⚠️ Draw inside inner area (0.5 cm offset). Rules →
🖱️ Drag — Draw inside inner frame
📏 H/V — Lines horizontal or vertical only
🧲 Snap — Connect to points (2 cm)
✏️ Edit — Click line: drag to move, drag endpoint to resize
💡 Draw frame first (4 corners), then dividers. Undo: Ctrl+Z