/* 
 * ============================================
 * LEARNING ACTIVITIES - DESIGN SYSTEM v4
 * "Amber Solace" — Warm · Tactile · Modern
 * No gradients — solid colors only
 * ============================================
 */

:root {
  /* Primary Colors — Amber Solace palette */
  --primary-blue: #8f4e00;
  --primary-purple: #AE5600;
  --primary-green: #47b8a1;
  --primary-orange: #fd9937;
  --primary-pink: #893A00;
  --primary-cyan: #AE5600;

  /* Accent Colors - Feedback */
  --success-green: #47b8a1;
  --error-red: #ba1a1a;
  --warning-orange: #fd9937;
  --info-cyan: #AE5600;

  /* Neutrals — warm cream/brown */
  --white: #FFFFFF;
  --gray-50: #fff8f3;
  --gray-100: #fff2e1;
  --gray-200: #ffebcf;
  --gray-300: #dbc2b0;
  --gray-400: #887364;
  --gray-500: #544336;
  --gray-600: #544336;
  --gray-700: #3a2f1b;
  --gray-800: #241a08;
  --gray-900: #241a08;

  /* Shadows — warm amber-tinted, ambient */
  --shadow-sm: 0 2px 10px rgba(143, 78, 0, .06);
  --shadow-md: 0 6px 20px rgba(143, 78, 0, .10);
  --shadow-lg: 0 12px 32px rgba(143, 78, 0, .12);
  --shadow-xl: 0 20px 48px rgba(143, 78, 0, .16);
  --shadow-2xl: 0 28px 60px rgba(143, 78, 0, .20);

  /* Typography — Plus Jakarta Sans + Nunito Sans */
  --font-sans: 'Plus Jakarta Sans', 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: 1.875rem;
  --font-size-4xl: 2.25rem;

  /* 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;

  /* Border Radius */
  --radius-sm: 0.5rem;
  --radius-md: 1rem;
  --radius-lg: 1.5rem;
  --radius-xl: 2rem;
  --radius-2xl: 2.5rem;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============================================
 * BASE STYLES
 * ============================================ */

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: var(--font-sans);
  background: #fff8f3;
  color: var(--gray-800);
  line-height: 1.6;
}

/* ============================================
 * ACTIVITY CONTAINER & LAYOUT
 * ============================================ */

.activity-container {
  max-width: 900px;
  margin: var(--spacing-3xl) auto;
  padding: var(--spacing-xl);
}

.activity-header {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
  animation: fadeInDown 0.6s ease;
}

.activity-header h1 {
  font-size: var(--font-size-3xl);
  color: var(--gray-900);
  margin-bottom: var(--spacing-md);
  font-weight: 700;
}

.activity-header p {
  font-size: var(--font-size-lg);
  color: var(--gray-600);
  font-weight: 500;
}

/* ============================================
 * EXERCISE CARDS
 * ============================================ */

.exercise-card,
.question-card,
.sentence-builder-card,
.matching-card,
.spelling-card {
  background: var(--white);
  border-radius: var(--radius-2xl);
  padding: var(--spacing-3xl);
  box-shadow: var(--shadow-xl);
  text-align: center;
  border: 2px solid transparent;
  transition: all var(--transition-base);
}

.exercise-card:hover,
.question-card:hover,
.sentence-builder-card:hover,
.matching-card:hover,
.spelling-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-2xl);
  border-color: var(--primary-orange);
}

/* Emoji Display */
.exercise-emoji,
.question-emoji,
.builder-emoji,
.matching-emoji,
.spelling-emoji {
  font-size: 4rem;
  margin-bottom: var(--spacing-xl);
  display: block;
  animation: bounce 1s infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

/* Sentences and Questions */
.exercise-sentence,
.question-text {
  font-size: var(--font-size-2xl);
  color: var(--gray-900);
  margin-bottom: var(--spacing-2xl);
  font-weight: 600;
  line-height: 1.5;
}

.builder-hint {
  font-size: var(--font-size-lg);
  color: var(--gray-600);
  margin-bottom: var(--spacing-2xl);
  background: var(--gray-100);
  border: 1.5px solid var(--gray-200);
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: var(--radius-lg);
  font-weight: 500;
}

