/*
 * Reference Panel - Slide-in Side Panel
 * ======================================
 * Right-edge panel for displaying reference information.
 * Used for race traits, class features, spell details, etc.
 *
 * Slides in from the right when opened, includes backdrop overlay.
 */

/* ========================================
 * PANEL CONTAINER
 * ======================================== */

.reference-panel {
  position: fixed;
  top: 0;
  right: 0;
  width: var(--panel-width-default);
  max-width: 90vw;
  height: 100vh;
  background: var(--color-bg-primary);
  border-left: 1px solid var(--color-accent-primary);
  transform: translateX(100%);
  transition: transform var(--transition-slow);
  z-index: var(--z-modal);
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-xl);
}

.reference-panel--open {
  transform: translateX(0);
}

/* ========================================
 * BACKDROP
 * ======================================== */

.reference-panel__backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-slow);
  z-index: calc(var(--z-modal) - 1);
}

.reference-panel__backdrop--visible {
  opacity: 1;
  pointer-events: auto;
}

/* ========================================
 * PANEL HEADER
 * ======================================== */

.reference-panel__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-border-default);
  background: var(--color-bg-secondary);
  flex-shrink: 0;
}

.reference-panel__title {
  font-family: var(--font-mono);
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-bold);
  color: var(--color-accent-primary);
  margin: 0;
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.reference-panel__title-icon {
  font-size: 1.2em;
}

.reference-panel__close {
  background: transparent;
  border: none;
  color: var(--color-text-muted);
  cursor: pointer;
  padding: var(--space-2);
  border-radius: var(--radius-md);
  font-size: var(--font-size-lg);
  line-height: 1;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
}

.reference-panel__close:hover {
  color: var(--color-text-primary);
  background: var(--color-bg-hover);
}

/* ========================================
 * PANEL CONTENT
 * ======================================== */

.reference-panel__content {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
}

/* Custom scrollbar */
.reference-panel__content::-webkit-scrollbar {
  width: var(--scrollbar-width);
}

.reference-panel__content::-webkit-scrollbar-track {
  background: var(--scrollbar-track-color);
}

.reference-panel__content::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb-color);
  border-radius: var(--radius-full);
}

.reference-panel__content::-webkit-scrollbar-thumb:hover {
  background: var(--scrollbar-thumb-hover-color);
}

/* ========================================
 * PANEL SECTIONS
 * ======================================== */

.reference-panel__section {
  padding: var(--space-4);
  border-bottom: 1px solid var(--color-border-subtle);
}

.reference-panel__section:last-child {
  border-bottom: none;
}

.reference-panel__section-title {
  font-size: var(--font-size-xs);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  margin: 0 0 var(--space-3) 0;
}

/* ========================================
 * LOADING STATE
 * ======================================== */

.reference-panel__loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-8);
  color: var(--color-text-muted);
  gap: var(--space-3);
}

.reference-panel__spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--color-border-subtle);
  border-top-color: var(--color-accent-primary);
  border-radius: 50%;
  animation: referencePanelSpin 0.8s linear infinite;
}

.reference-panel__loading-text {
  font-family: var(--font-mono);
  font-size: var(--font-size-sm);
}

/* ========================================
 * EMPTY STATE
 * ======================================== */

.reference-panel__empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-8);
  text-align: center;
  color: var(--color-text-muted);
}

.reference-panel__empty-icon {
  font-size: 2em;
  margin-bottom: var(--space-3);
  opacity: 0.5;
}

.reference-panel__empty-text {
  font-family: var(--font-mono);
  font-size: var(--font-size-sm);
}

/* ========================================
 * HISTORY (breadcrumb navigation)
 * ======================================== */

.reference-panel__history {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: var(--color-bg-tertiary);
  border-bottom: 1px solid var(--color-border-subtle);
  font-family: var(--font-mono);
  font-size: var(--font-size-xs);
  flex-shrink: 0;
}

.reference-panel__history-back {
  background: transparent;
  border: none;
  color: var(--color-accent-primary);
  cursor: pointer;
  padding: var(--space-1);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--font-size-xs);
  transition: all var(--transition-fast);
}

.reference-panel__history-back:hover {
  background: var(--color-bg-hover);
}

.reference-panel__history-back:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.reference-panel__history-current {
  color: var(--color-text-secondary);
}

/* ========================================
 * ANIMATIONS
 * ======================================== */

@keyframes referencePanelSpin {
  to {
    transform: rotate(360deg);
  }
}

/* ========================================
 * RESPONSIVE
 * ======================================== */

@media (max-width: 600px) {
  .reference-panel {
    width: 100vw;
    max-width: none;
  }
}

/* ========================================
 * REDUCED MOTION
 * ======================================== */

@media (prefers-reduced-motion: reduce) {
  .reference-panel {
    transition: none;
  }

  .reference-panel__backdrop {
    transition: none;
  }

  .reference-panel__spinner {
    animation: none;
  }
}