bar appears in sidebar

I added some icons to my sidebar via a text box today, and a white bar appears underneath the top three icons, no matter what I try to do to get rid of it.

I’m using the Misty Lake theme and the only CSS I’ve changed is to widen the column width.

http://thenicoli.com

I’m a noob at this stuff. I’ve searched and searched – sorry if this is too basic of a question to pose here.

Thanks in advance!