Hello,
Please add this code to the Theme Settings > Custom CSS > Global:
.whb-sticked .whb-main-header .whb-general-header {
background-color:yellow;
}
.whb-sticked .whb-main-header .whb-header-bottom {
background-color:yellow;
}
.whb-sticked .whb-main-header .whb-general-header .wd-nav[class*="wd-style-"]>li>a {
color: red;
}
.whb-sticked .whb-main-header .whb-header-bottom .wd-nav[class*="wd-style-"]>li>a {
color: red;
}
.whb-sticked .whb-main-header .whb-general-header .wd-tools-element>a {
color: red;
}
Please replace the colors as per your needs and replace the logo for the sticky header.
Best Regards