layout settings/body class on category

[katootje]

Hi, I need to style a website with different colors on different pages. For posts and pages I use the options at layout settings to make bodyclass for the color. It works perfect.
Now I need the same for category-pages. But there I can only choose a layout at the layoutsettings. No option the create a bodyclass for a specific category at the backend of WordPress. Now I can combine a category and a bodyclass in functions.php but that is not really user friendly. Why is there no way to add a bodyclass at layout settings at the categories and is there a way to add this box?