/* public/css/main.css */
/* EduSolve Platform - World-Class Design System */

/* ============================================
   GOOGLE FONTS - Loaded via HTML for better LCP
   ============================================ */
/* Font is preloaded in the HTML head for better performance */

/* ============================================
   CSS CUSTOM PROPERTIES (Design Tokens)
   ============================================ */
:root {
  /* Primary: Deep Indigo - Trust & Intelligence */
  --primary: #4F46E5;
  --primary-dark: #4338CA;
  --primary-light: #6366F1;
  --primary-lighter: #A5B4FC;
  --primary-gradient: linear-gradient(135deg, #4F46E5 0%, #7C3AED 100%);

  /* Secondary: Vibrant Teal - Growth & Innovation */
  --secondary: #0D9488;
  --secondary-dark: #0F766E;
  --secondary-light: #14B8A6;

  /* Accent: Warm Coral - Energy & Engagement */
  --accent: #F97316;
  --accent-dark: #EA580C;
  --accent-light: #FB923C;

  /* Semantic Colors */
  --success: #10B981;
  --success-light: #D1FAE5;
  --danger: #EF4444;
  --danger-light: #FEE2E2;
  --warning: #F59E0B;
  --warning-light: #FEF3C7;
  --info: #3B82F6;
  --info-light: #DBEAFE;

  /* Backgrounds - Warm & Inviting */
  --bg: #FAFAFA;
  --bg-secondary: #F5F5F4;
  --bg-tertiary: #E7E5E4;
  --bg-elevated: #FFFFFF;
  --bg-overlay: rgba(0, 0, 0, 0.5);

  /* Text - Warm Gray Palette (WCAG AA Compliant) */
  --text: #1C1917;
  --text-secondary: #44403C;
  --text-light: #57534E;  /* Improved contrast: 5.74:1 on white */
  --text-lighter: #78716C;  /* For decorative/non-essential text only */
  --text-muted: #6B7280;  /* For secondary info: 4.62:1 on white */
  --text-inverse: #FFFFFF;

  /* Borders */
  --border: #E7E5E4;
  --border-light: #F5F5F4;
  --border-dark: #D6D3D1;
  --border-focus: var(--primary);

  /* Shadows - Layered Depth System */
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  --shadow-primary: 0 4px 14px rgba(79, 70, 229, 0.4);
  --shadow-glow: 0 0 40px rgba(79, 70, 229, 0.15);

  /* 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;
  --space-20: 5rem;
  --space-24: 6rem;

  /* Layout */
  --container-width: 1280px;
  --container-narrow: 768px;
  --header-height: 72px;
  --sidebar-width: 280px;

  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius: 0.5rem;
  --radius-md: 0.625rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition: 200ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-bounce: 500ms cubic-bezier(0.34, 1.56, 0.64, 1);

  /* Z-Index Scale */
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-fixed: 300;
  --z-modal-backdrop: 400;
  --z-modal: 500;
  --z-popover: 600;
  --z-tooltip: 700;
}

/* ============================================
   DARK MODE - Premium Dark Theme
   ============================================ */
[data-theme="dark"] {
  --primary: #818CF8;
  --primary-dark: #6366F1;
  --primary-light: #A5B4FC;
  --primary-gradient: linear-gradient(135deg, #6366F1 0%, #8B5CF6 100%);

  --secondary: #2DD4BF;
  --secondary-dark: #14B8A6;

  --accent: #FB923C;

  --bg: #0F172A;
  --bg-secondary: #1E293B;
  --bg-tertiary: #334155;
  --bg-elevated: #1E293B;

  --text: #F8FAFC;
  --text-secondary: #E2E8F0;
  --text-light: #CBD5E1;  /* Improved contrast for dark mode */
  --text-lighter: #94A3B8;
  --text-muted: #A1A1AA;

  --border: #334155;
  --border-light: #1E293B;
  --border-dark: #475569;

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.4);
  --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.5);
  --shadow-primary: 0 4px 14px rgba(129, 140, 248, 0.3);
  --shadow-glow: 0 0 40px rgba(129, 140, 248, 0.1);
}

