/* Modern Dark Theme Variables */
:root {
  --bg-primary: #09090b;
  --bg-secondary: #18181b;
  --bg-tertiary: #27272a;
  --text-primary: #fafafa;
  --text-secondary: #a1a1aa;
  --text-muted: #71717a;
  --border-color: #27272a;
  --border-hover: #3f3f46;
  --accent-cyan: #22d3ee;
  --accent-purple: #a855f7;
  --accent-blue: #3b82f6;
  --accent-green: #22c55e;
  --gradient-start: #06b6d4;
  --gradient-end: #8b5cf6;
}

/* Base */
* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 5rem;
}

body {
  margin: 0;
  padding: 0;
  background: var(--bg-primary);
  color: var(--text-primary);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  line-height: 1.7;
  font-size: 16px;
}

/* Container */
.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* Glassmorphism Header */
header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(9, 9, 11, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
}

header nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
}

header nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

/* Brand */
.brand {
  display: flex;
  align-items: center;
  gap: 1rem;
  text-decoration: none;
}

.logo {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  object-fit: cover;
  border: 2px solid var(--border-color);
  transition: border-color 0.3s ease;
}

.logo:hover {
  border-color: var(--accent-cyan);
}

.brand-text {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.brand-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.brand-author {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.brand-author a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s ease;
}

.brand-author a:hover {
  color: var(--accent-cyan);
}

/* Header Links */
header nav ul:last-child a {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  padding: 0.5rem 1rem;
  border-radius: 8px;
  transition: all 0.2s ease;
}

header nav ul:last-child a:hover {
  color: var(--text-primary);
  background: var(--bg-tertiary);
}

/* Nav Icon Button */
.nav-icon {
  display: flex;
  align-items: center;
  padding: 0 !important;
}

.nav-icon img {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  object-fit: cover;
  border: 2px solid var(--border-color);
  transition: all 0.2s ease;
}

.nav-icon:hover img {
  border-color: var(--accent-cyan);
  transform: scale(1.05);
}

/* Theme Toggle */
#theme-toggle {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  cursor: pointer;
  font-size: 1.1rem;
  padding: 0.5rem 0.75rem;
  transition: all 0.2s ease;
}

#theme-toggle:hover {
  border-color: var(--border-hover);
  background: var(--bg-secondary);
}

/* Main Layout */
main.container {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 3rem;
  padding-top: 6rem;
  padding-bottom: 4rem;
  align-items: start;
}

/* Sidebar */
#sidebar {
  position: sticky;
  top: 6rem;
  max-height: calc(100vh - 8rem);
  overflow-y: auto;
  padding-right: 1.5rem;
}

#sidebar::-webkit-scrollbar {
  width: 4px;
}

#sidebar::-webkit-scrollbar-track {
  background: transparent;
}

#sidebar::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 4px;
}

.toc-header {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-color);
}

#toc a {
  display: block;
  padding: 0.4rem 0;
  padding-left: 1rem;
  text-decoration: none;
  color: var(--text-muted);
  border-left: 2px solid transparent;
  font-size: 0.875rem;
  line-height: 1.5;
  transition: all 0.2s ease;
}

#toc a:hover {
  color: var(--text-secondary);
  border-left-color: var(--border-hover);
}

#toc a.active {
  color: var(--accent-cyan);
  border-left-color: var(--accent-cyan);
  background: linear-gradient(90deg, rgba(34, 211, 238, 0.1), transparent);
}

#toc a[data-level="3"] {
  padding-left: 1.75rem;
  font-size: 0.8125rem;
}

#toc a[data-level="4"] {
  padding-left: 2.5rem;
  font-size: 0.75rem;
}

/* Content */
#content {
  max-width: 100%;
  overflow-x: hidden;
}

/* Typography */
#content h1 {
  font-size: 2.5rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 2rem;
  background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

#content h2 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-top: 4rem;
  margin-bottom: 1.5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  color: var(--text-primary);
}

#content h2:first-child {
  border-top: none;
  margin-top: 0;
  padding-top: 0;
}

#content h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

#content h4 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
  color: var(--text-secondary);
}

#content p {
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
}

#content strong {
  color: var(--text-primary);
  font-weight: 600;
}

#content a {
  color: var(--accent-cyan);
  text-decoration: none;
  transition: color 0.2s ease;
}

#content a:hover {
  color: var(--accent-purple);
  text-decoration: underline;
}

