/* ==========================================================================
   GRADEBOOK CSS - MOBILE FIRST GRADE MANAGEMENT SYSTEM
   ========================================================================== */

.gradebook-container {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  padding-bottom: 90px; /* Space for sticky bottom bar */
}

/* Header & Controls Toolbar */
.gradebook-toolbar {
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-4) var(--space-5);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.toolbar-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.class-header-info {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.class-code-tag {
  font-size: var(--font-size-base);
  font-weight: 800;
  color: var(--primary);
  background-color: var(--primary-light);
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-md);
  letter-spacing: 0.02em;
}

.class-title-text {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--text-muted);
}

.toolbar-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-wrap: wrap;
}

/* Fast Column Navigator */
.column-navigator-bar {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  background: linear-gradient(135deg, #f8fafc 0%, #f1f5f9 100%);
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-3) var(--space-4);
}

.col-nav-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: 0.5rem 0.875rem;
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  font-weight: 700;
  color: var(--text-main);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-fast);
}

.col-nav-btn:hover:not(:disabled) {
  background-color: var(--primary-light);
  color: var(--primary);
  border-color: var(--primary);
}

.col-nav-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.column-select-wrapper {
  flex: 1;
  min-width: 160px;
  position: relative;
}

.column-select-wrapper select {
  font-weight: 800;
  font-size: var(--font-size-base);
  color: var(--primary);
  background-color: #ffffff;
  border: 2px solid var(--primary);
  border-radius: var(--radius-md);
  padding: 0.5rem 1rem;
  cursor: pointer;
  box-shadow: 0 2px 6px rgba(79, 70, 229, 0.15);
}

/* Search & Filter Bar */
.grade-filter-bar {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
}

.grade-search-input {
  flex: 1;
  min-width: 200px;
}

.grade-status-tabs {
  display: flex;
  background-color: var(--bg-surface-secondary);
  border-radius: var(--radius-md);
  padding: 3px;
  gap: 2px;
}

.status-tab-btn {
  padding: 0.4rem 0.75rem;
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: var(--text-muted);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.status-tab-btn.active {
  background-color: #ffffff;
  color: var(--primary);
  box-shadow: var(--shadow-sm);
  font-weight: 700;
}

/* ==========================================================================
   GRADEBOOK TABLE & INPUT UX
   ========================================================================== */

.gradebook-card {
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}

.grade-table-wrap {
  width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  max-height: calc(100vh - 280px);
}

.grade-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  text-align: left;
  font-size: var(--font-size-sm);
}

.grade-table th {
  position: sticky;
  top: 0;
  background-color: #f8fafc;
  color: var(--text-main);
  font-weight: 700;
  font-size: var(--font-size-xs);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.875rem 1rem;
  border-bottom: 2px solid var(--border-color);
  z-index: 10;
  white-space: nowrap;
}

.grade-table td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-color);
  vertical-align: middle;
  background-color: #ffffff;
}

.grade-table tr:hover td {
  background-color: #f8fafc;
}

/* Sticky Columns for Full Gradebook */
.grade-table .sticky-col-1 {
  position: sticky;
  left: 0;
  z-index: 5;
  background-color: #ffffff;
  font-weight: 700;
  width: 130px;
  min-width: 130px;
}

.grade-table .sticky-col-2 {
  position: sticky;
  left: 130px;
  z-index: 5;
  background-color: #ffffff;
  font-weight: 600;
  width: 200px;
  min-width: 200px;
  box-shadow: 4px 0 6px -2px rgba(0, 0, 0, 0.05);
}

.grade-table th.sticky-col-1,
.grade-table th.sticky-col-2 {
  z-index: 15;
  background-color: #f1f5f9;
}

/* Grade Input Box */
.grade-input-cell {
  position: relative;
  min-width: 110px;
  text-align: center;
}

.grade-input {
  width: 84px;
  height: 44px;
  font-size: 1.15rem;
  font-weight: 800;
  text-align: center;
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-md);
  background-color: #ffffff;
  color: var(--text-main);
  transition: all var(--transition-fast);
  outline: none;
  -webkit-appearance: none;
  margin: 0 auto;
  display: block;
}

.grade-input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-focus);
  background-color: #ffffff;
  transform: scale(1.04);
}

.grade-input.is-graded {
  background-color: #f0fdf4;
  border-color: #86efac;
  color: #15803d;
}

