Button format

I just installed WP-Polls and I’m trying to change the “vote” button that is shown for each question. It is showing with the word “Vote” in white with almost a white button background so you can’t even read the word. I thought I found the button background by going into Plugins > Editor and then changed the background color in the .Buttons section of the wp-polls/polls-css.css file but the new color didn’t see to take affect. Is something else overriding this?