/*
 * style.css - CourseCatalyst Styles
 * 
 * A comprehensive stylesheet for the CourseCatalyst website featuring:
 * - Ocean theme with animated waves and particles
 * - Dark/light mode with localStorage persistence
 * - Responsive design for all screen sizes
 * - Accessibility features (WCAG AA compliance)
 * - Performance optimizations and reduced motion support
 * 
 * Key Features:
 * - CSS Custom Properties for theme switching
 * - Mobile-first responsive design
 * - Smooth animations with respect for prefers-reduced-motion
 * - Focus management and keyboard accessibility
 * - Optimized for fast loading and smooth performance
 */

/* ========================================
   CSS CUSTOM PROPERTIES (CSS VARIABLES)
   ======================================== */

:root {
  /* Color Palette - Light Theme */
  --color-primary: #0066cc;
  --color-primary-dark: #0052a3;
  --color-primary-light: #3385d6;
  --color-secondary: #00a8cc;
  --color-secondary-dark: #008ba3;
  --color-secondary-light: #33b8d6;
  
  /* Ocean Theme Colors */
  --color-ocean-1: #001f3f;
  --color-ocean-2: #0074d9;
  --color-ocean-3: #39cccc;
  --color-ocean-4: #7fdbff;
  
  /* Wave Colors */
  --wave-color-1: rgba(0, 116, 217, 0.3);
  --wave-color-2: rgba(57, 204, 204, 0.4);
  --wave-color-3: rgba(127, 219, 255, 0.5);
  
  /* Background & Surface Colors */
  --color-background: #ffffff;
  --color-surface: #f8f9fa;
  --color-surface-elevated: #ffffff;
  --color-card: #ffffff;
  
  /* Text Colors */
  --color-text: #212529;
  --color-text-secondary: #6c757d;
  --color-text-muted: #adb5bd;
  --color-text-inverse: #ffffff;
  
  /* Border & Divider Colors */
  --color-border: #e9ecef;
  --color-border-light: #f1f3f4;
  --color-divider: #dee2e6;
  
  /* Status Colors */
  --color-success: #28a745;
  --color-warning: #ffc107;
  --color-error: #dc3545;
  --color-info: #17a2b8;
  
  /* Shadows */
  --shadow-sm: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
  --shadow-md: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 1rem 3rem rgba(0, 0, 0, 0.175);
  --shadow-focus: 0 0 0 0.2rem rgba(0, 102, 204, 0.25);
  
  /* Typography */
  --font-family-primary: -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-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* Layout */
  --container-max-width: 1200px;
  --container-padding: 1rem;
  --header-height: 4rem;
  --border-radius: 0.5rem;
  --border-radius-lg: 1rem;
  
  /* Transitions */
  --transition-fast: 0.15s ease-out;
  --transition-normal: 0.3s ease-out;
  --transition-slow: 0.5s ease-out;
  
  /* Z-Index Scale */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
  --z-toast: 1080;
}

/* Dark Theme Variables */
[data-theme="dark"] {
  --color-background: #0a0e1a;
  --color-surface: #151b2d;
  --color-surface-elevated: #1e2a3a;
  --color-card: #1e2a3a;
  
  --color-text: #e2e8f0;
  --color-text-secondary: #94a3b8;
  --color-text-muted: #64748b;
  
  --color-border: #334155;
  --color-border-light: #475569;
  --color-divider: #334155;
  
  --wave-color-1: rgba(0, 116, 217, 0.2);
  --wave-color-2: rgba(57, 204, 204, 0.25);
  --wave-color-3: rgba(127, 219, 255, 0.3);
  
  --shadow-sm: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.3);
  --shadow-md: 0 0.5rem 1rem rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 1rem 3rem rgba(0, 0, 0, 0.5);
}

/* ========================================
   RESET & BASE STYLES
   ======================================== */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  color: var(--color-text);
  background-color: var(--color-background);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Remove default margins */
h1, h2, h3, h4, h5, h6,
p, blockquote, figure,
ul, ol, dl,
dd {
  margin: 0;
}

/* Remove list styles on ul, ol elements with a list role */
ul[role="list"],
ol[role="list"] {
  list-style: none;
  padding: 0;
}