/* ============================================
   RESET & BASE STYLES
   ============================================ */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  font-feature-settings: 'cv11', 'ss01', 'ss03';
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  line-height: 1.7;  /* Improved for readability */
  letter-spacing: -0.01em;  /* Slightly tighter for Inter font */
  color: var(--text);
  background: var(--bg);
  min-height: 100vh;
  overflow-x: hidden;
  font-size: 1rem;  /* 16px base - optimal for reading */
}

/* Typography - Optimized for International Readability */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;  /* Better for multi-line headings */
  letter-spacing: -0.025em;
  color: var(--text);
  margin-bottom: 0.5em;
  word-wrap: break-word;  /* Prevent overflow */
}

h1 { font-size: clamp(1.875rem, 4vw, 2.5rem); }  /* Responsive sizing */
h2 { font-size: clamp(1.5rem, 3vw, 2rem); }
h3 { font-size: clamp(1.25rem, 2.5vw, 1.5rem); }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
  color: var(--text-secondary);
  line-height: 1.8;  /* Optimal for reading long content */
  margin-bottom: 1em;
  max-width: 75ch;  /* Optimal line length for readability */
}

/* Better paragraph spacing for articles/content */
article p,
.content p {
  margin-bottom: 1.5em;
}

/* Small text - ensure minimum readable size */
small, .text-sm {
  font-size: 0.875rem;  /* 14px - minimum for readability */
  line-height: 1.6;
}

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

a:hover {
  color: var(--primary-dark);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* Responsive Image Utilities */
picture {
  display: block;
}

picture img {
  width: 100%;
  height: auto;
}

.img-responsive {
  width: 100%;
  height: auto;
  object-fit: cover;
}

.img-contain {
  object-fit: contain;
}

.img-cover {
  object-fit: cover;
}

/* Aspect ratio containers for CLS prevention */
.aspect-video {
  aspect-ratio: 16 / 9;
}

.aspect-square {
  aspect-ratio: 1 / 1;
}

.aspect-4-3 {
  aspect-ratio: 4 / 3;
}

.aspect-3-2 {
  aspect-ratio: 3 / 2;
}

/* Placeholder shimmer for lazy loading images */
.img-placeholder {
  background: linear-gradient(90deg, var(--bg-secondary) 0%, var(--bg-tertiary) 50%, var(--bg-secondary) 100%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}

@keyframes shimmer {
  0% {
    background-position: 200% 0;
  }
  100% {
    background-position: -200% 0;
  }
}

/* Responsive srcset helper - explicit width/height for CLS */
img[width][height] {
  max-width: 100%;
  height: auto;
}

/* ============================================
   CONTAINER
   ============================================ */
.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.container-narrow {
  max-width: var(--container-narrow);
}

/* ============================================
   HEADER - Glassmorphism Design
   ============================================ */
.header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  height: var(--header-height);
  background: rgba(250, 250, 250, 0.85);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid rgba(231, 229, 228, 0.5);
  transition: all var(--transition);
}

[data-theme="dark"] .header {
  background: rgba(15, 23, 42, 0.85);
  border-bottom: 1px solid rgba(51, 65, 85, 0.5);
}

.header-content {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
  text-decoration: none;
  letter-spacing: -0.03em;
  transition: transform var(--transition);
}

.logo:hover {
  transform: scale(1.02);
  color: var(--primary);
}

.logo-img {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  object-fit: contain;
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: var(--primary-gradient);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  box-shadow: var(--shadow-primary);
}

/* Navigation */
.nav {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.nav a {
  padding: var(--space-2) var(--space-4);
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.9375rem;
  border-radius: var(--radius);
  transition: all var(--transition);
  position: relative;
}

.nav a:hover {
  color: var(--primary);
  background: rgba(79, 70, 229, 0.08);
}

.nav a.active {
  color: var(--primary);
  background: rgba(79, 70, 229, 0.1);
}

/* Header Search */
.header-search {
  display: flex;
  align-items: center;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-full);
  overflow: hidden;
  transition: all var(--transition);
  box-shadow: var(--shadow-xs);
}

.header-search:focus-within {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1), var(--shadow-sm);
}

