/* ==========================================================================
   CMU CS Curriculum 2569 (หลักสูตรปรับปรุง พ.ศ. 2569) - Design System & Styles
   ========================================================================== */

:root {
  /* CMU Purple Palette */
  --cmu-purple-dark: #3F1D5B;
  --cmu-purple: #512D6D;
  --cmu-purple-light: #72479B;
  --cmu-purple-subtle: rgba(81, 45, 109, 0.08);
  --cmu-purple-glow: rgba(114, 71, 155, 0.35);

  /* Accents */
  --accent-amber: #E76F51;
  --accent-amber-subtle: rgba(231, 111, 81, 0.12);
  --accent-emerald: #10B981;
  --accent-emerald-subtle: rgba(16, 185, 129, 0.12);
  --accent-cyan: #0EA5E9;
  --accent-cyan-subtle: rgba(14, 165, 233, 0.12);
  --accent-indigo: #6366F1;

  /* Course Category Colors */
  --cat-core: #2563EB;
  --cat-core-bg: rgba(37, 99, 235, 0.1);
  --cat-compulsory: #7C3AED;
  --cat-compulsory-bg: rgba(124, 58, 237, 0.1);
  --cat-proj-elective: #059669;
  --cat-proj-elective-bg: rgba(5, 150, 105, 0.1);
  --cat-nonproj-elective: #D97706;
  --cat-nonproj-elective-bg: rgba(217, 119, 6, 0.1);
  --cat-gened: #0284C7;
  --cat-gened-bg: rgba(2, 132, 199, 0.1);
  --cat-free: #64748B;
  --cat-free-bg: rgba(100, 116, 139, 0.1);

  /* Light Theme (Default) */
  --bg-primary: #F8F9FC;
  --bg-surface: #FFFFFF;
  --bg-surface-elevated: #F1F4F9;
  --bg-card: #FFFFFF;
  --text-primary: #1E1B2E;
  --text-secondary: #525266;
  --text-muted: #888899;
  --border-light: rgba(0, 0, 0, 0.07);
  --border-medium: rgba(0, 0, 0, 0.14);
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 14px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.12);
  --shadow-purple: 0 8px 24px rgba(81, 45, 109, 0.18);
  --font-base: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Sarabun", sans-serif;
  --drawer-width: 440px;
}

[data-theme="dark"] {
  --bg-primary: #0C0C12;
  --bg-surface: #14141E;
  --bg-surface-elevated: #1B1B2A;
  --bg-card: #181826;
  --text-primary: #F4F4F8;
  --text-secondary: #A6A6B8;
  --text-muted: #8E8EA0;
  --border-light: rgba(255, 255, 255, 0.08);
  --border-medium: rgba(255, 255, 255, 0.16);
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 14px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.5);
  --shadow-purple: 0 8px 24px rgba(192, 132, 252, 0.25);
  --cmu-purple: #C084FC; /* Light radiant purple for high contrast font on dark backgrounds */
  --cmu-purple-light: #D8B4FE;
  --cmu-purple-dark: #E9D5FF;
  --cmu-purple-subtle: rgba(192, 132, 252, 0.15);
  --cmu-purple-glow: rgba(192, 132, 252, 0.4);
}

