/* ========================================
 * Course Studio Styles
 * Layout: sidebar (250px) + main content area
 * ======================================== */

.studio {
  display: flex;
  min-height: 100vh;
}

/* --- Sidebar --- */

.studio__sidebar {
  width: 250px;
  flex-shrink: 0;
  background: var(--color-surface, #f8f9fa);
  border-right: 1px solid var(--color-border, #e2e8f0);
  display: flex;
  flex-direction: column;
}

.studio__sidebar-header {
  padding: var(--spacing-md, 1rem) var(--spacing-lg, 1.5rem);
  border-bottom: 1px solid var(--color-border, #e2e8f0);
}

.studio__logo {
  font-weight: 700;
  font-size: var(--font-size-lg);
  color: var(--color-text, #1a202c);
  text-decoration: none;
}

.studio__logo:hover {
  color: var(--color-primary, #3b82f6);
}

.studio__sidebar-nav {
  flex: 1;
  overflow-y: auto;
  padding: var(--spacing-md, 1rem);
}

.studio__sidebar-empty {
  color: var(--color-text-muted, #718096);
  font-size: var(--font-size-sm);
  padding: var(--spacing-sm, 0.5rem);
}

/* --- Main area --- */

.studio__main {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.studio__header {
  padding: var(--spacing-sm, 0.5rem) var(--spacing-lg, 1.5rem);
  border-bottom: 1px solid var(--color-border, #e2e8f0);
  background: var(--color-background, #fff);
}

.studio__breadcrumbs ol {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: var(--font-size-sm);
}

.studio__breadcrumbs li:not(:last-child)::after {
  content: '/';
  margin-left: 0.5rem;
  color: var(--color-text-muted, #718096);
}

.studio__breadcrumbs a {
  color: var(--color-primary, #3b82f6);
  text-decoration: none;
}

.studio__breadcrumbs a:hover {
  text-decoration: underline;
}

.studio__breadcrumbs span[aria-current='page'] {
  color: var(--color-text, #1a202c);
  font-weight: 500;
}

.studio__content {
  flex: 1;
  padding: var(--spacing-lg, 1.5rem);
}

/* --- Dashboard cards --- */

.studio__empty {
  color: var(--color-text-muted, #718096);
  font-size: var(--font-size-base);
}

.studio-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--spacing-lg, 1.5rem);
  margin-top: var(--spacing-lg, 1.5rem);
}

.studio-card {
  display: block;
  padding: var(--spacing-lg, 1.5rem);
  border: 1px solid var(--color-border, #e2e8f0);
  border-radius: 8px;
  background: var(--color-background, #fff);
  text-decoration: none;
  color: var(--color-text, #1a202c);
  transition: border-color 0.15s, box-shadow 0.15s;
}

.studio-card:hover {
  border-color: var(--color-primary, #3b82f6);
  box-shadow: var(--shadow-md);
}

.studio-card__lang {
  display: inline-block;
  font-size: var(--font-size-caption);
  font-weight: 600;
  letter-spacing: 0.05em;
  color: var(--color-primary, #3b82f6);
  background: var(--color-surface, #f8f9fa);
  padding: 0.125rem 0.5rem;
  border-radius: 4px;
  margin-bottom: var(--spacing-sm, 0.5rem);
}

.studio-card__title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin: 0 0 var(--spacing-md, 1rem);
  line-height: 1.3;
}

.studio-card__stats {
  display: flex;
  gap: var(--spacing-md, 1rem);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted, #718096);
}

/* --- Mobile: collapsible sidebar --- */

@media (max-width: 768px) {
  .studio {
    flex-direction: column;
  }

  .studio__sidebar {
    width: 100%;
    max-height: 50vh;
    overflow-y: auto;
    border-right: none;
    border-bottom: 1px solid var(--color-border, #e2e8f0);
  }
}

/* =============================================================================
   Slide Preview (#509)
   ============================================================================= */

.studio-slide-header {
  margin-bottom: 1rem;
}

.studio-slide-file {
  color: var(--color-text-muted, #64748b);
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
}

.studio-slide-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.studio-slide-meta-tag {
  background: var(--color-surface-alt, #f1f5f9);
  border-radius: 4px;
  padding: 0.25rem 0.5rem;
  font-size: var(--font-size-caption);
  color: var(--color-text-muted, #64748b);
}

.studio-preview {
  border: 2px solid var(--color-border, #e2e8f0);
  border-radius: 8px;
  margin-bottom: 1.5rem;
  overflow: hidden;
}

