@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

/* Default / Light Mode Tokens */
:root {
  --bg-dark: #f8fafc;
  --bg-sidebar: rgba(255, 255, 255, 0.85);
  --panel-bg: #ffffff;
  --panel-border: #e2e8f0;
  --accent-blue: #2563eb;
  --accent-blue-hover: #1d4ed8;
  --accent-glow: rgba(37, 99, 235, 0.15);
  --text-main: #1e293b;
  --text-muted: #64748b;
  --text-heading: #0f172a;
  --code-bg: #f1f5f9;
  --code-text: #0284c7;
  --table-header-bg: #f8fafc;
  --sidebar-width: 280px;
}

/* Dark Mode Tokens (Used via data-theme="dark" or media query) */
[data-theme="dark"] {
  --bg-dark: #090a0f;
  --bg-sidebar: rgba(13, 14, 22, 0.85);
  --panel-bg: rgba(255, 255, 255, 0.03);
  --panel-border: rgba(255, 255, 255, 0.08);
  --accent-blue: #3b82f6;
  --accent-blue-hover: #60a5fa;
  --accent-glow: rgba(59, 130, 246, 0.25);
  --text-main: #e5e7eb;
  --text-muted: #9ca3af;
  --text-heading: #ffffff;
  --code-bg: #11131e;
  --code-text: #93c5fd;
  --table-header-bg: rgba(255, 255, 255, 0.04);
}

/* Automatic System Dark Mode Detection */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg-dark: #090a0f;
    --bg-sidebar: rgba(13, 14, 22, 0.85);
    --panel-bg: rgba(255, 255, 255, 0.03);
    --panel-border: rgba(255, 255, 255, 0.08);
    --accent-blue: #3b82f6;
    --accent-blue-hover: #60a5fa;
    --accent-glow: rgba(59, 130, 246, 0.25);
    --text-main: #e5e7eb;
    --text-muted: #9ca3af;
    --text-heading: #ffffff;
    --code-bg: #11131e;
    --code-text: #93c5fd;
    --table-header-bg: rgba(255, 255, 255, 0.04);
  }
}

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background-color: var(--bg-dark);
  color: var(--text-main);
  line-height: 1.65;
  display: flex;
  min-height: 100vh;
  overflow-x: hidden;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Sidebar Navigation */
.sidebar {
  width: var(--sidebar-width);
  height: 100vh;
  position: fixed;
  top: 0;
  left: 0;
  background: var(--bg-sidebar);
  backdrop-filter: blur(16px);
  border-right: 1px solid var(--panel-border);
  padding: 2rem 1.5rem;
  display: flex;
  flex-direction: column;
  z-index: 100;
  overflow-y: auto;
  transition: background 0.3s ease, border-color 0.3s ease;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-heading);
  font-weight: 700;
  font-size: 1.25rem;
  margin-bottom: 2rem;
}

.brand img {
  width: 32px;
  height: 32px;
  filter: drop-shadow(0 2px 8px rgba(59, 130, 246, 0.3));
}

/* Theme Toggle Button */
.theme-toggle-btn {
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  color: var(--text-muted);
  padding: 0.5rem 0.85rem;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 500;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 2rem;
  transition: all 0.2s ease;
}

.theme-toggle-btn:hover {
  color: var(--text-heading);
  border-color: var(--accent-blue);
}

.nav-title {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
  font-weight: 600;
}

.nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.nav-link {
  display: block;
  padding: 0.6rem 0.85rem;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.925rem;
  border-radius: 8px;
  transition: all 0.2s ease;
  font-weight: 400;
}

.nav-link:hover {
  color: var(--text-heading);
  background: var(--panel-bg);
}

.nav-link.active {
  color: var(--text-heading);
  background: var(--accent-glow);
  border: 1px solid var(--panel-border);
  font-weight: 500;
}

/* Section headers between groups of chapters in the sidebar (frontmatter "part") */
.nav-group {
  margin-top: 1.25rem;
  margin-bottom: 0.35rem;
  padding: 0 0.85rem;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  font-weight: 600;
  opacity: 0.7;
}

.nav-group:first-child {
  margin-top: 0;
}

.back-home {
  margin-top: auto;
  padding-top: 1.5rem;
  border-top: 1px solid var(--panel-border);
}

/* Main Content Area */
.main-wrapper {
  margin-left: var(--sidebar-width);
  flex: 1;
  max-width: 960px;
  padding: 3.5rem 4rem;
}

.content {
  font-size: 1.05rem;
  color: var(--text-main);
}

/* Typography */
.content h1 {
  font-size: 2.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 1.5rem;
  color: var(--text-heading);
  line-height: 1.2;
}

.content h2 {
  font-size: 1.6rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--panel-border);
  color: var(--text-heading);
}

.content h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-top: 1.75rem;
  margin-bottom: 0.75rem;
  color: var(--text-heading);
}

.content p {
  margin-bottom: 1.25rem;
}

.content hr {
  border: none;
  height: 1px;
  background: var(--panel-border);
  margin: 2rem 0;
}

.content ul, .content ol {
  margin-bottom: 1.25rem;
  padding-left: 1.5rem;
}

.content li {
  margin-bottom: 0.4rem;
}

.content strong {
  color: var(--text-heading);
}

/* Code Formatting */
.content code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.875em;
  background: var(--code-bg);
  padding: 0.2em 0.4em;
  border-radius: 6px;
  border: 1px solid var(--panel-border);
  color: var(--code-text);
}

.content pre {
  background: var(--code-bg);
  padding: 1.25rem;
  border-radius: 12px;
  border: 1px solid var(--panel-border);
  overflow-x: auto;
  margin-bottom: 1.5rem;
}

.content pre code {
  background: transparent;
  padding: 0;
  border: none;
  color: var(--text-main);
}

/* Callouts / Blockquotes */
.content blockquote {
  background: var(--accent-glow);
  border-left: 4px solid var(--accent-blue);
  padding: 1rem 1.25rem;
  border-radius: 0 10px 10px 0;
  margin-bottom: 1.5rem;
  color: var(--text-main);
}

/* Tables */
.content table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin: 1.5rem 0;
  border-radius: 12px;
  overflow: hidden;
  border: 1px solid var(--panel-border);
  background: var(--panel-bg);
}

.content th, .content td {
  padding: 0.85rem 1.1rem;
  text-align: left;
  border-bottom: 1px solid var(--panel-border);
  font-size: 0.95rem;
}

.content th {
  background: var(--table-header-bg);
  font-weight: 600;
  color: var(--text-heading);
}

.content tr:last-child td {
  border-bottom: none;
}

/* Images & Screenshots */
.content img {
  max-width: 100%;
  border-radius: 12px;
  border: 1px solid var(--panel-border);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
  margin: 1.5rem 0;
}

/* Mobile Responsive */
@media (max-width: 860px) {
  body {
    flex-direction: column;
  }
  .sidebar {
    width: 100%;
    height: auto;
    position: relative;
    border-right: none;
    border-bottom: 1px solid var(--panel-border);
    padding: 1.5rem;
  }
  .main-wrapper {
    margin-left: 0;
    padding: 2rem 1.5rem;
  }
}