/* Dark mode font color readability enhancements */
[data-theme="dark"] a {
  color: #D8B4FE;
}
[data-theme="dark"] a:hover {
  color: #F3E8FF;
}
[data-theme="dark"] .nav-link:hover {
  color: #D8B4FE;
}
[data-theme="dark"] .nav-link.active {
  background-color: #7C3AED;
  color: #FFFFFF;
}
[data-theme="dark"] .track-btn.active,
[data-theme="dark"] .map-plan-btn.active,
[data-theme="dark"] .filter-chip-btn.active,
[data-theme="dark"] .sem-tab-btn.active,
[data-theme="dark"] .ge-lang-btn.active {
  background-color: #7C3AED;
  color: #FFFFFF;
  border-color: #8B5CF6;
}
[data-theme="dark"] .card-code {
  color: #D8B4FE;
}
[data-theme="dark"] .drawer-code-badge {
  color: #D8B4FE;
}
[data-theme="dark"] .sem-course-code {
  color: #D8B4FE;
}
[data-theme="dark"] .link-course-tag {
  color: #D8B4FE;
  border-color: rgba(216, 180, 254, 0.25);
  background: var(--bg-surface-elevated);
}
[data-theme="dark"] .link-course-tag:hover {
  background: #7C3AED;
  color: #FFFFFF;
}
[data-theme="dark"] .meta-pill.offered-both {
  color: #D8B4FE;
  background: rgba(216, 180, 254, 0.12);
  border-color: rgba(216, 180, 254, 0.25);
}
[data-theme="dark"] .ge-expand-badge {
  color: #D8B4FE;
  background: rgba(216, 180, 254, 0.12);
  border-color: rgba(216, 180, 254, 0.25);
}
[data-theme="dark"] .list-badge-count {
  color: #D8B4FE;
  background: rgba(216, 180, 254, 0.15);
}
[data-theme="dark"] .ge-expandable-card[open] .ge-expand-icon {
  color: #D8B4FE;
}
[data-theme="dark"] .ge-lang-btn:hover {
  color: #D8B4FE;
}

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

body {
  font-family: var(--font-base);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.55;
  transition: background-color 0.25s ease, color 0.25s ease;
  overflow-x: hidden;
}

a {
  color: var(--cmu-purple-light);
  text-decoration: none;
  transition: color 0.2s;
}
a:hover {
  color: var(--cmu-purple);
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border-light);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: var(--shadow-sm);
}

.nav-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  text-decoration: none;
  color: inherit;
}

.brand-badge {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--cmu-purple), var(--cmu-purple-light));
  color: #FFF;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1.2rem;
  box-shadow: 0 4px 10px rgba(81, 45, 109, 0.3);
}

.brand-titles {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-size: 1.05rem;
  font-weight: 700;
  line-height: 1.25;
  color: var(--text-primary);
}

.brand-sub {
  font-size: 0.78rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  list-style: none;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 0.95rem;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
  transition: all 0.2s ease;
}

.nav-link:hover {
  background-color: var(--cmu-purple-subtle);
  color: var(--cmu-purple);
}

.nav-link.active {
  background-color: var(--cmu-purple);
  color: #FFFFFF;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.btn-icon {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-light);
  color: var(--text-primary);
  width: 38px;
  height: 38px;
  border-radius: 8px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-icon:hover {
  border-color: var(--cmu-purple-light);
  background: var(--cmu-purple-subtle);
}

.lang-btn {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-light);
  color: var(--text-primary);
  font-size: 0.8rem;
  font-weight: 700;
  padding: 0.45rem 0.75rem;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s;
}

.lang-btn:hover {
  border-color: var(--cmu-purple);
  color: var(--cmu-purple);
}

.btn-pdf-link {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-light);
  color: var(--text-primary);
  font-size: 0.8rem;
  font-weight: 700;
  padding: 0.45rem 0.75rem;
  border-radius: 8px;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  text-decoration: none;
  transition: all 0.2s;
  white-space: nowrap;
}

.btn-pdf-link:hover {
  border-color: var(--cmu-purple-light);
  color: var(--cmu-purple);
  background: var(--cmu-purple-subtle);
}

[data-theme="dark"] .btn-pdf-link {
  border-color: var(--border-medium);
}

[data-theme="dark"] .btn-pdf-link:hover {
  color: #D8B4FE;
  border-color: #A855F7;
  background: rgba(192, 132, 252, 0.15);
}

.hero-pdf-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--cmu-purple-subtle);
  color: var(--cmu-purple);
  border: 1.5px solid rgba(81, 45, 109, 0.25);
  font-size: 0.88rem;
  font-weight: 700;
  padding: 0.55rem 1.15rem;
  border-radius: 10px;
  text-decoration: none;
  transition: all 0.2s ease;
  box-shadow: var(--shadow-sm);
}

.hero-pdf-btn:hover {
  background: var(--cmu-purple);
  color: #FFFFFF;
  border-color: var(--cmu-purple);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

