Hello Klaus,
Sorry for the inconvenience. While the Maxora template doesn't have a built-in setting to directly change the underline color of the active menu item, you can easily customize this with CSS.
Please add the following code to Template Options → Custom Code → Custom CSS:
#sp-header .sp-megamenu-parent .sp-menu-item > a:hover,
#sp-header .sp-megamenu-parent .sp-menu-item.active > a {
text-decoration-color: #123456;
}
Remember to replace #123456 with your preferred color code. Hope this helps!
Best regards