:root {
    --bg-primary: #f8f9fc;
    --bg-secondary: #eef0f5;
    --bg-card: #ffffff;
    --text-primary: #1e1b4b;
    --text-secondary: #4a4a6a;
    --text-muted: #7c7c9a;
    --primary: #7c3aed;
    --primary-light: #a78bfa;
    --secondary: #a855f7;
    --accent: #ec4899;
    --border: #e2e4ea;
    --shadow: 0 2px 12px rgba(30, 27, 75, 0.08);
    --shadow-hover: 0 6px 24px rgba(30, 27, 75, 0.12);
    --radius: 12px;
    --radius-sm: 6px;
    --font: 'Segoe UI', system-ui, -apple-system, sans-serif;
    --code-bg: #f4f6f9;
    --code-text: #1e293b;
    --code-keyword: #7c3aed;
    --code-string: #059669;
    --code-comment: #94a3b8;
    --code-function: #2563eb;
    --code-number: #d97706;
}

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

body {
    font-family: var(--font);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.75;
    font-size: 16px;
}

/* Header */
.header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
    padding: 0 24px;
}
.header-inner {
    max-width: 1300px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 60px;
}
.header a {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 600;
    font-size: 18px;
}
.header a:hover { color: var(--primary); }

/* Layout */
.wrapper {
    max-width: 1300px;
    margin: 0 auto;
    padding: 32px 24px;
    display: flex;
    gap: 32px;
}

/* Sidebar */
.sidebar {
    width: 260px;
    flex-shrink: 0;
    position: sticky;
    top: 92px;
    max-height: calc(100vh - 100px);
    overflow-y: auto;
    padding-right: 8px;
}
.sidebar::-webkit-scrollbar { width: 4px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
.sidebar-section { margin-bottom: 24px; }
.sidebar-title {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 1.2px;
    color: var(--text-muted);
    font-weight: 700;
    margin-bottom: 8px;
    padding: 0 8px;
}
.sidebar-link {
    display: block;
    padding: 6px 8px;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 14px;
    transition: all 0.15s;
}
.sidebar-link:hover {
    background: var(--bg-secondary);
    color: var(--primary);
}
.sidebar-link.active {
    background: var(--primary);
    color: #fff;
}

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

/* Page header */
.page-header { margin-bottom: 40px; }
.page-header h1 {
    font-size: 32px;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: 8px;
    line-height: 1.2;
}
.page-header p {
    color: var(--text-secondary);
    font-size: 18px;
}

/* Card */
.card {
    background: var(--bg-card);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 32px;
    margin-bottom: 24px;
}
.card h2 {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text-primary);
}
.card h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
    margin-top: 28px;
    color: var(--text-primary);
}
.card h3:first-child { margin-top: 0; }
.card p {
    color: var(--text-secondary);
    margin-bottom: 16px;
}
.card p:last-child { margin-bottom: 0; }
.card ul, .card ol {
    color: var(--text-secondary);
    margin-bottom: 16px;
    padding-left: 24px;
}
.card li { margin-bottom: 6px; }

/* Code blocks */
pre {
    background: var(--code-bg);
    border-radius: var(--radius-sm);
    padding: 16px 20px;
    overflow-x: auto;
    margin-bottom: 16px;
    font-size: 14px;
    line-height: 1.65;
    border: 1px solid var(--border);
}
code {
    font-family: 'Cascadia Code', 'Fira Code', 'Consolas', monospace;
    font-size: 0.9em;
}
:not(pre) > code {
    background: var(--code-bg);
    padding: 2px 6px;
    border-radius: 4px;
    color: var(--primary);
    font-size: 0.85em;
}
pre .kw { color: var(--code-keyword); }
pre .st { color: var(--code-string); }
pre .cm { color: var(--code-comment); }
pre .fn { color: var(--code-function); }
pre .nm { color: var(--code-number); }

