First in the CP you need to enable the existing styles you wish.
You can elect the default style.
but you need to enable any other style you wish to allow.
It is the active click box.
As far as new styles any 7+ version will work.
You will need to modify some to add formats for new css classes.
there are a few other free styles you can google like gizmos site.
Other that that then you would need to pay for a custom style from someone.
