/* ============================================
   Vue to React Migration Guide - Design System
   ============================================ */

/* CSS Variables - Design Tokens */
:root {
  /* Colors - Vue Green + React Blue Palette */
  --vue-primary: #42b883;
  --vue-dark: #35495e;
  --vue-light: #e8f5ef;
  --react-primary: #61dafb;
  --react-dark: #282c34;
  --react-light: #e6f7ff;

  /* Neutral Colors */
  --bg-primary: #fafbfc;
  --bg-secondary: #ffffff;
  --bg-code: #1e1e2e;
  --text-primary: #1a1a2e;
  --text-secondary: #4a5568;
  --text-muted: #718096;
  --border-color: #e2e8f0;
  --border-hover: #cbd5e0;

  /* Accent Colors */
  --accent-yellow: #fbbf24;
  --accent-red: #ef4444;
  --accent-green: #10b981;
  --accent-purple: #8b5cf6;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;

  /* Spacing Scale */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;

  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -1px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.08), 0 8px 10px -6px rgba(0, 0, 0, 0.03);
  --shadow-xl: 0 20px 40px -10px rgba(0, 0, 0, 0.1);

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Layout */
  --sidebar-width: 280px;
  --content-max-width: 900px;
  --header-height: 64px;
}

/* Reset & Base */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  color: var(--text-primary);
  background: var(--bg-primary);
  line-height: 1.7;
  min-height: 100vh;
}

/* ============================================
   Layout Structure
   ============================================ */

.app-layout {
  display: flex;
  min-height: 100vh;
}

/* Sidebar Navigation */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  overflow-y: auto;
  z-index: 100;
  transition: transform var(--transition-normal);
}

.sidebar-header {
  padding: var(--space-6);
  border-bottom: 1px solid var(--border-color);
}

.sidebar-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--text-primary);
}

.sidebar-logo-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--vue-primary), var(--react-primary));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 14px;
  color: white;
}

.sidebar-logo-text {
  font-size: 15px;
  font-weight: 600;
  line-height: 1.3;
}

.sidebar-logo-text small {
  display: block;
  font-size: 11px;
  font-weight: 400;
  color: var(--text-muted);
}

/* Navigation Menu */
.nav-menu {
  padding: var(--space-4);
}

.nav-section {
  margin-bottom: var(--space-4);
}

.nav-section-title {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  padding: var(--space-2) var(--space-3);
  margin-bottom: var(--space-1);
}

.nav-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-3);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: all var(--transition-fast);
  position: relative;
}

.nav-item:hover {
  background: var(--bg-primary);
  color: var(--text-primary);
}

.nav-item.active {
  background: linear-gradient(135deg, rgba(66, 184, 131, 0.1), rgba(97, 218, 251, 0.1));
  color: var(--text-primary);
  font-weight: 600;
}

.nav-item.active::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 3px;
  height: 20px;
  background: linear-gradient(to bottom, var(--vue-primary), var(--react-primary));
  border-radius: 0 3px 3px 0;
}

.nav-item-number {
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  font-weight: 700;
  background: var(--bg-primary);
  border-radius: var(--radius-sm);
  flex-shrink: 0;
}

.nav-item.active .nav-item-number {
  background: linear-gradient(135deg, var(--vue-primary), var(--react-primary));
  color: white;
}

/* Main Content */
.main-content {
  margin-left: var(--sidebar-width);
  flex: 1;
  min-width: 0;
}

.content-wrapper {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: var(--space-8) var(--space-10);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  display: none;
  position: fixed;
  top: var(--space-4);
  left: var(--space-4);
  z-index: 200;
  width: 44px;
  height: 44px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  cursor: pointer;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
}

.mobile-menu-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--text-primary);
  margin: 3px 0;
  transition: all var(--transition-fast);
}

/* ============================================
   Typography
   ============================================ */

.page-header {
  margin-bottom: var(--space-10);
  padding-bottom: var(--space-8);
  border-bottom: 1px solid var(--border-color);
}

.page-breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: var(--space-4);
}

.page-breadcrumb a {
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.page-breadcrumb a:hover {
  color: var(--vue-primary);
}

.page-title {
  font-size: 2.5rem;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-4);
}

.page-title .gradient-text {
  background: linear-gradient(135deg, var(--vue-primary), var(--react-primary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.page-description {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 600px;
}

/* Section Headers */
.section {
  margin-bottom: var(--space-12);
}

.section-anchor {
  scroll-margin-top: var(--space-8);
}

.section-header {
  margin-bottom: var(--space-6);
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-2);
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.section-title-icon {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--vue-light);
  border-radius: var(--radius-sm);
  font-size: 16px;
  flex-shrink: 0;
}

.section-subtitle {
  font-size: 1rem;
  color: var(--text-muted);
}

/* Headings */
h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-top: var(--space-8);
  margin-bottom: var(--space-4);
}

h4 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-top: var(--space-6);
  margin-bottom: var(--space-3);
}

p {
  margin-bottom: var(--space-4);
}

/* ============================================
   Cards & Containers
   ============================================ */

