Click group name (Natural/Global/Civilization...) to collapse/expand
▸ Highlight mode
Double-click any axis → highlight it, others dimmed Double-click again to exit
▸ Highlight opacity
When active, drag the slider to adjust background opacity (0%~50%)
💡 Example: Compare civilizations & religions
1. Click era jump at bottom → "Pre-civilization" 2. Click "Show All" to expand all axes 3. Click "Collapse All" to close all groups 4. Expand only "Civilization" group 5. Then expand "Religion" group
→ Only civilization & religion axes remain visible!