@import url('https://fonts.googleapis.com/css2?family=Kanit:wght@300;400;500;600;700;800;900&family=Sarabun:wght@300;400;500;600;700;800&display=swap');

:root {
  --skill-bg: #f1f5f9;
  --skill-card: rgba(255, 255, 255, 0.78);
  --skill-text: #0f172a;
  --skill-muted: #64748b;
  --skill-blue: #123a6f;
  --skill-gold: #c69a2d;
  --skill-gold-light: #fdfaf2;
  --skill-gold-border: rgba(198, 154, 45, 0.25);
  --skill-green: #10b981;
  --skill-red: #ef4444;
  --radius-lg: 24px;
  --radius-md: 16px;
  --radius-sm: 8px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
  --shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -2px rgba(0, 0, 0, 0.02);
  --shadow-lg: 0 20px 25px -5px rgba(15, 23, 42, 0.08), 0 10px 10px -5px rgba(15, 23, 42, 0.04);
}

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

body {
  background: var(--skill-bg);
  color: var(--skill-text);
  font-family: 'Sarabun', sans-serif;
  line-height: 1.65;
  overflow-x: hidden;
  padding-bottom: 60px;
}

/* Background overlay matching main site styling */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.9) 0%, rgba(241, 245, 249, 0.8) 50%, rgba(226, 232, 240, 0.95) 100%),
    linear-gradient(120deg, rgba(198, 154, 45, 0.06) 0%, transparent 40%, rgba(18, 58, 111, 0.05) 100%);
}

.container {
  max-width: 1000px;
  margin: 0 auto;
  padding: 20px 4vw;
}

/* Glass Card */
.skill-glass-card {
  border-radius: var(--radius-lg);
  background: var(--skill-card);
  border: 1px solid rgba(255, 255, 255, 0.8);
  box-shadow: var(--shadow-lg);
  backdrop-filter: blur(20px) saturate(145%);
  -webkit-backdrop-filter: blur(20px) saturate(145%);
  padding: 30px;
  margin-bottom: 30px;
  transition: var(--transition);
}

.skill-glass-card:hover {
  border-color: rgba(255, 255, 255, 0.95);
  box-shadow: 0 25px 50px -12px rgba(15, 23, 42, 0.12);
}

/* Headings */
h1, h2, h3, h4 {
  font-family: 'Kanit', sans-serif;
  font-weight: 800;
  color: var(--skill-blue);
  line-height: 1.3;
}

/* Breadcrumb Navigation */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: 'Kanit', sans-serif;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--skill-muted);
  margin-bottom: 20px;
  list-style: none;
}

.breadcrumb a {
  color: var(--skill-muted);
  text-decoration: none;
  transition: var(--transition);
}

.breadcrumb a:hover {
  color: var(--skill-gold);
}

.breadcrumb li::after {
  content: '→';
  margin-left: 8px;
  color: #cbd5e1;
}

.breadcrumb li:last-child::after {
  content: '';
}

.breadcrumb li:last-child {
  color: var(--skill-gold);
}

/* Hero Section */
.lesson-hero {
  text-align: center;
  padding: 20px 0;
  margin-bottom: 25px;
}

.lesson-badge {
  display: inline-block;
  background: var(--skill-gold-light);
  border: 1px solid var(--skill-gold-border);
  color: var(--skill-gold);
  padding: 4px 14px;
  border-radius: 30px;
  font-family: 'Kanit', sans-serif;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  margin-bottom: 12px;
}

.lesson-title {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  margin-bottom: 8px;
}

.lesson-subtitle {
  font-size: clamp(0.95rem, 2vw, 1.15rem);
  color: var(--skill-muted);
  font-weight: 400;
  max-width: 600px;
  margin: 0 auto;
}

/* Meta info strip */
.meta-strip {
  display: flex;
  justify-content: center;
  gap: 15px;
  margin-top: 15px;
  flex-wrap: wrap;
}

.meta-item {
  font-family: 'Kanit', sans-serif;
  font-size: 0.75rem;
  font-weight: 600;
  background: rgba(226, 232, 240, 0.5);
  padding: 4px 12px;
  border-radius: 20px;
  color: var(--skill-text);
  display: flex;
  align-items: center;
  gap: 5px;
}

/* Learning goals & prerequisites */
.goal-pre-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 20px;
}

@media (max-width: 768px) {
  .goal-pre-grid {
    grid-template-columns: 1fr;
  }
}

.box-title {
  font-size: 1.1rem;
  margin-bottom: 15px;
  display: flex;
  align-items: center;
  gap: 8px;
  border-bottom: 2px solid var(--skill-gold-border);
  padding-bottom: 6px;
}

