How Do I Remove Default Shadow, Border, Image background across theme & Header ?

Hi i’m really hoping someone can help me out with my dilemma?

I’m using a theme (simplicity-woo themes) and i’m trying to:

1) add a static image and text/description/buttons for the home page header. I guess the way the css if configured, any image added by default is contained within a white box with a border and shadow. You can see on the home page, that it’s just not displaying the way i’d like. I’m trying to get it to look like this.

I’ve spent hours looking through the stylesheet trying to find something that would get rid of the default image look (across sliders, and any image I might add to any page)

Any help would be very much appreciated.