Horizontal lines

I have a three-column template I am trying to use, and I put the widget in one of the narrower sidebar columns. It created horizontal lines all the way across the webpage, cutting across the main body of the site, too. Can you fix this? I looked around in the CSS and couldn’t find anything obvious. Help!

backyardbookkeeper.com/wordpress

https://www.ads-software.com/extend/plugins/simple-contact-info/