.header-search input {
  border: none;
  background: transparent;
  padding: var(--space-3) var(--space-4);
  width: 240px;
  font-size: 0.875rem;
  color: var(--text);
  outline: none;
}

.header-search input::placeholder {
  color: var(--text-lighter);
}

.header-search button {
  background: transparent;
  border: none;
  padding: var(--space-3) var(--space-4);
  cursor: pointer;
  color: var(--text-light);
  display: flex;
  align-items: center;
  transition: color var(--transition);
}

.header-search button:hover {
  color: var(--primary);
}

@media (max-width: 900px) {
  .header-search {
    display: none;
  }
}

/* Mobile Search */
.mobile-search {
  display: none;
  width: 100%;
  margin-bottom: var(--space-4);
}

.mobile-search input {
  flex: 1;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--border);
  border-radius: var(--radius) 0 0 var(--radius);
  font-size: 1rem;
  background: var(--bg-elevated);
  color: var(--text);
}

.mobile-search button {
  padding: var(--space-3) var(--space-4);
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 0 var(--radius) var(--radius) 0;
  cursor: pointer;
}

/* ============================================
   BUTTONS - Premium Design
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.9375rem;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(255,255,255,0.1) 0%, rgba(255,255,255,0) 50%);
  opacity: 0;
  transition: opacity var(--transition);
}

.btn:hover::before {
  opacity: 1;
}

.btn-primary {
  background: var(--primary-gradient);
  color: var(--text-inverse);
  box-shadow: var(--shadow-primary);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(79, 70, 229, 0.5);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-secondary {
  background: var(--bg-elevated);
  color: var(--text);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-xs);
}

.btn-secondary:hover {
  background: var(--bg-secondary);
  border-color: var(--border-dark);
  transform: translateY(-1px);
}

.btn-success {
  background: linear-gradient(135deg, var(--success) 0%, #059669 100%);
  color: var(--text-inverse);
  box-shadow: 0 4px 14px rgba(16, 185, 129, 0.4);
}

.btn-danger {
  background: linear-gradient(135deg, var(--danger) 0%, #DC2626 100%);
  color: var(--text-inverse);
  box-shadow: 0 4px 14px rgba(239, 68, 68, 0.4);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
}

.btn-ghost:hover {
  background: var(--bg-secondary);
  color: var(--text);
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: 1.0625rem;
  border-radius: var(--radius-lg);
}

.btn-sm {
  padding: var(--space-2) var(--space-4);
  font-size: 0.8125rem;
}

.btn-icon {
  width: 40px;
  height: 40px;
  padding: 0;
  border-radius: var(--radius);
}

/* ============================================
   CARDS - Modern Design
   ============================================ */
.card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  transition: all var(--transition-bounce);
  position: relative;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
  border-color: var(--border-dark);
}

.card-highlight {
  border-color: var(--primary-lighter);
  box-shadow: var(--shadow-glow);
}

.card-highlight:hover {
  border-color: var(--primary);
}

/* Category Cards */
.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-6);
  margin: var(--space-8) 0;
}

.category-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  text-decoration: none;
  color: var(--text);
  transition: all var(--transition-bounce);
  position: relative;
  overflow: hidden;
}

.category-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: var(--primary-gradient);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}

.category-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary-lighter);
}

.category-card:hover::before {
  transform: scaleX(1);
}

.category-card h3 {
  font-size: 1.25rem;
  margin-bottom: var(--space-2);
  color: var(--text);
  transition: color var(--transition);
}

.category-card:hover h3 {
  color: var(--primary);
}

.category-card p {
  color: var(--text-light);
  font-size: 0.875rem;
}

/* Problem Cards */
.problem-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  margin-bottom: var(--space-4);
  transition: all var(--transition);
}

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

.problem-card h3 {
  margin-bottom: var(--space-3);
  font-size: 1.125rem;
}

.problem-card h3 a {
  color: var(--text);
  text-decoration: none;
  transition: color var(--transition);
}

.problem-card h3 a:hover {
  color: var(--primary);
}

.problem-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  font-size: 0.875rem;  /* Increased from 0.8125rem for readability */
  color: var(--text-light);
  margin-top: var(--space-3);
}

.problem-meta span {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

/* ============================================
   BADGES
   ============================================ */
.badge {
  display: inline-flex;
  align-items: center;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: capitalize;
}

