delete search box

I wanted to get rid of a search box that was in the top-right corner of my pages. I went to appearance/widgets, then I deleted the search-box. Once I deleted the search-box i was left with a box that says, “in archives.” I went to firebug but to mess around with it, but I am not seeing the css rule to delete this box. How do i add custom css to delete this in archive box? Is there a way on firebug to get the custom css?

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