/* CSS Reset & Variables */
:root {
  /* Fonts */
  --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-display: 'Outfit', var(--font-sans);

  /* Light Theme Colors (Default) */
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f5f9;
  --border-color: #e2e8f0;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-tertiary: #94a3b8;
  
  /* Accent Colors */
  --color-primary: #4f46e5;
  --color-primary-hover: #4338ca;
  --color-primary-light: rgba(79, 70, 229, 0.08);
  --color-secondary: #8b5cf6;
  --color-secondary-hover: #7c3aed;
  --color-success: #10b981;
  --color-success-hover: #059669;
  --color-success-light: rgba(16, 185, 129, 0.08);
  --color-danger: #ef4444;
  --color-danger-hover: #dc2626;
  --color-danger-light: rgba(239, 68, 68, 0.08);
  --color-warning: #f59e0b;
  
  /* Shadows & Glassmorphism */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -2px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.03);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
  --glass-bg: rgba(255, 255, 255, 0.75);
  --glass-border: rgba(255, 255, 255, 0.5);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Dark Theme Variables */
body.dark-mode {
  --bg-primary: #0b0f19;
  --bg-secondary: #111827;
  --bg-tertiary: #1f2937;
  --border-color: #374151;
  --text-primary: #f9fafb;
  --text-secondary: #d1d5db;
  --text-tertiary: #6b7280;
  
  --color-primary: #6366f1;
  --color-primary-hover: #4f46e5;
  --color-primary-light: rgba(99, 102, 241, 0.15);
  --color-secondary: #a78bfa;
  --color-secondary-hover: #8b5cf6;
  --color-success: #34d399;
  --color-success-hover: #10b981;
  --color-success-light: rgba(52, 211, 153, 0.15);
  --color-danger: #f87171;
  --color-danger-hover: #ef4444;
  --color-danger-light: rgba(248, 113, 113, 0.15);
  
  --glass-bg: rgba(17, 24, 39, 0.75);
  --glass-border: rgba(255, 255, 255, 0.05);
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.5);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.2);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.4);
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.5;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* Scrollbar styling */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: var(--radius-sm);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--text-tertiary);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}
a:hover {
  text-decoration: underline;
  color: var(--color-primary-hover);
}

/* Layout Styles */
.app-container {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.navbar {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background-color: var(--glass-bg);
  border-bottom: 1px solid var(--border-color);
  backdrop-filter: blur(12px);
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.4rem;
  color: var(--text-primary);
  cursor: pointer;
  user-select: none;
}

.brand-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  color: #ffffff;
  border-radius: var(--radius-md);
  box-shadow: 0 4px 10px rgba(79, 70, 229, 0.3);
}

.current-session-title {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  font-size: 0.95rem;
}

.back-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  color: var(--text-secondary);
  font-weight: 600;
  padding: 0.4rem 0.8rem;
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}
.back-btn:hover {
  background-color: var(--border-color);
  color: var(--text-primary);
}

.session-doc-name {
  font-weight: 700;
  max-width: 300px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  font-family: var(--font-display);
  color: var(--text-primary);
}

.navbar-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.main-content {
  flex: 1;
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

.view-panel {
  animation: fadeIn var(--transition-slow);
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* View Headers */
.view-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
  gap: 1rem;
}

.view-header h1 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 2.2rem;
  letter-spacing: -0.025em;
  background: linear-gradient(to right, var(--text-primary), var(--text-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.view-header p {
  color: var(--text-secondary);
  font-size: 1rem;
  margin-top: 0.25rem;
}

/* Button UI */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  border: 1px solid transparent;
  user-select: none;
}

.btn-sm {
  padding: 0.4rem 1rem;
  font-size: 0.85rem;
  border-radius: var(--radius-sm);
}

.btn-block {
  display: flex;
  width: 100%;
}

.btn-primary {
  background-color: var(--color-primary);
  color: #ffffff;
}
.btn-primary:hover {
  background-color: var(--color-primary-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(79, 70, 229, 0.2);
}
.btn-primary:active {
  transform: translateY(0);
}

