Apologies for the inconvenience.

Yes, it’s absolutely possible to replicate the moving underline effect from the "Revstat" template and apply it to your Helix-based template.

Please follow this official documentation for guidance on adding custom CSS to your Helix template: 👉 Using Custom CSS in Helix

Below is the CSS code responsible for the animated underline effect on the main menu:

.sp-megamenu-parent>li.active:before {
    visibility: visible;
    opacity: 1;
    width: calc(100% - 30px);
}

.sp-megamenu-parent>li:hover:before, .sp-megamenu-parent>li:focus:before {
    visibility: visible;
    opacity: 1;
    width: calc(100% - 30px);
}

.sp-megamenu-parent>li:before {
    content: "";
    position: absolute;
    width: calc(0% - 30px);
    height: 2px;
    background-color: #16151A;
    bottom: 20px;
    left: 15px;
    transition: all 0.3s ease;
    visibility: hidden;
    opacity: 0;
}

You can paste this CSS into the custom.css file (located at /templates/your-template-name/css/custom.css) or via the Custom Code > Custom CSS section in your Helix template settings.