/* ========================================
   Mobile-First Responsive CSS for Know Your Damned Computer
   Interactive DH Computer Skills Guide
   ======================================== */

/* ========================================
   CSS Variables (Custom Properties)
   ======================================== */
:root {
  /* Colors - Enhanced for better mobile readability */
  --color-primary: #2c3e50;
  --color-primary-light: #34495e;
  --color-primary-dark: #1a252f;
  --color-secondary: #3498db;
  --color-secondary-light: #5dade2;
  --color-secondary-dark: #2980b9;
  --color-accent: #e74c3c;
  --color-success: #27ae60;
  --color-warning: #f39c12;
  --color-info: #17a2b8;
  
  /* Backgrounds - Optimized for mobile */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #e9ecef;
  --bg-dark: var(--color-primary);
  --bg-code: #f4f4f4;
  
  /* Text colors */
  --text-primary: #2c3e50;
  --text-secondary: #5a6c7d;
  --text-muted: #6c757d;
  --text-light: #ffffff;
  --text-code: #e83e8c;
  
  /* Spacing - Mobile-first values */
  --space-xs: 0.25rem;    /* 4px */
  --space-sm: 0.5rem;     /* 8px */
  --space-md: 1rem;       /* 16px */
  --space-lg: 1.5rem;     /* 24px */
  --space-xl: 2rem;       /* 32px */
  --space-2xl: 3rem;      /* 48px */
  
  /* Typography - Mobile-optimized */
  --font-family-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, 
                       "Helvetica Neue", Arial, sans-serif;
  --font-family-mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", 
                       Consolas, "Courier New", monospace;
  
  /* Font sizes - Mobile-first */
  --font-size-xs: 0.75rem;   /* 12px */
  --font-size-sm: 0.875rem;  /* 14px */
  --font-size-base: 1rem;    /* 16px */
  --font-size-lg: 1.125rem;  /* 18px */
  --font-size-xl: 1.25rem;   /* 20px */
  --font-size-2xl: 1.5rem;   /* 24px */
  --font-size-3xl: 1.875rem; /* 30px */
  --font-size-4xl: 2.25rem;  /* 36px */
  
  /* Line heights */
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;
  
  /* Border radius - Mobile-friendly */
  --border-radius: 0.375rem;
  --border-radius-sm: 0.25rem;
  --border-radius-lg: 0.5rem;
  --border-radius-xl: 0.75rem;
  
  /* Borders */
  --border-color: #dee2e6;
  --border-color-light: #f1f3f4;
  --border-color-dark: #adb5bd;
  
  /* Shadows - Subtle for mobile */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 2px 4px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 4px 8px rgba(0, 0, 0, 0.15);
  --shadow-xl: 0 8px 16px rgba(0, 0, 0, 0.2);
  
  /* Transitions */
  --transition-fast: 0.15s ease-in-out;
  --transition-normal: 0.3s ease-in-out;
  --transition-slow: 0.5s ease-in-out;
  
  /* Z-indices */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
}

/* ========================================
   Dark Theme Variables
   ======================================== */
[data-theme="dark"] {
  /* Dark Colors */
  --color-primary: #1a252f;
  --color-primary-light: #2c3e50;
  --color-primary-dark: #0f1419;
  --color-secondary: #5dade2;
  --color-secondary-light: #85c1e9;
  --color-secondary-dark: #3498db;

  /* Dark Backgrounds */
  --bg-primary: #1a1a1a;
  --bg-secondary: #2d2d2d;
  --bg-tertiary: #3a3a3a;
  --bg-dark: #000000;
  --bg-code: #2d2d2d;

  /* Dark Text */
  --text-primary: #e8e8e8;
  --text-secondary: #b8b8b8;
  --text-muted: #888888;
  --text-light: #ffffff;
  --text-code: #ff6b9d;

  /* Dark Borders */
  --border-color: #3a3a3a;
  --border-color-light: #2d2d2d;
  --border-color-dark: #555555;
}

