Toggling CSS classes is fundamental for creating interactive UI elements like dropdown menus, modal dialogs, and state-based styling. With over 25 years of experience in software development and as the creator of CoreUI, I’ve implemented class toggling in numerous interactive components and animation systems. From my expertise, the most efficient approach is using the classList.toggle() method which adds the class if absent or removes it if present. This method provides clean, readable code while handling the conditional logic automatically.