The Colloquy IRC client offers a stylish and minimalist design for a clean and modern user experience. Its theme is simple and easy on the eyes, allowing users to focus on their conversations without any distractions.
Installing Clean is easy and straightforward. First, unzip the file and then move it to the following location: ~/Library/Application Support/Colloquy/Styles/. If this folder doesn't exist, simply create it. After that, head to Preferences -> Appearance, and select the new Style from the Default Style drop-down.
When you're in a chat room, you can use the Style drop-down menu on the toolbar and re-select Default to apply the new theme. If you don't want to use it as a default but only for specific rooms, simply select the Style from the Style drop-down menu in the toolbar, as needed.
Overall, Clean is an excellent Colloquy IRC client theme that's easy to install and offers a clean and organized chat interface. If you're looking for something simple yet effective, this one is worth a try.