Hi chilli,
ajamm is right, please locate this in classialerts_style.css
Code:
#classialerts_container p#cta_desc.note {
margin:0;}
and then add your own CSS to it, the current styling is inherited from the default ClassiPress theme so any styling you add in it will overwrite the inherited styling, ajamm has provided a good example.
Regards,
Mohsin