.studio-preview-label {
  background: var(--color-surface-alt, #f1f5f9);
  padding: 0.5rem 1rem;
  font-size: var(--font-size-caption);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted, #64748b);
  border-bottom: 1px solid var(--color-border, #e2e8f0);
}

.studio-preview-content {
  padding: 2rem;
  max-width: none;
}

.studio-preview-error {
  background: var(--color-error-bg, #fef2f2);
  border: 1px solid var(--color-error, #ef4444);
  border-radius: 8px;
  padding: 1rem;
  margin-bottom: 1rem;
}

.studio-preview-raw {
  white-space: pre-wrap;
  word-break: break-word;
  font-size: var(--font-size-sm);
}

.studio-slide-source {
  margin-bottom: 1.5rem;
}

.studio-slide-source summary {
  cursor: pointer;
  font-weight: 500;
  padding: 0.5rem 0;
  color: var(--color-text-muted, #64748b);
}

.studio-slide-source pre {
  background: var(--color-surface-alt, #f1f5f9);
  border-radius: 8px;
  padding: 1rem;
  overflow-x: auto;
  font-size: var(--font-size-sm);
  line-height: 1.6;
}

.studio-slide-nav {
  display: flex;
  justify-content: space-between;
  padding: 1rem 0;
  border-top: 1px solid var(--color-border, #e2e8f0);
}

.studio-nav-link {
  color: var(--color-primary, #3b82f6);
  text-decoration: none;
  font-weight: 500;
}

.studio-nav-link:hover {
  text-decoration: underline;
}
/* ========================================
 * Studio Sidebar Tree
 * ======================================== */
.studio-tree {
  font-size: var(--font-size-sm);
.studio-tree__loading,
.studio-tree__error {
  padding: var(--spacing-sm, 0.5rem);
  color: var(--color-text-muted, #718096);
  font-size: var(--font-size-sm);
.studio-tree__error {
  color: var(--color-danger, #e53e3e);
}

.studio-tree__retry-btn {
  margin-top: 0.5rem;
  padding: 0.25rem 0.75rem;
  font-size: var(--font-size-sm);
  border: 1px solid var(--color-danger, #e53e3e);
  border-radius: 4px;
  background: transparent;
  color: var(--color-danger, #e53e3e);
  cursor: pointer;
}

.studio-tree__retry-btn:hover {
  background: var(--color-danger, #e53e3e);
  color: var(--color-text-inverse);
/* Module button */
.studio-tree__module-btn,
.studio-tree__lesson-btn {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  width: 100%;
  padding: 0.375rem 0.5rem;
  border: none;
  background: none;
  cursor: pointer;
  font: inherit;
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text, #1a202c);
  text-align: left;
.studio-tree__module-btn:hover,
.studio-tree__lesson-btn:hover {
  background: var(--color-hover, rgba(0, 0, 0, 0.04));
.studio-tree__module-btn:focus-visible,
.studio-tree__lesson-btn:focus-visible {
  outline: 2px solid var(--color-primary, #3b82f6);
  outline-offset: -2px;
.studio-tree__lesson-btn {
  font-weight: 500;
  padding-left: 1.25rem;
.studio-tree__chevron {
  flex-shrink: 0;
  width: 0.75rem;
  font-size: var(--font-size-caption);
  color: var(--color-text-muted, #718096);
.studio-tree__icon {
  flex-shrink: 0;
  font-size: var(--font-size-sm);
.studio-tree__label {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
/* Lessons group */
.studio-tree__lessons {
  margin-left: 0.25rem;
  border-left: 1px solid var(--color-border, #e2e8f0);
  padding-left: 0.25rem;
/* Slides list */
.studio-tree__slides {
  list-style: none;
  margin: 0;
  padding: 0 0 0 1.5rem;
.studio-tree__slide-link {
  align-items: center;
  gap: 0.375rem;
  padding: 0.25rem 0.5rem;
  color: var(--color-text, #1a202c);
  text-decoration: none;
  border-radius: 4px;
  font-size: var(--font-size-sm);
.studio-tree__slide-link:hover {
  background: var(--color-hover, rgba(0, 0, 0, 0.04));
}

.studio-tree__slide--active .studio-tree__slide-link {
  background: var(--color-primary-light, #ebf5ff);
  font-weight: 600;
}