.card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: all var(--transition-normal);
}

.card:hover {
  border-color: var(--border-hover);
  box-shadow: var(--shadow-md);
}

.card-header {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}

.card-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--vue-light), var(--react-light));
  border-radius: var(--radius-md);
  font-size: 24px;
  flex-shrink: 0;
}

.card-title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
}

.card-badge {
  display: inline-block;
  padding: var(--space-1) var(--space-2);
  background: var(--vue-light);
  color: var(--vue-primary);
  border-radius: var(--radius-sm);
  font-size: 11px;
  font-weight: 600;
  margin-top: var(--space-1);
}

/* Grid Layouts */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-6);
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

/* ============================================
   Comparison Tables
   ============================================ */

.comparison-table-wrapper {
  overflow-x: auto;
  margin: var(--space-6) 0;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.comparison-table th {
  background: linear-gradient(135deg, var(--vue-dark), #2c3e50);
  color: white;
  padding: var(--space-4) var(--space-5);
  text-align: left;
  font-weight: 600;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.comparison-table th:first-child {
  width: 200px;
}

.comparison-table td {
  padding: var(--space-4) var(--space-5);
  border-bottom: 1px solid var(--border-color);
  vertical-align: top;
}

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

.comparison-table tr:hover td {
  background: var(--bg-primary);
}

.comparison-table code {
  background: var(--bg-primary);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent-purple);
}

/* ============================================
   Code Blocks
   ============================================ */

.code-block-wrapper {
  margin: var(--space-6) 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.code-block-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-3) var(--space-4);
  background: #181825;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.code-block-dots {
  display: flex;
  gap: var(--space-2);
}

.code-block-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.code-block-dot:nth-child(1) { background: #f38ba8; }
.code-block-dot:nth-child(2) { background: #f9e2af; }
.code-block-dot:nth-child(3) { background: #a6e3a1; }

.code-block-title {
  font-size: 12px;
  color: #6c7086;
  font-family: var(--font-mono);
}

.code-block-copy {
  padding: var(--space-1) var(--space-3);
  background: rgba(255, 255, 255, 0.06);
  border: none;
  border-radius: var(--radius-sm);
  color: #cdd6f4;
  font-size: 12px;
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: var(--font-sans);
}

.code-block-copy:hover {
  background: rgba(255, 255, 255, 0.1);
}

.code-block-copy.copied {
  background: var(--accent-green);
  color: white;
}

.code-block {
  background: var(--bg-code);
  padding: var(--space-5);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.6;
  color: #cdd6f4;
  tab-size: 2;
}

.code-block code {
  font-family: inherit;
}

/* Inline Code */
:not(pre) > code {
  background: rgba(139, 92, 246, 0.1);
  color: var(--accent-purple);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.9em;
}

/* ============================================
   Code Tabs (Vue vs React)
   ============================================ */

.code-tabs {
  margin: var(--space-6) 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.code-tabs-header {
  display: flex;
  background: #181825;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.code-tab {
  flex: 1;
  padding: var(--space-3) var(--space-4);
  background: transparent;
  border: none;
  color: #6c7086;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  font-family: var(--font-sans);
}

.code-tab:hover {
  color: #cdd6f4;
  background: rgba(255, 255, 255, 0.03);
}

.code-tab.active {
  color: #cdd6f4;
  background: rgba(255, 255, 255, 0.06);
}

.code-tab-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
}

.code-tab[data-tab="vue"] .code-tab-dot { background: var(--vue-primary); }
.code-tab[data-tab="react"] .code-tab-dot { background: var(--react-primary); }

.code-tab.active[data-tab="vue"] {
  background: rgba(66, 184, 131, 0.1);
  color: var(--vue-primary);
}

.code-tab.active[data-tab="react"] {
  background: rgba(97, 218, 251, 0.1);
  color: var(--react-primary);
}

.code-tab-content {
  display: none;
  background: var(--bg-code);
  padding: var(--space-5);
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.6;
  color: #cdd6f4;
  overflow-x: auto;
}

.code-tab-content.active {
  display: block;
}

/* ============================================
   Info Boxes & Callouts
   ============================================ */

.callout {
  padding: var(--space-5);
  border-radius: var(--radius-md);
  margin: var(--space-6) 0;
  display: flex;
  gap: var(--space-4);
}

.callout-icon {
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  flex-shrink: 0;
  margin-top: 2px;
}

.callout-content {
  flex: 1;
}

.callout-title {
  font-weight: 600;
  margin-bottom: var(--space-2);
}

.callout-text {
  font-size: 14px;
  line-height: 1.6;
  margin-bottom: 0;
}

.callout.info {
  background: var(--react-light);
  border: 1px solid rgba(97, 218, 251, 0.3);
}

.callout.info .callout-icon { color: var(--react-primary); }

.callout.tip {
  background: var(--vue-light);
  border: 1px solid rgba(66, 184, 131, 0.3);
}

.callout.tip .callout-icon { color: var(--vue-primary); }

.callout.warning {
  background: #fef3c7;
  border: 1px solid rgba(251, 191, 36, 0.3);
}

