a:hover,
.sidebar nav a:focus {
  background: rgba(51, 102, 255, 0.08);
  color: var(--accent-dark);
  outline: none;
}

.content {
  display: block;
}

.doc-panel {
  display: none;
  background: var(--surface);
  padding: 36px;
  border-radius: 20px;
  box-shadow: 0 28px 60px rgba(15, 23, 42, 0.12);
  border: 1px solid rgba(226, 232, 240, 0.85);
}

.doc-panel.active {
  display: block;
}

.doc-panel h1 {
  margin-top: 0;
  font-size: 32px;
  font-weight: 600;
  margin-bottom: 24px;
}

.doc-panel h2 {
  font-size: 26px;
  margin-top: 36px;
  margin-bottom: 12px;
}

.doc-panel h3 {
  font-size: 20px;
  margin-top: 18px;
  margin-bottom: 10px;
}

.doc-panel p {
  margin-top: 8px;
  margin-bottom: 12px;
}

.doc-panel ul,
.doc-panel ol {
  margin: 0 0 18px 20px;
  padding: 0;
}

.doc-panel ul li,
.doc-panel ol li {
  margin-bottom: 8px;
}

.table-wrapper {
  overflow-x: auto;
  margin: 16px 0 22px;
  border-radius: 12px;
  border: 1px solid var(--border);
}

table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
}

table thead {
  background: rgba(51, 102, 255, 0.08);
}

table th,
table td {
  padding: 12px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border);
  font-size: 15px;
}

table tbody tr:hover {
  background: rgba(51, 102, 255, 0.04);
}

.tip {
  background: rgba(59, 130, 246, 0.08);
  border-left: 4px solid var(--accent);
  padding: 12px 16px;
  border-radius: 8px;
  color: var(--accent-dark);
  margin: 18px 0;
}

.footnote {
  font-size: 14px;
  color: var(--muted);
  margin-top: 24px;
  border-top: 1px solid var(--border);
  padding-top: 12px;
}

code {
  font-family: 'Fira Code', 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
  font-size: 13px;
  background: rgba(229, 231, 235, 0.6);
  padding: 2px 6px;
  border-radius: 6px;
}

@media (max-width: 1100px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
    max-height: none;
    display: flex;
    gap: 24px;
    flex-wrap: wrap;
  }

  .sidebar nav ul {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  }
}

@media (max-width: 768px) {
  .topbar {
    flex-direction: column;
    align-items: flex-start;
    gap: 18px;
  }

  .layout {
    padding: 20px 18px 48px;
  }

  .doc-panel {
    padding: 24px 20px;
  }
}