.badge-beginner {
  background: var(--info-light);
  color: #1E40AF;
}

.badge-intermediate {
  background: var(--warning-light);
  color: #92400E;
}

.badge-advanced {
  background: #FEE2E2;
  color: #991B1B;
}

.badge-expert {
  background: #F3E8FF;
  color: #6B21A8;
}

.badge-open {
  background: var(--success-light);
  color: #065F46;
}

.badge-solved {
  background: var(--info-light);
  color: #1E40AF;
}

.badge-closed {
  background: var(--bg-tertiary);
  color: var(--text-light);
}

.badge-featured {
  background: var(--primary-gradient);
  color: white;
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
  background: var(--primary-gradient);
  background-size: 400% 400%;
  animation: gradientShift 15s ease infinite;
  color: white;
  padding: var(--space-20) 0;
  position: relative;
  overflow: hidden;
}

@keyframes gradientShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
  opacity: 0.5;
}

/* Floating particles animation */
.hero::after {
  content: '';
  position: absolute;
  width: 300px;
  height: 300px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.1);
  top: -150px;
  right: -150px;
  animation: float 20s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translate(0, 0) rotate(0deg); }
  25% { transform: translate(-50px, 50px) rotate(90deg); }
  50% { transform: translate(0, 100px) rotate(180deg); }
  75% { transform: translate(50px, 50px) rotate(270deg); }
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
}

.hero h1 {
  font-size: 3.5rem;
  font-weight: 800;
  margin-bottom: var(--space-6);
  line-height: 1.1;
  color: white;
  text-shadow: 0 2px 40px rgba(0, 0, 0, 0.2);
}

.hero p {
  font-size: 1.25rem;
  opacity: 0.95;
  margin-bottom: var(--space-8);
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.9);
}

.hero-buttons {
  display: flex;
  gap: var(--space-4);
  justify-content: center;
  flex-wrap: wrap;
}

.hero-btn-primary {
  background: white;
  color: var(--primary);
  padding: var(--space-4) var(--space-8);
  font-size: 1.125rem;
  font-weight: 700;
  border-radius: var(--radius-lg);
  text-decoration: none;
  transition: all var(--transition);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
}

.hero-btn-primary:hover {
  transform: translateY(-3px) scale(1.02);
  box-shadow: 0 15px 50px rgba(0, 0, 0, 0.3);
  color: var(--primary-dark);
}

.hero-btn-secondary {
  background: rgba(255, 255, 255, 0.15);
  color: white;
  padding: var(--space-4) var(--space-8);
  font-size: 1.125rem;
  font-weight: 600;
  border-radius: var(--radius-lg);
  text-decoration: none;
  border: 2px solid rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(10px);
  transition: all var(--transition);
}

.hero-btn-secondary:hover {
  background: rgba(255, 255, 255, 0.25);
  border-color: rgba(255, 255, 255, 0.5);
  color: white;
}

/* ============================================
   FORMS
   ============================================ */
.form-group {
  margin-bottom: var(--space-6);
}

.form-label {
  display: block;
  margin-bottom: var(--space-2);
  font-weight: 600;
  font-size: 0.9375rem;
  color: var(--text);
}

.form-label-required::after {
  content: ' *';
  color: var(--danger);
}

.form-input,
.form-textarea,
.form-select {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  border: 2px solid var(--border);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-family: inherit;
  background: var(--bg-elevated);
  color: var(--text);
  transition: all var(--transition);
}

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

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.1);
}

.form-input::placeholder,
.form-textarea::placeholder {
  color: var(--text-lighter);
}

.form-textarea {
  resize: vertical;
  min-height: 120px;
}

.form-error {
  color: var(--danger);
  font-size: 0.875rem;
  margin-top: var(--space-2);
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.form-hint {
  color: var(--text-lighter);
  font-size: 0.8125rem;
  margin-top: var(--space-2);
}

/* Footer styles are defined in the footer.ejs partial */

/* ============================================
   USER MENU (Enhanced version - components.css has basic version)
   ============================================ */
.user-menu {
  position: relative;
}

