/**
 * World Flags Master - Styles
 * Mobile-first responsive design with accessibility
 * 
 * @author LEARNature-ly Team
 * @version 1.0.0
 */

/* ============================================
   CSS VARIABLES
   ============================================ */
:root {
  /* Colors */
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-secondary: #64748b;
  --color-success: #10b981;
  --color-error: #ef4444;
  --color-warning: #f59e0b;

  /* Backgrounds */
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #e2e8f0;
  --bg-dark: #1e293b;

  /* Text */
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-tertiary: #94a3b8;
  --text-inverse: #ffffff;

  /* Borders */
  --border-color: #e2e8f0;
  --border-radius-sm: 8px;
  --border-radius-md: 12px;
  --border-radius-lg: 16px;

  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;

  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  --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: 2rem;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;
}

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

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

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--text-primary);
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  padding: var(--spacing-sm);
}

/* ============================================
   SCREENS & CONTAINERS
   ============================================ */
.screen {
  opacity: 1;
  transition: opacity var(--transition-base);
}

.screen.hidden {
  display: none;
  opacity: 0;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  background: var(--bg-primary);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-lg);
}

/* ============================================
   TYPOGRAPHY
   ============================================ */
.game-title {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--color-primary);
  text-align: center;
  margin-bottom: var(--spacing-xs);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
}

.title-icon {
  font-size: 3rem;
}

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

.section-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--spacing-md);
  text-align: center;
}

/* ============================================
   WELCOME SCREEN
   ============================================ */
.game-header {
  margin-bottom: var(--spacing-xl);
}

/* Mode Selection */
.mode-selection {
  margin-bottom: var(--spacing-xl);
}

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

.mode-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-md);
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius-md);
  background: var(--bg-secondary);
  cursor: pointer;
  transition: all var(--transition-base);
  font-family: inherit;
}

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

.mode-btn.active {
  border-color: var(--color-primary);
  background: var(--color-primary);
  color: var(--text-inverse);
}

.mode-icon {
  font-size: 2rem;
}

.mode-name {
  font-size: var(--font-size-lg);
  font-weight: 600;
}

.mode-desc {
  font-size: var(--font-size-sm);
  opacity: 0.8;
}

/* Difficulty Selection */
.difficulty-selection {
  margin-bottom: var(--spacing-xl);
}

.difficulty-dropdown {
  width: 100%;
  padding: var(--spacing-md);
  font-size: var(--font-size-base);
  font-family: inherit;
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius-md);
  background: var(--bg-secondary);
  cursor: pointer;
  transition: border-color var(--transition-base);
}

.difficulty-dropdown:hover,
.difficulty-dropdown:focus {
  border-color: var(--color-primary);
  outline: none;
}

/* Continent Selection */
.continent-selection {
  margin-bottom: var(--spacing-xl);
}

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

.continent-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-lg);
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius-md);
  background: var(--bg-secondary);
  cursor: pointer;
  transition: all var(--transition-base);
  font-family: inherit;
}

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

.continent-card.active {
  border-color: var(--color-primary);
  background: linear-gradient(
    135deg,
    var(--color-primary) 0%,
    var(--color-primary-dark) 100%
  );
  color: var(--text-inverse);
}

.continent-card-world {
  background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  color: var(--text-inverse);
}

.continent-card-world.active {
  background: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
}

.continent-icon {
  font-size: 3rem;
}

.continent-name {
  font-size: var(--font-size-xl);
  font-weight: 600;
}

.continent-count {
  font-size: var(--font-size-sm);
  opacity: 0.8;
}

/* Start Button */
.start-action {
  text-align: center;
}

/* ============================================
   GAME SCREEN
   ============================================ */
.game-header-compact {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-md);
  padding: var(--spacing-md);
  background: var(--bg-secondary);
  border-radius: var(--border-radius-md);
}

.score-display,
.streak-display,
.question-counter-display {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-size: var(--font-size-lg);
  font-weight: 600;
}

.streak-icon {
  font-size: 1.5rem;
}

/* Progress Bar */
.progress-container {
  width: 100%;
  height: 8px;
  background: var(--bg-tertiary);
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: var(--spacing-lg);
}

.progress-bar {
  height: 100%;
  background: linear-gradient(
    90deg,
    var(--color-primary) 0%,
    var(--color-success) 100%
  );
  transition: width var(--transition-slow);
}

/* Question Area */
.question-area {
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

.question-prompt {
  font-size: var(--font-size-xl);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
}

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

.country-name {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--color-primary);
}

.btn-audio {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
}

/* Flag Options */
.flags-area {
  margin-bottom: var(--spacing-lg);
}

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

.flag-option {
  aspect-ratio: 3 / 2;
  border: 3px solid var(--border-color);
  border-radius: var(--border-radius-md);
  background: var(--bg-secondary);
  cursor: pointer;
  transition: all var(--transition-base);
  overflow: hidden;
  padding: var(--spacing-xs);
}

.flag-option:hover:not(:disabled) {
  border-color: var(--color-primary);
  transform: scale(1.05);
  box-shadow: var(--shadow-lg);
}

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

.flag-option img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: var(--border-radius-sm);
}

.flag-option.correct {
  border-color: var(--color-success);
  background: rgba(16, 185, 129, 0.1);
  animation: pulse-correct 0.5s ease;
}