[data-theme="dark"] .hero-pdf-btn {
  background: rgba(192, 132, 252, 0.12);
  color: #D8B4FE;
  border-color: rgba(216, 180, 254, 0.3);
}

[data-theme="dark"] .hero-pdf-btn:hover {
  background: #7C3AED;
  color: #FFFFFF;
  border-color: #8B5CF6;
}

.mobile-menu-toggle {
  display: none;
}

/* ==========================================================================
   Common Layout & Container
   ========================================================================= */
.page-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 1.75rem 1.5rem 4rem;
}

.page-container.page-container-map {
  max-width: 100%;
  padding: 1.25rem 1.25rem 3rem;
}

.page-header {
  margin-bottom: 2rem;
}

.page-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: var(--cmu-purple-subtle);
  color: var(--cmu-purple);
  padding: 0.3rem 0.75rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 700;
  margin-bottom: 0.65rem;
  border: 1px solid rgba(81, 45, 109, 0.15);
}

[data-theme="dark"] .page-badge {
  color: #B892E6;
}

.page-title {
  font-size: 1.85rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.page-subtitle {
  font-size: 0.98rem;
  color: var(--text-secondary);
  max-width: 800px;
}

/* ==========================================================================
   Page 1: Overview & Graduation Requirements
   ========================================================================== */
.track-switcher-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: 14px;
  padding: 1.5rem;
  margin-bottom: 2rem;
  box-shadow: var(--shadow-sm);
}

.switcher-group {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  margin-bottom: 1.25rem;
}

.switcher-label {
  font-size: 0.88rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-secondary);
}

.switcher-options {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
}

.track-btn {
  padding: 0.65rem 1.15rem;
  border: 1.5px solid var(--border-medium);
  background: var(--bg-surface);
  color: var(--text-primary);
  border-radius: 10px;
  font-size: 0.92rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.track-btn:hover {
  border-color: var(--cmu-purple-light);
  background: var(--cmu-purple-subtle);
}

.track-btn.active {
  background: var(--cmu-purple);
  border-color: var(--cmu-purple);
  color: #FFFFFF;
  box-shadow: 0 4px 12px rgba(81, 45, 109, 0.25);
}

/* Requirements Summary Grid */
.req-stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin-bottom: 2.25rem;
}

.stat-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: 12px;
  padding: 1.25rem;
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
  transition: transform 0.2s, box-shadow 0.2s;
}

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

.stat-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: var(--cat-core);
}

.stat-card.stat-total::before { background: var(--cmu-purple); }
.stat-card.stat-compulsory::before { background: var(--cat-compulsory); }
.stat-card.stat-elective::before { background: var(--cat-proj-elective); }
.stat-card.stat-minor::before { background: var(--cat-nonproj-elective); }
.stat-card.stat-free::before { background: var(--cat-free); }

.stat-value {
  font-size: 2rem;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1.1;
  margin-bottom: 0.35rem;
}

.stat-label {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.stat-sub {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.35rem;
}

/* Credit Category Breakdown Table */
.section-block {
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: 14px;
  padding: 1.75rem;
  margin-bottom: 2.5rem;
  box-shadow: var(--shadow-sm);
}

.section-title-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
  padding-bottom: 0.85rem;
  border-bottom: 1px solid var(--border-light);
}

.section-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.custom-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
}

.custom-table th {
  background: var(--bg-surface-elevated);
  padding: 0.75rem 1rem;
  text-align: left;
  font-weight: 700;
  color: var(--text-secondary);
  border-bottom: 2px solid var(--border-medium);
}

.custom-table td {
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--border-light);
  color: var(--text-primary);
}

.custom-table tr:hover td {
  background-color: var(--cmu-purple-subtle);
}

/* GE Specific Interactive Enhancements */
.ge-subgroup-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 1.5rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.4rem;
  border-bottom: 1.5px solid var(--border-light);
}

.ge-lang-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-medium);
  border-radius: 10px;
  padding: 0.65rem 1rem;
  margin-bottom: 0.85rem;
}

.ge-lang-label {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-secondary);
}