/* ========================================
   Dark Theme Specific Overrides
   ======================================== */
[data-theme="dark"] .site-header {
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
}

[data-theme="dark"] .hero-section {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
}

[data-theme="dark"] .guide-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
}

[data-theme="dark"] .guide-card:hover {
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
}

[data-theme="dark"] .sidebar-content {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
}

[data-theme="dark"] .quiz-container {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
}

[data-theme="dark"] .terminal-container {
  background: #0d1117;
  border: 1px solid var(--border-color);
}

[data-theme="dark"] .reading-mode-content {
  background: var(--bg-primary);
}

[data-theme="dark"] .close-reading-mode {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
}

[data-theme="dark"] .notification {
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.4);
}

/* ========================================
   Base Styles - Mobile First
   ======================================== */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  font-size: 100%; /* 16px base */
  line-height: var(--line-height-normal);
  -webkit-text-size-adjust: 100%;
  -webkit-tap-highlight-color: transparent;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-family-sans);
  font-size: var(--font-size-base);
  font-weight: 400;
  line-height: var(--line-height-normal);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.main-content {
  flex: 1;
  padding: var(--space-md) 0;
}

/* ========================================
   Typography - Mobile Optimized
   ======================================== */
h1, h2, h3, h4, h5, h6 {
  margin-top: 0;
  margin-bottom: var(--space-md);
  font-weight: 600;
  line-height: var(--line-height-tight);
  color: var(--text-primary);
}

/* Mobile-first heading sizes */
h1 { font-size: var(--font-size-2xl); }
h2 { font-size: var(--font-size-xl); }
h3 { font-size: var(--font-size-lg); }
h4 { font-size: var(--font-size-base); }
h5 { font-size: var(--font-size-sm); }
h6 { font-size: var(--font-size-xs); }

p {
  margin-top: 0;
  margin-bottom: var(--space-md);
}

a {
  color: var(--color-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover,
a:focus {
  color: var(--color-secondary-dark);
  text-decoration: underline;
}

/* ========================================
   Layout - Mobile First
   ======================================== */
.container {
  width: 100%;
  max-width: 100%;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

.main-content {
  padding: var(--space-md) 0;
}

/* ========================================
   Navigation - Mobile First
   ======================================== */
.site-header {
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  width: 100%;
}

.main-nav {
  width: 100%;
}

.nav-container {
  background: var(--bg-primary);
  padding: var(--space-sm) var(--space-md);
  width: 100%;
  max-width: 100%;
}

.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--text-primary);
  text-decoration: none;
}

.nav-logo {
  height: 32px;
  width: auto;
  object-fit: contain;
}

.nav-brand-text {
  white-space: nowrap;
}

.nav-links {
  display: none; /* Hidden on mobile by default */
}

.menu-toggle {
  display: flex; /* Visible on mobile by default */
  flex-direction: column;
  background: none;
  border: none;
  padding: var(--space-sm);
  cursor: pointer;
}

.menu-toggle span {
  width: 1.5rem;
  height: 2px;
  background: var(--text-primary);
  margin: 2px 0;
  transition: var(--transition-fast);
}

.menu-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.menu-toggle.active span:nth-child(2) {
  opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -6px);
}

.theme-toggle {
  background: none;
  border: none;
  color: var(--text-primary);
  cursor: pointer;
  padding: var(--space-sm);
  border-radius: var(--border-radius);
  transition: background-color var(--transition-fast);
}

.theme-toggle:hover {
  background-color: var(--bg-tertiary);
}

.nav-controls {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

/* ========================================
   Hero Section - Mobile First
   ======================================== */
.hero-section {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
  color: var(--text-light);
  padding: var(--space-xl) 0;
  text-align: center;
}

.hero-title {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  margin-bottom: var(--space-md);
}

.hero-subtitle {
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-md);
  color: rgba(255, 255, 255, 0.9);
}

