Hello,
Please add this code to the Theme Settings > Custom CSS > Global:
/*sticky background*/
body .whb-sticked .whb-general-header {
background-color: white;
}
/*sticky main menu color*/
body .whb-sticked .woodmart-navigation .item-level-0.current-menu-item>a{
color:yellow;
}
body .whb-sticked .woodmart-navigation .item-level-0>a{
color:yellow;
}
body .whb-sticked .woodmart-navigation .item-level-0>a:hover{
color:orange;
}
body .whb-sticked .woodmart-navigation .item-level-0.menu-item-has-children>a:after{
color:orange;
}
Replace the colors as per your need
Best Regards