@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;600;700&family=Noto+Sans+KR:wght@300;400;500;700&display=swap');

:root {
  /* Modern Premium Palette */
  --primary-color: #6366f1; /* Indigo-500 */
  --primary-hover: #4f46e5;
  --secondary-color: #ec4899; /* Pink-500 */
  --accent-color: #f59e0b; /* Amber-500 */
  
  --bg-color: #f8fafc; /* Slate-50 */
  --card-bg: rgba(255, 255, 255, 0.85);
  --text-color: #1e293b; /* Slate-800 */
  --text-dim: #64748b; /* Slate-500 */
  --border-color: #e2e8f0; /* Slate-200 */
  
  --success-color: #10b981; /* Emerald-500 */
  --error-color: #ef4444; /* Red-500 */
  
  --glass-bg: rgba(255, 255, 255, 0.7);
  --glass-border: rgba(255, 255, 255, 0.4);
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --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 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  --shadow-xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
  --bg-color: #0f172a; /* Slate-900 */
  --card-bg: rgba(30, 41, 59, 0.85); /* Slate-800 */
  --text-color: #f1f5f9; /* Slate-100 */
  --text-dim: #94a3b8; /* Slate-400 */
  --border-color: #334155; /* Slate-700 */
  
  --glass-bg: rgba(15, 23, 42, 0.7);
  --glass-border: rgba(255, 255, 255, 0.1);
  --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.4), 0 10px 10px -5px rgba(0, 0, 0, 0.3);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: 'Outfit', 'Noto Sans KR', sans-serif;
  -webkit-font-smoothing: antialiased;
}

body {
  background-color: var(--bg-color);
  color: var(--text-color);
  transition: background-color var(--transition-normal), color var(--transition-normal);
  min-height: 100vh;
  min-height: 100dvh; /* Support dynamic viewport height */
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  line-height: 1.5;
}

/* Background Gradients */
body::before {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle at 0% 0%, rgba(99, 102, 241, 0.05) 0%, transparent 50%),
              radial-gradient(circle at 100% 100%, rgba(236, 72, 153, 0.05) 0%, transparent 50%);
  pointer-events: none;
  z-index: -1;
}

.container {
  max-width: 1200px;
  width: 95%;
  margin: 2rem auto;
  flex: 1;
}

/* Animations */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

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

@keyframes pulseSuccess {
  0% { box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.4); }
  70% { box-shadow: 0 0 0 15px rgba(16, 185, 129, 0); }
  100% { box-shadow: 0 0 0 0 rgba(16, 185, 129, 0); }
}

.fade-in {
  animation: fadeInUp 0.6s cubic-bezier(0.22, 1, 0.36, 1) forwards;
}

/* Glassmorphism Cards */
.card {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: 24px;
  padding: 2.5rem;
  box-shadow: var(--shadow-lg);
  margin-bottom: 2rem;
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

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

/* Header */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 10%;
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  position: sticky;
  top: 0;
  z-index: 1000;
  border-bottom: 1px solid var(--glass-border);
  box-shadow: var(--shadow-sm);
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.header-actions {
  display: flex;
  gap: 1rem;
  align-items: center;
}

.btn-theme {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text-color);
  transition: all var(--transition-fast);
}

.btn-theme:hover {
  background: var(--primary-color);
  color: white;
  transform: rotate(15deg);
}

/* Buttons */
.btn {
  padding: 1rem 2rem;
  border-radius: 16px;
  border: none;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  position: relative;
  overflow: hidden;
}

.btn::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(255, 255, 255, 0.1);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

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

.btn:active {
  transform: scale(0.95);
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary-color), var(--primary-hover));
  color: white;
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.6);
}

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

.btn-outline:hover {
  background: rgba(99, 102, 241, 0.05);
}

/* Quiz Interface */
.question-header {
  margin-bottom: 2rem;
}

.badge {
  display: inline-block;
  padding: 0.4rem 1rem;
  border-radius: 99px;
  font-size: 0.85rem;
  font-weight: 700;
  background: rgba(99, 102, 241, 0.1);
  color: var(--primary-color);
  margin-right: 0.75rem;
  border: 1px solid rgba(99, 102, 241, 0.2);
}

