Admin CSS MU is a versatile WordPress plugin designed for developers looking to customize the appearance of the WordPress Admin interface. It is compatible with both single installations and multisite setups, making it a flexible option for various WordPress environments. The plugin features a user-friendly Admin interface accessible through the Appearance menu, allowing users to easily add and manage their custom CSS styles.

The latest version, 2.0, incorporates CSSTidy to optimize CSS code by cleaning and optionally minifying it, ensuring that the styles are efficient and easy to maintain. While the editor displays un-minified CSS for straightforward editing, the plugin automatically minifies the CSS for better performance. For users interested in adding custom styles to the Login and Front-end areas as well, a separate plugin is available that caters to those needs.