.hero-description {
  font-size: var(--font-size-base);
  margin-bottom: var(--space-xl);
  color: rgba(255, 255, 255, 0.8);
  line-height: var(--line-height-relaxed);
}

.hero-actions {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
  align-items: center;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-lg);
  flex-wrap: wrap;
}

.stat {
  text-align: center;
}

.stat strong {
  display: block;
  font-size: var(--font-size-xl);
  font-weight: 700;
}

.stat span {
  font-size: var(--font-size-sm);
  color: rgba(255, 255, 255, 0.8);
}

/* ========================================
   Buttons - Mobile Optimized
   ======================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-base);
  font-weight: 500;
  line-height: 1.5;
  text-align: center;
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: all var(--transition-fast);
  min-height: 44px; /* Touch-friendly minimum */
  gap: var(--space-sm);
}

.btn-primary {
  background: var(--color-secondary);
  border-color: var(--color-secondary);
  color: var(--text-light);
}

.btn-primary:hover,
.btn-primary:focus {
  background: var(--color-secondary-dark);
  border-color: var(--color-secondary-dark);
  color: var(--text-light);
  text-decoration: none;
}

.btn-secondary {
  background: transparent;
  border-color: rgba(255, 255, 255, 0.3);
  color: var(--text-light);
}

.btn-secondary:hover,
.btn-secondary:focus {
  background: rgba(255, 255, 255, 0.1);
  color: var(--text-light);
  text-decoration: none;
}

/* Secondary buttons in sidebar context */
.sidebar-content .btn-secondary {
  background: transparent;
  border-color: var(--border-color-dark);
  color: var(--text-primary);
}

.sidebar-content .btn-secondary:hover,
.sidebar-content .btn-secondary:focus {
  background: var(--bg-tertiary);
  border-color: var(--color-secondary);
  color: var(--color-secondary-dark);
  text-decoration: none;
}

.btn-large {
  padding: var(--space-md) var(--space-lg);
  font-size: var(--font-size-lg);
  min-height: 48px;
}

.btn-block {
  width: 100%;
}

/* ========================================
   Guides Grid - Mobile First
   ======================================== */
.guides-section {
  padding: var(--space-xl) 0;
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.section-header h2 {
  font-size: var(--font-size-3xl);
  margin-bottom: var(--space-md);
}

.guides-grid {
  display: grid;
  grid-template-columns: 1fr; /* Single column on mobile */
  gap: var(--space-lg);
  padding: 0 var(--space-md);
}

.guide-card {
  background: var(--bg-primary);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-md);
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
  border: 1px solid var(--border-color);
  height: 100%;
  min-height: auto; /* No fixed height on mobile */
}

.guide-card:hover,
.guide-card:focus-within {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

/* Guide card header (for homepage cards) */
.guide-card .guide-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: var(--space-md);
}

/* Guide page header (for individual guide pages) */
.guide-content .guide-header {
  margin-bottom: var(--space-xl);
}

.guide-icon {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: white;
  width: 40px;
  height: 40px;
  border-radius: var(--border-radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-lg);
  flex-shrink: 0;
}

.difficulty-badge {
  font-size: var(--font-size-xs);
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--border-radius-sm);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.difficulty-beginner {
  background: var(--color-success);
  color: white;
}

.difficulty-intermediate {
  background: var(--color-warning);
  color: white;
}

.difficulty-advanced {
  background: var(--color-accent);
  color: white;
}

.guide-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin: var(--space-sm) 0;
  line-height: var(--line-height-tight);
}

.guide-description {
  font-size: var(--font-size-base);
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
  line-height: var(--line-height-relaxed);
  flex-grow: 1;
}

.guide-meta {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
  font-size: var(--font-size-sm);
  color: var(--text-muted);
}