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

.btn-danger {
  background-color: var(--color-danger);
  color: #ffffff;
}
.btn-danger:hover {
  background-color: var(--color-danger-hover);
  box-shadow: 0 4px 12px rgba(239, 68, 68, 0.2);
  transform: translateY(-1px);
}

.btn-success {
  background-color: var(--color-success);
  color: #ffffff;
}
.btn-success:hover {
  background-color: var(--color-success-hover);
  box-shadow: 0 4px 12px rgba(16, 185, 129, 0.2);
  transform: translateY(-1px);
}

.nav-btn {
  padding: 0.5rem 1.25rem;
  border-radius: var(--radius-md);
  font-size: 0.9rem;
}

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}
.icon-btn:hover {
  color: var(--text-primary);
  border-color: var(--text-secondary);
  background-color: var(--bg-tertiary);
}

.icon-btn.danger {
  color: var(--color-danger);
  border-color: transparent;
  background-color: var(--color-danger-light);
}
.icon-btn.danger:hover {
  background-color: var(--color-danger);
  color: #ffffff;
}

.icon-btn-large {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  font-size: 1.1rem;
}

/* Card Styles */
.card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast), background-color var(--transition-normal);
}

/* Dashboard View Styles */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-bottom: 3rem;
}

.stat-card {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
}

.stat-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  color: #ffffff;
  font-size: 1.3rem;
}

.stat-icon.bg-indigo { background: linear-gradient(135deg, #6366f1, #4f46e5); box-shadow: 0 4px 10px rgba(99, 102, 241, 0.2); }
.stat-icon.bg-purple { background: linear-gradient(135deg, #a855f7, #8b5cf6); box-shadow: 0 4px 10px rgba(168, 85, 247, 0.2); }
.stat-icon.bg-emerald { background: linear-gradient(135deg, #10b981, #059669); box-shadow: 0 4px 10px rgba(16, 185, 129, 0.2); }

.stat-details {
  display: flex;
  flex-direction: column;
}

.stat-value {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.75rem;
  line-height: 1.2;
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.materials-section {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.section-title-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.section-title-bar h2 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.6rem;
}

.search-box {
  position: relative;
  width: 100%;
  max-width: 320px;
}

.search-box i {
  position: absolute;
  left: 1rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-tertiary);
}

.search-box input {
  width: 100%;
  padding: 0.65rem 1rem 0.65rem 2.5rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  transition: all var(--transition-fast);
}

.search-box input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

.materials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
}

/* Material Library Cards */
.material-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 240px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.material-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary);
}

.mat-card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
}

.mat-icon-badge {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background-color: var(--bg-tertiary);
  color: var(--color-primary);
  font-size: 1.2rem;
  flex-shrink: 0;
}

.mat-card-header h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.15rem;
  line-height: 1.3;
  margin-top: 0.1rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  color: var(--text-primary);
  flex-grow: 1;
}

.mat-meta-info {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
}

.mat-meta-item {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background-color: var(--bg-tertiary);
  padding: 0.25rem 0.5rem;
  border-radius: var(--radius-sm);
}

.mat-progress-section {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  border-top: 1px solid var(--border-color);
  padding-top: 1rem;
  margin-bottom: 1.25rem;
}

.mat-progress-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  gap: 1.5rem;
}

.mat-progress-label {
  color: var(--text-secondary);
  font-weight: 500;
}

.mat-progress-bar-container {
  flex-grow: 1;
  height: 6px;
  background-color: var(--bg-tertiary);
  border-radius: 3px;
  overflow: hidden;
  max-width: 140px;
}

.mat-progress-bar-fill {
  height: 100%;
  border-radius: 3px;
}

.bg-purple-fill { background-color: var(--color-secondary); }
.bg-emerald-fill { background-color: var(--color-success); }

.mat-progress-value {
  font-weight: 600;
  min-width: 32px;
  text-align: right;
}

