/* ==========================================================================
   Page Panel - Unified container component
   Replaces: .card, .ad-panel, .dashboard-panel, .content-section, .stat-card
   ========================================================================== */

.page-panel {
  background: var(--color-surface);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-card);
  padding: var(--space-6);
  transition: box-shadow var(--transition-base);
}

.page-panel:hover {
  box-shadow: var(--shadow-card-hover);
}

/* Panel Sizes */
.page-panel--sm {
  padding: var(--space-4);
  border-radius: var(--radius-lg);
}

.page-panel--lg {
  padding: var(--space-8);
  border-radius: var(--radius-2xl);
}

/* Panel Variants */
.page-panel--flat {
  box-shadow: none;
  border: 1px solid var(--color-border);
}

.page-panel--flat:hover {
  box-shadow: none;
  border-color: var(--color-border-hover);
}

.page-panel--interactive {
  cursor: pointer;
}

.page-panel--interactive:hover {
  transform: translateY(-2px);
}

/* Panel with accent border */
.page-panel--accent-high {
  border-left: 4px solid var(--color-red);
}

.page-panel--accent-medium {
  border-left: 4px solid var(--color-orange);
}

.page-panel--accent-low {
  border-left: 4px solid var(--color-blue);
}

.page-panel--accent-success {
  border-left: 4px solid var(--color-green);
}

/* Panel Header */
.page-panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}

.page-panel-header--no-margin {
  margin-bottom: 0;
}

.page-panel-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin: 0;
  line-height: var(--line-height-tight);
}

.page-panel-title--sm {
  font-size: var(--font-size-base);
}

.page-panel-title--lg {
  font-size: var(--font-size-xl);
}

.page-panel-subtitle {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-top: var(--space-1);
}

.page-panel-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}

/* Panel Action Link */
.page-panel-action {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-blue);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.page-panel-action:hover {
  color: var(--color-blue-hover);
}

.page-panel-action svg {
  transition: transform var(--transition-fast);
}

.page-panel-action:hover svg {
  transform: translateX(2px);
}

/* Panel Content */
.page-panel-content {
  flex: 1;
}

/* Panel Footer */
.page-panel-footer {
  margin-top: var(--space-4);
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-border-light);
}

/* Panel Divider */
.page-panel-divider {
  border: none;
  border-top: 1px solid var(--color-border-light);
  margin: var(--space-4) 0;
}

/* Metric Panel Variant */
.page-panel--metric {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  min-width: 0;
}

.page-panel--metric:hover {
  transform: translateY(-2px);
}

/* Panel Grid Layouts */
.page-panel-grid {
  display: grid;
  gap: var(--space-4);
}

.page-panel-grid--2 {
  grid-template-columns: repeat(2, 1fr);
}

.page-panel-grid--3 {
  grid-template-columns: repeat(3, 1fr);
}

.page-panel-grid--4 {
  grid-template-columns: repeat(4, 1fr);
}

.page-panel-grid--auto {
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

@media (max-width: 1200px) {
  .page-panel-grid--4,
  .page-panel-grid--3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 640px) {
  .page-panel-grid--4,
  .page-panel-grid--3,
  .page-panel-grid--2 {
    grid-template-columns: 1fr;
  }
}

/* Empty State within Panel */
.page-panel-empty {
  text-align: center;
  padding: var(--space-8) var(--space-6);
}

.page-panel-empty-icon {
  font-size: 48px;
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-4);
}

.page-panel-empty-icon svg {
  stroke: var(--color-text-tertiary);
}

.page-panel-empty-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-2);
}

.page-panel-empty-description {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  max-width: 320px;
  margin: 0 auto;
  line-height: var(--line-height-relaxed);
}

/* Scrollable Panel Content */
.page-panel-scroll {
  max-height: 400px;
  overflow-y: auto;
}

/* Section Spacing for Page Layout */
.page-section {
  margin-bottom: var(--space-6);
}

.page-section:last-child {
  margin-bottom: 0;
}

/* Expandable Panel Content */
.page-panel-expandable {
  border: none;
  padding: 0;
  margin: 0;
}

.page-panel-expandable summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  padding: var(--space-3) 0;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  list-style: none;
  transition: color var(--transition-fast);
}

.page-panel-expandable summary::-webkit-details-marker {
  display: none;
}

.page-panel-expandable summary:hover {
  color: var(--color-text-primary);
}

.page-panel-expandable summary::after {
  content: '';
  width: 16px;
  height: 16px;
  background-image: url("data:image/svg+xml,%3Csvg width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2386868B' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: center;
  transition: transform var(--transition-fast);
}

.page-panel-expandable[open] summary::after {
  transform: rotate(180deg);
}

.page-panel-expandable-content {
  padding-top: var(--space-3);
}

/* Link for "See More" style navigation */
.page-panel-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.page-panel-link:hover {
  color: var(--color-blue);
}

/* AI Panel Modifier */
.page-panel--ai {
  background: linear-gradient(135deg, var(--color-purple-light) 0%, var(--color-surface) 100%);
}

.page-panel--ai .page-panel-title::before {
  content: '';
  display: inline-block;
  width: 8px;
  height: 8px;
  background: var(--color-purple);
  border-radius: 50%;
  margin-right: var(--space-2);
  vertical-align: middle;
}