.ge-lang-btns {
  display: inline-flex;
  gap: 0.35rem;
  background: var(--bg-surface);
  padding: 3px;
  border-radius: 8px;
  border: 1px solid var(--border-light);
}

.ge-lang-btn {
  border: none;
  background: transparent;
  padding: 0.35rem 0.85rem;
  border-radius: 6px;
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s;
}

.ge-lang-btn:hover {
  color: var(--cmu-purple);
}

.ge-lang-btn.active {
  background: var(--cmu-purple);
  color: #FFF;
  box-shadow: var(--shadow-sm);
}

.ge-expandable-card {
  background: var(--bg-surface-elevated);
  border: 1.5px solid var(--border-medium);
  border-radius: 10px;
  margin-top: 0.85rem;
  margin-bottom: 0.85rem;
  overflow: hidden;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.ge-expandable-card[open] {
  border-color: var(--cmu-purple-light);
  box-shadow: var(--shadow-sm);
}

.ge-expand-summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  cursor: pointer;
  user-select: none;
  list-style: none;
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-primary);
  background: var(--bg-surface-elevated);
}

.ge-expand-summary::-webkit-details-marker {
  display: none;
}

.ge-expand-left {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.ge-expand-badge {
  background: var(--cmu-purple-subtle);
  color: var(--cmu-purple);
  font-size: 0.74rem;
  font-weight: 800;
  padding: 0.2rem 0.6rem;
  border-radius: 6px;
  border: 1px solid rgba(81, 45, 109, 0.2);
}

.ge-expand-icon {
  font-size: 0.85rem;
  color: var(--text-muted);
  transition: transform 0.2s ease;
}

.ge-expandable-card[open] .ge-expand-icon {
  transform: rotate(180deg);
  color: var(--cmu-purple);
}

.ge-expand-body {
  padding: 0.85rem 1rem 1.15rem;
  border-top: 1px solid var(--border-light);
  background: var(--bg-surface);
}

.ge-directive-text {
  font-size: 0.84rem;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
  font-weight: 600;
}

/* 4-Year Study Plan Cards & Grid */
.plan-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.25rem;
}

.semester-box {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-light);
  border-radius: 12px;
  padding: 1.15rem;
}

.semester-box-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.85rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--border-light);
}

.sem-title {
  font-weight: 700;
  font-size: 1rem;
  color: var(--text-primary);
}

.sem-credits-badge {
  background: var(--cmu-purple);
  color: #FFF;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.25rem 0.6rem;
  border-radius: 12px;
}

.sem-courses-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.sem-course-item {
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: 8px;
  padding: 0.65rem 0.85rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  cursor: pointer;
  transition: all 0.2s;
}

.sem-course-item:hover {
  border-color: var(--cmu-purple-light);
  transform: translateX(2px);
}

.sem-course-code {
  font-family: monospace;
  font-weight: 700;
  font-size: 0.88rem;
  color: var(--cmu-purple);
}

[data-theme="dark"] .sem-course-code {
  color: #C09BF4;
}

.sem-course-name {
  flex: 1;
  font-size: 0.85rem;
  line-height: 1.3;
}

.sem-course-cr {
  font-size: 0.75rem;
  color: var(--text-muted);
  white-space: nowrap;
}

/* ==========================================================================
   Page 2: Curriculum Map (8-Column Grid)
   ========================================================================== */
.map-controls-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: 12px;
  padding: 0.85rem 1.25rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow-sm);
}

.legend-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
}

.legend-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.legend-dot {
  width: 10px;
  height: 10px;
  border-radius: 3px;
}

.legend-dot.dot-core { background: var(--cat-core); }
.legend-dot.dot-comp { background: var(--cat-compulsory); }
.legend-dot.dot-pelec { background: var(--cat-proj-elective); }
.legend-dot.dot-npelec { background: var(--cat-nonproj-elective); }
.legend-dot.dot-gened { background: var(--cat-gened); }
.legend-dot.dot-prereq { background: var(--accent-emerald); }
.legend-dot.dot-postreq { background: var(--accent-amber); }

