Change color in widget latest news in sidebar

Hi! I have a doubt about a widget of Enfold theme. I´ve changed the color of the sidebar with Quick CSS. In this sidebar, I´ve the widget of Latest News from Enfold, but I want to change the color of the title of each post to blank.

How can I do that? I´ve tried with this code:

.main_color .newsbox .news-headline {
color: #ffffff;
}

But when I put it, it changes all the sidebar color to blank, not the titles.

Thanks!