.goals-list, .pre-list {
  list-style: none;
}

.goals-list li, .pre-list li {
  position: relative;
  padding-left: 24px;
  margin-bottom: 10px;
  font-size: 0.9rem;
}

.goals-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--skill-green);
  font-weight: bold;
}

.pre-list li::before {
  content: '•';
  position: absolute;
  left: 4px;
  color: var(--skill-blue);
  font-size: 1.4rem;
  line-height: 1;
  top: -2px;
}

/* Concept Cards */
.concept-card {
  margin-bottom: 35px;
}

.concept-card h3 {
  font-size: 1.3rem;
  margin-bottom: 12px;
  color: var(--skill-blue);
}

.concept-explanation {
  font-size: 0.95rem;
  color: var(--skill-text);
  margin-bottom: 20px;
  text-indent: 20px;
}

/* Teacher Voice Block */
.teacher-block {
  background: var(--skill-gold-light);
  border-left: 4px solid var(--skill-gold);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 20px;
  margin: 15px 0;
  display: flex;
  gap: 15px;
  align-items: flex-start;
  box-shadow: var(--shadow-sm);
}

.teacher-avatar {
  font-size: 2.2rem;
  line-height: 1;
  filter: drop-shadow(0 2px 4px rgba(0,0,0,0.1));
}

.teacher-voice-content {
  flex: 1;
}

.teacher-voice-label {
  font-family: 'Kanit', sans-serif;
  font-size: 0.72rem;
  font-weight: 800;
  color: var(--skill-gold);
  text-transform: uppercase;
  margin-bottom: 4px;
  letter-spacing: 0.05em;
  display: flex;
  align-items: center;
  gap: 6px;
}

.teacher-text {
  font-size: 0.88rem;
  color: var(--skill-text);
  font-style: italic;
}

.audio-mock-btn {
  background: white;
  border: 1px solid var(--skill-gold-border);
  color: var(--skill-gold);
  font-family: 'Kanit', sans-serif;
  font-weight: 700;
  font-size: 0.65rem;
  padding: 2px 8px;
  border-radius: 12px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  margin-top: 6px;
  transition: var(--transition);
}

.audio-mock-btn:hover {
  background: var(--skill-gold);
  color: white;
}

/* Visual Placeholder Map style */
.visual-map-box {
  width: 100%;
  background: white;
  border: 1px solid #cbd5e1;
  border-radius: var(--radius-md);
  padding: 25px;
  margin: 20px 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  box-shadow: inset 0 2px 4px rgba(0,0,0,0.02);
}

/* Inline Interactive Tree Chart styling */
.tree-node-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
}

.tree-root {
  background: var(--skill-blue);
  color: white;
  font-family: 'Kanit', sans-serif;
  font-weight: 700;
  font-size: 1rem;
  padding: 8px 24px;
  border-radius: 30px;
  box-shadow: var(--shadow-sm);
  margin-bottom: 25px;
}

.tree-branches {
  display: flex;
  justify-content: space-around;
  width: 100%;
  gap: 20px;
  position: relative;
}

.tree-branch {
  flex: 1;
  background: var(--skill-gold-light);
  border: 2px solid var(--skill-gold-border);
  border-radius: var(--radius-md);
  padding: 15px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  transition: var(--transition);
}

.tree-branch:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.tree-branch-title {
  font-family: 'Kanit', sans-serif;
  font-weight: 800;
  color: var(--skill-blue);
  font-size: 0.9rem;
  margin-bottom: 8px;
}

.tree-leaves {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 6px;
  margin-top: 8px;
}

.tree-leaf {
  background: white;
  border: 1px solid #e2e8f0;
  font-size: 0.74rem;
  padding: 3px 8px;
  border-radius: 20px;
  color: var(--skill-text);
  font-weight: 500;
}

/* Number line rendering inside HTML */
.html-number-line {
  width: 100%;
  max-width: 600px;
  margin: 30px auto;
  position: relative;
  padding: 20px 0;
}

.axis-line {
  width: 100%;
  height: 2px;
  background: var(--skill-blue);
  position: relative;
}

.axis-line::before, .axis-line::after {
  content: '';
  position: absolute;
  top: -4px;
  width: 10px;
  height: 10px;
  border-top: 2px solid var(--skill-blue);
  border-right: 2px solid var(--skill-blue);
}

.axis-line::before {
  left: 0;
  transform: rotate(-135deg);
}

.axis-line::after {
  right: 0;
  transform: rotate(45deg);
}

.axis-ticks {
  display: flex;
  justify-content: space-between;
  position: absolute;
  top: 10px;
  width: calc(100% - 20px);
  left: 10px;
}

