By adding an event listener for DOMContentLoaded, the code now runs only after the DOM is fully loaded, ensuring that all elements are available for manipulation. Frequently accessed DOM elements are cached in variables to avoid multiple queries, improving efficiency. The loops have been optimized using forEach with an index to assign colors directly, which ensures the color array wraps correctly. Event handling has been made consistent by using addEventListener for attaching all event listeners. Additionally, the use of closest simplifies DOM traversal, enhancing readability and efficiency.