Nice, but broken border

This is a nifty little plugin, but on my website it displays with a default dashed border on three sides but not on the bottom, which looks unbalanced.

Tried turning it off, but can’t find the proper code section. It’s driving me bats, I may have to look for another plugin, much as I like the simplicity of this one.

https://ww.wp.xz.cn/plugins/vertically-scroll-rss-feed/