.studio-tree__slide-link:focus-visible {
  outline: 2px solid var(--color-primary, #3b82f6);
  outline-offset: -2px;
/* Module spacing */
.studio-tree__module + .studio-tree__module {
  margin-top: 0.25rem;
/* --- Slide View --- */
.studio-slide__path {
  margin-bottom: var(--spacing-md, 1rem);
.studio-slide__toggle {
  gap: 0;
  margin-bottom: var(--spacing-md, 1rem);
  border: 1px solid var(--color-border, #e2e8f0);
  border-radius: 6px;
  width: fit-content;
.studio-slide__toggle-btn {
  padding: 0.375rem 1rem;
  font-size: var(--font-size-sm);
  font-weight: 500;
  border: none;
  background: var(--color-background, #fff);
  color: var(--color-text-muted, #718096);
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
.studio-slide__toggle-btn:not(:last-child) {
  border-right: 1px solid var(--color-border, #e2e8f0);
.studio-slide__toggle-btn--active {
  background: var(--color-primary, #3b82f6);
  color: var(--color-text-inverse);
.studio-slide__toggle-btn:hover:not(.studio-slide__toggle-btn--active) {
  background: var(--color-surface, #f8f9fa);
.studio-slide__content {
  min-height: 200px;
  margin-bottom: var(--spacing-lg, 1.5rem);
.studio-slide__toggle {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
}
.studio-slide__source {
  background: var(--color-code-bg, #1e1e2e);
  color: var(--color-code-text, #cdd6f4);
  padding: var(--spacing-md, 1rem);
  font-size: var(--font-size-sm);
  font-family: var(--font-family-mono);
  white-space: pre-wrap;
  word-break: break-word;
}
.studio-slide__source-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-left: 1rem;
}
.studio-slide__save-btn {
  padding: 0.375rem 1rem;
  font-size: var(--font-size-sm);
  font-weight: 600;
  border: none;
  border-radius: 4px;
  background: var(--color-primary, #3b82f6);
  color: var(--color-text-inverse);
  cursor: pointer;
  transition: opacity 0.15s;
}
.studio-slide__save-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}
.studio-slide__save-btn:hover:not(:disabled) {
  opacity: 0.85;
}
.studio-slide__dirty-indicator {
  font-size: var(--font-size-caption);
  color: var(--color-warning, #f59e0b);
}
.studio-slide__message {
  font-size: var(--font-size-caption);
  font-weight: 500;
}
.studio-slide__message--success {
  color: var(--color-success, #22c55e);
}
.studio-slide__message--error {
  color: var(--color-error, #ef4444);
}
.studio-slide__source-editor {
  display: block;
  width: 100%;
  min-height: 400px;
  padding: var(--spacing-md, 1rem);
  background: var(--color-code-bg, #1e1e2e);
  color: var(--color-code-text, #cdd6f4);
  border: 1px solid var(--color-code-border, var(--color-border));
  border-radius: 6px;
  font-size: var(--font-size-sm);
  font-family: var(--font-family-mono);
  line-height: 1.6;
  resize: vertical;
  tab-size: 2;
  white-space: pre;
  overflow-x: auto;
  box-sizing: border-box;
}
.studio-slide__nav {
  align-items: center;
  padding-top: var(--spacing-md, 1rem);
  gap: var(--spacing-sm, 0.5rem);
.studio-slide__nav-btn {
  font-size: var(--font-size-sm);
  padding: 0.5rem 0.75rem;
  border-radius: 6px;
  transition: background 0.15s;
.studio-slide__nav-btn:hover {
  background: var(--color-surface, #f8f9fa);

.studio-slide__nav-btn--disabled {
  opacity: 0.5;
  pointer-events: none;
.studio-slide__nav-info {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted, #718096);
/* --- Mobile: collapsible sidebar --- */

@media (max-width: 768px) {
  .studio {
    flex-direction: column;
  }

  .studio__sidebar {
    width: 100%;
    max-height: 50vh;
    overflow-y: auto;
    border-right: none;
    border-bottom: 1px solid var(--color-border, #e2e8f0);
  }
}

/* --- Review Panel --- */

.review-panel {
  margin-top: 1.5rem;
  border: 1px solid var(--color-border, #e2e8f0);
  border-radius: 8px;
  overflow: hidden;
}

.review-panel__toggle {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  width: 100%;
  padding: 0.75rem 1rem;
  background: var(--color-bg-subtle, #f7fafc);
  border: none;
  cursor: pointer;
  font-size: var(--font-size-base);
  font-weight: 600;
  color: var(--color-text, #1a202c);
  text-align: left;
}

