Remove bullets from Category Grid View Plugin

I am using the Mantra theme. I want to have bullets shown on my posts, but I also want to be able to use the Category Grid View Plugin. This plugin works like a list, so there are bullets showing on my pages using this plugin. I know that the bullet is an image. I tried adding:
list-style-type: none !important;
to the css style sheet of the plugin, but it doesn’t do anything. Is there a way to remove the bullets from the pages using the other plugin while still keeping the bullets in my main posts being formatted by this theme?