.mat-card-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

/* Empty State / Upload Panel */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 4rem 2rem;
  background-color: var(--bg-secondary);
  border: 2px dashed var(--border-color);
  border-radius: var(--radius-xl);
  text-align: center;
  max-width: 600px;
  margin: 3rem auto 0;
}

.empty-icon {
  font-size: 4rem;
  color: var(--text-tertiary);
  margin-bottom: 1.5rem;
}

.empty-state h3 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.empty-state p {
  color: var(--text-secondary);
  margin-bottom: 2rem;
  max-width: 400px;
}

.empty-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
}

/* File Upload View */
.upload-container-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 2rem;
}

@media (max-width: 900px) {
  .upload-container-grid {
    grid-template-columns: 1fr;
  }
}

.form-group {
  margin-bottom: 1.5rem;
}

.form-label {
  display: block;
  font-weight: 600;
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.form-help-text {
  font-size: 0.8rem;
  color: var(--text-tertiary);
  margin-top: 0.5rem;
}

/* Drag & Drop Zone */
.drop-zone {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 250px;
  border: 2px dashed var(--border-color);
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-lg);
  padding: 2rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: center;
}

.drop-zone:hover, .drop-zone.dragover {
  border-color: var(--color-primary);
  background-color: var(--color-primary-light);
}

.drop-icon {
  font-size: 3rem;
  color: var(--text-tertiary);
  margin-bottom: 1rem;
  transition: color var(--transition-fast);
}
.drop-zone:hover .drop-icon {
  color: var(--color-primary);
}

.drop-zone h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.15rem;
  margin-bottom: 0.25rem;
}

.drop-zone p {
  color: var(--text-secondary);
  font-size: 0.85rem;
  margin-bottom: 1.25rem;
}

.drop-zone-selected {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
}

.drop-zone-selected .file-icon {
  font-size: 3.5rem;
  color: var(--color-primary);
  margin-bottom: 1rem;
}

.drop-zone-selected .file-name {
  font-weight: 700;
  font-size: 1rem;
  max-width: 80%;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  margin-bottom: 0.25rem;
}

.drop-zone-selected .file-size {
  color: var(--text-secondary);
  font-size: 0.85rem;
  margin-bottom: 1rem;
}

.divider {
  display: flex;
  align-items: center;
  text-align: center;
  color: var(--text-tertiary);
  font-weight: 700;
  font-size: 0.85rem;
  margin: 2rem 0;
}
.divider::before, .divider::after {
  content: '';
  flex: 1;
  border-bottom: 1px solid var(--border-color);
}
.divider:not(:empty)::before {
  margin-right: 1rem;
}
.divider:not(:empty)::after {
  margin-left: 1rem;
}

textarea {
  width: 100%;
  height: 200px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1rem;
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  resize: vertical;
  transition: all var(--transition-fast);
}

textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

input[type="text"] {
  width: 100%;
  padding: 0.75rem 1rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  transition: all var(--transition-fast);
}

input[type="text"]:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

select {
  width: 100%;
  padding: 0.75rem 1.2rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  appearance: none;
  background-image: url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23475569' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  background-size: 1.2em;
}

body.dark-mode select {
  background-image: url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23d1d5db' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E");
}

select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

/* Difficulty Selector Cards */
.difficulty-selector {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.difficulty-option {
  cursor: pointer;
}

.difficulty-option input[type="radio"] {
  display: none;
}

.difficulty-card {
  display: flex;
  flex-direction: column;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.75rem 1rem;
  transition: all var(--transition-fast);
}

.diff-title {
  font-weight: 700;
  font-size: 0.95rem;
}

.diff-desc {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.difficulty-option input[type="radio"]:checked + .difficulty-card {
  border-color: var(--color-primary);
  background-color: var(--color-primary-light);
  box-shadow: var(--shadow-sm);
}

/* Study View Navigation Tabs */
.tab-navbar {
  display: flex;
  border-bottom: 2px solid var(--border-color);
  margin-bottom: 2rem;
  gap: 1.5rem;
}

.tab-link {
  background: none;
  border: none;
  padding: 0.75rem 0.5rem;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-secondary);
  cursor: pointer;
  position: relative;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: color var(--transition-fast);
}