.review-panel__toggle:hover {
  background: var(--color-bg-muted, #edf2f7);
}

.review-panel__toggle-icon {
  font-size: var(--font-size-caption);
  color: var(--color-text-muted, #718096);
}

.review-panel__content {
  padding: 1rem;
  border-top: 1px solid var(--color-border, #e2e8f0);
}

.review-panel__controls {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 1rem;
}

.review-panel__select {
  flex: 1;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--color-border, #e2e8f0);
  border-radius: 6px;
  font-size: var(--font-size-sm);
  background: var(--color-bg, #fff);
  color: var(--color-text, #1a202c);
}

.review-panel__run-btn {
  padding: 0.5rem 1rem;
  background: var(--color-primary, #3182ce);
  color: var(--color-text-inverse);
  border: none;
  border-radius: 6px;
  font-size: var(--font-size-sm);
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
}

.review-panel__run-btn:hover:not(:disabled) {
  background: var(--color-primary-dark, #2b6cb0);
}

.review-panel__run-btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.review-panel__spinner {
  animation: review-spin 1s linear infinite;
  display: inline-block;
}

@keyframes review-spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.review-panel__error {
  padding: 0.75rem 1rem;
  background: var(--color-error-bg);
  color: var(--color-error);
  border-radius: 6px;
  font-size: var(--font-size-sm);
  margin-bottom: 1rem;
}

.review-panel__results {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.review-card {
  border: 1px solid var(--color-border, #e2e8f0);
  border-radius: 8px;
  padding: 1rem;
  background: var(--color-bg, #fff);
}

.review-card__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}

.review-card__agent {
  display: flex;
  flex-direction: column;
  gap: 0.125rem;
}

.review-card__role {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted, #718096);
}

.review-rating {
  font-size: var(--font-size-sm);
}

.review-star {
  color: var(--color-text-muted);
}

.review-star--filled {
  color: var(--color-warning);
}

.review-rating-num {
  margin-left: 0.25rem;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted, #718096);
}

.review-card__feedback {
  font-size: var(--font-size-sm);
  line-height: 1.5;
  color: var(--color-text, #1a202c);
  margin: 0 0 0.75rem;
}

.review-card__suggestions h4 {
  font-size: var(--font-size-sm);
  font-weight: 600;
  margin: 0 0 0.5rem;
  color: var(--color-text-muted, #718096);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.review-card__suggestions ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.review-suggestion {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  background: var(--color-bg-subtle, #f7fafc);
  border-radius: 6px;
  font-size: var(--font-size-sm);
}

.review-suggestion__diff {
  flex: 1;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.review-suggestion__original {
  text-decoration: line-through;
  color: var(--color-error);
}

.review-suggestion__arrow {
  color: var(--color-text-muted, #718096);
}

.review-suggestion__suggested {
  color: var(--color-success);
  font-weight: 500;
}

/* --- Error Pages & Empty States --- */

.studio-error-page {
  text-align: center;
  padding: 3rem 1rem;
  max-width: 480px;
  margin: 0 auto;
}

.studio-error-page__link {
  display: inline-block;
  margin-top: 1.5rem;
  padding: 0.5rem 1.25rem;
  background: var(--color-primary, #3b82f6);
  color: var(--color-text-inverse);
  border-radius: 6px;
  text-decoration: none;
  font-weight: 500;
  font-size: var(--font-size-sm);
}

.studio-error-page__link:hover {
  background: var(--color-primary-dark, #2563eb);
}

.studio-empty-state {
  text-align: center;
  padding: 3rem 1rem;
  color: var(--color-text-muted, #718096);
}

.studio-empty-state__icon {
  font-size: 2.5rem;
  margin: 0 0 0.75rem;
}

.studio-empty-state__text {
  font-size: var(--font-size-base);
  margin: 0;
}

/* --- Loading Spinner --- */

.studio-loading-spinner {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
}

.studio-loading-spinner::after {
  content: '';
  width: 1.5rem;
  height: 1.5rem;
  border: 2px solid var(--color-border, #e2e8f0);
  border-top-color: var(--color-primary, #3b82f6);
  border-radius: 50%;
  animation: studio-spin 0.6s linear infinite;
}

