/* ==========================================================================
   AI Courses Knowledge Hub & Syllabus Dashboard
   Vanilla CSS Design System & Theme Tokens
   ========================================================================== */

:root {
  /* Color Palette (Theme Dark Baseline) */
  --bg-app: #0d1117;
  --bg-surface: #161b22;
  --bg-surface-elevated: #1f242c;
  --bg-surface-hover: #262c36;
  --border-subtle: #30363d;
  --border-focus: #1e88e5;

  /* Typography Colors */
  --text-primary: #f0f6fc;
  --text-secondary: #8b949e;
  --text-muted: #6e7681;
  --text-on-accent: #ffffff;

  /* Course Signature Blue (`#1E88E5`) */
  --color-blue: #1e88e5;
  --color-blue-hover: #1976d2;
  --color-blue-bg: rgba(30, 136, 229, 0.12);
  --color-blue-border: rgba(30, 136, 229, 0.35);

  /* Functional Status Colors */
  --color-success: #238636;
  --color-success-bg: rgba(35, 134, 54, 0.15);
  --color-warning: #d29922;
  --color-warning-bg: rgba(210, 153, 34, 0.15);
  --color-purple: #8957e5;
  --color-purple-bg: rgba(137, 87, 229, 0.12);

  /* Shadows & Depth */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-heading: 'Plus Jakarta Sans', var(--font-sans);
  --font-mono: 'JetBrains Mono', monospace;

  /* Sizing & Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-full: 9999px;
  --header-height: 64px;
  --sidebar-width: 400px;
  --transition-fast: 0.18s ease;
  --transition-normal: 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Light Theme Variables */
body.theme-light {
  --bg-app: #f6f8fa;
  --bg-surface: #ffffff;
  --bg-surface-elevated: #f0f2f5;
  --bg-surface-hover: #e5e8ed;
  --border-subtle: #d0d7de;
  --border-focus: #1e88e5;

  --text-primary: #1f2328;
  --text-secondary: #656d76;
  --text-muted: #8c959f;
  --text-on-accent: #ffffff;

  --color-blue: #1e88e5;
  --color-blue-hover: #1565c0;
  --color-blue-bg: rgba(30, 136, 229, 0.08);
  --color-blue-border: rgba(30, 136, 229, 0.3);

  --shadow-sm: 0 1px 3px rgba(31, 35, 40, 0.08);
  --shadow-md: 0 4px 12px rgba(31, 35, 40, 0.1);
  --shadow-lg: 0 12px 28px rgba(31, 35, 40, 0.14);
}

/* Base Reset & Typography */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-app);
  color: var(--text-primary);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
  height: 100vh;
}

/* App Container */
.app-container {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* ==========================================================================
   Header Navigation
   ========================================================================== */
.app-header {
  height: var(--header-height);
  background-color: var(--bg-surface);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  z-index: 10;
  flex-shrink: 0;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-badge {
  font-size: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.brand-titles h1 {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text-primary);
  line-height: 1.2;
}

.accent-text {
  color: var(--color-blue);
}

.brand-sub {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
}

.header-stats {
  display: flex;
  align-items: center;
  gap: 10px;
}

.stat-pill {
  font-size: 0.78rem;
  font-family: var(--font-mono);
  background-color: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  padding: 4px 10px;
  border-radius: var(--radius-full);
  color: var(--text-secondary);
}

.stat-num {
  font-weight: 700;
  color: var(--color-blue);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  line-height: 1;
}

.btn-primary {
  background-color: var(--color-blue);
  color: var(--text-on-accent);
}

.btn-primary:hover {
  background-color: var(--color-blue-hover);
  box-shadow: 0 2px 8px rgba(30, 136, 229, 0.4);
}

.btn-action {
  background-color: var(--color-blue);
  color: var(--text-on-accent);
}

.btn-action:hover {
  background-color: var(--color-blue-hover);
}

.btn-outline {
  background-color: var(--bg-surface-elevated);
  border-color: var(--border-subtle);
  color: var(--text-primary);
}