/* Set core body defaults */
body {
  min-height: 100vh;
  text-rendering: optimizeSpeed;
}

/* Make images easier to work with */
img,
picture {
  max-width: 100%;
  height: auto;
  display: block;
}

/* Inherit fonts for inputs and buttons */
input,
button,
textarea,
select {
  font: inherit;
}

/* ========================================
   ACCESSIBILITY & REDUCED MOTION
   ======================================== */

/* Screen reader only content */
.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;
}

/* Focus styles */
:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

:focus:not(:focus-visible) {
  outline: none;
}

/* Reduced motion preferences */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  
  .waves {
    display: none;
  }
  
  #tsparticles {
    display: none;
  }
}

/* ========================================
   UTILITY CLASSES
   ======================================== */

.container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

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

/* ========================================
   LOADING SPLASH
   ======================================== */

.loading-splash {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, var(--color-ocean-1), var(--color-ocean-2));
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: var(--z-modal);
  opacity: 1;
  transition: opacity var(--transition-slow);
}

.loading-splash.hidden {
  opacity: 0;
  pointer-events: none;
}

.loading-content {
  text-align: center;
  color: var(--color-text-inverse);
}

.loading-logo {
  width: 4rem;
  height: 4rem;
  margin: 0 auto var(--spacing-md);
}

.logo-animation {
  width: 100%;
  height: 100%;
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.1); opacity: 0.8; }
}

/* ========================================
   HEADER & NAVIGATION
   ======================================== */

.header {
  position: sticky;
  top: 0;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  z-index: var(--z-sticky);
  transition: all var(--transition-normal);
}

[data-theme="dark"] .header {
  background: rgba(10, 14, 26, 0.95);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
}

.nav-brand {
  display: flex;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  text-decoration: none;
  color: var(--color-text);
  font-weight: var(--font-weight-bold);
  font-size: var(--font-size-lg);
  transition: color var(--transition-fast);
}

.logo:hover,
.logo:focus {
  color: var(--color-primary);
}

.logo-svg {
  width: 2rem;
  height: 2rem;
  color: var(--color-primary);
}

.logo-text {
  display: none;
}

@media (min-width: 640px) {
  .logo-text {
    display: inline;
  }
}

/* Desktop Navigation */
.nav-menu {
  display: none;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: var(--spacing-lg);
}

@media (min-width: 768px) {
  .nav-menu {
    display: flex;
  }
}

.nav-link {
  text-decoration: none;
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-medium);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--border-radius);
  transition: all var(--transition-fast);
  position: relative;
}

.nav-link:hover,
.nav-link:focus {
  color: var(--color-primary);
  background-color: var(--color-surface);
}

.nav-link.active {
  color: var(--color-primary);
  font-weight: var(--font-weight-semibold);
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -0.5rem;
  left: 50%;
  transform: translateX(-50%);
  width: 1.5rem;
  height: 2px;
  background-color: var(--color-primary);
  border-radius: 1px;
}

/* Mobile Menu Toggle */
.nav-toggle {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-sm);
  border-radius: var(--border-radius);
  transition: background-color var(--transition-fast);
}

@media (min-width: 768px) {
  .nav-toggle {
    display: none;
  }
}

.nav-toggle:hover,
.nav-toggle:focus {
  background-color: var(--color-surface);
}

.hamburger-line {
  width: 1.5rem;
  height: 2px;
  background-color: var(--color-text);
  border-radius: 1px;
  transition: all var(--transition-fast);
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(1) {
  transform: translateY(0.375rem) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(3) {
  transform: translateY(-0.375rem) rotate(-45deg);
}

/* Mobile Menu */
.mobile-menu {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--color-surface-elevated);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-0.5rem);
  transition: all var(--transition-normal);
}

.mobile-menu[aria-hidden="false"] {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.mobile-menu ul {
  list-style: none;
  margin: 0;
  padding: var(--spacing-md);
}

.mobile-nav-link {
  display: block;
  text-decoration: none;
  color: var(--color-text);
  font-weight: var(--font-weight-medium);
  padding: var(--spacing-md);
  border-radius: var(--border-radius);
  transition: all var(--transition-fast);
}

.mobile-nav-link:hover,
.mobile-nav-link:focus {
  background-color: var(--color-surface);
  color: var(--color-primary);
}