.axis-tick {
  display: flex;
  flex-direction: column;
  align-items: center;
  position: relative;
}

.axis-tick::before {
  content: '';
  position: absolute;
  top: -12px;
  width: 2px;
  height: 10px;
  background: var(--skill-blue);
}

.axis-label {
  font-family: 'Kanit', sans-serif;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--skill-text);
  margin-top: 4px;
}

/* Interactive Classifier Game styling */
.game-container {
  background: white;
  border-radius: var(--radius-md);
  border: 1px solid #e2e8f0;
  padding: 24px;
  margin-top: 15px;
  box-shadow: var(--shadow-sm);
  text-align: center;
}

.game-header {
  display: flex;
  justify-content: space-between;
  font-family: 'Kanit', sans-serif;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--skill-muted);
  border-bottom: 1px solid #f1f5f9;
  padding-bottom: 8px;
  margin-bottom: 20px;
}

.game-number-display {
  font-family: 'Kanit', sans-serif;
  font-size: 3.5rem;
  font-weight: 900;
  color: var(--skill-blue);
  margin: 15px 0;
  text-shadow: 0 2px 10px rgba(18, 58, 111, 0.06);
}

.game-choices {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-bottom: 20px;
}

@media (max-width: 480px) {
  .game-choices {
    grid-template-columns: 1fr;
  }
}

.game-btn {
  background: var(--skill-bg);
  border: 1px solid #e2e8f0;
  border-radius: var(--radius-sm);
  padding: 12px 15px;
  font-family: 'Kanit', sans-serif;
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--skill-blue);
  cursor: pointer;
  transition: var(--transition);
  outline: none;
}

.game-btn:hover {
  background: var(--skill-gold-light);
  border-color: var(--skill-gold);
  transform: translateY(-1px);
}

.game-btn.correct {
  background: #d1fae5;
  border-color: var(--skill-green);
  color: #065f46;
}

.game-btn.incorrect {
  background: #fee2e2;
  border-color: var(--skill-red);
  color: #991b1b;
}

.feedback-box {
  background: #f8fafc;
  border-radius: var(--radius-sm);
  padding: 15px;
  font-size: 0.88rem;
  margin-bottom: 18px;
  border-left: 4px solid var(--skill-blue);
  text-align: left;
  display: none;
}

.feedback-box.show {
  display: block;
  animation: fadeIn 0.3s ease;
}

.feedback-box.correct-fb {
  border-color: var(--skill-green);
  background: #f0fdf4;
}

.feedback-box.incorrect-fb {
  border-color: var(--skill-red);
  background: #fef2f2;
}

.feedback-title {
  font-family: 'Kanit', sans-serif;
  font-weight: 800;
  font-size: 0.95rem;
  margin-bottom: 4px;
}

.feedback-title.correct-txt { color: var(--skill-green); }
.feedback-title.incorrect-txt { color: var(--skill-red); }

/* Number Line Compare layout */
.compare-container {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 30px;
  margin: 25px 0;
}

@media (max-width: 480px) {
  .compare-container {
    flex-direction: column;
    gap: 15px;
  }
}

.compare-card {
  flex: 1;
  background: var(--skill-bg);
  border: 1px solid #cbd5e1;
  border-radius: var(--radius-md);
  padding: 20px;
  cursor: pointer;
  transition: var(--transition);
  position: relative;
  font-family: 'Kanit', sans-serif;
  font-weight: 800;
  font-size: 2.2rem;
  color: var(--skill-blue);
  text-align: center;
  box-shadow: var(--shadow-sm);
}

.compare-card:hover {
  transform: translateY(-3px);
  border-color: var(--skill-gold);
  background: white;
  box-shadow: var(--shadow-md);
}

.compare-vs {
  font-family: 'Kanit', sans-serif;
  font-weight: 900;
  font-style: italic;
  font-size: 1.1rem;
  color: var(--skill-muted);
}

/* Quiz styling */
.quiz-box {
  background: white;
  border-radius: var(--radius-md);
  border: 1px solid #e2e8f0;
  padding: 25px;
  box-shadow: var(--shadow-sm);
}

.quiz-q-num {
  font-family: 'Kanit', sans-serif;
  font-size: 0.82rem;
  font-weight: 800;
  color: var(--skill-gold);
  letter-spacing: 0.05em;
  margin-bottom: 4px;
}

.quiz-question {
  font-family: 'Kanit', sans-serif;
  font-weight: 800;
  font-size: 1.05rem;
  color: var(--skill-blue);
  margin-bottom: 18px;
}

