Hi there,
try this CSS:
/* LSI Facebook */
.icon-set-lsi_widget-1 .lsi-social-facebook a,
.icon-set-lsi_widget-1 .lsi-social-facebook a:visited,
.icon-set-lsi_widget-1 .lsi-social-facebook a:focus {
background-color: #3b5998 !important;
color: #fff !important;
}
/* Facebook Hover */
.icon-set-lsi_widget-1 .lsi-social-facebook a:hover {
background-color: #3b5998 !important;
color: #fff !important;
}
/* LSI Youtube */
.icon-set-lsi_widget-1 .lsi-social-youtube a,
.icon-set-lsi_widget-1 .lsi-social-youtube a:visited,
.icon-set-lsi_widget-1 .lsi-social-youtube a:focus {
background-color: #c4302b !important;
color: #fff !important;
}
/* Youtube hover */
.icon-set-lsi_widget-1 .lsi-social-youtube a:hover {
background-color: #c4302b !important;
color: #fff !important;
}