.callout.warning .callout-icon { color: var(--accent-yellow); }

.callout.danger {
  background: #fee2e2;
  border: 1px solid rgba(239, 68, 68, 0.3);
}

.callout.danger .callout-icon { color: var(--accent-red); }

/* ============================================
   Concept Cards (for mappings)
   ============================================ */

.concept-mapping {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: var(--space-4);
  align-items: center;
  padding: var(--space-4);
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-3);
  transition: all var(--transition-fast);
}

.concept-mapping:hover {
  border-color: var(--border-hover);
  box-shadow: var(--shadow-sm);
}

.concept-vue,
.concept-react {
  padding: var(--space-3);
  border-radius: var(--radius-sm);
}

.concept-vue {
  background: var(--vue-light);
  border-left: 3px solid var(--vue-primary);
}

.concept-react {
  background: var(--react-light);
  border-left: 3px solid var(--react-primary);
}

.concept-label {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-1);
}

.concept-vue .concept-label { color: var(--vue-primary); }
.concept-react .concept-label { color: var(--react-primary); }

.concept-code {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text-primary);
}

.concept-arrow {
  font-size: 20px;
  color: var(--text-muted);
}

/* ============================================
   Sidebar Table of Contents (In-page)
   ============================================ */

.toc-sidebar {
  position: fixed;
  right: var(--space-8);
  top: var(--header-height);
  width: 200px;
  padding: var(--space-4);
  max-height: calc(100vh - var(--header-height));
  overflow-y: auto;
}

.toc-title {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: var(--space-3);
}

.toc-list {
  list-style: none;
}

.toc-item {
  margin-bottom: var(--space-1);
}

.toc-link {
  display: block;
  padding: var(--space-1) var(--space-2);
  font-size: 12px;
  color: var(--text-muted);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.toc-link:hover {
  color: var(--text-primary);
  background: var(--bg-primary);
}

.toc-link.active {
  color: var(--vue-primary);
  background: var(--vue-light);
  font-weight: 500;
}

/* ============================================
   Responsive Design
   ============================================ */

@media (max-width: 1280px) {
  .toc-sidebar {
    display: none;
  }
}

@media (max-width: 1024px) {
  .sidebar {
    transform: translateX(-100%);
  }

  .sidebar.open {
    transform: translateX(0);
    box-shadow: var(--shadow-xl);
  }

  .mobile-menu-toggle {
    display: flex;
  }

  .main-content {
    margin-left: 0;
  }

  .content-wrapper {
    padding: var(--space-6) var(--space-4);
    padding-top: calc(var(--header-height) + var(--space-4));
  }

  .page-title {
    font-size: 2rem;
  }

  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .comparison-table-wrapper {
    margin: var(--space-4) calc(-1 * var(--space-4));
    border-radius: 0;
    border-left: none;
    border-right: none;
  }

  .code-block-wrapper {
    margin: var(--space-4) calc(-1 * var(--space-4));
    border-radius: 0;
  }

  .code-tabs {
    margin: var(--space-4) calc(-1 * var(--space-4));
    border-radius: 0;
  }

  .concept-mapping {
    grid-template-columns: 1fr;
    gap: var(--space-2);
  }

  .concept-arrow {
    transform: rotate(90deg);
    text-align: center;
  }
}

/* ============================================
   Animations
   ============================================ */

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-in {
  animation: fadeInUp 0.5s ease-out forwards;
}

.animate-delay-1 { animation-delay: 0.1s; }
.animate-delay-2 { animation-delay: 0.2s; }
.animate-delay-3 { animation-delay: 0.3s; }

/* ============================================
   Syntax Highlighting (Catppuccin Mocha)
   ============================================ */

.code-block .keyword { color: #cba6f7; }
.code-block .string { color: #a6e3a1; }
.code-block .comment { color: #6c7086; font-style: italic; }
.code-block .function { color: #89b4fa; }
.code-block .number { color: #fab387; }
.code-block .operator { color: #89dceb; }
.code-block .class-name { color: #f9e2af; }
.code-block .punctuation { color: #bac2de; }
.code-block .property { color: #f38ba8; }
.code-block .tag { color: #cba6f7; }
.code-block .attr-name { color: #89b4fa; }
.code-block .attr-value { color: #a6e3a1; }

/* TypeScript specific */
.code-block .type { color: #f9e2af; }
.code-block .decorator { color: #fab387; }
.code-block .parameter { color: #eba0ac; }

/* JSX specific */
.code-block .jsx-tag { color: #f38ba8; }
.code-block .jsx-attr { color: #89b4fa; }

/* ============================================
   Utility Classes
   ============================================ */

.text-vue { color: var(--vue-primary); }
.text-react { color: var(--react-primary); }
.text-muted { color: var(--text-muted); }
.text-center { text-align: center; }

.bg-vue { background: var(--vue-light); }
.bg-react { background: var(--react-light); }

.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }

.flex { display: flex; }
.items-center { align-items: center; }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }