how to override styles?

On this page , using Gravity Forms, what should be + signs are showing as gray boxes, instead. They worked fine before we changed to Enfold theme.

There are some at the bottom (it’s what looks like a gray box now; it should be a + sign.

Please list the qualities that your ideal dog would have, in order of importance (most to least):

Add a row
(click + to add new rows)

this is the rule that is no longer working: img.add_list_item {
background-image: url(data:image/svg+xml;base64,PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0idXRmLTgiP…R2LTk2aC05NnYtNjRoOTZ2LTk2aDY0djk2aDk2djY0aC05NnY5NnoiPjwvcGF0aD48L3N2Zz4=);
}