.user-menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  background: var(--primary-gradient);
  color: white;
  border: none;
  border-radius: var(--radius-full);
  cursor: pointer;
  font-weight: 700;
  font-size: 1rem;
  transition: all var(--transition);
  box-shadow: var(--shadow-sm);
}

.user-menu-toggle:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-primary);
}

.user-menu-dropdown {
  position: absolute;
  top: calc(100% + var(--space-2));
  right: 0;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  min-width: 200px;
  z-index: var(--z-dropdown);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px) scale(0.95);
  transition: all var(--transition);
  overflow: hidden;
}

.user-menu-dropdown:not([hidden]) {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) scale(1);
}

.user-menu-dropdown a {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  color: var(--text);
  text-decoration: none;
  font-size: 0.9375rem;
  transition: all var(--transition);
}

.user-menu-dropdown a:hover {
  background: var(--bg-secondary);
  color: var(--primary);
}

.user-menu-dropdown a:last-child {
  border-top: 1px solid var(--border);
  color: var(--danger);
}

.user-menu-dropdown a:last-child:hover {
  background: var(--danger-light);
}

/* ============================================
   MOBILE MENU
   ============================================ */
.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
  z-index: var(--z-sticky);
  border-radius: var(--radius);
  transition: background var(--transition);
}

.mobile-menu-toggle:hover {
  background: var(--bg-secondary);
}

.mobile-menu-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--text);
  border-radius: var(--radius-full);
  transition: all var(--transition);
}

.mobile-menu-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.mobile-menu-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.mobile-menu-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

@media (max-width: 900px) {
  .mobile-menu-toggle {
    display: flex;
  }

  .nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg);
    flex-direction: column;
    align-items: stretch;
    padding: var(--space-6);
    transform: translateX(-100%);
    transition: transform var(--transition-slow);
    overflow-y: auto;
    gap: 0;
  }

  .nav.nav-open {
    transform: translateX(0);
  }

  .nav a {
    padding: var(--space-4);
    font-size: 1.125rem;
    border-bottom: 1px solid var(--border);
    border-radius: 0;
  }

  .nav .btn {
    margin-top: var(--space-4);
    text-align: center;
  }

  .mobile-search {
    display: flex;
  }

  .user-menu {
    width: 100%;
  }

  .user-menu-toggle {
    width: 100%;
    border-radius: var(--radius);
    justify-content: flex-start;
    padding: var(--space-4);
    height: auto;
    background: var(--bg-secondary);
    color: var(--text);
  }

  .user-menu-dropdown {
    position: static;
    border: none;
    box-shadow: none;
    opacity: 1;
    visibility: visible;
    transform: none;
    background: var(--bg-secondary);
    margin-top: var(--space-2);
    border-radius: var(--radius);
  }

  .user-menu-dropdown[hidden] {
    display: none;
  }
}

@media (max-width: 600px) {
  .hero h1 {
    font-size: 2rem;
  }

  .hero p {
    font-size: 1rem;
  }

  .hero-buttons {
    flex-direction: column;
  }

  .hero-btn-primary,
  .hero-btn-secondary {
    width: 100%;
    text-align: center;
    justify-content: center;
  }

  .container {
    padding: 0 var(--space-4);
  }

  .header-content {
    padding: 0 var(--space-4);
  }

  .logo {
    font-size: 1.25rem;
  }

  .logo-icon {
    width: 36px;
    height: 36px;
    font-size: 1.125rem;
  }
}

/* Extra small screens */
@media (max-width: 375px) {
  .container {
    padding: 0 var(--space-3);
  }

  .header-content {
    padding: 0 var(--space-3);
  }

  .logo {
    font-size: 1.125rem;
  }

  .logo-icon {
    width: 32px;
    height: 32px;
    font-size: 1rem;
  }
}

/* ============================================
   ALERTS
   ============================================ */
.alert {
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-4);
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  border: 1px solid transparent;
}

.alert-icon {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
}

.alert-success {
  background: var(--success-light);
  color: #065F46;
  border-color: #6EE7B7;
}

.alert-error {
  background: var(--danger-light);
  color: #991B1B;
  border-color: #FCA5A5;
}

.alert-warning {
  background: var(--warning-light);
  color: #92400E;
  border-color: #FCD34D;
}