.tab-link:hover {
  color: var(--text-primary);
}

.tab-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: transparent;
  transition: background-color var(--transition-fast);
}

.tab-link.active {
  color: var(--color-primary);
}

.tab-link.active::after {
  background-color: var(--color-primary);
}

.tab-panel {
  display: none;
  animation: fadeIn var(--transition-normal);
}

.tab-panel.active {
  display: block;
}

/* Summary Tab */
.summary-layout {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.summary-actions-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.help-hint {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-secondary);
  font-size: 0.85rem;
}
.help-hint i {
  color: var(--color-warning);
}

.summary-heading {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 800;
  border-left: 4px solid var(--color-primary);
  padding-left: 0.75rem;
  margin-bottom: 1.25rem;
  color: var(--text-primary);
}

.markdown-body {
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--text-secondary);
}

/* Basic Markdown Styling inside Summary */
.markdown-body h1, .markdown-body h2, .markdown-body h3 {
  color: var(--text-primary);
  font-family: var(--font-display);
  font-weight: 700;
  margin-top: 1.5rem;
  margin-bottom: 0.75rem;
}
.markdown-body h1 { font-size: 1.4rem; }
.markdown-body h2 { font-size: 1.25rem; }
.markdown-body h3 { font-size: 1.1rem; }

.markdown-body p {
  margin-bottom: 1rem;
}

.markdown-body ul, .markdown-body ol {
  margin-left: 1.5rem;
  margin-bottom: 1.25rem;
}

.markdown-body li {
  margin-bottom: 0.5rem;
}

.markdown-body strong {
  color: var(--text-primary);
  font-weight: 600;
}

.markdown-body blockquote {
  border-left: 4px solid var(--border-color);
  padding-left: 1rem;
  font-style: italic;
  margin: 1.25rem 0;
  color: var(--text-tertiary);
}

.mt-6 { margin-top: 1.5rem; }

/* Flashcards Tab CSS */
.flashcards-layout {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
  max-width: 650px;
  margin: 0 auto;
}

.flashcard-controls-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  margin-bottom: 1.5rem;
}

.study-stats {
  display: flex;
  gap: 0.5rem;
}

.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.35rem 0.75rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 700;
}

.badge-neutral { background-color: var(--bg-tertiary); color: var(--text-secondary); }
.badge-success { background-color: var(--color-success-light); color: var(--color-success); }

.flashcard-controls-bar .actions {
  display: flex;
  gap: 0.5rem;
}

/* Flashcard 3D Card */
.flashcard-card-wrapper {
  width: 100%;
  height: 320px;
  perspective: 1200px;
  margin-bottom: 1.5rem;
}

.flashcard-card {
  width: 100%;
  height: 100%;
  cursor: pointer;
}

.card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.flashcard-card.flipped .card-inner {
  transform: rotateY(180deg);
}

.card-face {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: var(--radius-lg);
  border: 2px solid var(--border-color);
  background-color: var(--bg-secondary);
  box-shadow: var(--shadow-lg);
  padding: 2.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  text-align: center;
  overflow-y: auto;
}

.card-back {
  transform: rotateY(180deg);
  background-color: var(--bg-secondary);
  border-color: var(--color-primary);
}

.card-header-icon {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background-color: var(--bg-tertiary);
  color: var(--text-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.15rem;
}
.card-back .card-header-icon {
  background-color: var(--color-primary-light);
  color: var(--color-primary);
}

.card-text {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 600;
  line-height: 1.5;
  color: var(--text-primary);
  margin: auto;
  max-width: 90%;
}

.card-flip-prompt {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

/* Navigation progress bar */
.fc-navigation-progress {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 2rem;
}

.fc-progress-track {
  flex-grow: 1;
  height: 8px;
  background-color: var(--border-color);
  border-radius: 4px;
  overflow: hidden;
}

.fc-progress-bar {
  height: 100%;
  background: linear-gradient(to right, var(--color-primary), var(--color-secondary));
  border-radius: 4px;
  transition: width 0.3s ease;
}

