/* ==========================================================================
   CSS Design System & Design System Tokens (Dark / Light Themes)
   ========================================================================== */

:root {
  /* Color Palette - Dark Theme (Default) */
  --bg-base: #0f172a;
  --bg-surface: #1e293b;
  --bg-surface-elevated: #334155;
  --bg-glass: rgba(30, 41, 59, 0.75);
  
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;

  --border-color: rgba(255, 255, 255, 0.1);
  --border-focus: #6366f1;

  --primary: #6366f1;
  --primary-hover: #4f46e5;
  --primary-light: rgba(99, 102, 241, 0.15);

  --secondary: #475569;
  --secondary-hover: #64748b;

  --success: #10b981;
  --success-bg: rgba(16, 185, 129, 0.15);
  --warning: #f59e0b;
  --warning-bg: rgba(245, 158, 11, 0.15);
  --danger: #ef4444;
  --danger-bg: rgba(239, 68, 68, 0.15);

  --shadow-sm: 0 2px 4px rgba(0,0,0,0.2);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.3);
  --shadow-lg: 0 10px 25px rgba(0,0,0,0.4);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;

  --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="light"] {
  --bg-base: #f1f5f9;
  --bg-surface: #ffffff;
  --bg-surface-elevated: #f8fafc;
  --bg-glass: rgba(255, 255, 255, 0.85);

  --text-main: #0f172a;
  --text-muted: #475569;
  --text-dim: #94a3b8;

  --border-color: rgba(0, 0, 0, 0.08);
  --border-focus: #4f46e5;

  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --primary-light: rgba(79, 70, 229, 0.08);

  --secondary: #e2e8f0;
  --secondary-hover: #cbd5e1;

  --shadow-sm: 0 2px 4px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 10px 25px rgba(0,0,0,0.12);
}

/* Reset & Base Styles */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background-color: var(--bg-base);
  color: var(--text-main);
  line-height: 1.5;
  min-height: 100vh;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* App Container */
.app-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 16px 24px 48px;
}

/* Header & Navbar */
.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 20px;
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  margin-bottom: 24px;
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 12px;
  z-index: 100;
}

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

.logo-icon {
  width: 42px;
  height: 42px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, #6366f1, #a855f7);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
}

.brand-text h1 {
  font-family: 'Outfit', sans-serif;
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.sub-title {
  font-size: 0.75rem;
  color: var(--text-muted);
  display: block;
}

.nav-tabs {
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--bg-base);
  padding: 4px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.nav-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  font-size: 0.88rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
}

.nav-btn:hover {
  color: var(--text-main);
  background: var(--primary-light);
}

.nav-btn.active {
  background: var(--primary);
  color: #ffffff;
  box-shadow: 0 2px 8px rgba(99, 102, 241, 0.3);
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--success);
  display: inline-block;
  box-shadow: 0 0 6px var(--success);
}

.status-dot.offline {
  background: var(--warning);
  box-shadow: 0 0 6px var(--warning);
}

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

/* Icon Buttons & Buttons */
.icon-btn {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-main);
  width: 38px;
  height: 38px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.icon-btn:hover {
  background: var(--bg-surface-elevated);
  border-color: var(--border-focus);
}

[data-theme="dark"] .sun-icon { display: block; }
[data-theme="dark"] .moon-icon { display: none; }
[data-theme="light"] .sun-icon { display: none; }
[data-theme="light"] .moon-icon { display: block; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  font-size: 0.9rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), #4338ca);
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.25);
}

.btn-primary:hover {
  filter: brightness(1.1);
  box-shadow: 0 6px 16px rgba(99, 102, 241, 0.35);
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--secondary);
  color: var(--text-main);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: var(--secondary-hover);
}

.btn-danger {
  background: var(--danger);
  color: #ffffff;
}

.btn-danger:hover {
  filter: brightness(1.1);
}

.btn-sm {
  padding: 6px 12px;
  font-size: 0.82rem;
  border-radius: var(--radius-sm);
}

.btn-lg {
  padding: 12px 24px;
  font-size: 1rem;
}

.icon-btn-sm {
  width: 34px;
  height: 34px;
  padding: 0;
}

/* Tab Panels */
.tab-panel {
  display: none;
  animation: fadeIn 0.25s ease-out;
}

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

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Panel Header Controls */
.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 20px;
  background: var(--bg-surface);
  padding: 16px 20px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}

.date-controls {
  display: flex;
  align-items: center;
  gap: 8px;
}

.date-input {
  background: var(--bg-base);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 0.95rem;
  outline: none;
  transition: border-color var(--transition-fast);
}

.date-input:focus {
  border-color: var(--border-focus);
}

.day-info {
  display: flex;
  align-items: center;
  gap: 12px;
}

.badge {
  display: inline-flex;
  align-items: center;
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
}

.badge-primary {
  background: var(--primary-light);
  color: var(--primary);
  border: 1px solid rgba(99, 102, 241, 0.3);
}

