Can you create a custom Dashboard view rules and modify it's colour?

I am doing a dashboard and would like to change the colour of the data depending on the data.

I know I can use the view rules and set the style to either OK, Warning, Error, Highlight.

I wondered if you can create custom ones and then amend them in the Runtime Styler?

It looks as if you can create something under Style filter manager but I can't seem to modify this in the runtime styler that will have any affect on the dashboard?

Any help would be greatly appreciated..