.fc-progress-text {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
  min-width: 80px;
  text-align: right;
}

/* Interaction buttons */
.fc-interaction-buttons {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  gap: 1rem;
}

.fc-rating-buttons {
  display: flex;
  gap: 0.75rem;
  flex-grow: 1;
  justify-content: center;
}

.fc-rating-buttons .btn {
  flex-grow: 1;
  max-width: 200px;
}

/* Quiz Tab CSS */
.quiz-layout {
  width: 100%;
  max-width: 700px;
  margin: 0 auto;
}

.quiz-progress-bar-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.quiz-progress-track {
  flex-grow: 1;
  height: 8px;
  background-color: var(--border-color);
  border-radius: 4px;
  overflow: hidden;
}

.quiz-progress-bar {
  height: 100%;
  background: linear-gradient(to right, var(--color-primary), var(--color-secondary));
  border-radius: 4px;
  transition: width 0.3s ease;
}

#quiz-progress-text {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  min-width: 90px;
  text-align: right;
}

.quiz-card {
  min-height: 250px;
  margin-bottom: 2rem;
  padding: 2rem;
}

.quiz-question-number {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-primary);
  margin-bottom: 0.5rem;
}

.quiz-question-text {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
}

.quiz-options-container {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

/* Choice Option Button Style */
.quiz-option-btn {
  display: flex;
  align-items: center;
  width: 100%;
  padding: 1rem 1.25rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.95rem;
  font-weight: 500;
  text-align: left;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.quiz-option-btn:hover {
  background-color: var(--bg-tertiary);
  border-color: var(--text-tertiary);
}

.quiz-option-btn.selected {
  border-color: var(--color-primary);
  background-color: var(--color-primary-light);
  font-weight: 600;
}

.quiz-option-prefix {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background-color: var(--bg-tertiary);
  color: var(--text-secondary);
  font-weight: 700;
  font-size: 0.85rem;
  margin-right: 1rem;
  flex-shrink: 0;
  transition: all var(--transition-fast);
}

.quiz-option-btn.selected .quiz-option-prefix {
  background-color: var(--color-primary);
  color: #ffffff;
}

.quiz-navigation-buttons {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Quiz Results */
.results-header {
  display: flex;
  align-items: center;
  gap: 2.5rem;
  margin-bottom: 2.5rem;
  padding: 2.5rem;
}

@media (max-width: 600px) {
  .results-header {
    flex-direction: column;
    text-align: center;
    gap: 1.5rem;
    padding: 1.5rem;
  }
}

.circular-score {
  width: 140px;
  height: 140px;
  flex-shrink: 0;
}

.circular-chart {
  display: block;
  margin: 10px auto;
  max-width: 100%;
  max-height: 100%;
}

.circle-bg {
  fill: none;
  stroke: var(--border-color);
  stroke-width: 2.8;
}

.circle {
  fill: none;
  stroke-width: 2.8;
  stroke-linecap: round;
  transition: stroke-dasharray 1s ease-in-out;
}

/* Determine circle score color dynamically */
.circle.green { stroke: var(--color-success); }
.circle.yellow { stroke: var(--color-warning); }
.circle.red { stroke: var(--color-danger); }

.percentage {
  fill: var(--text-primary);
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 0.55em;
  text-anchor: middle;
}

.results-summary-text h2 {
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
}

.results-summary-text p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
}

.quiz-diff-badge-container {
  margin-bottom: 1.25rem !important;
}

.results-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.review-title {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 800;
  margin-bottom: 1.25rem;
  color: var(--text-primary);
}

.quiz-review-list {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.quiz-review-card {
  padding: 1.5rem;
}

.review-q-header {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 1rem;
}

.review-status-icon {
  font-size: 1.2rem;
  margin-top: 0.1rem;
}
.review-status-icon.correct { color: var(--color-success); }
.review-status-icon.incorrect { color: var(--color-danger); }

.review-q-text {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--text-primary);
  line-height: 1.4;
}