/* Mobile Semester Tabs */
.mobile-sem-tabs {
  display: none;
  overflow-x: auto;
  gap: 0.5rem;
  padding-bottom: 0.5rem;
  margin-bottom: 1rem;
  -webkit-overflow-scrolling: touch;
}

.sem-tab-btn {
  padding: 0.5rem 0.9rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: 8px;
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--text-secondary);
  white-space: nowrap;
  cursor: pointer;
}

.sem-tab-btn.active {
  background: var(--cmu-purple);
  color: #FFF;
  border-color: var(--cmu-purple);
}

/* 8-Column Grid */
.curriculum-map-wrapper {
  overflow-x: auto;
  width: 100%;
  padding-bottom: 1rem;
}

.curriculum-map-grid {
  display: grid;
  grid-template-columns: repeat(8, minmax(0, 1fr));
  gap: 0.35rem;
  width: 100%;
  min-width: 0;
}

.map-column {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-medium);
  border-radius: 10px;
  padding: 0.45rem 0.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  min-width: 0;
}

.map-col-header {
  text-align: center;
  padding: 0.2rem 0.15rem 0.35rem;
  border-bottom: 2px solid var(--border-medium);
}

.map-col-title {
  font-size: 0.78rem;
  font-weight: 800;
  color: var(--text-primary);
  white-space: nowrap;
  letter-spacing: -0.01em;
}

.map-col-sub {
  font-size: 0.65rem;
  color: var(--text-muted);
  font-weight: 600;
}

/* Course Card in Map */
.map-course-card {
  background: var(--bg-surface);
  border: 1.5px solid #CBD5E1;
  border-radius: 7px;
  padding: 0.4rem 0.35rem 0.4rem 0.5rem;
  cursor: pointer;
  position: relative;
  transition: background-color 0.15s ease, border-color 0.15s ease;
  user-select: none;
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  min-width: 0;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
}

[data-theme="dark"] .map-course-card {
  border-color: #475569;
}

.map-course-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  width: 4px;
  border-radius: 7px 0 0 7px;
}

.map-course-card[data-type="core"]::before { background: var(--cat-core); }
.map-course-card[data-type="compulsory"]::before { background: var(--cat-compulsory); }
.map-course-card[data-type="project_elective"]::before { background: var(--cat-proj-elective); }
.map-course-card[data-type="non_project_elective"]::before { background: var(--cat-nonproj-elective); }
.map-course-card[data-type="gened"]::before { background: var(--cat-gened); }
.map-course-card[data-type="free"]::before { background: var(--cat-free); }
.map-course-card[data-type="elective"]::before { background: var(--cat-proj-elective); }

.card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.2rem;
  line-height: 1.1;
}

.card-code {
  font-family: monospace;
  font-weight: 800;
  font-size: 0.74rem;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  white-space: nowrap;
}

.card-credits {
  font-size: 0.62rem;
  font-weight: 600;
  color: var(--text-muted);
  white-space: nowrap;
}

.card-title {
  font-size: 0.68rem;
  font-weight: 600;
  line-height: 1.25;
  color: var(--text-primary);
  word-break: break-word;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-terms-row {
  display: flex;
  gap: 0.25rem;
  margin-top: 0.15rem;
}

.term-pill {
  font-size: 0.62rem;
  font-weight: 800;
  padding: 0.1rem 0.35rem;
  border-radius: 4px;
  line-height: 1.1;
  display: inline-block;
  letter-spacing: 0.02em;
}

.term-pill.t1-pill {
  background: #2563EB;
  color: #FFFFFF;
  border: 1px solid #1D4ED8;
  box-shadow: 0 1px 2px rgba(37, 99, 235, 0.25);
}

.term-pill.t2-pill {
  background: #0D9488;
  color: #FFFFFF;
  border: 1px solid #0F766E;
  box-shadow: 0 1px 2px rgba(13, 148, 136, 0.25);
}

/* /* Hover / Dependency Highlight States - Background and border color only, NO cell resizing */
.map-course-card.is-active {
  border-color: #7C3AED !important;
  background-color: #F5EEFF !important;
  z-index: 5;
}

