Hello,

Please try to use the below custom CSS code and paste it to Theme Settings >> Custom CSS >> Global CSS code section:

.whb-sticked .whb-header-bottom .wd-dropdown {
    overflow-y: scroll;
}

.wd-nav-vertical>li>a {
    padding: 10px 18px;
    font-size: 11px;
    line-height: 16px;
}

Best Regards.