Please add the following CSS code to your Template Options -> Custom Code -> Custom CSS
/* Default Tab Style */
.sppb-tab .sppb-nav > li > a,
.sppb-tab .sppb-nav-modern > li > a {
background-color: #333333 !important;
color: #ffffff !important;
}
/* Link states */
.sppb-tab .sppb-nav > li > a:link,
.sppb-tab .sppb-nav > li > a:visited,
.sppb-tab .sppb-nav-modern > li > a:link,
.sppb-tab .sppb-nav-modern > li > a:visited {
color: #ffffff !important;
}
/* Hover State */
.sppb-tab .sppb-nav > li > a:hover,
.sppb-tab .sppb-nav-modern > li > a:hover {
background-color: #007bff !important;
color: #000000 !important;
}
/* Active Tab */
.sppb-tab .sppb-nav > li.active > a,
.sppb-tab .sppb-nav > li.active > a:hover,
.sppb-tab .sppb-nav-modern > li.active > a,
.sppb-tab .sppb-nav-modern > li.active > a:hover {
background-color: #007bff !important;
color: #000000 !important;
}