/* === Reset & Base === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: #F3F4F6; color: #1F2937; font-size: 14px; line-height: 1.5;
}

/* === Toolbar === */
.toolbar { display:flex; justify-content:space-between; align-items:center; padding:10px 14px; background:#F9FAFB; color:#374151; border-bottom:1px solid #E5E7EB; position:sticky; top:0; z-index:100; }
.title { font-size:18px; font-weight:600; }
.toolbar-right { display:flex; align-items:center; gap:8px; }
.user-info { font-size:13px; opacity:.9; }

/* === Buttons === */
.btn { padding:6px 14px; border:none; border-radius:6px; cursor:pointer; font-size:13px; background:#E5E7EB; color:#374151; transition:.15s; }
.btn:active { opacity:.7; }
.btn-primary { background:#1F2937; color:#fff; font-weight:600; }
.btn-outline { background:transparent; color:#374151; border:1px solid #D1D5DB; }
.btn-danger { background:#FEE2E2; color:#DC2626; }
.btn-sm { padding:4px 10px; font-size:12px; }
.btn:disabled { opacity:.4; cursor:default; }

/* === Semester Bar === */
.semester-bar { display:flex; align-items:center; gap:8px; padding:8px 14px; background:#fff; border-bottom:1px solid #E5E7EB; flex-wrap:wrap; }
.select { padding:6px 10px; border:1px solid #D1D5DB; border-radius:6px; font-size:13px; background:#fff; }
.select-sm { min-width:90px; }
.week-picker { display:flex; align-items:center; gap:2px; }

/* === Modal === */
.modal { position:fixed; inset:0; background:rgba(0,0,0,.4); z-index:200; display:flex; align-items:center; justify-content:center; }
.modal-box { background:#fff; border-radius:12px; padding:24px; width:min(380px,90vw); box-shadow:0 8px 30px rgba(0,0,0,.15); max-height:85vh; overflow-y:auto; }
.modal-wide { width:min(640px,95vw); }
.modal-box h2 { font-size:18px; margin-bottom:12px; }
.hint { font-size:12px; color:#9CA3AF; margin-bottom:8px; }
.input { width:100%; padding:8px 10px; border:1px solid #D1D5DB; border-radius:6px; margin-bottom:10px; font-size:14px; }
.field-label { display:block; font-size:13px; color:#4B5563; margin-bottom:4px; font-weight:500; }
.modal-btns { display:flex; gap:8px; justify-content:flex-end; margin-top:12px; }
.error { color:#DC2626; font-size:13px; margin-top:8px; }
.hidden { display:none !important; }

/* === Import Preview === */
.import-preview { max-height:280px; overflow-y:auto; border:1px solid #E5E7EB; border-radius:6px; margin-bottom:10px; }
.preview-row { padding:8px 10px; border-bottom:1px solid #F3F4F6; cursor:pointer; display:flex; justify-content:space-between; align-items:center; }
.preview-row:hover { background:#F9FAFB; }
.preview-row .preview-name { font-weight:600; }
.preview-row .preview-meta { font-size:12px; color:#6B7280; }
.preview-detail { padding:8px 16px; background:#F9FAFB; font-size:12px; border-bottom:1px solid #E5E7EB; }
.preview-detail table { width:100%; border-collapse:collapse; }
.preview-detail td { padding:2px 4px; }

/* === Main Area === */
.main-area { position:relative; }
#calendar-view { min-height:300px; }

/* === Calendar Grid (Timeline) === */
.calendar-container { overflow-x:auto; padding:4px; -webkit-overflow-scrolling:touch; }
.calendar-grid {
  display:grid; grid-template-columns:28px repeat(7, 1fr);
  gap:0; background:#fff; border-radius:8px; overflow:hidden;
  width:100%; max-width:100vw;
}
.grid-header { background:#F3F4F6; color:#374151; padding:8px 4px; text-align:center; font-size:13px; font-weight:600; border-bottom:1px solid #E5E7EB; }
.grid-header:first-child { background:#E5E7EB; }
.grid-header .today-dot { display:inline-flex; align-items:center; justify-content:center; background:#1F2937; color:#fff; border-radius:50%; width:22px; height:22px; font-size:11px; font-weight:600; }
.time-axis { background:#FAFBFC; border-right:1px solid #E5E7EB; }
.day-column { background:#fff; min-height:200px; }
.course-chip { display:flex; flex-direction:column; justify-content:center; padding:2px 4px; border-radius:5px; font-size:10px; line-height:1.35; overflow:hidden; cursor:pointer; transition:box-shadow .15s, opacity .15s; word-break:break-all; }
.course-chip:hover { box-shadow:0 0 0 2px rgba(0,0,0,.15); z-index:5; }
.course-chip .chip-name { font-weight:600; font-size:10px; line-height:1.3; word-break:break-all; overflow:hidden; max-height:2.6em; }
.course-chip .chip-detail { font-size:8px; opacity:.75; line-height:1.3; word-break:break-all; overflow:hidden; max-height:1.3em; }
.time-block { position:absolute; left:1px;right:1px; }
.chip-offset { border:1px dashed rgba(255,255,255,.6); }
.loading { text-align:center; padding:40px; color:#9CA3AF; }