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

.btn-sm {
  padding: 5px 10px;
  font-size: 0.78rem;
}

.btn-icon {
  background-color: transparent;
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  padding: 8px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.btn-icon:hover {
  background-color: var(--bg-surface-hover);
  color: var(--text-primary);
}

.btn-text-small {
  background: transparent;
  border: none;
  color: var(--color-blue);
  font-size: 0.78rem;
  font-weight: 600;
  cursor: pointer;
}

.btn-text-small:hover {
  text-decoration: underline;
}

/* Theme Icon Switch */
body.theme-dark .icon-sun { display: block; }
body.theme-dark .icon-moon { display: none; }
body.theme-light .icon-sun { display: none; }
body.theme-light .icon-moon { display: block; }

/* ==========================================================================
   Workspace Layout (Sidebar + Main Pane)
   ========================================================================== */
.workspace-layout {
  display: flex;
  flex: 1;
  height: calc(100vh - var(--header-height));
  overflow: hidden;
}

/* Sidebar: Divided Half-Half (Categories & Items) */
.sidebar {
  width: var(--sidebar-width);
  background-color: var(--bg-surface);
  border-right: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
  height: 100%;
  overflow: hidden;
}

/* 50/50 Half Containers */
.sidebar-half {
  flex: 1 1 50%;
  height: 50%;
  min-height: 0;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.sidebar-items-half {
  border-bottom: 2px solid var(--border-subtle);
  background-color: var(--bg-surface);
}

.sidebar-categories-half {
  background-color: var(--bg-surface);
}

/* Search Box */
.search-box {
  padding: 12px 14px 10px 14px;
  border-bottom: 1px solid var(--border-subtle);
  flex-shrink: 0;
}

.search-input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.search-icon {
  position: absolute;
  left: 11px;
  color: var(--text-muted);
  pointer-events: none;
}

.search-input-wrapper input {
  width: 100%;
  padding: 8px 34px 8px 34px;
  background-color: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.83rem;
  font-family: var(--font-sans);
  outline: none;
  transition: border-color var(--transition-fast);
}

.search-input-wrapper input:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 2px rgba(30, 136, 229, 0.2);
}

.btn-clear {
  position: absolute;
  right: 8px;
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 11px;
  cursor: pointer;
  padding: 4px;
  border-radius: var(--radius-full);
}

.btn-clear:hover {
  color: var(--text-primary);
}

/* Section Headers inside Sidebar Halves */
.pane-section-header {
  padding: 8px 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background-color: var(--bg-surface-elevated);
  border-bottom: 1px solid var(--border-subtle);
  flex-shrink: 0;
}

.pane-section-title {
  display: flex;
  align-items: center;
  gap: 7px;
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
}

.section-icon {
  font-size: 0.85rem;
}

.items-header-right {
  display: flex;
  align-items: center;
  gap: 8px;
}

.count-badge {
  font-size: 0.72rem;
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--color-blue);
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  padding: 2px 7px;
  border-radius: var(--radius-full);
}

.select-small {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  font-size: 0.72rem;
  padding: 2px 5px;
  border-radius: var(--radius-sm);
  outline: none;
  cursor: pointer;
}

/* Category List in Top Half */
.category-list-container {
  flex: 1;
  overflow-y: auto;
  padding: 6px 10px;
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.category-row-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 7px 11px;
  border-radius: var(--radius-md);
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-size: 0.8rem;
  font-weight: 500;
  user-select: none;
}

.category-row-item:hover {
  background-color: var(--bg-surface-elevated);
  color: var(--text-primary);
  border-color: var(--text-muted);
  transform: translateX(2px);
}

.category-row-item.active {
  background-color: var(--bg-surface-elevated);
  border-color: var(--color-blue);
  color: var(--text-primary);
  font-weight: 600;
  box-shadow: inset 3px 0 0 var(--color-blue);
}

.category-row-item.is-syllabus-cat.active {
  border-color: #eab308;
  box-shadow: inset 3px 0 0 #eab308;
}

.category-row-left {
  display: flex;
  align-items: center;
  gap: 8px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.category-icon {
  font-size: 0.95rem;
  flex-shrink: 0;
}