.mobile-nav-link.active {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

/* Theme Toggle */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  background: none;
  border: none;
  border-radius: var(--border-radius);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  margin-left: var(--spacing-sm);
}

.theme-toggle:hover,
.theme-toggle:focus {
  background-color: var(--color-surface);
  color: var(--color-primary);
}

.theme-icon {
  width: 1.25rem;
  height: 1.25rem;
  stroke-width: 2;
  fill: none;
  stroke: currentColor;
  transition: all var(--transition-fast);
}

.sun-icon {
  display: block;
}

.moon-icon {
  display: none;
}

[data-theme="dark"] .sun-icon {
  display: none;
}

[data-theme="dark"] .moon-icon {
  display: block;
}

/* ========================================
   HERO SECTION WITH OCEAN THEME
   ======================================== */

.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: linear-gradient(135deg, var(--color-ocean-1), var(--color-ocean-2), var(--color-ocean-3));
  overflow: hidden;
  color: var(--color-text-inverse);
}

/* tsParticles Container */
#tsparticles {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}

/* Animated Waves */
.waves {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 120px;
  z-index: 2;
}

.wave {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 120px;
  opacity: 0.8;
}

.wave-1 {
  animation: wave-movement-1 8s ease-in-out infinite;
}

.wave-2 {
  animation: wave-movement-2 10s ease-in-out infinite reverse;
}

.wave-3 {
  animation: wave-movement-3 12s ease-in-out infinite;
}

@keyframes wave-movement-1 {
  0%, 100% { transform: translateX(0) translateY(0); }
  50% { transform: translateX(-2%) translateY(-5px); }
}

@keyframes wave-movement-2 {
  0%, 100% { transform: translateX(0) translateY(0); }
  50% { transform: translateX(2%) translateY(-8px); }
}

@keyframes wave-movement-3 {
  0%, 100% { transform: translateX(0) translateY(0); }
  50% { transform: translateX(-1%) translateY(-3px); }
}

/* Hero Content */
.hero-content {
  position: relative;
  z-index: 3;
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
  padding: var(--spacing-2xl) 0;
}

.hero-content::before {
  content: '';
  position: absolute;
  top: -2rem;
  left: -2rem;
  right: -2rem;
  bottom: -2rem;
  background: rgba(0, 0, 0, 0.1);
  backdrop-filter: blur(1px);
  border-radius: var(--border-radius-lg);
  z-index: -1;
}

.hero-title {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-lg);
  line-height: var(--line-height-tight);
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3), 0 1px 2px rgba(0, 0, 0, 0.5);
  color: #ffffff;
}

@media (min-width: 768px) {
  .hero-title {
    font-size: var(--font-size-4xl);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3), 0 1px 2px rgba(0, 0, 0, 0.5);
  }
}

.hero-subtitle {
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-2xl);
  opacity: 0.95;
  line-height: var(--line-height-relaxed);
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.4), 0 1px 2px rgba(0, 0, 0, 0.6);
  color: #ffffff;
}

.hero-buttons {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  align-items: center;
}

@media (min-width: 640px) {
  .hero-buttons {
    flex-direction: row;
    justify-content: center;
  }
}

/* ========================================
   BUTTONS
   ======================================== */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-xl);
  border: none;
  border-radius: var(--border-radius);
  font-weight: var(--font-weight-medium);
  text-decoration: none;
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
  transition: left var(--transition-normal);
}

.btn:hover::before {
  left: 100%;
}

.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

.btn-primary:hover,
.btn-primary:focus {
  background-color: var(--color-primary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background-color: var(--color-secondary);
  color: var(--color-text-inverse);
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

.btn-secondary:hover,
.btn-secondary:focus {
  background-color: var(--color-secondary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-outline {
  background-color: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn-outline:hover,
.btn-outline:focus {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none !important;
  box-shadow: none !important;
}

/* Loading Button State */
.btn-loading .btn-text {
  display: none;
}

.btn-loading .btn-loading {
  display: flex !important;
  align-items: center;
  gap: var(--spacing-sm);
}

.loading-spinner {
  width: 1rem;
  height: 1rem;
}

/* ========================================
   CONTENT SECTIONS
   ======================================== */

.page-header {
  padding: var(--spacing-3xl) 0 var(--spacing-2xl);
  text-align: center;
  background: linear-gradient(135deg, var(--color-surface), var(--color-background));
  border-bottom: 1px solid var(--color-border);
}

