Modifying Theme's Slider

I am not a techie so please be specific.

Problem:
Producto Theme: My slider on the front page looks great. I can also input the Nivo slider into the sidebar no problem. I can change the size of the slides inside the nivo slider. HOWEVER, the outline of the entire slider is the same size as the home page slider. The outline is huge when I want it small and snug to the slides.

Question:
How do I override the formatting of th theme to make the slider shell outline not show and fit snug against the slides?

I realize that I will need to add some code such as, “padding=0” but I don’t know exactly where to place it. I’d prefer to simply over ride the existing styles for this one instance at the page insert level. Does this make any sense? Help would be great!