.alert-info {
  background: var(--info-light);
  color: #1E40AF;
  border-color: #93C5FD;
}

/* ============================================
   LOADING STATES
   ============================================ */
.loading {
  display: inline-block;
  width: 20px;
  height: 20px;
  border: 2px solid var(--border);
  border-top-color: var(--primary);
  border-radius: var(--radius-full);
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.skeleton {
  background: linear-gradient(90deg, var(--bg-secondary) 25%, var(--bg-tertiary) 50%, var(--bg-secondary) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: var(--radius);
}

@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ============================================
   UTILITIES
   ============================================ */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.font-bold { font-weight: 700; }
.font-semibold { font-weight: 600; }
.font-medium { font-weight: 500; }

.text-primary { color: var(--primary); }
.text-secondary { color: var(--text-secondary); }
.text-light { color: var(--text-light); }
.text-success { color: var(--success); }
.text-danger { color: var(--danger); }
.text-warning { color: var(--warning); }

.bg-primary { background: var(--primary); }
.bg-secondary { background: var(--bg-secondary); }

.mt-1 { margin-top: var(--space-1); }
.mt-2 { margin-top: var(--space-2); }
.mt-3 { margin-top: var(--space-3); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }

.mb-1 { margin-bottom: var(--space-1); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-3 { margin-bottom: var(--space-3); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }

.p-2 { padding: var(--space-2); }
.p-4 { padding: var(--space-4); }
.p-6 { padding: var(--space-6); }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: var(--space-2); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }

.grid { display: grid; }

.hidden { display: none; }
.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;
}

/* ============================================
   ACCESSIBILITY FEATURES
   ============================================ */

/* Skip to Main Content Link */
.skip-link {
  position: absolute;
  top: -100%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--primary);
  color: white;
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius);
  font-weight: 600;
  z-index: 9999;
  transition: top var(--transition);
  text-decoration: none;
}

.skip-link:focus {
  top: var(--space-4);
}

/* Focus Styles - High visibility for keyboard users */
:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 3px;
}

button:focus-visible,
a:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 3px;
}

input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.2);
}

/* Ensure focus is visible on dark backgrounds */
.hero a:focus-visible,
.hero button:focus-visible {
  outline: 3px solid white;
  outline-offset: 3px;
}

/* Reduced Motion for users who prefer it */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* High Contrast Mode Support */
@media (prefers-contrast: high) {
  :root {
    --text-light: #1C1917;
    --border: #1C1917;
  }

  .badge {
    border: 2px solid currentColor;
  }
}

/* ============================================
   SCROLLBAR STYLES
   ============================================ */
::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
  background: var(--border-dark);
  border-radius: var(--radius-full);
  border: 2px solid var(--bg-secondary);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-lighter);
}

/* ============================================
   IMPROVED READABILITY - INTERNATIONAL STANDARDS
   ============================================ */

/* Prose content - optimal reading experience */
.prose {
  font-size: 1.0625rem;  /* 17px - slightly larger for better readability */
  line-height: 1.8;
  color: var(--text-secondary);
  max-width: 75ch;  /* Optimal line length */
}

.prose p {
  margin-bottom: 1.5em;
}

.prose h2 {
  margin-top: 2em;
  margin-bottom: 0.75em;
  font-size: 1.5rem;
}

.prose h3 {
  margin-top: 1.5em;
  margin-bottom: 0.5em;
  font-size: 1.25rem;
}

.prose ul,
.prose ol {
  margin: 1.25em 0;
  padding-left: 1.5em;
}

.prose li {
  margin-bottom: 0.5em;
  line-height: 1.7;
}

.prose a {
  text-decoration: underline;
  text-underline-offset: 2px;
}

.prose blockquote {
  margin: 1.5em 0;
  padding: 1em 1.25em;
  border-left: 4px solid var(--primary);
  background: var(--bg-secondary);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--text);
  font-style: italic;
}

.prose code {
  background: var(--bg-secondary);
  padding: 0.2em 0.4em;
  border-radius: var(--radius-sm);
  font-size: 0.9em;
  font-family: 'Fira Code', 'Consolas', monospace;
}