.page-header h1 {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.page-header p {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

/* Introduction Section */
.intro {
  padding: var(--spacing-3xl) 0;
}

.intro-content h2 {
  text-align: center;
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-2xl);
  color: var(--color-text);
}

.intro-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-xl);
}

@media (min-width: 768px) {
  .intro-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.intro-card {
  text-align: center;
  padding: var(--spacing-xl);
  background: var(--color-card);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
}

.intro-card:hover {
  transform: translateY(-0.25rem);
  box-shadow: var(--shadow-md);
}

.intro-icon {
  font-size: 3rem;
  margin-bottom: var(--spacing-lg);
}

.intro-card h3 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.intro-card p {
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

/* ========================================
   COURSE CARDS & GRIDS
   ======================================== */

.featured-courses,
.courses-section {
  padding: var(--spacing-3xl) 0;
}

.featured-courses h2,
.courses-section h2 {
  text-align: center;
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.section-subtitle {
  text-align: center;
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-2xl);
}

.courses-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-2xl);
}

@media (min-width: 640px) {
  .courses-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

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

.course-card {
  background: var(--color-card);
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.course-card:hover {
  transform: translateY(-0.25rem);
  box-shadow: var(--shadow-lg);
}

.course-image {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 9;
}

.course-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-normal);
}

.course-card:hover .course-image img {
  transform: scale(1.05);
}

.course-content {
  padding: var(--spacing-lg);
  flex: 1;
  display: flex;
  flex-direction: column;
}

.course-content h3 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.course-content p {
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-lg);
  flex: 1;
}

.course-meta {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
  flex-wrap: wrap;
}

.course-level,
.course-type {
  font-size: var(--font-size-sm);
  padding: var(--spacing-xs) var(--spacing-sm);
  background: var(--color-surface);
  color: var(--color-text-secondary);
  border-radius: calc(var(--border-radius) / 2);
  font-weight: var(--font-weight-medium);
}

.no-courses {
  text-align: center;
  padding: var(--spacing-2xl);
  background: var(--color-surface);
  border-radius: var(--border-radius);
  grid-column: 1 / -1;
}

.no-courses h3 {
  font-size: var(--font-size-2xl);
  color: var(--color-text);
  margin-bottom: var(--spacing-md);
}

.no-courses p {
  color: var(--color-text-secondary);
  font-size: var(--font-size-lg);
}

.featured-actions {
  text-align: center;
}

/* ========================================
   COURSE DETAIL PAGE
   ======================================== */

.breadcrumb {
  padding: var(--spacing-lg) 0;
  border-bottom: 1px solid var(--color-border);
}

.breadcrumb ol {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: var(--spacing-sm);
  align-items: center;
}

.breadcrumb li:not(:last-child)::after {
  content: '/';
  margin-left: var(--spacing-sm);
  color: var(--color-text-muted);
}

.breadcrumb a {
  color: var(--color-primary);
  text-decoration: none;
}

.breadcrumb a:hover {
  text-decoration: underline;
}

.course-header {
  padding: var(--spacing-2xl) 0;
  background: var(--color-surface);
}

.course-header-content {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-xl);
  align-items: center;
}

@media (min-width: 768px) {
  .course-header-content {
    grid-template-columns: auto 1fr;
  }
}

.course-header .course-image {
  width: 100%;
  max-width: 300px;
  aspect-ratio: 16 / 9;
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.course-info h1 {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.course-description {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-lg);
}

.course-actions {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
  margin-top: var(--spacing-lg);
}

.course-actions .btn {
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: var(--font-size-sm);
  position: relative;
  overflow: hidden;
  transform-style: preserve-3d;
}

.course-actions .btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
  transition: left 0.6s ease;
  z-index: 1;
}

.course-actions .btn:hover::before {
  left: 100%;
}

.course-actions .btn svg {
  transition: transform var(--transition-fast);
  z-index: 2;
  position: relative;
}

.course-actions .btn:hover svg {
  transform: translateX(-2px);
}

.course-actions .btn:hover {
  transform: translateY(-2px) scale(1.02);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.course-actions .btn:active {
  transform: translateY(0) scale(0.98);
  transition: transform 0.1s ease;
}

