I updated src/css/custom_shape_menu.css with new styles for a modern look and feel, and I refactored src/CustomShapeMenu.ts to use a new HTML structure for the checkboxes that works with the updated CSS. The menu should now be fully functional with the new design.
moved all CSS from src/CustomShapeMenu.ts to a new file src/css/custom_shape_menu.css and updated the TypeScript file to use the external stylesheet. This improves code organization and maintainability.