.guide-actions {
  margin-top: auto;
}

/* Guide footer with button positioning */
.guide-footer {
  margin-top: auto;
  display: flex;
  flex-direction: row;
  justify-content: space-between;
  align-items: flex-end;
  gap: var(--space-md);
}

.guide-footer .progress-bar {
  flex: 1;
  max-width: 60%;
}

.guide-footer .btn {
  flex-shrink: 0;
}

/* ========================================
   Guide Layout - Mobile First
   ======================================== */
.guide-container {
  display: grid;
  grid-template-columns: 1fr; /* Single column on mobile */
  gap: var(--space-lg);
  max-width: 100%;
  margin: 0 auto;
  padding: 0 var(--space-md);
  min-height: calc(100vh - 80px); /* Account for navigation height */
}

.guide-sidebar {
  position: static; /* Not sticky on mobile */
  order: 2; /* Sidebar goes after content on mobile */
}

.guide-content {
  padding: var(--space-md);
  background: var(--bg-primary);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-sm);
  order: 1;
}

.sidebar-content {
  background: var(--bg-secondary);
  padding: var(--space-md);
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--border-color);
}

.sidebar-content h3 {
  margin-top: 0;
  font-size: var(--font-size-lg);
}

.mode-controls {
  margin-bottom: var(--space-lg);
}

.mode-controls .btn {
  margin-bottom: var(--space-sm);
}

/* ========================================
   Interactive Components - Mobile Optimized
   ======================================== */
.quiz-container {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: var(--space-lg);
  margin: var(--space-lg) 0;
}

.quiz-option {
  display: flex;
  align-items: center;
  padding: var(--space-md);
  margin: var(--space-sm) 0;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: all var(--transition-fast);
  min-height: 44px; /* Touch-friendly */
}

.quiz-option:hover {
  background: var(--bg-tertiary);
  border-color: var(--color-secondary);
}

.quiz-option input[type="radio"] {
  margin-right: var(--space-sm);
}

.terminal-container {
  background: #1a1a1a;
  color: #ffffff;
  border-radius: var(--border-radius-lg);
  padding: var(--space-md);
  margin: var(--space-lg) 0;
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
  overflow-x: auto;
}

.terminal-input {
  background: transparent;
  border: none;
  color: inherit;
  font-family: inherit;
  font-size: inherit;
  width: 100%;
  outline: none;
}

/* ========================================
   Code and Pre - Mobile Optimized
   ======================================== */
code {
  font-family: var(--font-family-mono);
  font-size: 0.9em;
  background: var(--bg-code);
  padding: 0.125rem 0.25rem;
  border-radius: var(--border-radius-sm);
  color: var(--text-code);
}

pre {
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
  background: var(--bg-code);
  padding: var(--space-md);
  border-radius: var(--border-radius);
  border: 1px solid var(--border-color);
  overflow-x: auto;
  line-height: var(--line-height-normal);
}

pre code {
  background: none;
  padding: 0;
  color: inherit;
}

/* ========================================
   Progress Indicators
   ======================================== */
.progress-bar {
  width: 100%;
  height: 8px;
  background: var(--bg-tertiary);
  border-radius: var(--border-radius-sm);
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--color-secondary), var(--color-secondary-light));
  border-radius: var(--border-radius-sm);
  transition: width var(--transition-normal);
}

/* ========================================
   Mobile Navigation Enhancements
   ======================================== */
.mobile-menu {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--bg-primary);
  border-top: 1px solid var(--border-color);
  box-shadow: var(--shadow-lg);
  z-index: var(--z-dropdown);
  padding: var(--space-md);
  transform: translateY(-100%);
  opacity: 0;
  transition: all var(--transition-normal);
}

.mobile-menu.active {
  display: block;
  transform: translateY(0);
  opacity: 1;
}

.mobile-menu .nav-link {
  display: block;
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--border-color-light);
  font-size: var(--font-size-lg);
}