/* Info/tip/warning boxes */
.box {
    border-radius: var(--radius-sm);
    padding: 16px 20px;
    margin-bottom: 16px;
    border-left: 4px solid;
}
.box-info {
    background: #eef2ff;
    border-color: var(--primary);
    color: #4338ca;
}
.box-tip {
    background: #ecfdf5;
    border-color: var(--code-string);
    color: #065f46;
}
.box-warning {
    background: #fffbeb;
    border-color: var(--code-number);
    color: #92400e;
}
.box-note {
    background: var(--bg-secondary);
    border-color: var(--text-muted);
    color: var(--text-secondary);
}

/* Table */
.table-wrap { overflow-x: auto; margin-bottom: 16px; }
table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
}
th, td {
    text-align: left;
    padding: 10px 14px;
    border-bottom: 1px solid var(--border);
}
th {
    background: var(--bg-secondary);
    font-weight: 600;
    color: var(--text-primary);
    font-size: 13px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}
tr:hover td { background: var(--bg-secondary); }

/* TOC on index */
.toc-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 16px;
}
.toc-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    transition: all 0.2s;
    text-decoration: none;
    color: inherit;
    display: block;
}
.toc-card:hover {
    border-color: var(--primary-light);
    box-shadow: var(--shadow-hover);
    transform: translateY(-2px);
}
.toc-card h3 {
    font-size: 16px;
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 6px;
}
.toc-card p {
    font-size: 13px;
    color: var(--text-muted);
    margin: 0;
}

/* Footer */
.footer {
    text-align: center;
    padding: 40px 24px;
    color: var(--text-muted);
    font-size: 13px;
    border-top: 1px solid var(--border);
    margin-top: 32px;
}

/* Responsive */
.menu-toggle {
  display: none;
  position: absolute;
  top: 12px;
  right: 12px;
  width: 36px;
  height: 36px;
  background: rgba(255,255,255,0.15);
  border: 1px solid rgba(255,255,255,0.3);
  border-radius: 8px;
  cursor: pointer;
  z-index: 101;
  padding: 0;
  align-items: center;
  justify-content: center;
}
.menu-toggle span,
.menu-toggle span::before,
.menu-toggle span::after {
  display: block;
  width: 20px;
  height: 2px;
  background: #fff;
  border-radius: 2px;
  position: relative;
  transition: 0.3s;
}
.menu-toggle span::before,
.menu-toggle span::after {
  content: '';
  position: absolute;
  left: 0;
}
.menu-toggle span::before { top: -6px; }
.menu-toggle span::after { top: 6px; }
.sidebar-close {
  display: none;
  position: absolute;
  top: 12px;
  right: 12px;
  width: 32px;
  height: 32px;
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-size: 28px;
  cursor: pointer;
  line-height: 1;
  border-radius: 6px;
  z-index: 102;
  align-items: center;
  justify-content: center;
  padding: 0;
}
.sidebar-close:hover { background: var(--hover); }
.sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0,0,0,0.5);
  z-index: 98;
  opacity: 0;
  transition: opacity 0.3s;
}
.sidebar-overlay.active { opacity: 1; }

@media (max-width: 900px) {
  .menu-toggle { display: flex; }
  .sidebar-close { display: flex; }
  .sidebar-overlay { display: block; pointer-events: none; }
  .sidebar-overlay.active { pointer-events: auto; }
  .header-inner { padding-right: 48px; }
  .sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: 300px;
    max-width: 80vw;
    height: 100vh;
    max-height: 100vh;
    z-index: 99;
    border-radius: 0 16px 16px 0;
    border: none;
    border-right: 1px solid var(--border);
    transform: translateX(-100%);
    transition: transform 0.3s ease;
    overflow-y: auto;
    padding-top: 48px;
    background: var(--card-bg);
  }
  .sidebar.active { transform: translateX(0); }
  .sidebar-section { padding: 0 16px; }
  .sidebar-title { padding: 8px 12px; }
  .sidebar-link { display: block; padding: 7px 12px; font-size: 13px; border-radius: 6px; }
  .wrapper { flex-direction: column; }
  .main { padding: 16px; }
}

body.sidebar-open { overflow: hidden; }

/* Print */
@media print {
    .sidebar, .header { display: none; }
    .wrapper { display: block; }
    .card { box-shadow: none; border: 1px solid var(--border); }
}