:root {
  --primary: #2563eb;
  --core: #1e40af;
  --elective: #7c3aed;
  --pbl: #059669;
  --open-elective: #d97706;
  --bg: #ffffff;
  --card: #ffffff;
  --text: #0f172a;
  --muted: #475569;
  --border: #e2e8f0;
  --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 4px 12px rgba(0,0,0,0.06);
  --radius: 12px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  font-size: 16px;
}

.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 16px;
}

.site-header {
  background: #f8fafc;
  color: var(--text);
  border-bottom: 1px solid var(--border);
  padding: 28px 0 24px;
}
.header-inner h1 {
  font-size: 1.6rem;
  letter-spacing: 0.2px;
  color: var(--text);
}
.subtitle {
  color: var(--muted);
  font-size: 0.95rem;
  margin-top: 4px;
}

.view {
  display: none;
}
.view.active {
  display: block;
}

.controls {
  display: flex;
  padding: 18px 0 12px;
  position: sticky;
  top: 0;
  background: var(--bg);
  z-index: 10;
  gap: 12px;
}
.back-btn {
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #ffffff;
  font-size: 0.95rem;
  color: var(--text);
  cursor: pointer;
}
.back-btn:hover {
  background: #f1f5f9;
}
.search-wrap {
  width: 100%;
  max-width: 480px;
}
.search-wrap input {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #ffffff;
  font-size: 0.95rem;
  color: var(--text);
  outline: none;
}
.search-wrap input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.semester-panel {
  padding: 18px 0 24px;
}
.semester-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 16px 0 10px;
  flex-wrap: wrap;
}
.semester-header h2 {
  font-size: 1.35rem;
  color: var(--text);
}
.semester-meta { display: flex; gap: 8px; flex-wrap: wrap; }
.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: #f1f5f9;
  color: #334155;
  border: 1px solid var(--border);
  padding: 6px 10px;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
}

#detail-grid {
  display: block;
}

.cards-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

@media (min-width: 641px) {
  .cards-grid { grid-template-columns: repeat(2, 1fr); }
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  display: flex;
  flex-direction: row;
  align-items: stretch;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  cursor: pointer;
}
.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.08);
}
.card-select .card-body {
  padding: 24px 16px;
}
.card-select .card-title {
  font-size: 1.3rem;
  margin-bottom: 8px;
}

.card-strip {
  width: 6px;
  min-width: 6px;
  align-self: stretch;
}
.strip-core { background: var(--core); }
.strip-elective { background: var(--elective); }
.strip-pbl { background: var(--pbl); }
.strip-open-elective { background: var(--open-elective); }

.card-body {
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  flex: 1;
  min-width: 0;
}
.card-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.4;
  overflow-wrap: anywhere;
  word-break: break-word;
}
.card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}
.meta-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: #f1f5f9;
  color: #334155;
  border: 1px solid var(--border);
  padding: 5px 9px;
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 600;
  white-space: nowrap;
}
.meta-pill.code-pill {
  background: #f1f5f9;
  color: #0f172a;
  border-color: var(--border);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  letter-spacing: 0.2px;
}
.meta-pill.credit-pill {
  background: #eff6ff;
  color: #1e40af;
  border-color: #dbeafe;
}
.meta-pill.hour-pill {
  background: #f0fdf4;
  color: #166534;
  border-color: #bbf7d0;
}

.card-footer {
  padding: 12px 16px;
  border-top: 1px solid var(--border);
  background: #fafafa;
}
.youtube-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  background: #fef2f2;
  color: #dc2626;
  border: 1px solid #fecaca;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.15s ease, border-color 0.15s ease;
}
.youtube-link:hover {
  background: #fee2e2;
  border-color: #fca5a5;
}

.resources-section {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 8px;
}

.resource-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.resource-group-title {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 700;
  color: var(--muted);
}

.resource-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 10px;
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.15s ease, border-color 0.15s ease;
  word-break: break-word;
}

.resource-youtube {
  background: #fef2f2;
  color: #dc2626;
  border: 1px solid #fecaca;
}

.resource-gdrive {
  background: #eff6ff;
  color: #2563eb;
  border: 1px solid #dbeafe;
}

.resource-gdocs {
  background: #eff6ff;
  color: #2563eb;
  border: 1px solid #dbeafe;
}

.resource-gsheets {
  background: #f0fdf4;
  color: #166534;
  border: 1px solid #bbf7d0;
}

.resource-gclassroom {
  background: #fffbeb;
  color: #d97706;
  border: 1px solid #fde68a;
}
.card-note {
  font-size: 0.9rem;
  color: var(--muted);
}

.card-intro {
  font-size: 0.95rem;
  color: var(--muted);
  line-height: 1.5;
}

.category-tag {
  display: inline-block;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 700;
  padding: 4px 8px;
  border-radius: 6px;
  background: #f1f5f9;
  color: #334155;
  border: 1px solid var(--border);
}

.site-footer {
  background: #ffffff;
  border-top: 1px solid var(--border);
  color: var(--muted);
  padding: 18px 0;
  text-align: center;
  font-size: 0.9rem;
  margin-top: 8px;
}

.hidden { display: none !important; }
.text-muted { color: var(--muted); }
.mt-2 { margin-top: 8px; }
.mt-3 { margin-top: 12px; }

.empty-state {
  text-align: center;
  color: var(--muted);
  padding: 24px;
}

.semester-select-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  padding: 32px 0;
}

@media (min-width: 641px) {
  .semester-select-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1025px) {
  .semester-select-grid { grid-template-columns: repeat(3, 1fr); }
}

.sem-select-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  cursor: pointer;
  text-align: center;
  padding: 28px 20px 24px;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
}

.sem-select-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.1);
}

.sem-select-card .sem-name {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 14px;
}

.sem-select-card .sem-stats {
  display: flex;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
}

.subject-folder {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  margin-top: 24px;
}
.folder-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 16px;
  background: #f8fafc;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
  user-select: none;
}
.folder-header:hover {
  background: #f1f5f9;
}
.folder-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
}
.folder-count {
  font-size: 0.85rem;
  color: var(--muted);
  font-weight: 600;
}
.folder-toggle {
  width: 28px;
  height: 28px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  background: #ffffff;
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 1rem;
  font-weight: 700;
  line-height: 1;
}
.folder-body {
  padding: 14px;
}
.folder-body.collapsed {
  display: none;
}

.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.5);
  display: none;
  align-items: center;
  justify-content: center;
  padding: 16px;
  z-index: 1000;
}
.modal-sheet {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: 0 20px 60px rgba(0,0,0,0.15);
  width: 100%;
  max-width: 640px;
  max-height: 90vh;
  overflow: auto;
  padding: 20px;
  position: relative;
}
.modal-close {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 32px;
  height: 32px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  background: #ffffff;
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 1.1rem;
  font-weight: 700;
  cursor: pointer;
}
.modal-close:hover {
  background: #f1f5f9;
}
.modal-header {
  display: flex;
  align-items: center;
  gap: 10px;
  padding-right: 36px;
}
.modal-title {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.4;
}
.modal-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}
.modal-section {
  margin-top: 16px;
}
.modal-section-title {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 700;
  color: var(--muted);
  margin-bottom: 6px;
}
.modal-section-body {
  font-size: 0.95rem;
  color: var(--text);
  line-height: 1.5;
}
.modal-roadmap {
  margin: 0;
  padding-left: 18px;
  font-size: 0.9rem;
  color: var(--text);
  line-height: 1.5;
}
.modal-roadmap li + li {
  margin-top: 6px;
}
.modal-roadmap li::marker {
  color: var(--primary);
}