.flag-option.incorrect {
  border-color: var(--color-error);
  background: rgba(239, 68, 68, 0.1);
  animation: shake 0.5s ease;
}

.flag-option.removed {
  opacity: 0.3;
  filter: grayscale(100%);
}

/* Game Actions */
.game-actions {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
}

/* ============================================
   RESULTS SCREEN
   ============================================ */
.results-header {
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

.results-title {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--color-primary);
}

/* Score Summary */
.score-summary {
  margin-bottom: var(--spacing-xl);
}

.score-card-main {
  text-align: center;
  padding: var(--spacing-xl);
  background: linear-gradient(
    135deg,
    var(--color-primary) 0%,
    var(--color-primary-dark) 100%
  );
  color: var(--text-inverse);
  border-radius: var(--border-radius-lg);
  margin-bottom: var(--spacing-lg);
}

.score-card-label {
  display: block;
  font-size: var(--font-size-lg);
  opacity: 0.9;
  margin-bottom: var(--spacing-xs);
}

.score-card-value {
  display: block;
  font-size: 4rem;
  font-weight: 700;
}

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

.stat-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-md);
  background: var(--bg-secondary);
  border-radius: var(--border-radius-md);
  border: 2px solid var(--border-color);
}

.stat-icon {
  font-size: 2rem;
}

.stat-label {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
}

.stat-value {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-primary);
}

/* Badges */
.badges-section {
  margin-bottom: var(--spacing-xl);
}

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

.badge-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-md);
  background: linear-gradient(135deg, #ffeaa7 0%, #fdcb6e 100%);
  border-radius: var(--border-radius-md);
  box-shadow: var(--shadow-md);
}

.badge-icon {
  font-size: 3rem;
}

.badge-name {
  font-size: var(--font-size-sm);
  font-weight: 600;
  text-align: center;
}

.no-badges {
  text-align: center;
  color: var(--text-secondary);
  font-style: italic;
}

/* Skills Progress */
.skills-section {
  margin-bottom: var(--spacing-xl);
}

.skills-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.skill-progress-item {
  padding: var(--spacing-md);
  background: var(--bg-secondary);
  border-radius: var(--border-radius-md);
  border: 2px solid var(--border-color);
}

.skill-name {
  font-size: var(--font-size-base);
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
}

.skill-bar {
  width: 100%;
  height: 12px;
  background: var(--bg-tertiary);
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: var(--spacing-xs);
}

.skill-bar-fill {
  height: 100%;
  background: linear-gradient(
    90deg,
    var(--color-primary) 0%,
    var(--color-success) 100%
  );
  transition: width var(--transition-slow);
}

.skill-level {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
}

/* Results Actions */
.results-actions {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: var(--font-size-base);
  font-weight: 600;
  font-family: inherit;
  border: none;
  border-radius: var(--border-radius-md);
  cursor: pointer;
  transition: all var(--transition-base);
  min-height: 44px; /* WCAG touch target */
}

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

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

.btn-primary:hover:not(:disabled) {
  background: var(--color-primary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background: var(--bg-secondary);
  color: var(--text-primary);
  border: 2px solid var(--border-color);
}

.btn-secondary:hover:not(:disabled) {
  border-color: var(--color-primary);
  transform: translateY(-2px);
}

.btn-large {
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: var(--font-size-lg);
  min-height: 56px;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* ============================================
   BADGE NOTIFICATION (Toast)
   ============================================ */
.badge-notification {
  position: fixed;
  top: var(--spacing-lg);
  right: var(--spacing-lg);
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-md);
  background: linear-gradient(135deg, #ffeaa7 0%, #fdcb6e 100%);
  border-radius: var(--border-radius-md);
  box-shadow: var(--shadow-lg);
  z-index: 1000;
  animation: slide-in-right 0.5s ease;
}

.badge-notification-icon {
  font-size: 3rem;
}

.badge-notification-text strong {
  display: block;
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-xs);
}

.badge-notification.fade-out {
  animation: fade-out 0.5s ease forwards;
}

/* ============================================
   ANIMATIONS
   ============================================ */
@keyframes pulse-correct {
  0%,
  100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.1);
  }
}

@keyframes shake {
  0%,
  100% {
    transform: translateX(0);
  }
  25% {
    transform: translateX(-10px);
  }
  75% {
    transform: translateX(10px);
  }
}

@keyframes slide-in-right {
  from {
    transform: translateX(100%);
    opacity: 0;
  }
  to {
    transform: translateX(0);
    opacity: 1;
  }
}

@keyframes fade-out {
  to {
    opacity: 0;
    transform: translateY(-20px);
  }
}

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

/* Tablets (768px+) */
@media (min-width: 768px) {
  body {
    padding: var(--spacing-lg);
  }

  .container {
    padding: var(--spacing-xl);
  }

  .mode-buttons {
    grid-template-columns: 1fr 1fr;
  }

  .continent-grid {
    grid-template-columns: 1fr 1fr;
  }

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

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

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

  .results-actions {
    flex-direction: row;
  }
}

/* Desktops (1024px+) */
@media (min-width: 1024px) {
  .continent-grid {
    grid-template-columns: repeat(3, 1fr);
  }

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

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

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

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

/* Focus Visible (keyboard navigation) */
.btn:focus-visible,
.mode-btn:focus-visible,
.continent-card:focus-visible,
.flag-option:focus-visible,
.difficulty-dropdown:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 3px;
}