.category-name {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.category-count-badge {
  font-size: 0.7rem;
  font-family: var(--font-mono);
  font-weight: 600;
  background-color: var(--bg-surface-hover);
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
  padding: 1px 6px;
  border-radius: var(--radius-full);
  flex-shrink: 0;
  transition: all var(--transition-fast);
}

.category-row-item.active .category-count-badge {
  background-color: var(--color-blue);
  color: #ffffff;
  border-color: var(--color-blue);
}

.category-row-item.is-syllabus-cat.active .category-count-badge {
  background-color: #eab308;
  color: #000000;
  border-color: #eab308;
}

/* Course Items List in Bottom Half */
.course-list-container {
  flex: 1;
  overflow-y: auto;
  padding: 6px 10px;
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.course-card-item {
  padding: 12px 14px;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
}

.course-card-item:hover {
  background-color: var(--bg-surface-elevated);
  border-color: var(--text-muted);
  transform: translateY(-1px);
}

.course-card-item.active {
  background-color: var(--bg-surface-elevated);
  border-color: var(--color-blue);
  box-shadow: inset 3px 0 0 var(--color-blue);
}

.card-item-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 6px;
}

.card-item-tag {
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--color-blue);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.card-item-tag.tag-syllabus {
  color: #eab308;
}

.course-card-item.is-syllabus.active {
  border-color: #eab308;
  box-shadow: inset 3px 0 0 #eab308;
}

.card-item-rating {
  font-size: 0.72rem;
  color: var(--color-warning);
  font-weight: 600;
}

.card-item-title {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.3;
  margin-bottom: 6px;
}

.card-item-instructor {
  font-size: 0.76rem;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.card-item-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.72rem;
  color: var(--text-muted);
}

.card-pill-badges {
  display: flex;
  gap: 4px;
}

.badge-mini {
  font-size: 0.65rem;
  padding: 2px 6px;
  border-radius: var(--radius-full);
  background-color: var(--bg-app);
  border: 1px solid var(--border-subtle);
}

.badge-mini.badge-mini-gold {
  background-color: rgba(234, 179, 8, 0.12);
  color: #eab308;
  border-color: rgba(234, 179, 8, 0.3);
}

/* ==========================================================================
   Main Content Pane
   ========================================================================== */
.main-pane {
  flex: 1;
  background-color: var(--bg-app);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

/* Empty State */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  text-align: center;
  padding: 40px;
  color: var(--text-secondary);
}

.empty-icon {
  font-size: 48px;
  margin-bottom: 16px;
}

.empty-state h2 {
  font-family: var(--font-heading);
  font-size: 1.4rem;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.empty-state p {
  max-width: 480px;
  font-size: 0.92rem;
}

/* Course Detail View */
.course-detail-view {
  display: flex;
  flex-direction: column;
  min-height: 100%;
}

/* Hero Section */
.course-hero {
  background-color: var(--bg-surface);
  border-bottom: 1px solid var(--border-subtle);
  padding: 28px 36px 20px 36px;
}

.hero-top-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 12px;
}

.badge {
  font-size: 0.72rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.badge-blue {
  background-color: var(--color-blue-bg);
  color: var(--color-blue);
  border: 1px solid var(--color-blue-border);
}

.badge-gold, .badge-syllabus {
  background-color: rgba(234, 179, 8, 0.15);
  color: #eab308;
  border: 1px solid rgba(234, 179, 8, 0.35);
}

.badge-outline {
  background-color: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
}

.badge-platform {
  background-color: rgba(255, 255, 255, 0.05);
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
}

.badge-concept {
  background-color: var(--color-purple-bg);
  color: var(--color-purple);
  border: 1px solid rgba(137, 87, 229, 0.3);
}

.course-title {
  font-family: var(--font-heading);
  font-size: 1.65rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin-bottom: 8px;
  line-height: 1.25;
}

.course-subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 20px;
  max-width: 900px;
}

.course-meta-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  padding: 14px 0;
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 18px;
}

.meta-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.meta-label {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.05em;
}