.review-choices {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 0.5rem;
  margin-left: 2.2rem;
  margin-bottom: 1rem;
}

.review-choice {
  font-size: 0.85rem;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
}

.review-choice.correct-ans {
  border-color: var(--color-success);
  background-color: var(--color-success-light);
  color: var(--color-success);
  font-weight: 600;
}

.review-choice.wrong-ans {
  border-color: var(--color-danger);
  background-color: var(--color-danger-light);
  color: var(--color-danger);
  font-weight: 600;
}

.review-explanation {
  margin-left: 2.2rem;
  padding: 0.75rem 1rem;
  border-radius: var(--radius-sm);
  background-color: var(--bg-tertiary);
  font-size: 0.85rem;
  color: var(--text-secondary);
  border-left: 3px solid var(--color-primary);
}

.review-explanation strong {
  color: var(--text-primary);
}

/* Modals CSS Styling */
.modal-overlay, .drawer-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(15, 23, 42, 0.6);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(4px);
  animation: fadeInModal 0.25s ease-out;
}

.drawer-overlay {
  justify-content: flex-end; /* Drawer slides from right */
}

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

.modal {
  width: 90%;
  max-width: 550px;
  max-height: 90vh;
  overflow-y: auto;
  animation: scaleUpModal 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes scaleUpModal {
  from { transform: scale(0.9); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}

.modal-header, .drawer-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1rem;
  margin-bottom: 1.5rem;
}

.modal-header h2, .drawer-header h2 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.5rem;
}

.modal-footer, .drawer-footer {
  display: flex;
  justify-content: flex-end;
  gap: 0.75rem;
  border-top: 1px solid var(--border-color);
  padding-top: 1.25rem;
  margin-top: 1.5rem;
}

/* Settings Specific styles */
.api-key-input-container {
  display: flex;
  position: relative;
  width: 100%;
}

.api-key-input-container input {
  padding-right: 3rem;
}

.api-key-input-container button {
  position: absolute;
  right: 1px;
  top: 1px;
  bottom: 1px;
  border: none;
  background: none;
}

.backend-status-card {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem 1rem;
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-md);
  margin-top: 0.75rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.status-indicator {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}
.status-indicator.success { background-color: var(--color-success); box-shadow: 0 0 0 4px var(--color-success-light); }
.status-indicator.warning { background-color: var(--color-warning); box-shadow: 0 0 0 4px rgba(245, 158, 11, 0.15); }
.status-indicator.danger { background-color: var(--color-danger); box-shadow: 0 0 0 4px var(--color-danger-light); }

.theme-select-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.theme-select-option {
  cursor: pointer;
}

.theme-select-option input[type="radio"] {
  display: none;
}

.theme-card {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.75rem;
  font-weight: 600;
  transition: all var(--transition-fast);
}

.theme-select-option input[type="radio"]:checked + .theme-card {
  border-color: var(--color-primary);
  background-color: var(--color-primary-light);
  color: var(--color-primary);
}

/* Explain Simply Drawer (Slides from Right) */
.drawer {
  width: 100%;
  max-width: 460px;
  height: 100vh;
  border-radius: 0;
  border-left: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  animation: slideInDrawer 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes slideInDrawer {
  from { transform: translateX(100%); }
  to { transform: translateX(0); }
}

.drawer-title-area {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.drawer-title-area .icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  background-color: var(--color-primary-light);
  color: var(--color-primary);
}

.drawer-body {
  flex-grow: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.explain-selected-block, .explain-result-block {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.block-label-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.block-label {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
}

.explain-selected-block blockquote {
  border-left: 3px solid var(--border-color);
  padding: 0.5rem 0.75rem;
  font-style: italic;
  font-size: 0.9rem;
  color: var(--text-secondary);
  background-color: var(--bg-tertiary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  max-height: 120px;
  overflow-y: auto;
}

.explain-response-text {
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--text-secondary);
  white-space: pre-line;
}

.explain-response-text p {
  margin-bottom: 0.75rem;
}

/* Typing Indicator Loading */
.explain-loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  padding: 2rem 0;
  color: var(--text-tertiary);
  font-size: 0.85rem;
}