.progress-container {
  height: 10px;
  background: var(--border-color);
  border-radius: 99px;
  margin: 1.5rem 0 0.5rem;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
  width: 0%;
  transition: width 0.5s cubic-bezier(0.65, 0, 0.35, 1);
}

/* Vision Area */
.vision-container {
  display: flex;
  flex-direction: column;
  align-items: center; /* Crucial: Prevent children from stretching to 100% width */
  gap: 2.5rem;
  margin-top: 2rem;
}


.pdf-panel {
  display: table;
  margin: 0 auto;
  max-width: 95%;
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: 24px;
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

[data-theme="dark"] .pdf-panel {
  background: #ffffff;
}

.pdf-viewport {
  display: block;
  width: fit-content;
  margin: 0 auto;
  height: auto;
  min-height: 150px;
  max-height: 55vh;
  padding: 0.5rem;
  overflow: auto;
  background: #f1f5f9;
}

.pdf-viewport img {
  display: block;
  margin: 0 auto;
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  box-shadow: var(--shadow-sm);
  transition: transform 0.3s;
}

/* Interaction Panel */
.interaction-panel {
  width: 100%; /* Force width back to 100% as parent is now align-items: center */
  max-width: 900px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
  background: rgba(99, 102, 241, 0.03);
  padding: 1.5rem;
  border-radius: 20px;
  border: 1px solid var(--primary-light);
}

.answer-pad {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
}

@media (max-width: 640px) {
  .answer-pad {
    grid-template-columns: repeat(2, 1fr);
  }
}

.pad-btn {
  height: 80px;
  font-size: 1.5rem;
  border-radius: 20px;
  border: 2px solid var(--border-color);
  background: var(--card-bg);
  cursor: pointer;
  transition: all var(--transition-fast);
  color: var(--text-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
}

.pad-btn:hover {
  border-color: var(--primary-color);
  transform: translateY(-5px);
  background: rgba(99, 102, 241, 0.05);
}

.pad-btn.selected {
  background: var(--primary-color);
  color: white;
  border-color: var(--primary-color);
  box-shadow: 0 10px 20px rgba(99, 102, 241, 0.3);
}

.pad-btn.correct {
  background: var(--success-color);
  color: white;
  border-color: var(--success-color);
  box-shadow: 0 10px 20px rgba(16, 185, 129, 0.3);
}

.pad-btn.incorrect {
  background: var(--error-color);
  color: white;
  border-color: var(--error-color);
  box-shadow: 0 10px 20px rgba(239, 68, 68, 0.3);
}

/* Sidebar Navigator */
.quiz-layout {
  display: flex;
  gap: 2.5rem;
  align-items: flex-start;
}

.quiz-main {
  flex: 3;
}

.quiz-navigator {
  flex: 1;
  min-width: 320px;
  position: sticky;
  top: 100px;
  padding: 2rem !important;
}

.nav-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 0.5rem;
  max-height: 400px;
  overflow-y: auto;
  padding: 1rem;
  background: rgba(0, 0, 0, 0.03);
  border-radius: 16px;
  scrollbar-width: thin;
}

.nav-btn {
  aspect-ratio: 1;
  border-radius: 10px;
  border: 1px solid var(--border-color);
  background: var(--card-bg);
  color: var(--text-color);
  font-weight: 700;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.nav-btn:hover {
  background: var(--primary-color);
  color: white;
  transform: scale(1.1);
}

.nav-btn.active {
  background: var(--primary-color);
  color: white;
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.3);
}

.nav-btn.solved {
  background: rgba(99, 102, 241, 0.1);
  border-color: var(--primary-color);
  color: var(--primary-color);
}

.nav-btn.correct {
  background: var(--success-color) !important;
  color: white !important;
}

.nav-btn.incorrect {
  background: var(--error-color) !important;
  color: white !important;
}

.nav-btn.mastered {
  opacity: 0.4;
  text-decoration: line-through;
}

/* Explanation Area */
.explanation-fixed {
  margin-top: 3rem;
  padding: 3rem 0;
  background: var(--card-bg);
  border-top: 8px solid var(--primary-color);
  border-radius: 32px 32px 0 0;
  box-shadow: 0 -20px 40px rgba(0,0,0,0.05);
}