.map-course-card.is-active .card-code {
  color: #6B21A8;
}

.map-course-card.is-prereq {
  border-color: #059669 !important;
  background-color: #ECFDF5 !important;
  z-index: 4;
}

.map-course-card.is-prereq .card-code {
  color: #047857;
}

.map-course-card.is-postreq {
  border-color: #EA580C !important;
  background-color: #FFF7ED !important;
  z-index: 4;
}

.map-course-card.is-postreq .card-code {
  color: #C2410C;
}

[data-theme="dark"] .map-course-card.is-active {
  border-color: #C084FC !important;
  background-color: #2E154B !important;
}

[data-theme="dark"] .map-course-card.is-active .card-code {
  color: #E9D5FF;
}

[data-theme="dark"] .map-course-card.is-prereq {
  border-color: #34D399 !important;
  background-color: #064E3B !important;
}

[data-theme="dark"] .map-course-card.is-prereq .card-code {
  color: #A7F3D0;
}

[data-theme="dark"] .map-course-card.is-postreq {
  border-color: #FB923C !important;
  background-color: #431407 !important;
}

[data-theme="dark"] .map-course-card.is-postreq .card-code {
  color: #FED7AA;
}


/* ==========================================================================
   Page 3: CS Electives Course Tree (Canvas & Mobile List)
   ========================================================================== */
.tree-controls-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: 12px;
  padding: 0.85rem 1.25rem;
  margin-bottom: 1.25rem;
  box-shadow: var(--shadow-sm);
}

.search-box {
  position: relative;
  min-width: 260px;
  flex: 1;
  max-width: 420px;
}

.search-box input {
  width: 100%;
  padding: 0.55rem 1rem 0.55rem 2.25rem;
  border-radius: 8px;
  border: 1.5px solid var(--border-medium);
  background: var(--bg-surface);
  color: var(--text-primary);
  font-size: 0.88rem;
  outline: none;
  transition: border-color 0.2s;
}

.search-box input:focus {
  border-color: var(--cmu-purple);
}

.search-icon {
  position: absolute;
  left: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  font-size: 0.9rem;
}

.filter-chips-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.filter-chip-btn {
  padding: 0.4rem 0.75rem;
  border-radius: 8px;
  font-size: 0.8rem;
  font-weight: 600;
  border: 1px solid var(--border-light);
  background: var(--bg-surface-elevated);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s;
}

.filter-chip-btn:hover {
  border-color: var(--cmu-purple-light);
}

.filter-chip-btn.active {
  background: var(--cmu-purple);
  color: #FFF;
  border-color: var(--cmu-purple);
}

.view-mode-toggle {
  display: flex;
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-light);
  border-radius: 8px;
  padding: 2px;
}

.view-mode-btn {
  padding: 0.4rem 0.75rem;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.82rem;
  font-weight: 700;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.2s;
}

.view-mode-btn.active {
  background: var(--bg-surface);
  color: var(--text-primary);
  box-shadow: var(--shadow-sm);
}

/* Canvas Viewport */
.canvas-wrapper {
  position: relative;
  height: 720px;
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: 14px;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.canvas-viewport {
  width: 100%;
  height: 100%;
  cursor: grab;
  position: relative;
  user-select: none;
}

.canvas-viewport.is-dragging {
  cursor: grabbing;
}

.canvas-plane {
  position: absolute;
  top: 0;
  left: 0;
  transform-origin: 0 0;
  width: 2400px;
  height: 1600px;
}

.canvas-svg-layer {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.canvas-svg-layer path {
  fill: none;
  stroke: var(--border-medium);
  stroke-width: 2;
  transition: stroke 0.2s, stroke-width 0.2s;
}

.canvas-svg-layer path.highlight-link {
  stroke: var(--cmu-purple);
  stroke-width: 3;
}

/* Node Elements inside Canvas */
.tree-section-header {
  position: absolute;
  padding: 0.5rem 1.25rem;
  border-radius: 10px;
  font-weight: 800;
  font-size: 1.1rem;
  color: #FFF;
  box-shadow: var(--shadow-md);
  z-index: 10;
}

