/* ==============================================
   UNIFIED DESIGN SYSTEM - ESL Fun Online
   Consolidated CSS variables and base styles
   ============================================== */

/* Unified CSS Custom Properties */
:root {
  /* Consistent Primary Color System */
  --primary-color: #46bbe5;
  --primary-hover: #05425c;
  --primary-light: rgba(70, 187, 229, 0.1);
  --primary-dark: #0d4f66;

  /* Secondary Color System */
  --secondary-color: #10b981;
  --secondary-hover: #059669;
  --secondary-light: rgba(16, 185, 129, 0.1);

  /* Accent Colors */
  --accent-color: #f59e0b;
  --accent-hover: #d97706;
  --accent-light: rgba(245, 158, 11, 0.1);

  /* Semantic Colors */
  --success-color: #10b981;
  --error-color: #ef4444;
  --warning-color: #f59e0b;
  --info-color: #3b82f6;

  /* Text Colors */
  --text-primary: #1f2937;
  --text-secondary: #6b7280;
  --text-muted: #9ca3af;
  --text-inverse: #ffffff;

  /* Background Colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f9fafb;
  --bg-tertiary: #f3f4f6;
  --bg-overlay: rgba(0, 0, 0, 0.5);

  /* Border Colors */
  --border-color: #e5e7eb;
  --border-light: #f3f4f6;
  --border-dark: #d1d5db;

  /* Shadows */
  --shadow-xs: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-sm: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1),
    0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1),
    0 8px 10px -6px rgb(0 0 0 / 0.1);
  --shadow-2xl: 0 25px 50px -12px rgb(0 0 0 / 0.25);

  /* Gradients */
  --gradient-primary: linear-gradient(135deg, #46bbe5 0%, #0d4f66 100%);
  --gradient-secondary: linear-gradient(135deg, #10b981 0%, #059669 100%);
  --gradient-accent: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
  --gradient-hero: linear-gradient(
    135deg,
    #667eea 0%,
    #764ba2 50%,
    #f093fb 100%
  );

  /* 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;

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

  /* Typography */
  --font-family-primary: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI",
    Roboto, sans-serif;
  --font-family-brand: "Poppins", sans-serif;
  --font-weight-light: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-extrabold: 800;

  /* Animation Timing */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;
  --transition-bounce: 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);

  /* Z-index Scale */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-tooltip: 1070;

  /* Layout */
  --header-height: 80px;
  --header-height-mobile: 70px;
  --container-max-width: 1200px;
  --container-padding: 1rem;
}

/* Dark Mode Variables */
.dark-mode {
  --text-primary: #f9fafb;
  --text-secondary: #d1d5db;
  --text-muted: #9ca3af;
  --text-inverse: #1f2937;
  --bg-primary: #1f2937;
  --bg-secondary: #111827;
  --bg-tertiary: #374151;
  --border-color: #374151;
  --border-light: #4b5563;
  --border-dark: #6b7280;
  --bg-overlay: rgba(0, 0, 0, 0.7);
}

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

html {
  line-height: 1.15;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-primary);
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-primary);
  transition: background-color var(--transition-normal),
    color var(--transition-normal);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  min-height: 100vh;
}

/* Improved Container System */
.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.container-fluid {
  width: 100%;
  padding: 0 var(--container-padding);
}

/* Responsive Container Padding */
@media (min-width: 640px) {
  :root {
    --container-padding: 1.5rem;
  }
}

@media (min-width: 1024px) {
  :root {
    --container-padding: 2rem;
  }
}

/* Typography System */
.text-xs {
  font-size: 0.75rem;
  line-height: 1rem;
}
.text-sm {
  font-size: 0.875rem;
  line-height: 1.25rem;
}
.text-base {
  font-size: 1rem;
  line-height: 1.5rem;
}
.text-lg {
  font-size: 1.125rem;
  line-height: 1.75rem;
}
.text-xl {
  font-size: 1.25rem;
  line-height: 1.75rem;
}
.text-2xl {
  font-size: 1.5rem;
  line-height: 2rem;
}
.text-3xl {
  font-size: 1.875rem;
  line-height: 2.25rem;
}
.text-4xl {
  font-size: 2.25rem;
  line-height: 2.5rem;
}
.text-5xl {
  font-size: 3rem;
  line-height: 1;
}

.font-light {
  font-weight: var(--font-weight-light);
}
.font-normal {
  font-weight: var(--font-weight-normal);
}
.font-medium {
  font-weight: var(--font-weight-medium);
}
.font-semibold {
  font-weight: var(--font-weight-semibold);
}
.font-bold {
  font-weight: var(--font-weight-bold);
}
.font-extrabold {
  font-weight: var(--font-weight-extrabold);
}

/* Utility Classes */
.text-center {
  text-align: center;
}
.text-left {
  text-align: left;
}
.text-right {
  text-align: right;
}

.text-primary {
  color: var(--text-primary);
}
.text-secondary {
  color: var(--text-secondary);
}
.text-muted {
  color: var(--text-muted);
}
.text-accent {
  color: var(--accent-color);
}

