Since nobody replied to you, let me tell you how I did it:
In Appearance>Customize>Custom Css, I’ve added a little code – I wanted the background to be solid white and the text dark. You should change it accordingly ??
.tos-desktop .tos-wrapper.tos-fixed {
background-color: rgba(255, 255, 255); }
.tos-wrapper .tos-caption {
text-shadow: none;
color: #222;
}