Product and Category Management System

Create a user interface for a product and category management system. The interface should allow users (sellers) to add, edit, and delete products and categories. Each product should have fields for its name, description, price, stock quantity, and an option to upload an image. Additionally, the user should be able to assign the product to one or more categories. For the categories, provide fields for the category name and a list of associated products. The design should be clean, intuitive, and easy to navigate, with clear buttons for actions like 'Save', 'Cancel', 'Edit', and 'Delete'.