/* ========================================
   Tablet Styles (min-width: 768px)
   ======================================== */
@media (min-width: 768px) {
  /* Typography enhancements for tablet */
  h1 { font-size: var(--font-size-4xl); }
  h2 { font-size: var(--font-size-3xl); }
  h3 { font-size: var(--font-size-xl); }
  
  /* Layout improvements */
  .container {
    max-width: 750px;
    padding: 0 var(--space-lg);
  }
  
  .main-content {
    padding: var(--space-xl) 0;
  }
  
  /* Hero section */
  .hero-section {
    padding: var(--space-2xl) 0;
  }
  
  .hero-actions {
    flex-direction: row;
    justify-content: center;
  }
  
  /* Guides grid - 2 columns on tablet */
  .guides-grid {
    grid-template-columns: repeat(2, 1fr);
    padding: 0;
  }
  
  .guide-card {
    min-height: 350px;
  }
  
  .guide-icon {
    width: 48px;
    height: 48px;
    font-size: var(--font-size-xl);
  }
  
  .guide-meta {
    flex-direction: row;
    justify-content: space-between;
  }
  
  /* Guide layout improvements */
  .guide-container {
    grid-template-columns: 280px 1fr;
    max-width: 1200px;
    padding: 0 var(--space-lg);
  }

  .guide-sidebar {
    position: sticky;
    top: 100px;
    height: fit-content;
    order: 1;
  }

  .guide-content {
    padding: var(--space-xl);
    order: 2;
  }
}

/* ========================================
   Desktop Styles (min-width: 1024px)
   ======================================== */
@media (min-width: 1024px) {
  /* Show desktop navigation */
  .nav-links {
    display: flex;
    gap: var(--space-lg);
  }
  
  .menu-toggle {
    display: none;
  }
  
  /* Container improvements */
  .container {
    max-width: 1200px;
  }
  
  /* Hero enhancements */
  .hero-title {
    font-size: 3.5rem;
  }
  
  .hero-subtitle {
    font-size: var(--font-size-2xl);
  }
  
  /* Guides grid - 3 columns on desktop */
  .guides-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .guide-card {
    min-height: 400px;
  }
  
  /* Guide sidebar positioning */
  .guide-container {
    grid-template-columns: 320px 1fr;
  }
  
  .guide-sidebar {
    top: 120px;
  }
}

/* ========================================
   Large Desktop Styles (min-width: 1200px)
   ======================================== */
@media (min-width: 1200px) {
  .container {
    max-width: 1400px;
  }
  
  .guide-container {
    grid-template-columns: 360px 1fr;
  }
}

/* ========================================
   Touch and Accessibility Improvements
   ======================================== */
@media (hover: none) and (pointer: coarse) {
  /* Touch device optimizations */
  .btn {
    min-height: 48px;
    padding: var(--space-md) var(--space-lg);
  }
  
  .quiz-option {
    min-height: 48px;
    padding: var(--space-md) var(--space-lg);
  }
  
  .guide-card:hover {
    transform: none; /* Disable hover transforms on touch devices */
  }
}

/* ========================================
   Print Styles
   ======================================== */
@media print {
  .nav-container,
  .hero-section,
  .guide-sidebar,
  .btn {
    display: none;
  }
  
  .guide-content {
    box-shadow: none;
    border: none;
  }
  
  body {
    font-size: 12pt;
    line-height: 1.4;
  }
}

/* ========================================
   Utility Classes
   ======================================== */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.d-none { display: none; }
.d-block { display: block; }
.d-flex { display: flex; }

/* Spacing utilities */
.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }
.mt-sm { margin-top: var(--space-sm); }
.mb-sm { margin-bottom: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mb-md { margin-bottom: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mb-lg { margin-bottom: var(--space-lg); }

.p-0 { padding: 0; }
.p-sm { padding: var(--space-sm); }
.p-md { padding: var(--space-md); }
.p-lg { padding: var(--space-lg); }