.tree-section-header.project {
  background: linear-gradient(135deg, var(--cat-proj-elective), #047857);
}

.tree-section-header.nonproject {
  background: linear-gradient(135deg, var(--cat-nonproj-elective), #B45309);
}

.tree-section-header.roots {
  background: linear-gradient(135deg, var(--cat-core), var(--cat-compulsory));
}

.tree-node-card {
  position: absolute;
  width: 230px;
  background: var(--bg-surface);
  border: 1.5px solid var(--border-medium);
  border-radius: 10px;
  padding: 0.75rem 0.85rem;
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
  z-index: 20;
}

.tree-node-card:hover {
  transform: translateY(-3px) scale(1.03);
  box-shadow: var(--shadow-md);
  border-color: var(--cmu-purple);
  z-index: 60;
}

.tree-node-card.is-active {
  border-color: var(--cmu-purple-light) !important;
  box-shadow: 0 0 0 3px var(--cmu-purple), var(--shadow-purple);
  z-index: 70;
}

.tree-node-card.is-prereq {
  border-color: var(--accent-emerald) !important;
  box-shadow: 0 0 0 2.5px var(--accent-emerald);
  z-index: 65;
}

.tree-node-card.is-postreq {
  border-color: var(--accent-amber) !important;
  box-shadow: 0 0 0 2.5px var(--accent-amber);
  z-index: 65;
}

.tree-node-card.is-dimmed {
  opacity: 0.2;
}

.canvas-controls {
  position: absolute;
  bottom: 1.25rem;
  right: 1.25rem;
  display: flex;
  gap: 0.4rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: 10px;
  padding: 0.35rem;
  box-shadow: var(--shadow-md);
  z-index: 80;
}

/* List View (Page 3 - Single View Mode) */
.tree-list-view {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.tree-list-section-title {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.15rem;
  font-weight: 800;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--border-light);
}

.list-badge-count {
  font-size: 0.8rem;
  padding: 0.2rem 0.55rem;
  border-radius: 12px;
  background: var(--cmu-purple-subtle);
  color: var(--cmu-purple);
  font-weight: 700;
}

.tree-cards-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
}

.list-course-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: 12px;
  padding: 1rem;
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: all 0.2s;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.list-course-card:hover {
  border-color: var(--cmu-purple-light);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* ==========================================================================
   Course Inspector Drawer (Slide-out Right Panel)
   ========================================================================== */
.drawer-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.45);
  backdrop-filter: blur(4px);
  z-index: 2000;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

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

.course-drawer {
  position: fixed;
  top: 0;
  right: 0;
  width: var(--drawer-width);
  max-width: 100vw;
  height: 100vh;
  background: var(--bg-surface);
  box-shadow: var(--shadow-lg);
  z-index: 2001;
  transform: translateX(100%);
  transition: transform 0.35s cubic-bezier(0.16, 1, 0.3, 1);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

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

.drawer-header {
  padding: 1.25rem 1.5rem;
  background: var(--bg-surface-elevated);
  border-bottom: 1px solid var(--border-light);
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
}

.drawer-close-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-size: 1.4rem;
  cursor: pointer;
  padding: 0.2rem;
  line-height: 1;
  border-radius: 6px;
  transition: all 0.2s;
}

.drawer-close-btn:hover {
  background: var(--border-light);
  color: var(--text-primary);
}

.drawer-body {
  padding: 1.5rem;
  overflow-y: auto;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 1.4rem;
}

.drawer-code-badge {
  font-family: monospace;
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--cmu-purple);
  margin-bottom: 0.25rem;
}

[data-theme="dark"] .drawer-code-badge {
  color: #C09BF4;
}

.drawer-title-th {
  font-size: 1.15rem;
  font-weight: 800;
  line-height: 1.35;
  color: var(--text-primary);
}

.drawer-title-en {
  font-size: 0.95rem;
  color: var(--text-secondary);
  font-weight: 500;
  margin-top: 0.2rem;
}

.drawer-meta-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.meta-pill {
  font-size: 0.78rem;
  font-weight: 700;
  padding: 0.3rem 0.65rem;
  border-radius: 8px;
  background: var(--bg-surface-elevated);
  color: var(--text-secondary);
  border: 1px solid var(--border-light);
}