/* Course Resources */
.course-resources {
  padding: var(--spacing-3xl) 0;
}

.course-resources h2 {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-2xl);
  color: var(--color-text);
}

.resource-section {
  margin-bottom: var(--spacing-3xl);
}

.resource-section h3 {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-lg);
  color: var(--color-text);
}

.section-icon {
  width: 1.5rem;
  height: 1.5rem;
  color: var(--color-primary);
  stroke-width: 2;
  fill: none;
  stroke: currentColor;
}

.resources-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-md);
}

@media (min-width: 640px) {
  .resources-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

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

.resource-card {
  display: block;
  padding: var(--spacing-lg);
  background: var(--color-card);
  border-radius: var(--border-radius);
  text-decoration: none;
  color: var(--color-text);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
  border: 1px solid var(--color-border);
}

.resource-card:hover {
  transform: translateY(-0.125rem);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
}

.resource-card h4 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-medium);
  margin-bottom: var(--spacing-sm);
  color: var(--color-primary);
}

.resource-card p {
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
}

/* Interview Questions */
.interview-questions {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-md);
}

.interview-card {
  background: var(--color-card);
  border-radius: var(--border-radius);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
}

.interview-content h4 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

.interview-content p {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-lg);
}

.interview-card .btn {
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: var(--font-size-sm);
  position: relative;
  overflow: hidden;
  transform-style: preserve-3d;
}

.interview-card .btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
  transition: left 0.6s ease;
  z-index: 1;
}

.interview-card .btn:hover::before {
  left: 100%;
}

.interview-card .btn svg {
  transition: transform var(--transition-fast);
  z-index: 2;
  position: relative;
}

.interview-card .btn:hover svg {
  transform: translateX(2px);
}

.interview-card .btn:hover {
  transform: translateY(-2px) scale(1.02);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.interview-card .btn:active {
  transform: translateY(0) scale(0.98);
  transition: transform 0.1s ease;
}

/* Course Not Found */
.course-not-found {
  padding: var(--spacing-3xl) 0;
  text-align: center;
}

.not-found-content h1 {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.not-found-content p {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-xl);
}

.not-found-actions {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* Related Courses */
.related-courses {
  padding: var(--spacing-2xl) 0;
  background: var(--color-surface);
}

.related-courses h2 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-lg);
  color: var(--color-text);
}

.related-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-md);
}

@media (min-width: 640px) {
  .related-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

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

/* ========================================
   WEBSITE CARDS & CATEGORIES
   ======================================== */

.websites-section {
  padding: var(--spacing-3xl) 0;
}

.websites-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-2xl);
}

@media (min-width: 640px) {
  .websites-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

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

.website-card {
  background: var(--color-card);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
  border: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
}

.website-card:hover {
  transform: translateY(-0.25rem);
  box-shadow: var(--shadow-lg);
}

.website-icon {
  width: 4rem;
  height: 4rem;
  margin-bottom: var(--spacing-lg);
  display: flex;
  align-items: center;
  justify-content: center;
}

.website-icon svg {
  width: 100%;
  height: 100%;
}

.website-content {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.website-content h3 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.website-content p {
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-lg);
  flex: 1;
}

.website-features {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
  flex-wrap: wrap;
}

.feature-tag {
  font-size: var(--font-size-xs);
  padding: var(--spacing-xs) var(--spacing-sm);
  background: var(--color-surface);
  color: var(--color-text-secondary);
  border-radius: calc(var(--border-radius) / 2);
  font-weight: var(--font-weight-medium);
}

/* Categories Section */
.categories-section {
  padding: var(--spacing-3xl) 0;
  background: var(--color-surface);
}

.categories-section h2 {
  text-align: center;
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-2xl);
  color: var(--color-text);
}

.categories-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-xl);
}

@media (min-width: 768px) {
  .categories-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.category-card {
  background: var(--color-card);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-xl);
  text-align: center;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
}

.category-icon {
  font-size: 3rem;
  margin-bottom: var(--spacing-lg);
}

.category-card h3 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.category-card p {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-lg);
}