.grade-input.is-graded.is-low,
.grade-input.is-low {
  background-color: #fef2f2;
  border-color: #fca5a5;
  color: #dc2626;
}

.grade-input.is-empty {
  background-color: #fafafa;
  color: var(--text-light);
}

.grade-input.is-invalid {
  border-color: var(--danger);
  background-color: var(--danger-light);
  color: var(--danger-text);
}

.grade-input.is-saving {
  border-color: var(--warning);
  background-color: var(--warning-light);
}

/* Cell Status Dot */
.cell-status-dot {
  position: absolute;
  top: 6px;
  right: 6px;
  width: 7px;
  height: 7px;
  border-radius: 50%;
}
.cell-status-dot.saved { background-color: var(--success); }
.cell-status-dot.saving { background-color: var(--warning); animation: pulse 1s infinite; }
.cell-status-dot.error { background-color: var(--danger); }

@keyframes pulse {
  0% { transform: scale(0.9); opacity: 0.7; }
  50% { transform: scale(1.3); opacity: 1; }
  100% { transform: scale(0.9); opacity: 0.7; }
}

/* Summary / Average Columns */
.grade-table .avg-col {
  background-color: #f8fafc;
  font-weight: 700;
  text-align: center;
}

.grade-table .avg-col.is-low {
  color: #dc2626;
  font-weight: 800;
}

.grade-table .overall-col {
  background: linear-gradient(135deg, #eef2ff 0%, #ede9fe 100%);
  font-weight: 800;
  color: var(--primary);
  text-align: center;
}

.grade-table .overall-col.is-low {
  color: #dc2626;
  background: linear-gradient(135deg, #fef2f2 0%, #fee2e2 100%);
}

/* ==========================================================================
   MOBILE CARD MODE
   ========================================================================== */

.grade-cards-grid {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.student-grade-card {
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: var(--space-3) var(--space-4);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.student-grade-card:focus-within {
  border-color: var(--primary);
  box-shadow: 0 4px 12px rgba(79, 70, 229, 0.15);
}

.student-card-info {
  flex: 1;
  min-width: 0;
}

.student-card-code {
  font-size: 0.8rem;
  font-weight: 800;
  color: var(--primary);
  background-color: var(--primary-light);
  padding: 2px 6px;
  border-radius: 4px;
  display: inline-block;
  margin-bottom: 2px;
}

.student-card-name {
  font-size: var(--font-size-sm);
  font-weight: 700;
  color: var(--text-main);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.student-card-email {
  font-size: var(--font-size-xs);
  color: var(--text-muted);
}

.student-card-input-wrap {
  width: 90px;
  flex-shrink: 0;
}

/* ==========================================================================
   STICKY BOTTOM ACTION BAR (MOBILE FIRST)
   ========================================================================== */

.grade-bottom-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background-color: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(10px);
  border-top: 1.5px solid var(--border-color);
  padding: 0.75rem var(--space-6);
  box-shadow: 0 -4px 15px rgba(0, 0, 0, 0.08);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.bottom-bar-left {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.current-col-pill {
  font-weight: 800;
  font-size: var(--font-size-sm);
  color: #ffffff;
  background: linear-gradient(135deg, var(--primary) 0%, #6366f1 100%);
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-full);
}

.grading-progress-badge {
  font-size: var(--font-size-xs);
  font-weight: 700;
  color: var(--text-main);
  background-color: var(--bg-surface-secondary);
  padding: 0.35rem 0.65rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.bottom-bar-center {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.auto-save-indicator {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: var(--font-size-xs);
  font-weight: 600;
  padding: 0.3rem 0.65rem;
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
}

.auto-save-indicator.saved {
  background-color: var(--success-light);
  color: var(--success-text);
}

.auto-save-indicator.saving {
  background-color: var(--warning-light);
  color: var(--warning-text);
}

.auto-save-indicator.error {
  background-color: var(--danger-light);
  color: var(--danger-text);
}

.bottom-bar-right {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* Column Visibility Popover */
.columns-checkbox-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
  gap: var(--space-3);
  margin-top: var(--space-3);
}

.col-checkbox-label {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: var(--font-size-xs);
  font-weight: 600;
  cursor: pointer;
  background-color: #ffffff;
  transition: all var(--transition-fast);
}

.col-checkbox-label:hover {
  background-color: var(--primary-light);
  border-color: var(--primary);
}

.col-checkbox-label input[type="checkbox"]:checked + span {
  color: var(--primary);
  font-weight: 700;
}