.badge-warning {
  background: var(--warning-bg);
  color: var(--warning);
}

.daily-summary-tag {
  font-size: 0.9rem;
  font-weight: 600;
  color: #a855f7;
  background: rgba(168, 85, 247, 0.15);
  padding: 4px 12px;
  border-radius: 20px;
  border: 1px solid rgba(168, 85, 247, 0.3);
}

.schedule-notice {
  display: flex;
  align-items: center;
  gap: 12px;
  background: rgba(99, 102, 241, 0.1);
  border: 1px solid rgba(99, 102, 241, 0.25);
  padding: 12px 18px;
  border-radius: var(--radius-md);
  margin-bottom: 20px;
  font-size: 0.88rem;
}

/* Cards Grid */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 20px;
}

/* Class Slot Card */
.slot-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 20px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  overflow: hidden;
}

.slot-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: rgba(99, 102, 241, 0.4);
}

.slot-card.makeup-card {
  border-left: 4px solid #a855f7;
}

.slot-card.has-data {
  border-color: var(--primary);
}

.slot-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.slot-time {
  font-family: 'Outfit', sans-serif;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 8px;
}

.slot-duration {
  font-size: 0.8rem;
  color: var(--text-muted);
  background: var(--bg-base);
  padding: 2px 8px;
  border-radius: 12px;
}

.slot-tag {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 12px;
  background: var(--primary-light);
  color: var(--primary);
}

.slot-tag.makeup {
  background: rgba(168, 85, 247, 0.15);
  color: #a855f7;
}

/* Headcount Counter Box */
.counter-box {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-base);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 6px 12px;
  margin-bottom: 14px;
}

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

.counter-controls {
  display: flex;
  align-items: center;
  gap: 8px;
}

.cnt-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  background: var(--bg-surface);
  color: var(--text-main);
  font-size: 1.2rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  user-select: none;
  transition: all var(--transition-fast);
}

.cnt-btn:hover {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.cnt-input {
  width: 50px;
  text-align: center;
  font-family: 'Outfit', sans-serif;
  font-size: 1.2rem;
  font-weight: 700;
  background: transparent;
  border: none;
  color: var(--text-main);
  outline: none;
}

.slot-calc-summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-muted);
  padding: 8px 0;
  border-top: 1px dashed var(--border-color);
  margin-bottom: 12px;
}

.slot-calc-summary .headhours-val {
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  color: #a855f7;
  font-size: 1.05rem;
}

.slot-note-input {
  width: 100%;
  background: var(--bg-base);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  outline: none;
  transition: border-color var(--transition-fast);
}

.slot-note-input:focus {
  border-color: var(--border-focus);
}

.slot-footer {
  margin-top: 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.slot-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

/* Metrics Overview Grid */
.metrics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.metric-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 20px;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.metric-card.highlighted {
  border-color: rgba(168, 85, 247, 0.4);
  background: linear-gradient(135deg, var(--bg-surface), rgba(168, 85, 247, 0.1));
}

.metric-card.salary-card {
  border-color: rgba(16, 185, 129, 0.4);
  background: linear-gradient(135deg, var(--bg-surface), rgba(16, 185, 129, 0.12));
}

.metric-icon {
  font-size: 1.5rem;
  margin-bottom: 8px;
}

.metric-label {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.metric-value {
  font-family: 'Outfit', sans-serif;
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--text-main);
  margin: 4px 0;
}

.metric-value.salary-val {
  color: var(--success);
}

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

/* Sub Tab Controls */
.sub-tab-container {
  margin-bottom: 16px;
}

.sub-tabs {
  display: inline-flex;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  padding: 4px;
  border-radius: var(--radius-md);
  gap: 4px;
}

.sub-tab-btn {
  padding: 6px 16px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  font-size: 0.88rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  cursor: pointer;
}

.sub-tab-btn.active {
  background: var(--primary-light);
  color: var(--primary);
  font-weight: 600;
}

.sub-tab-content {
  display: none;
}

.sub-tab-content.active {
  display: block;
}

/* Monthly Calendar View */
.calendar-wrapper {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 20px;
  box-shadow: var(--shadow-sm);
}

.calendar-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 8px;
}

.cal-header-cell {
  text-align: center;
  font-weight: 600;
  font-size: 0.82rem;
  color: var(--text-muted);
  padding: 8px;
}

.cal-day-cell {
  background: var(--bg-base);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  min-height: 90px;
  padding: 8px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all var(--transition-fast);
  cursor: pointer;
}

.cal-day-cell:hover {
  border-color: var(--primary);
  background: var(--bg-surface-elevated);
}

.cal-day-cell.other-month {
  opacity: 0.3;
  pointer-events: none;
}

.cal-day-cell.is-today {
  border-color: var(--primary);
  box-shadow: 0 0 0 1px var(--primary);
}

.cal-day-num {
  font-weight: 700;
  font-size: 0.88rem;
}

.cal-day-badges {
  display: flex;
  flex-direction: column;
  gap: 3px;
  margin-top: 4px;
}

