Twitter icon disappeared after updating theme

Hello,

The blue Twitter icon disappeared after updating to the new Enfold theme. If I scroll over it, the box is still there on the top right just above the main menu on my homepage as it should be, but the Twitter icon is not visible. I can still press on the invisible box and go to my Twitter page.

Hylandgraphics in the forum suggested using the following code to fix the issue via the dashboard. However, I’m not sure where to place the code as I’m not a programmer. A copy of the code is below.

/* enfold social media icons fix */
.social_bookmarks_twitter a::before, .av-social-link-twitter a::before {
font-family: ‘entypo-fontello’;
content: ‘’;
}

Any ideas on how to fix the problem or can you share instructions on how to implement the code.

Thank you,

Bob