.meta-val {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-primary);
}

.hero-actions {
  display: flex;
  gap: 10px;
}

/* Tabs Navigation */
.course-tabs {
  background-color: var(--bg-surface);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  padding: 0 36px;
  gap: 8px;
  position: sticky;
  top: 0;
  z-index: 5;
}

.tab-btn {
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--text-secondary);
  font-family: var(--font-heading);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 12px 14px;
  cursor: pointer;
  transition: all var(--transition-fast);
}

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

.tab-btn.active {
  color: var(--color-blue);
  border-bottom-color: var(--color-blue);
}

/* Tab Content */
.tab-content-wrapper {
  padding: 28px 36px 60px 36px;
  flex: 1;
}

.tab-pane {
  display: none;
  animation: fadeIn 0.2s ease;
}

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

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

.content-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 24px 28px;
  margin-bottom: 24px;
  box-shadow: var(--shadow-sm);
}

.card-header-row {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 16px;
}

.card-caption {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.section-heading {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 14px;
}

.section-sub {
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-bottom: 20px;
}

.prose-text {
  font-size: 0.95rem;
  line-height: 1.68;
  color: var(--text-primary);
}

.two-col-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.styled-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.styled-list li {
  position: relative;
  padding-left: 22px;
  font-size: 0.9rem;
  color: var(--text-primary);
  line-height: 1.45;
}

.styled-list li::before {
  content: "•";
  color: var(--color-blue);
  font-weight: bold;
  font-size: 1.2rem;
  position: absolute;
  left: 4px;
  top: -2px;
}

/* Modules Accordion */
.modules-accordion {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.module-item {
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  background-color: var(--bg-surface-elevated);
  overflow: hidden;
}

.module-header {
  padding: 14px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  user-select: none;
  background-color: var(--bg-surface-elevated);
  transition: background-color var(--transition-fast);
}

.module-header:hover {
  background-color: var(--bg-surface-hover);
}

.module-title-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
}

.module-num {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-blue);
  background-color: var(--color-blue-bg);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
}

.module-name {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-primary);
}

.module-meta {
  display: flex;
  align-items: center;
  gap: 12px;
}

.module-duration {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.module-chevron {
  transition: transform var(--transition-fast);
  color: var(--text-muted);
}

.module-item.open .module-chevron {
  transform: rotate(180deg);
}

.module-body {
  display: none;
  padding: 16px 20px;
  background-color: var(--bg-surface);
  border-top: 1px solid var(--border-subtle);
  font-size: 0.88rem;
  line-height: 1.6;
  color: var(--text-secondary);
}

.module-item.open .module-body {
  display: block;
}

.lecture-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 10px;
}

.lecture-item {
  display: flex;
  justify-content: space-between;
  padding: 6px 10px;
  background-color: var(--bg-surface-elevated);
  border-radius: var(--radius-sm);
  font-size: 0.82rem;
}

/* Structured Syllabus Render */
.syllabus-render {
  background-color: var(--bg-app);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 24px 28px;
  font-family: var(--font-sans);
}

.syllabus-day-block {
  margin-bottom: 24px;
  padding-bottom: 20px;
  border-bottom: 1px dashed var(--border-subtle);
}

.syllabus-day-block:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.day-badge {
  display: inline-block;
  font-family: var(--font-heading);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--color-blue);
  background-color: var(--color-blue-bg);
  border: 1px solid var(--color-blue-border);
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
}

/* Concepts Grid */
.concepts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
}

.concept-card {
  background-color: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px 18px;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.concept-card:hover {
  background-color: var(--bg-surface-hover);
  border-color: var(--color-blue);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.concept-card-title {
  font-family: var(--font-heading);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.concept-card-desc {
  font-size: 0.82rem;
  color: var(--text-secondary);
  line-height: 1.45;
  margin-bottom: 12px;
  flex: 1;
}

.concept-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.72rem;
  color: var(--color-blue);
  font-weight: 600;
}

/* Sources List */
.sources-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.source-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  background-color: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  font-size: 0.85rem;
}

.source-name {
  font-family: var(--font-mono);
  font-weight: 500;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