.quiz-options {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 20px;
}

.quiz-option {
  background: var(--skill-bg);
  border: 1px solid #e2e8f0;
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  font-size: 0.9rem;
  color: var(--skill-text);
  cursor: pointer;
  transition: var(--transition);
  text-align: left;
  display: flex;
  align-items: center;
  gap: 12px;
}

.quiz-option:hover {
  background: var(--skill-gold-light);
  border-color: var(--skill-gold-border);
}

.quiz-option-index {
  display: inline-flex;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: white;
  border: 1px solid #cbd5e1;
  align-items: center;
  justify-content: center;
  font-family: 'Kanit', sans-serif;
  font-weight: 700;
  font-size: 0.72rem;
  color: var(--skill-muted);
  flex-shrink: 0;
}

.quiz-option.correct {
  background: #d1fae5;
  border-color: var(--skill-green);
  color: #065f46;
}

.quiz-option.correct .quiz-option-index {
  background: var(--skill-green);
  border-color: var(--skill-green);
  color: white;
}

.quiz-option.incorrect {
  background: #fee2e2;
  border-color: var(--skill-red);
  color: #991b1b;
}

.quiz-option.incorrect .quiz-option-index {
  background: var(--skill-red);
  border-color: var(--skill-red);
  color: white;
}

/* Score display summary */
.score-summary {
  text-align: center;
  padding: 30px 10px;
  display: none;
}

.score-summary.show {
  display: block;
  animation: fadeIn 0.4s ease;
}

.score-num {
  font-family: 'Kanit', sans-serif;
  font-weight: 900;
  font-size: 3.5rem;
  color: var(--skill-gold);
  line-height: 1;
  margin-bottom: 10px;
}

/* Step-by-Step interactive elements */
.step-container {
  display: flex;
  flex-direction: column;
  gap: 15px;
  margin-top: 15px;
}

.step-row {
  display: flex;
  gap: 15px;
  align-items: flex-start;
  background: #f8fafc;
  padding: 16px;
  border-radius: var(--radius-md);
  border: 1px solid #e2e8f0;
}

.step-number-badge {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--skill-blue);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Kanit', sans-serif;
  font-weight: 800;
  font-size: 0.8rem;
  flex-shrink: 0;
  box-shadow: var(--shadow-sm);
}

.step-details h4 {
  font-size: 0.95rem;
  margin-bottom: 4px;
}

.step-details p {
  font-size: 0.84rem;
  color: var(--skill-muted);
}

/* Common Mistakes styles */
.mistake-list {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.mistake-box {
  background: white;
  border: 1px solid #fee2e2;
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.mistake-header {
  background: #fee2e2;
  padding: 10px 18px;
  font-family: 'Kanit', sans-serif;
  font-weight: 800;
  font-size: 0.88rem;
  color: var(--skill-red);
  display: flex;
  align-items: center;
  gap: 8px;
}

.mistake-body {
  padding: 18px;
}

.mistake-correction {
  font-size: 0.9rem;
  margin-bottom: 12px;
}

.mistake-correction strong {
  color: var(--skill-green);
}

/* Common CTA Button designs */
.btn-primary {
  background: var(--skill-gold);
  color: white;
  border: none;
  font-family: 'Kanit', sans-serif;
  font-weight: 800;
  font-size: 0.88rem;
  text-transform: uppercase;
  padding: 10px 22px;
  border-radius: 30px;
  cursor: pointer;
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  box-shadow: 0 4px 12px rgba(198, 154, 45, 0.25);
  text-decoration: none;
}

.btn-primary:hover {
  background: #af8621;
  box-shadow: 0 6px 16px rgba(198, 154, 45, 0.35);
  transform: translateY(-1px);
}

.btn-secondary {
  background: white;
  border: 1px solid var(--skill-blue);
  color: var(--skill-blue);
  font-family: 'Kanit', sans-serif;
  font-weight: 800;
  font-size: 0.88rem;
  text-transform: uppercase;
  padding: 10px 22px;
  border-radius: 30px;
  cursor: pointer;
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
}

.btn-secondary:hover {
  background: rgba(18, 58, 111, 0.05);
}

.action-row {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  margin-top: 15px;
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.05); }
  100% { transform: scale(1); }
}

.pulse-ani {
  animation: pulse 2s infinite ease-in-out;
}

/* Responsive adjust */
@media (max-width: 600px) {
  .skill-glass-card {
    padding: 20px;
    border-radius: var(--radius-md);
  }
  .action-row {
    flex-direction: column;
  }
  .btn-primary, .btn-secondary {
    width: 100%;
    justify-content: center;
  }
}