@keyframes studio-spin {
  to { transform: rotate(360deg); }
}

/* --- Review retry --- */

.review-panel__retry-btn {
  margin-left: 0.75rem;
  padding: 0.25rem 0.75rem;
  font-size: var(--font-size-sm);
  border: 1px solid var(--color-error);
  border-radius: 4px;
  background: transparent;
  color: var(--color-error);
  cursor: pointer;
}

.review-panel__retry-btn:hover {
  background: var(--color-error);
  color: var(--color-text-inverse);
}

.review-suggestion__apply {
  padding: 0.25rem 0.5rem;
  font-size: var(--font-size-caption);
  border: 1px solid var(--color-border, #e2e8f0);
  border-radius: 4px;
  background: var(--color-bg, #fff);
  cursor: not-allowed;
  opacity: 0.5;
  white-space: nowrap;
}

/* ==========================================================================
   Studio Edit Dialog (#517, #518)
   ========================================================================== */

.studio-edit-float-btn {
  position: absolute;
  z-index: 1000;
  transform: translateX(-50%);
  background: var(--color-primary, #6366f1);
  color: var(--color-text-inverse);
  border: none;
  border-radius: 6px;
  padding: 4px 12px;
  font-size: var(--font-size-caption);
  font-weight: 600;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  white-space: nowrap;
}
.studio-edit-float-btn:hover {
  background: var(--color-primary-dark, #4f46e5);
}

.studio-edit-overlay {
  position: fixed;
  inset: 0;
  z-index: 2000;
  background: var(--color-overlay-dark);
  display: flex;
  align-items: center;
  justify-content: center;
}

.studio-edit-dialog {
  background: var(--color-surface, #fff);
  border-radius: 12px;
  box-shadow: var(--shadow-lg);
  width: min(560px, 90vw);
  max-height: 80vh;
  overflow-y: auto;
  padding: 1.5rem;
}

.studio-edit-dialog-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}
.studio-edit-dialog-header h3 {
  margin: 0;
  font-size: 1.1rem;
}
.studio-edit-close {
  background: none;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  color: var(--color-text-muted, #666);
  padding: 4px 8px;
  border-radius: 4px;
}
.studio-edit-close:hover {
  background: var(--color-bg-hover, #f3f4f6);
}

.studio-edit-selected label,
.studio-edit-prompt-section label,
.studio-edit-diff-section label {
  display: block;
  font-size: var(--font-size-caption);
  font-weight: 600;
  color: var(--color-text-muted, #666);
  margin-bottom: 0.4rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.studio-edit-selected-box {
  background: var(--color-bg-alt, #f9fafb);
  border: 1px solid var(--color-border, #e5e7eb);
  border-radius: 6px;
  padding: 0.75rem;
  font-size: var(--font-size-sm);
  line-height: 1.5;
  max-height: 120px;
  overflow-y: auto;
  white-space: pre-wrap;
  margin-bottom: 1rem;
}

.studio-edit-prompt {
  width: 100%;
  border: 1px solid var(--color-border, #e5e7eb);
  border-radius: 6px;
  padding: 0.6rem 0.75rem;
  font-size: var(--font-size-sm);
  font-family: inherit;
  resize: vertical;
  box-sizing: border-box;
}
.studio-edit-prompt:focus {
  outline: none;
  border-color: var(--color-primary, #6366f1);
  box-shadow: 0 0 0 2px rgba(99,102,241,0.15);
}

.studio-edit-generate-btn {
  margin-top: 0.75rem;
  background: var(--color-primary, #6366f1);
  color: var(--color-text-inverse);
  border: none;
  border-radius: 6px;
  padding: 0.5rem 1.25rem;
  font-size: var(--font-size-sm);
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}
.studio-edit-generate-btn:hover:not(:disabled) {
  background: var(--color-primary-dark, #4f46e5);
}
.studio-edit-generate-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.studio-edit-spinner {
  display: inline-block;
  width: 14px;
  height: 14px;
  border: 2px solid var(--color-overlay-light);
  border-top-color: var(--color-text-inverse);
  border-radius: 50%;
  animation: studio-edit-spin 0.6s linear infinite;
}
@keyframes studio-edit-spin {
  to { transform: rotate(360deg); }
}

.studio-edit-error {
  background: var(--color-error-bg);
  color: var(--color-error);
  border: 1px solid var(--color-error);
  border-radius: 6px;
  padding: 0.6rem 0.75rem;
  font-size: var(--font-size-sm);
  margin-top: 0.75rem;
}