/* ==========================================================================
   Concept Drawer (Flyout)
   ========================================================================== */
.drawer-backdrop {
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(2px);
  z-index: 99;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-normal);
}

.drawer-backdrop.open {
  opacity: 1;
  pointer-events: auto;
}

.concept-drawer {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: 540px;
  max-width: 90vw;
  background-color: var(--bg-surface);
  border-left: 1px solid var(--border-subtle);
  box-shadow: var(--shadow-lg);
  z-index: 100;
  transform: translateX(100%);
  transition: transform var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.concept-drawer.open {
  transform: translateX(0);
}

.drawer-header {
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.drawer-title-group h3 {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  margin-top: 4px;
  color: var(--text-primary);
}

.drawer-body {
  padding: 24px;
  overflow-y: auto;
  flex: 1;
  font-size: 0.92rem;
  line-height: 1.65;
  color: var(--text-primary);
}

.drawer-body h4 {
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 700;
  margin: 18px 0 8px 0;
  color: var(--text-primary);
}

.drawer-body p {
  margin-bottom: 14px;
  color: var(--text-secondary);
}

/* ==========================================================================
   Modal Dialog (Syllabus Generator)
   ========================================================================== */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.65);
  backdrop-filter: blur(3px);
  z-index: 99;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-normal);
}

.modal-backdrop.open {
  opacity: 1;
  pointer-events: auto;
}

.modal-dialog {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) scale(0.95);
  width: 700px;
  max-width: 92vw;
  max-height: 88vh;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  z-index: 100;
  display: flex;
  flex-direction: column;
  opacity: 0;
  pointer-events: none;
  transition: all var(--transition-normal);
}

.modal-dialog.open {
  opacity: 1;
  pointer-events: auto;
  transform: translate(-50%, -50%) scale(1);
}

.modal-header {
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.modal-title-group h3 {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  margin-top: 4px;
}

.modal-body {
  padding: 24px;
  overflow-y: auto;
  flex: 1;
}

.modal-intro {
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-bottom: 18px;
  line-height: 1.5;
}

.form-group {
  margin-bottom: 16px;
}

.form-group label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.form-control {
  width: 100%;
  padding: 9px 12px;
  background-color: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.88rem;
  outline: none;
}

.form-control:focus {
  border-color: var(--border-focus);
}

.generator-preview-box {
  background-color: var(--bg-app);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  margin-top: 16px;
  overflow: hidden;
}

.preview-header {
  padding: 8px 14px;
  background-color: var(--bg-surface-elevated);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.preview-badge {
  font-family: var(--font-mono);
  color: var(--color-blue);
}

.preview-code {
  padding: 14px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-secondary);
  max-height: 240px;
  overflow-y: auto;
  white-space: pre-wrap;
  word-break: break-word;
  line-height: 1.5;
}

.modal-footer {
  padding: 16px 24px;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  justify-content: flex-end;
  gap: 10px;
}

/* Toast */
.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background-color: var(--bg-surface-elevated);
  border: 1px solid var(--color-blue);
  color: var(--text-primary);
  padding: 12px 20px;
  border-radius: var(--radius-md);
  font-size: 0.85rem;
  font-weight: 600;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  transform: translateY(12px);
  pointer-events: none;
  transition: all var(--transition-fast);
  z-index: 200;
}

.toast.show {
  opacity: 1;
  transform: translateY(0);
}

/* Custom Scrollbars */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: var(--border-subtle);
  border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

/* Responsive Breakpoints */
@media (max-width: 1024px) {
  :root {
    --sidebar-width: 320px;
  }
  .two-col-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .workspace-layout {
    flex-direction: column;
    overflow-y: auto;
  }
  .sidebar {
    width: 100%;
    height: auto;
    max-height: 40vh;
  }
  .main-pane {
    height: auto;
  }
}

/* ==========================================================================
   Environment Configuration: References Visibility Control
   ========================================================================== */
body.hide-references [data-tab="tab-citations"],
body.hide-references #tab-citations,
body.hide-references .sources-section,
body.hide-references .references-element {
  display: none !important;
}