/* ============================================
 * BUTTONS & OPTIONS
 * ============================================ */

.option-btn,
.option-card,
.word-btn,
.pair-btn,
.spelling-input {
  padding: var(--spacing-md) var(--spacing-lg);
  border: 2px solid var(--gray-300);
  background: var(--white);
  border-radius: var(--radius-lg);
  cursor: pointer;
  font-weight: 600;
  font-size: var(--font-size-base);
  transition: all var(--transition-base);
  color: var(--gray-800);
}

.option-btn:hover:not(:disabled),
.option-card:hover:not(:disabled),
.word-btn:hover:not(:disabled),
.pair-btn:hover:not(:disabled) {
  border-color: var(--primary-orange);
  background: var(--gray-100);
  transform: scale(1.05);
  box-shadow: var(--shadow-md);
}

.option-btn:active:not(:disabled),
.option-card:active:not(:disabled) {
  transform: scale(0.98);
}

.option-btn:disabled,
.option-card:disabled,
.word-btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

/* Correct Answer - Success State */
.option-btn.correct,
.option-card.correct,
.pair-btn.correct {
  background: var(--success-green);
  color: var(--white);
  border-color: var(--success-green);
  animation: slideInRight 0.4s ease;
}

/* Incorrect Answer - Error State */
.option-btn.incorrect,
.option-card.incorrect,
.pair-btn.incorrect {
  background: var(--error-red);
  color: var(--white);
  border-color: var(--error-red);
  animation: shake 0.4s ease;
}

@keyframes slideInRight {
  from {
    transform: translateX(-20px);
    opacity: 0;
  }
  to {
    transform: translateX(0);
    opacity: 1;
  }
}

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

/* ============================================
 * OPTION GRIDS
 * ============================================ */

.exercise-options,
.options-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: var(--spacing-md);
  margin: var(--spacing-2xl) 0;
}

@media (max-width: 768px) {
  .exercise-options,
  .options-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-sm);
  }
}

@media (max-width: 640px) {
  .exercise-options,
  .options-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-xs);
  }
  
  .option-btn,
  .option-card {
    padding: var(--spacing-md) var(--spacing-md);
  }
}

/* ============================================
 * SENTENCE BUILDER - DRAG & DROP
 * ============================================ */

.sentence-area {
  background: var(--gray-100);
  border: 3px dashed var(--primary-orange);
  border-radius: var(--radius-lg);
  padding: var(--spacing-2xl);
  margin: var(--spacing-xl) 0;
  min-height: 80px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-base);
}

.sentence-area:hover {
  border-color: var(--primary);
  background: var(--gray-200);
}

.sentence-area.drag-over {
  background: var(--primary-light);
  border-color: var(--primary);
  transform: scale(1.02);
}

.sentence-display {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  justify-content: center;
  align-items: center;
  min-width: 100%;
}

.word-bank {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  justify-content: center;
  padding: var(--spacing-lg);
  background: var(--gray-50);
  border-radius: var(--radius-lg);
  margin: var(--spacing-xl) 0;
}

.word-btn {
  background: var(--primary);
  color: var(--white);
  border: none;
  cursor: grab;
  padding: var(--spacing-md) var(--spacing-lg);
}

.word-btn:hover {
  filter: brightness(1.1);
  box-shadow: var(--shadow-lg);
  cursor: grabbing;
}

.selected-word {
  display: inline-block;
  background: var(--primary-container);
  color: #693700;
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: var(--radius-md);
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-base);
}

.selected-word:hover {
  opacity: 0.8;
  transform: scale(1.05);
}

/* ============================================
 * RESULTS CARD
 * ============================================ */

.results-card {
  background: var(--white);
  border-radius: var(--radius-2xl);
  padding: var(--spacing-3xl);
  box-shadow: var(--shadow-xl);
  text-align: center;
  animation: fadeInScale 0.5s ease;
}

.results-card h2 {
  font-size: var(--font-size-3xl);
  color: var(--gray-900);
  margin-bottom: var(--spacing-lg);
}

.score-display {
  font-size: 3.5rem;
  font-weight: 700;
  color: var(--primary);
  margin: var(--spacing-lg) 0;
}

.percentage {
  font-size: var(--font-size-2xl);
  color: var(--gray-600);
  font-weight: 600;
  margin-bottom: var(--spacing-xl);
}

.feedback {
  font-size: var(--font-size-lg);
  color: var(--gray-700);
  margin-bottom: var(--spacing-xl);
  font-style: italic;
}