/* Lists */
#content ul, #content ol {
  color: var(--text-secondary);
  padding-left: 1.5rem;
  margin-bottom: 1.5rem;
}

#content li {
  margin-bottom: 0.5rem;
}

/* Blockquotes */
blockquote {
  margin: 1.5rem 0;
  padding: 1.25rem 1.5rem;
  background: var(--bg-secondary);
  border-left: 4px solid var(--accent-purple);
  border-radius: 0 12px 12px 0;
  font-style: italic;
  color: var(--text-secondary);
}

blockquote p {
  margin: 0;
}

/* Code Blocks */
pre[class*="language-"] {
  background: var(--bg-secondary) !important;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  margin: 1.5rem 0;
  padding: 1.25rem !important;
  font-size: 0.875rem;
  overflow-x: auto;
}

pre[class*="language-"]::-webkit-scrollbar {
  height: 6px;
}

pre[class*="language-"]::-webkit-scrollbar-track {
  background: var(--bg-tertiary);
  border-radius: 3px;
}

pre[class*="language-"]::-webkit-scrollbar-thumb {
  background: var(--border-hover);
  border-radius: 3px;
}

pre[class*="language-"] code {
  line-height: 1.6;
}

/* Inline Code */
:not(pre) > code {
  padding: 0.2rem 0.5rem;
  border-radius: 6px;
  background: var(--bg-tertiary);
  color: var(--accent-cyan);
  font-size: 0.875em;
  border: 1px solid var(--border-color);
}

/* Tables */
.table-container {
  overflow-x: auto;
  margin: 1.5rem 0;
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.table-container table {
  margin: 0;
  width: 100%;
  min-width: 100%;
  border-collapse: collapse;
}

.table-container th,
.table-container td {
  padding: 0.875rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
}

.table-container th {
  background: var(--bg-secondary);
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.table-container td {
  color: var(--text-secondary);
}

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

.table-container tr:hover td {
  background: var(--bg-secondary);
}

/* Horizontal Rule */
hr {
  border: none;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border-color), transparent);
  margin: 3rem 0;
}

/* Footer */
footer {
  margin-top: 4rem;
  padding: 2rem 0;
  text-align: center;
  border-top: 1px solid var(--border-color);
  color: var(--text-muted);
  font-size: 0.875rem;
}

footer a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s ease;
}

footer a:hover {
  color: var(--accent-cyan);
}

/* Loading State */
#loading {
  text-align: center;
  padding: 4rem 2rem;
  color: var(--text-muted);
}

/* Responsive */
@media (max-width: 1024px) {
  main.container {
    grid-template-columns: 240px 1fr;
    gap: 2rem;
  }
}

@media (max-width: 768px) {
  main.container {
    grid-template-columns: 1fr;
    padding-top: 5rem;
  }

  #sidebar {
    display: none;
  }

  .container {
    padding: 0 1rem;
  }

  #content h1 {
    font-size: 1.75rem;
  }

  #content h2 {
    font-size: 1.5rem;
  }

  .brand-title {
    font-size: 1rem;
  }

  .brand-author {
    display: none;
  }

  header nav ul:last-child {
    gap: 0.75rem;
  }
}

/* Print */
@media print {
  header, #sidebar, #theme-toggle, footer {
    display: none !important;
  }

  main.container {
    display: block;
    padding-top: 0;
  }

  #content {
    max-width: 100%;
  }

  pre[class*="language-"] {
    white-space: pre-wrap;
    word-break: break-word;
  }
}

/* Accent Colors for Different Sections */
#content h2:nth-of-type(7n+1) { border-top-color: var(--accent-cyan); }
#content h2:nth-of-type(7n+2) { border-top-color: var(--accent-purple); }
#content h2:nth-of-type(7n+3) { border-top-color: var(--accent-blue); }
#content h2:nth-of-type(7n+4) { border-top-color: var(--accent-green); }
#content h2:nth-of-type(7n+5) { border-top-color: #f59e0b; }
#content h2:nth-of-type(7n+6) { border-top-color: #ec4899; }
#content h2:nth-of-type(7n+7) { border-top-color: #ef4444; }

/* Smooth animations */
* {
  transition-property: color, background-color, border-color;
  transition-duration: 0.15s;
  transition-timing-function: ease;
}

a, button, .logo {
  transition-duration: 0.2s;
}