/* === Legend === */
.legend { display:flex; flex-wrap:wrap; gap:8px; padding:10px 14px; border-top:1px solid #E5E7EB; background:#fff; }
.legend-item { display:flex; align-items:center; gap:4px; font-size:12px; }
.legend-color { width:14px; height:14px; border-radius:3px; flex-shrink:0; }

/* === Manage Panel === */
.manage-panel { position:absolute; top:0; left:0; right:0; background:#fff; min-height:400px; z-index:50; padding:14px; overflow-y:auto; }
.manage-panel h2 { font-size:16px; margin-bottom:10px; color:#374151; }
.manage-course { border:1px solid #E5E7EB; border-radius:8px; margin-bottom:8px; overflow:hidden; }
.manage-course-header { display:flex; justify-content:space-between; align-items:center; padding:10px 12px; background:#F9FAFB; cursor:pointer; }
.manage-course-header:hover { background:#F3F4F6; }
.manage-course-name { font-weight:600; }
.manage-course-meta { font-size:12px; color:#6B7280; }
.manage-course-body { padding:0 12px 12px; }
.manage-session-row { display:flex; align-items:center; gap:6px; padding:4px 0; font-size:13px; border-bottom:1px solid #F3F4F6; }
.manage-session-row .sess-info { flex:1; }
.manage-session-row .btn { font-size:11px; padding:2px 8px; }
.manage-actions { display:flex; gap:4px; margin-top:6px; }
.manage-inline-edit { display:flex; gap:4px; align-items:center; }
.manage-inline-edit input, .manage-inline-edit select { padding:4px 6px; border:1px solid #D1D5DB; border-radius:4px; font-size:12px; width:80px; }

/* === Detail Modal === */
.detail-section { margin-bottom:12px; }
.detail-section h3 { font-size:15px; color:#374151; margin-bottom:6px; border-bottom:1px solid #E5E7EB; padding-bottom:4px; }
.detail-table { width:100%; border-collapse:collapse; font-size:13px; }
.detail-table th, .detail-table td { padding:5px 8px; text-align:left; border-bottom:1px solid #F3F4F6; }
.detail-table th { color:#6B7280; font-weight:500; }
.detail-warning { background:#FEF3C7; color:#92400E; padding:6px 10px; border-radius:6px; font-size:12px; margin-top:4px; }

/* === Block Editor === */
.block-overlay { position:fixed; inset:0; background:rgba(0,0,0,.3); z-index:150; }
.block-editor { position:fixed; z-index:155; }
.block-editor-box { background:#fff; border-radius:10px; box-shadow:0 4px 24px rgba(0,0,0,.18); padding:12px; width:260px; font-size:13px; }
.block-editor-header { display:flex; justify-content:space-between; align-items:center; margin-bottom:8px; font-weight:600; }
.block-editor-box .input, .block-editor-box select { width:100%; padding:4px 6px; border:1px solid #D1D5DB; border-radius:4px; margin-bottom:4px; font-size:12px; }
.block-editor-box .input-row { display:flex; gap:4px; }
.block-editor-box .input-row .input, .block-editor-box .input-row select { flex:1; }

/* === Mobile === */
@media (max-width:600px) {
  body { font-size:13px; -webkit-tap-highlight-color:transparent; touch-action:manipulation; }
  .toolbar { padding:4px 6px; position:sticky; top:0; }
  .title { font-size:15px; }
  .toolbar .btn-sm { font-size:10px; padding:2px 6px; }
  .semester-bar { gap:2px 4px; padding:3px 4px; flex-wrap:wrap; }
  .semester-bar .select { font-size:11px; padding:3px 4px; min-width:90px; }
  .semester-bar .btn { font-size:10px; padding:2px 5px; white-space:nowrap; }
  .semester-bar .btn-sm { font-size:10px; padding:2px 5px; }
  .calendar-container { padding:4px; }
  .calendar-grid { font-size:9px; grid-template-columns:22px repeat(7, 1fr); width:100%; }
  .grid-header { font-size:11px; padding:4px 2px; }
  .grid-header .today-dot { width:18px; height:18px; font-size:10px; }
  .course-chip { font-size:10px; padding:2px 3px; border-radius:4px; }
  .course-chip .chip-detail { font-size:8px; }
  .day-column { min-height:120px; }
  .time-axis { font-size:9px; }
  .modal-box { width:96vw; padding:14px; max-height:90vh; }
  .block-editor-box { width:240px; }
  .manage-inline-edit { flex-wrap:wrap; gap:2px; }
  .manage-inline-edit input, .manage-inline-edit select { font-size:11px; padding:3px 4px; }
  .btn { padding:5px 10px; font-size:12px; }
  .btn-sm { padding:3px 7px; font-size:11px; }
}