.typing-indicator {
  display: flex;
  gap: 4px;
}

.typing-indicator span {
  width: 8px;
  height: 8px;
  background-color: var(--color-primary);
  border-radius: 50%;
  animation: typingBounce 1.4s infinite ease-in-out both;
}

.typing-indicator span:nth-child(1) { animation-delay: -0.32s; }
.typing-indicator span:nth-child(2) { animation-delay: -0.16s; }

@keyframes typingBounce {
  0%, 80%, 100% { transform: scale(0); }
  40% { transform: scale(1); }
}

/* Global Loading Overlay Styling */
.global-loading-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(15, 23, 42, 0.85);
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(6px);
  color: #ffffff;
}

.loading-box {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 3rem;
  text-align: center;
  max-width: 480px;
  width: 90%;
  box-shadow: var(--shadow-xl);
  color: var(--text-primary);
  display: flex;
  flex-direction: column;
  align-items: center;
}

body.dark-mode .loading-box {
  background-color: #111827;
}

.loading-spinner {
  width: 60px;
  height: 60px;
  border: 4px solid var(--bg-tertiary);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin-bottom: 1.5rem;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.loading-box h3 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
}

.loading-box p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 2rem;
}

/* Loading Steps List */
.loading-steps {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  width: 100%;
  max-width: 280px;
  gap: 1rem;
}

.loading-step {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-tertiary);
  transition: all var(--transition-fast);
}

.step-bullet {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 2px solid var(--border-color);
  font-size: 0.7rem;
  color: transparent;
  transition: all var(--transition-fast);
}

/* States of Loading Steps */
.loading-step.active {
  color: var(--color-primary);
}
.loading-step.active .step-bullet {
  border-color: var(--color-primary);
  animation: pulseBullet 1.5s infinite;
}

.loading-step.done {
  color: var(--color-success);
}
.loading-step.done .step-bullet {
  border-color: var(--color-success);
  background-color: var(--color-success);
  color: #ffffff;
}

@keyframes pulseBullet {
  0% { box-shadow: 0 0 0 0 rgba(79, 70, 229, 0.4); }
  70% { box-shadow: 0 0 0 6px rgba(79, 70, 229, 0); }
  100% { box-shadow: 0 0 0 0 rgba(79, 70, 229, 0); }
}

/* Selection Highlight Floating Button */
.floating-explain-btn {
  position: absolute;
  z-index: 90;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 0.8rem;
  background-color: var(--color-primary);
  color: #ffffff;
  border: none;
  border-radius: 20px;
  font-weight: 600;
  font-size: 0.8rem;
  cursor: pointer;
  box-shadow: var(--shadow-lg);
  animation: scaleIn 0.15s ease-out;
}

@keyframes scaleIn {
  from { transform: scale(0.8); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}

.floating-explain-btn:hover {
  background-color: var(--color-primary-hover);
  transform: scale(1.03);
}

/* Toasts CSS */
.toast-container {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 210;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  max-width: 320px;
  width: 90%;
}

.toast {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem 1.25rem;
  background-color: var(--bg-secondary);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-xl);
  color: var(--text-primary);
  font-size: 0.85rem;
  font-weight: 600;
  animation: slideInToast 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

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

.toast.toast-success { border-left-color: var(--color-success); }
.toast.toast-danger { border-left-color: var(--color-danger); }
.toast.toast-warning { border-left-color: var(--color-warning); }

/* Common Helpers */
.hidden { display: none !important; }
.visible { display: block !important; }

/* Responsive adjustments */
@media (max-width: 768px) {
  .navbar {
    padding: 1rem 1.25rem;
  }
  .navbar-actions button span {
    display: none; /* Hide button text on mobile icons */
  }
  .view-header h1 {
    font-size: 1.8rem;
  }
  .main-content {
    padding: 1.5rem 1rem;
  }
  .current-session-title {
    max-width: 50%;
  }
  .session-doc-name {
    font-size: 0.85rem;
  }
}