.prose pre {
  background: var(--bg-secondary);
  padding: 1.25rem;
  border-radius: var(--radius-lg);
  overflow-x: auto;
  margin: 1.5em 0;
}

.prose pre code {
  background: none;
  padding: 0;
}

.prose img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-lg);
  margin: 1.5em 0;
}

/* Content card improvements */
.content-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  transition: all var(--transition);
}

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

/* Meta information with improved contrast */
.meta-info {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.875rem;  /* Increased from 0.8125rem */
  color: var(--text-light);
}

.meta-info svg {
  width: 16px;
  height: 16px;
  opacity: 0.8;
}

/* High contrast badges - WCAG AA+ compliant */
.badge-hc-beginner {
  background: #DBEAFE;
  color: #1E40AF;
  border: 1px solid #3B82F6;
}

.badge-hc-intermediate {
  background: #FEF3C7;
  color: #92400E;
  border: 1px solid #F59E0B;
}

.badge-hc-advanced {
  background: #FEE2E2;
  color: #991B1B;
  border: 1px solid #EF4444;
}

.badge-hc-expert {
  background: #F3E8FF;
  color: #6B21A8;
  border: 1px solid #A855F7;
}

/* Dark mode high contrast badges */
[data-theme="dark"] .badge-hc-beginner {
  background: rgba(59, 130, 246, 0.2);
  color: #93C5FD;
  border: 1px solid #3B82F6;
}

[data-theme="dark"] .badge-hc-intermediate {
  background: rgba(245, 158, 11, 0.2);
  color: #FCD34D;
  border: 1px solid #F59E0B;
}

[data-theme="dark"] .badge-hc-advanced {
  background: rgba(239, 68, 68, 0.2);
  color: #FCA5A5;
  border: 1px solid #EF4444;
}

[data-theme="dark"] .badge-hc-expert {
  background: rgba(168, 85, 247, 0.2);
  color: #D8B4FE;
  border: 1px solid #A855F7;
}

/* Empty state improvements */
.empty-state-wrapper {
  text-align: center;
  padding: var(--space-16) var(--space-6);
}

.empty-state-icon-wrapper {
  width: 80px;
  height: 80px;
  margin: 0 auto var(--space-6);
  background: linear-gradient(135deg, rgba(79, 70, 229, 0.1) 0%, rgba(124, 58, 237, 0.1) 100%);
  border-radius: var(--radius-2xl);
  display: flex;
  align-items: center;
  justify-content: center;
}

.empty-state-icon-wrapper svg {
  width: 40px;
  height: 40px;
  color: var(--primary);
  opacity: 0.7;
}

.empty-state-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: var(--space-3);
}

.empty-state-description {
  color: var(--text-light);
  font-size: 1rem;
  max-width: 400px;
  margin: 0 auto var(--space-6);
  line-height: 1.6;
}

/* Tablet breakpoint helper */
@media (min-width: 600px) and (max-width: 968px) {
  .tablet-grid-2 {
    grid-template-columns: repeat(2, 1fr) !important;
  }

  .tablet-single-col {
    grid-template-columns: 1fr !important;
  }
}

/* Animation classes for page elements */
.animate-fade-in {
  animation: fadeIn 0.5s cubic-bezier(0.4, 0, 0.2, 1) forwards;
  opacity: 0;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Staggered animation delays */
.anim-order-0 { animation-delay: 0s; }
.anim-order-1 { animation-delay: 0.05s; }
.anim-order-2 { animation-delay: 0.1s; }
.anim-order-3 { animation-delay: 0.15s; }
.anim-order-4 { animation-delay: 0.2s; }
.anim-order-5 { animation-delay: 0.25s; }
.anim-order-6 { animation-delay: 0.3s; }
.anim-order-7 { animation-delay: 0.35s; }
.anim-order-8 { animation-delay: 0.4s; }
.anim-order-9 { animation-delay: 0.45s; }

/* ============================================
   PRINT STYLES
   ============================================ */
@media print {
  .header,
  .footer,
  .nav,
  .btn {
    display: none !important;
  }

  body {
    background: white;
    color: black;
  }

  a {
    color: black;
    text-decoration: underline;
  }
}