.studio-edit-success {
  background: var(--color-success-bg);
  color: var(--color-success);
  border: 1px solid var(--color-success);
  border-radius: 6px;
  padding: 0.75rem;
  font-size: var(--font-size-sm);
  font-weight: 600;
  text-align: center;
  margin-top: 0.75rem;
}

.studio-edit-diff-section {
  margin-top: 1rem;
}

.studio-edit-diff {
  background: var(--color-bg-alt, #f9fafb);
  border: 1px solid var(--color-border, #e5e7eb);
  border-radius: 6px;
  overflow: hidden;
  font-family: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
  font-size: 0.82rem;
  line-height: 1.6;
  max-height: 300px;
  overflow-y: auto;
}

.studio-edit-diff-line {
  display: flex;
  padding: 0 0.75rem;
  min-height: 1.6em;
}

.studio-edit-diff-marker {
  flex-shrink: 0;
  width: 1.5em;
  text-align: center;
  user-select: none;
  font-weight: 700;
}

.studio-edit-diff-removed {
  background: var(--color-error-bg);
  color: var(--color-error-text, var(--color-error));
  text-decoration: line-through;
}
.studio-edit-diff-removed .studio-edit-diff-marker { color: var(--color-error); }

.studio-edit-diff-added {
  background: var(--color-success-bg);
  color: var(--color-success);
}
.studio-edit-diff-added .studio-edit-diff-marker { color: var(--color-success); }

.studio-edit-diff-unchanged {
  color: var(--color-text-muted, #666);
}

.studio-edit-actions {
  display: flex;
  gap: 0.75rem;
  margin-top: 1rem;
}

.studio-edit-accept-btn {
  background: var(--color-success);
  color: var(--color-text-inverse);
  border: none;
  border-radius: 6px;
  padding: 0.5rem 1.25rem;
  font-size: var(--font-size-sm);
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}
.studio-edit-accept-btn:hover:not(:disabled) {
  background: var(--color-success);
}
.studio-edit-accept-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.studio-edit-reject-btn {
  background: transparent;
  color: var(--color-text-muted, #666);
  border: 1px solid var(--color-border, #e5e7eb);
  border-radius: 6px;
  padding: 0.5rem 1.25rem;
  font-size: var(--font-size-sm);
  font-weight: 600;
  cursor: pointer;
}
.studio-edit-reject-btn:hover {
  background: var(--color-bg-hover, #f3f4f6);
  color: var(--color-text, #111);
}

/* ==========================================================================
   History Panel
   ========================================================================== */

.history-panel {
  margin-top: 1.5rem;
  border: 1px solid var(--color-border, #e5e7eb);
  border-radius: 8px;
  overflow: hidden;
}

.history-panel__toggle {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  width: 100%;
  padding: 0.75rem 1rem;
  background: var(--color-bg-secondary, #f9fafb);
  border: none;
  cursor: pointer;
  font-size: var(--font-size-base);
  font-weight: 600;
  color: var(--color-text, #111);
  text-align: left;
}

.history-panel__toggle:hover {
  background: var(--color-bg-hover, #f3f4f6);
}

.history-panel__toggle-icon {
  font-size: var(--font-size-caption);
  width: 1rem;
  text-align: center;
}

.history-panel__content {
  padding: 0.75rem 1rem;
  border-top: 1px solid var(--color-border, #e5e7eb);
}

.history-panel__loading,
.history-panel__empty {
  color: var(--color-text-muted, #6b7280);
  font-size: var(--font-size-sm);
  padding: 0.5rem 0;
}

.history-panel__error {
  color: var(--color-danger, #dc2626);
  font-size: var(--font-size-sm);
  padding: 0.5rem 0;
}

.history-panel__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.history-commit {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  padding: 0.4rem 0;
  border-bottom: 1px solid var(--color-border, #e5e7eb);
  font-size: var(--font-size-sm);
}

.history-commit:last-child {
  border-bottom: none;
}

.history-commit__hash {
  font-family: var(--font-mono, monospace);
  font-size: var(--font-size-caption);
  background: var(--color-bg-secondary, #f3f4f6);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  white-space: nowrap;
  color: var(--color-primary, #2563eb);
}

.history-commit__message {
  flex: 1;
  color: var(--color-text, #111);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.history-commit__date {
  color: var(--color-text-muted, #6b7280);
  font-size: var(--font-size-caption);
  white-space: nowrap;
}