.cal-pill {
  font-size: 0.7rem;
  padding: 2px 4px;
  border-radius: 4px;
  background: var(--primary-light);
  color: var(--primary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.cal-pill.makeup {
  background: rgba(168, 85, 247, 0.15);
  color: #a855f7;
}

.cal-day-footer {
  font-size: 0.72rem;
  font-weight: 600;
  color: #a855f7;
  text-align: right;
}

/* Tables */
.table-responsive {
  width: 100%;
  overflow-x: auto;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  background: var(--bg-surface);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.88rem;
}

.data-table th {
  background: var(--bg-base);
  padding: 12px 16px;
  font-weight: 600;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border-color);
  white-space: nowrap;
}

.data-table td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-color);
  vertical-align: middle;
}

.data-table tbody tr:hover {
  background: var(--bg-surface-elevated);
}

/* Reconciliation Section */
.reconcile-filters {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.filter-group {
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--bg-base);
  padding: 4px;
  border-radius: var(--radius-md);
}

.filter-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  border-radius: var(--radius-sm);
  padding: 4px 10px;
}

.filter-btn.active {
  background: var(--bg-surface-elevated);
  color: var(--text-main);
  font-weight: 600;
}

.reconcile-summary-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.stat-pill {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 0.85rem;
}

.stat-pill.success { border-color: var(--success); color: var(--success); }
.stat-pill.warning { border-color: var(--warning); color: var(--warning); }
.stat-pill.pending { border-color: var(--text-dim); color: var(--text-muted); }
.stat-pill.primary { border-color: var(--primary); color: var(--primary); }

.rec-status-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 0.78rem;
  font-weight: 600;
  cursor: pointer;
}

.rec-status-badge.matched { background: var(--success-bg); color: var(--success); }
.rec-status-badge.discrepancy { background: var(--danger-bg); color: var(--danger); }
.rec-status-badge.unmatched { background: var(--bg-base); color: var(--text-muted); border: 1px solid var(--border-color); }

/* Forms & Panels Cards */
.panel-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-sm);
}

.max-width-card {
  max-width: 760px;
  margin: 0 auto;
}

.card-header {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  margin-bottom: 16px;
}

.card-icon {
  font-size: 1.8rem;
}

.card-desc {
  font-size: 0.88rem;
  color: var(--text-muted);
}

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

.form-label {
  display: block;
  font-size: 0.88rem;
  font-weight: 600;
  margin-bottom: 6px;
}

.form-label-inline {
  font-size: 0.88rem;
  font-weight: 600;
}

.form-control {
  width: 100%;
  background: var(--bg-base);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  padding: 10px 14px;
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  outline: none;
  transition: border-color var(--transition-fast);
}

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

.form-help {
  display: block;
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.input-with-button {
  display: flex;
  gap: 8px;
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
}

.checkbox-label {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
  cursor: pointer;
}

.sync-actions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
}

.log-box {
  background: var(--bg-base);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 12px;
  font-family: monospace;
  font-size: 0.82rem;
  color: var(--text-muted);
  max-height: 120px;
  overflow-y: auto;
}

.file-upload-btn {
  margin: 0;
  cursor: pointer;
}

.divider {
  border: none;
  border-top: 1px solid var(--border-color);
  margin: 24px 0;
}

.preset-slots-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.preset-item-row {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-base);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
}

/* Modals */
.modal-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 16px;
}

.modal-backdrop.active {
  display: flex;
  animation: fadeIn 0.2s ease-out;
}

.modal-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 480px;
  padding: 24px;
  box-shadow: var(--shadow-lg);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

.modal-footer {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 8px;
  margin-top: 20px;
}

/* Toast Notifications */
.toast-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 2000;
  display: flex;
  flex-direction: column;
  gap: 8px;
  pointer-events: none;
}

.toast {
  background: var(--bg-surface-elevated);
  color: var(--text-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 12px 18px;
  box-shadow: var(--shadow-lg);
  font-size: 0.88rem;
  display: flex;
  align-items: center;
  gap: 10px;
  pointer-events: auto;
  animation: slideInRight 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

.toast.success { border-left: 4px solid var(--success); }
.toast.warning { border-left: 4px solid var(--warning); }
.toast.error { border-left: 4px solid var(--danger); }

@keyframes slideInRight {
  from { opacity: 0; transform: translateX(30px); }
  to { opacity: 1; transform: translateX(0); }
}

/* Utility Helpers */
.margin-top-sm { margin-top: 8px; }
.margin-top-md { margin-top: 16px; }
.margin-top-lg { margin-top: 24px; }

/* Responsive Adaptations */
@media (max-width: 840px) {
  .app-header {
    flex-direction: column;
    align-items: stretch;
  }
  
  .nav-tabs {
    overflow-x: auto;
    white-space: nowrap;
    justify-content: flex-start;
  }

  .panel-header {
    flex-direction: column;
    align-items: stretch;
  }

  .calendar-grid {
    font-size: 0.75rem;
  }
  
  .cal-day-cell {
    min-height: 70px;
    padding: 4px;
  }
}