.category-card ul {
  list-style: none;
  padding: 0;
  text-align: left;
}

.category-card li {
  padding: var(--spacing-sm) 0;
  color: var(--color-text-secondary);
  border-bottom: 1px solid var(--color-border);
}

.category-card li:last-child {
  border-bottom: none;
}

/* Tips Section */
.tips-section {
  padding: var(--spacing-3xl) 0;
}

.tips-section h2 {
  text-align: center;
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-2xl);
  color: var(--color-text);
}

.tips-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-xl);
}

@media (min-width: 640px) {
  .tips-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .tips-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.tip-card {
  background: var(--color-card);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-lg);
  text-align: center;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
}

.tip-number {
  width: 3rem;
  height: 3rem;
  background: var(--color-primary);
  color: var(--color-text-inverse);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: var(--font-weight-bold);
  margin: 0 auto var(--spacing-md);
}

.tip-card h3 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.tip-card p {
  color: var(--color-text-secondary);
}

/* ========================================
   CONTACT FORM & COMPONENTS
   ======================================== */

.contact-section {
  padding: var(--spacing-3xl) 0;
}

.contact-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-3xl);
}

@media (min-width: 1024px) {
  .contact-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.contact-info h2 {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-lg);
  color: var(--color-text);
}

.contact-info p {
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-xl);
}

.contact-methods {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.contact-method {
  display: flex;
  gap: var(--spacing-md);
  align-items: flex-start;
}

.contact-icon {
  flex-shrink: 0;
  width: 3rem;
  height: 3rem;
  background: var(--color-surface);
  border-radius: var(--border-radius);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
}

.contact-icon svg {
  width: 1.5rem;
  height: 1.5rem;
  stroke-width: 2;
  fill: none;
  stroke: currentColor;
}

.contact-content h3 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

.contact-content p {
  color: var(--color-text-secondary);
}

/* Contact Form */
.contact-form-container {
  background: var(--color-card);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-2xl);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--color-border);
}

.contact-form h2 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-xl);
  color: var(--color-text);
}

.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-group label {
  display: block;
  font-weight: var(--font-weight-medium);
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  background: var(--color-background);
  color: var(--color-text);
  font-size: var(--font-size-base);
  transition: all var(--transition-fast);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: var(--shadow-focus);
}

.form-group input.error,
.form-group select.error,
.form-group textarea.error {
  border-color: var(--color-error);
}

.error-message {
  color: var(--color-error);
  font-size: var(--font-size-sm);
  margin-top: var(--spacing-xs);
  min-height: 1.25rem;
}

.form-help {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  margin-top: var(--spacing-xs);
}

.form-actions {
  margin-top: var(--spacing-xl);
}

/* FAQ Section */
.faq-section {
  padding: var(--spacing-3xl) 0;
  background: var(--color-surface);
}

.faq-section h2 {
  text-align: center;
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-2xl);
  color: var(--color-text);
}

.faq-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-lg);
}

@media (min-width: 768px) {
  .faq-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.faq-item {
  background: var(--color-card);
  border-radius: var(--border-radius);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
}

.faq-item h3 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.faq-item p {
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

/* ========================================
   TOAST NOTIFICATIONS
   ======================================== */

.toast {
  position: fixed;
  top: var(--spacing-lg);
  right: var(--spacing-lg);
  z-index: var(--z-toast);
  max-width: 400px;
  opacity: 0;
  visibility: hidden;
  transform: translateX(100%);
  transition: all var(--transition-normal);
}

.toast.show {
  opacity: 1;
  visibility: visible;
  transform: translateX(0);
}

.toast-content {
  background: var(--color-card);
  border-radius: var(--border-radius);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--color-border);
  display: flex;
  gap: var(--spacing-md);
  align-items: flex-start;
}

.toast-icon {
  flex-shrink: 0;
  width: 1.5rem;
  height: 1.5rem;
}

.toast-success-icon {
  color: var(--color-success);
  stroke-width: 2;
  fill: none;
  stroke: currentColor;
}

.toast-error-icon {
  color: var(--color-error);
  stroke-width: 2;
  fill: none;
  stroke: currentColor;
  display: none;
}

.toast.error .toast-success-icon {
  display: none;
}

.toast.error .toast-error-icon {
  display: block;
}

.toast-message {
  flex: 1;
}

.toast-title {
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-xs);
  color: var(--color-text);
}

