/* ============================================================
   AI DIFF VIEWER — Side by Side
   ============================================================ */
.diff-container {
  display: flex;
  gap: 1rem;
  animation: fadeIn 0.2s ease;
}
.diff-pane {
  flex: 1;
  min-width: 0;
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}
.diff-pane-header {
  padding: 0.5rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  font-family: var(--font-heading);
  text-transform: uppercase;
  letter-spacing: 0.03em;
  border-bottom: 1px solid var(--surface-border);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}
.diff-pane-old .diff-pane-header {
  background: var(--diff-del);
  color: var(--danger);
}
.diff-pane-new .diff-pane-header {
  background: var(--diff-add);
  color: var(--success);
}
.diff-pane-body {
  padding: 0.65rem 0.75rem;
  font-size: 0.82rem;
  line-height: 1.65;
  max-height: 300px;
  overflow-y: auto;
  background: var(--bg-surface);
  white-space: pre-wrap;
  word-break: break-word;
  color: var(--text-secondary);
}
.diff-pane-old .diff-pane-body { background: rgba(239, 68, 68, 0.04); }
.diff-pane-new .diff-pane-body { background: rgba(34, 197, 94, 0.04); }

.diff-del {
  background: var(--diff-del-word);
  color: var(--danger);
  border-radius: 2px;
  padding: 0.05em 0.1em;
  text-decoration: line-through;
  text-decoration-color: rgba(239, 68, 68, 0.5);
}
.diff-add {
  background: var(--diff-add-word);
  color: var(--success);
  border-radius: 2px;
  padding: 0.05em 0.1em;
}

.diff-empty {
  color: var(--text-muted);
  font-style: italic;
}

.diff-legend {
  display: flex;
  gap: 1rem;
  margin-bottom: 0.75rem;
  font-size: 0.72rem;
  color: var(--text-muted);
}
.diff-legend span {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}
.diff-legend .diff-del {
  text-decoration: none;
  font-size: 0.68rem;
}
.diff-legend .diff-add {
  font-size: 0.68rem;
}