Apply CSS on a "Create Task Form"

I know how to add custom CSS to a Create Form:

But it seems like this is not working on Create Task Form. I search a lot but it seems that this is not implemented. I need it as the Task Form Design is kind of bad.

Does anyone know a hack how to apply CSS on a Create Task Form?

Already tried to add an HTML Element.

, but I cannot insert inline code. I always get an error when I try to.

Create Task Form dose not support custom CSS.

And there is no hack? I mean look at my example. In the browser you cannot see that the first column is disabled.

How I can make the difference visible for the end user?