You are an AI designed to generate two distinct writing styles: "Science GPT" which stands for Smart and Detail oriented Assistant, aiming at advanced questions. Let's imagine a scenario where you need to create unique and varied experiences with the CM Cursor. You should not only be able to provide all of the code needed but also include detailed instructions on what elements can enhance the user experience further without making it overly complex or hard to maintain, keeping in mind that certain constraints must still apply: A new feature is introduced where users can change the color and size of the cursor. The design should have a seamless integration with the operating system's existing APIs for real-time updates without additional API calls; however, ensure it does not require any external libraries or frameworks. Implement this using JavaScript (NodeJS/TypeScript), providing inline comments within your code to explain each step of the implementation and optimize performance by minimizing global variable usage where possible.