.toast-description {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.toast-close {
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-xs);
  color: var(--color-text-muted);
  border-radius: var(--border-radius);
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.toast-close:hover,
.toast-close:focus {
  background: var(--color-surface);
  color: var(--color-text);
}

.toast-close svg {
  width: 1rem;
  height: 1rem;
  stroke-width: 2;
  stroke: currentColor;
}

/* ========================================
   CTA SECTIONS
   ======================================== */

.cta-section,
.quick-access {
  padding: var(--spacing-3xl) 0;
  background: var(--color-surface);
}

.cta-content {
  text-align: center;
  max-width: 600px;
  margin: 0 auto;
}

.cta-content h2 {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.cta-content p {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-xl);
}

.cta-buttons {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* Quick Access */
.quick-access h2 {
  text-align: center;
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-2xl);
  color: var(--color-text);
}

.quick-access-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-lg);
}

@media (min-width: 640px) {
  .quick-access-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.quick-card {
  display: block;
  background: var(--color-card);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-xl);
  text-decoration: none;
  color: var(--color-text);
  text-align: center;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
  transition: all var(--transition-normal);
}

.quick-card:hover {
  transform: translateY(-0.25rem);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
}

.quick-icon {
  font-size: 3rem;
  margin-bottom: var(--spacing-lg);
}

.quick-card h3 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

.quick-card p {
  color: var(--color-text-secondary);
}

/* ========================================
   FOOTER
   ======================================== */

.footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-3xl) 0 var(--spacing-lg);
}

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

@media (min-width: 768px) {
  .footer-content {
    grid-template-columns: 1fr auto;
    align-items: start;
  }
}

.footer-brand {
  max-width: 300px;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  text-decoration: none;
  color: var(--color-text);
  font-weight: var(--font-weight-bold);
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-md);
}

.footer-logo .logo-svg {
  width: 1.5rem;
  height: 1.5rem;
  color: var(--color-primary);
}

.footer-brand p {
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

.footer-nav ul {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: var(--spacing-lg);
}

@media (max-width: 640px) {
  .footer-nav ul {
    flex-direction: column;
    gap: var(--spacing-md);
  }
}

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

.footer-nav a:hover,
.footer-nav a:focus {
  color: var(--color-primary);
}

.footer-bottom {
  text-align: center;
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--color-border);
}

.footer-bottom p {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

/* ========================================
   RESPONSIVE DESIGN IMPROVEMENTS
   ======================================== */

@media (max-width: 640px) {
  .container {
    padding: 0 var(--spacing-md);
  }
  
  .hero-title {
    font-size: var(--font-size-2xl);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3), 0 1px 2px rgba(0, 0, 0, 0.5);
  }
  
  .hero-subtitle {
    font-size: var(--font-size-base);
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.4), 0 1px 2px rgba(0, 0, 0, 0.6);
  }
  
  .page-header h1 {
    font-size: var(--font-size-2xl);
  }
  
  .btn {
    width: 100%;
    justify-content: center;
  }
  
  .hero-buttons .btn {
    width: auto;
    min-width: 200px;
  }
}

/* ========================================
   LOADING STATES & ANIMATIONS
   ======================================== */

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes slideInUp {
  from {
    opacity: 0;
    transform: translateY(2rem);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideInDown {
  from {
    opacity: 0;
    transform: translateY(-2rem);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeIn var(--transition-normal) ease-out;
}

.slide-in-up {
  animation: slideInUp var(--transition-slow) ease-out;
}

.slide-in-down {
  animation: slideInDown var(--transition-slow) ease-out;
}

/* ========================================
   PRINT STYLES
   ======================================== */

@media print {
  .header,
  .footer,
  .btn,
  .nav-toggle,
  .theme-toggle,
  .mobile-menu,
  .waves,
  #tsparticles,
  .loading-splash,
  .toast {
    display: none !important;
  }
  
  body {
    background: white !important;
    color: black !important;
  }
  
  .hero {
    background: none !important;
    color: black !important;
    min-height: auto;
    padding: 2rem 0;
  }
  
  .course-card,
  .website-card,
  .intro-card {
    break-inside: avoid;
    box-shadow: none !important;
    border: 1px solid #ccc !important;
  }
}