#explanationText {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text-color);
}

/* Form Styling */
.form-group {
  margin-bottom: 2rem;
}

.form-group label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
  font-weight: 700;
  color: var(--text-color);
}

select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='%2364748b'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M19 9l-7 7-7-7'%3E%3C/path%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  background-size: 1.5rem;
  padding: 1rem 3rem 1rem 1.5rem;
  font-size: 1rem;
  border: 2px solid var(--border-color);
  border-radius: 16px;
  background-color: var(--card-bg);
  color: var(--text-color);
  cursor: pointer;
  transition: all var(--transition-fast);
}

select:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
}

/* Result Screen */
.result-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin: 3rem 0;
}

.stat-card {
  padding: 2.5rem;
  background: rgba(99, 102, 241, 0.05);
  border-radius: 24px;
  text-align: center;
}

.stat-value {
  font-size: 3rem;
  font-weight: 800;
  color: var(--primary-color);
  margin-bottom: 0.5rem;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 10px;
}

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

/* Responsive */
@media (max-width: 1024px) {
  .quiz-layout {
    flex-direction: column;
  }
  .quiz-navigator {
    width: 100%;
    position: static;
  }
  .nav-grid {
    grid-template-columns: repeat(10, 1fr);
  }
}

@media (max-width: 640px) {
  header {
    padding: 0.8rem 5%;
  }
  
  .logo span {
    font-size: 1.1rem;
  }

  .container {
    margin: 0 auto;
    width: 100%;
    max-width: 100%;
    padding: 0;
  }
  
  .card {
    padding: 1rem !important;
    border-radius: 0; /* Full width edge-to-edge look */
    margin-bottom: 0;
    border-left: none;
    border-right: none;
    box-shadow: none;
  }
  
  #startScreen.card, #resultScreen.card {
    border-radius: 20px;
    margin: 1rem;
    width: calc(100% - 2rem);
    box-shadow: var(--shadow-lg);
  }

  h1 { font-size: 1.8rem !important; }
  p { font-size: 0.95rem !important; }
  

  
  .pdf-viewport {
    max-height: 50vh !important;
    min-height: 120px !important;
  }
  
  .pad-btn {
    height: 60px !important;
    font-size: 1.2rem !important;
    border-radius: 12px;
  }
  
  .explanation-fixed {
    margin-top: 1rem !important;
    padding: 1.5rem 0 !important;
    border-radius: 20px 20px 0 0;
  }
  
  .explanation-fixed h2 {
    font-size: 1.2rem !important;
  }
  
  .explanation-fixed .container {
    padding: 0 1rem !important;
  }
  
  #explanationText {
    font-size: 0.95rem !important;
    line-height: 1.6;
  }

  .stat-value {
    font-size: 1.8rem;
  }
  .nav-grid {
    grid-template-columns: repeat(5, 1fr);
  }
  
  .header-actions .btn {
    padding: 0.4rem 0.8rem !important;
    font-size: 0.8rem !important;
  }
}

/* Landscape mode optimizations for small devices */
@media (max-height: 500px) and (orientation: landscape) {
  header {
    padding: 0.5rem 5%;
  }
  
  .container {
    margin: 0 auto;
  }

  .quiz-layout {
    flex-direction: row !important;
    gap: 1rem;
  }

  .quiz-main {
    flex: 2;
  }

  .quiz-navigator {
    flex: 1;
    min-width: 200px;
    height: calc(100vh - 80px);
    overflow-y: auto;
  }

  .pdf-viewport {
    max-height: 40vh !important;
  }

  .vision-container {
    gap: 1rem;
  }

  .interaction-panel {
    padding: 0.8rem;
  }

  .answer-pad {
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
  }

  .pad-btn {
    height: 50px !important;
    font-size: 1.1rem !important;
  }

  .explanation-fixed {
    position: relative;
    margin-top: 2rem;
  }
}

footer {
  padding: 2rem;
  text-align: center;
  color: var(--text-dim);
  font-size: 0.9rem;
  border-top: 1px solid var(--border-color);
  margin-top: auto;
}

.quiz-active footer {
  display: none;
}