/* Button System */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-family: var(--font-family-primary);
  font-size: 1rem;
  font-weight: var(--font-weight-medium);
  line-height: 1.5;
  text-align: center;
  text-decoration: none;
  border: 2px solid transparent;
  border-radius: var(--radius);
  cursor: pointer;
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
  min-height: 44px;
  white-space: nowrap;
}

.btn:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

/* Button Variants */
.btn-primary {
  background: var(--gradient-primary);
  color: var(--text-inverse);
  border-color: var(--primary-color);
}

.btn-primary:hover {
  background: var(--primary-hover);
  border-color: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

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

.btn-secondary:hover {
  background: var(--primary-color);
  color: var(--text-inverse);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

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

.btn-outline:hover {
  background: var(--bg-secondary);
  border-color: var(--primary-color);
  color: var(--primary-color);
}

/* Button Sizes */
.btn-sm {
  padding: var(--space-2) var(--space-4);
  font-size: 0.875rem;
  min-height: 36px;
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: 1.125rem;
  min-height: 52px;
}

/* Card System */
.card {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
  overflow: hidden;
}

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

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

.card-body {
  padding: var(--space-6);
}

.card-footer {
  padding: var(--space-6);
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
}

/* Grid System */
.grid {
  display: grid;
  gap: var(--space-6);
}

.grid-1 {
  grid-template-columns: 1fr;
}
.grid-2 {
  grid-template-columns: repeat(2, 1fr);
}
.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}
.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

@media (max-width: 1024px) {
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .grid-4,
  .grid-3,
  .grid-2 {
    grid-template-columns: 1fr;
  }
}

/* Responsive Grid */
.grid-responsive {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-6);
}

/* Animation Classes */
.fade-in {
  opacity: 0;
  animation: fadeIn 0.6s ease-out forwards;
}

.slide-up {
  opacity: 0;
  transform: translateY(30px);
  animation: slideUp 0.6s ease-out forwards;
}

.scale-in {
  opacity: 0;
  transform: scale(0.9);
  animation: scaleIn 0.6s ease-out forwards;
}

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

@keyframes slideUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes scaleIn {
  to {
    opacity: 1;
    transform: scale(1);
  }
}

/* Loading States */
.loading {
  position: relative;
  pointer-events: none;
}

.loading::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  width: 20px;
  height: 20px;
  margin: -10px 0 0 -10px;
  border: 2px solid var(--primary-light);
  border-top: 2px solid var(--primary-color);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

/* Accessibility Improvements */
.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;
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--primary-color);
  color: var(--text-inverse);
  padding: var(--space-2) var(--space-4);
  text-decoration: none;
  border-radius: var(--radius);
  z-index: var(--z-tooltip);
  font-weight: var(--font-weight-semibold);
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 6px;
}

/* Focus Management */
.focus-visible {
  outline: 3px solid var(--primary-color) !important;
  outline-offset: 2px !important;
}

/* Performance Optimizations */
.will-change-transform {
  will-change: transform;
}

.will-change-opacity {
  will-change: opacity;
}

/* Print Styles */
@media print {
  * {
    -webkit-print-color-adjust: exact !important;
    print-color-adjust: exact !important;
  }

  .no-print {
    display: none !important;
  }

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

/* Reduced Motion Support */
@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;
  }
}

/* High Contrast Mode Support */
@media (prefers-contrast: high) {
  .btn {
    border-width: 3px;
  }

  .card {
    border-width: 2px;
  }
}

/* Force GPU Acceleration for smooth animations */
.gpu-accelerated {
  transform: translateZ(0);
  -webkit-transform: translateZ(0);
  -webkit-perspective: 1000px;
  perspective: 1000px;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
}

/* ==============================================
   STANDARDIZED LAYOUT COMPONENTS
   ============================================== */

/* Base Section Spacing */
.section {
  padding: var(--space-16) 0;
}

/* Hero Section Standardization */
.hero {
  position: relative;
  padding: calc(var(--header-height) + var(--space-8)) 0 var(--space-16);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.page-header {
  position: relative;
  padding: calc(var(--header-height) + var(--space-12)) 0 var(--space-12);
  text-align: center;
  min-height: 60vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-content,
.page-header-content {
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
  padding: 0 var(--space-4);
}

/* Mobile Hero Adjustments */
@media (max-width: 768px) {
  .hero {
    padding: calc(var(--header-height-mobile) + var(--space-6)) 0
      var(--space-12);
    min-height: calc(100vh - var(--header-height-mobile));
  }

  .page-header {
    padding: calc(var(--header-height-mobile) + var(--space-8)) 0 var(--space-8);
    min-height: 50vh;
  }

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

  .hero h1,
  .page-header h1 {
    font-size: clamp(1.875rem, 8vw, 3rem);
    line-height: 1.2;
    margin-bottom: var(--space-4);
  }

  .hero p,
  .page-header p {
    font-size: clamp(1rem, 4vw, 1.125rem);
    line-height: 1.6;
    margin-bottom: var(--space-6);
  }

  .hero-buttons {
    flex-direction: column;
    gap: var(--space-4);
    margin-top: var(--space-6);
  }

  .hero-stats {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-4);
    margin: var(--space-6) 0;
  }
}