/* ========================================
   Notifications and Tooltips
   ======================================== */
.notification {
  position: fixed;
  top: var(--space-md);
  right: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--border-radius);
  color: white;
  font-weight: 500;
  z-index: var(--z-tooltip);
  transform: translateX(400px);
  transition: transform var(--transition-normal);
  box-shadow: var(--shadow-lg);
  max-width: 300px;
}

.notification.show {
  transform: translateX(0);
}

.notification-success {
  background-color: var(--color-success);
}

.notification-info {
  background-color: var(--color-info);
}

.notification-warning {
  background-color: var(--color-warning);
}

.notification-danger {
  background-color: var(--color-accent);
}

.tooltip {
  position: absolute;
  background-color: var(--text-primary);
  color: var(--text-light);
  padding: var(--space-sm);
  border-radius: var(--border-radius-sm);
  font-size: var(--font-size-sm);
  z-index: var(--z-tooltip);
  transform: translateX(-50%);
  pointer-events: none;
  white-space: nowrap;
}

.tooltip::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 5px solid transparent;
  border-top-color: var(--text-primary);
}

/* ========================================
   Interactive Element Highlighting
   ======================================== */
.highlight-interactive {
  box-shadow: 0 0 0 3px var(--color-secondary) !important;
  animation: pulse-highlight 2s ease-in-out infinite;
}

@keyframes pulse-highlight {
  0%, 100% {
    box-shadow: 0 0 0 3px var(--color-secondary);
  }
  50% {
    box-shadow: 0 0 0 6px rgba(52, 152, 219, 0.3);
  }
}

/* ========================================
   Reading Mode
   ======================================== */
.reading-mode-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.8);
  z-index: var(--z-modal);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-lg);
}

.reading-mode-content {
  background-color: var(--bg-primary);
  border-radius: var(--border-radius-lg);
  max-width: 800px;
  max-height: 90vh;
  width: 100%;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-xl);
}

.close-reading-mode {
  position: absolute;
  top: var(--space-md);
  right: var(--space-md);
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text-secondary);
  transition: all var(--transition-fast);
  z-index: calc(var(--z-modal) + 1);
}

.close-reading-mode:hover {
  background-color: var(--color-accent);
  color: white;
  border-color: var(--color-accent);
}

.reading-content {
  padding: var(--space-2xl);
  padding-top: calc(var(--space-2xl) + 40px);
  overflow-y: auto;
  max-height: 90vh;
  line-height: var(--line-height-relaxed);
  font-size: var(--font-size-lg);
}

.reading-content h1,
.reading-content h2,
.reading-content h3,
.reading-content h4,
.reading-content h5,
.reading-content h6 {
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
}

.reading-content p {
  margin-bottom: var(--space-lg);
}

.reading-content .quiz,
.reading-content .exercise,
.reading-content .terminal-simulator {
  display: none;
}

/* ========================================
   Footer Styles
   ======================================== */
.site-footer {
  background: var(--color-primary);
  color: var(--text-light);
  margin-top: auto;
  padding: var(--space-xl) 0 var(--space-md);
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

.footer-content {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
  margin-bottom: var(--space-lg);
}

.footer-section h3 {
  color: var(--text-light);
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-md);
  font-weight: 600;
}

.footer-section p {
  color: rgba(255, 255, 255, 0.8);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--space-sm);
}

.footer-section ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-section li {
  margin-bottom: var(--space-sm);
}

.footer-section a {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-section a:hover,
.footer-section a:focus {
  color: var(--text-light);
  text-decoration: underline;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.2);
  padding-top: var(--space-md);
  text-align: center;
}

.footer-bottom p {
  color: rgba(255, 255, 255, 0.6);
  font-size: var(--font-size-sm);
  margin: 0;
}

/* Footer responsive layout */
@media (min-width: 768px) {
  .footer-content {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .footer-content {
    grid-template-columns: repeat(3, 1fr);
  }

  .footer-container {
    padding: 0 var(--space-lg);
  }
}