.meta-pill.offered-both {
  background: var(--cmu-purple-subtle);
  color: var(--cmu-purple);
  border-color: rgba(81, 45, 109, 0.2);
}

.drawer-section {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.drawer-section-title {
  font-size: 0.82rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
}

.drawer-box {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-light);
  border-radius: 10px;
  padding: 0.85rem 1rem;
  font-size: 0.9rem;
  line-height: 1.5;
}

.drawer-box.prereq-box {
  border-left: 3.5px solid var(--accent-emerald);
}

.drawer-courses-taglist {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 0.4rem;
}

.link-course-tag {
  background: var(--bg-surface);
  border: 1px solid var(--border-medium);
  border-radius: 6px;
  padding: 0.35rem 0.65rem;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--cmu-purple);
  cursor: pointer;
  transition: all 0.2s;
}

.link-course-tag:hover {
  background: var(--cmu-purple);
  color: #FFF;
}

.map-switchers-group {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
}

/* ==========================================================================
   Responsive / Mobile Media Queries
   ========================================================================== */
@media (max-width: 900px) {
  .nav-container {
    flex-wrap: wrap;
  }
  
  .nav-links {
    order: 3;
    width: 100%;
    justify-content: space-around;
    padding-top: 0.5rem;
    border-top: 1px solid var(--border-light);
  }

}

@media (max-width: 880px) {
  /* Page 2 Mobile/Tablet Semester Tabs */
  .mobile-sem-tabs {
    display: flex;
  }

  .curriculum-map-grid {
    display: flex;
    flex-direction: column;
    min-width: unset;
  }

  .map-column {
    display: none;
  }

  .map-column.active-mobile-col {
    display: flex;
  }
}

@media (max-width: 768px) {
  .page-container {
    padding: 1.25rem 1rem 3rem;
  }

  .page-title {
    font-size: 1.5rem;
  }

  .nav-link {
    font-size: 0.82rem;
    padding: 0.45rem 0.65rem;
  }

  .brand-sub {
    display: none;
  }

  /* Page 1 Mobile */
  .req-stats-grid {
    grid-template-columns: 1fr 1fr;
  }

  .plan-grid {
    grid-template-columns: 1fr;
  }

  /* Page 3 Mobile */
  .canvas-wrapper {
    display: none; /* Hide graph canvas on mobile by default */
  }

  .tree-list-view {
    display: flex; /* Show list view on mobile by default */
  }

  .view-mode-toggle {
    display: none;
  }

  /* Drawer Mobile */
  .course-drawer {
    width: 100%;
    border-radius: 16px 16px 0 0;
    height: 85vh;
    top: auto;
    bottom: 0;
    transform: translateY(100%);
  }

  .course-drawer.open {
    transform: translateY(0);
  }
}

@media (max-width: 640px) {
  .btn-pdf-text {
    display: none;
  }
}

/* ==========================================================================
   Site Footer
   ========================================================================== */
.site-footer {
  background: var(--bg-surface);
  border-top: 1px solid var(--border-light);
  padding: 1.5rem 1.5rem 2.25rem;
  margin-top: 3.5rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.footer-container {
  max-width: 1400px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.footer-text {
  font-weight: 500;
  line-height: 1.4;
}

.footer-pdf-link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-weight: 700;
  color: var(--cmu-purple);
  text-decoration: none;
  padding: 0.4rem 0.85rem;
  border-radius: 8px;
  background: var(--cmu-purple-subtle);
  border: 1px solid rgba(81, 45, 109, 0.15);
  transition: all 0.2s;
}

.footer-pdf-link:hover {
  background: var(--cmu-purple);
  color: #FFFFFF;
}

[data-theme="dark"] .footer-pdf-link {
  color: #D8B4FE;
  background: rgba(192, 132, 252, 0.12);
  border-color: rgba(216, 180, 254, 0.25);
}

[data-theme="dark"] .footer-pdf-link:hover {
  background: #7C3AED;
  color: #FFFFFF;
}