@keyframes fadeInScale {
  from {
    opacity: 0;
    transform: scale(0.95);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

/* ============================================
 * BUTTONS - PRIMARY & SECONDARY
 * ============================================ */

.btn {
  padding: var(--spacing-md) var(--spacing-2xl);
  border: none;
  border-radius: 999px;
  cursor: pointer;
  font-weight: 700;
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  transition: all var(--transition-base);
  letter-spacing: 0.01em;
}

.btn-primary {
  background: var(--primary);
  color: var(--white);
  box-shadow: 0 4px 16px rgba(143, 78, 0, .25);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 28px rgba(143, 78, 0, .35);
  filter: brightness(1.05);
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background: var(--gray-200);
  color: var(--gray-900);
}

.btn-secondary:hover {
  background: var(--gray-300);
}

.btn-success {
  background: var(--success-green);
  color: var(--white);
}

/* ============================================
 * PROGRESS & INFO
 * ============================================ */

.progress-info {
  text-align: center;
  color: var(--gray-600);
  margin-top: var(--spacing-xl);
  font-weight: 600;
  font-size: var(--font-size-base);
}

.progress-bar {
  width: 100%;
  height: 10px;
  background: var(--gray-200);
  border-radius: 999px;
  margin: var(--spacing-xl) 0;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--primary-container);
  border-radius: 999px;
  transition: width var(--transition-slow) ease;
}

/* ============================================
 * ANIMATIONS
 * ============================================ */

.animate-slideIn {
  animation: slideInUp 0.5s ease forwards;
}

@keyframes slideInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

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

.fade-in {
  animation: fadeIn var(--transition-base);
}

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

@media (max-width: 768px) {
  .activity-header h1 {
    font-size: var(--font-size-2xl);
  }

  .activity-header p {
    font-size: var(--font-size-base);
  }

  .exercise-card,
  .question-card,
  .results-card {
    padding: var(--spacing-xl);
  }

  .exercise-emoji,
  .question-emoji {
    font-size: 2.5rem;
  }

  .exercise-sentence,
  .question-text {
    font-size: var(--font-size-xl);
  }

  .score-display {
    font-size: 2.5rem;
  }
}

@media (max-width: 640px) {
  .activity-container {
    padding: var(--spacing-md);
    margin: var(--spacing-2xl) var(--spacing-sm);
  }

  .exercise-card,
  .question-card,
  .results-card {
    padding: var(--spacing-lg);
    border-radius: var(--radius-xl);
  }

  .btn {
    padding: var(--spacing-md) var(--spacing-lg);
    font-size: var(--font-size-sm);
  }

  .sentence-area {
    padding: var(--spacing-lg);
    min-height: 60px;
  }

  .word-bank {
    padding: var(--spacing-md);
  }
}

/* ============================================
 * FOCUS INDICATORS
 * ============================================ */

:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

/* Suppress default focus ring on mouse users, keep for keyboard */
:focus:not(:focus-visible) {
  outline: none;
}

/* Ensure buttons and interactive elements have visible focus */
button:focus-visible,
a:focus-visible,
.option-btn:focus-visible,
.option-card:focus-visible,
.word-btn:focus-visible,
.pair-btn:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

/* ============================================
 * UTILITIES
 * ============================================ */

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

.mt-lg {
  margin-top: var(--spacing-lg);
}

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

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

.success {
  animation: successPulse 0.6s ease;
}

.error {
  animation: errorShake 0.6s ease;
}

@keyframes successPulse {
  0% { filter: brightness(1); }
  50% { filter: brightness(1.1); }
  100% { filter: brightness(1); }
}

@keyframes errorShake {
  0%, 100% { transform: translateX(0); }
  10%, 30%, 50%, 70%, 90% { transform: translateX(-5px); }
  20%, 40%, 60%, 80% { transform: translateX(5px); }
}

/* ============================================
 * REDUCED MOTION
 * ============================================ */

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

  .exercise-card:hover,
  .question-card:hover,
  .sentence-builder-card:hover,
  .matching-card:hover,
  .spelling-card:hover {
    transform: none;
  }

  .option-btn:hover:not(:disabled),
  .option-card:hover:not(:disabled),
  .word-btn:hover:not(:disabled),
  .pair-btn:hover:not(:disabled) {
    transform: none;
  }

  .btn-primary:hover {
    transform: none;
  }
}