Default Styling

Hi, when i type the accordion shortcode, there are odd grey colored small rectangles in the beginning and ending of the accordion block. can i get rid of them? I am working on a custom theme locally on my computer; here is a screenshot:

http://i.imgur.com/kpYekUg.png?1

any help will be much appreciated, Thank-you.

https://ww.wp.xz.cn/plugins/accordion-shortcodes/