Hi there!

Thanks for contacting us.

Here is the code snippet you may try to put into your custom.css file:

#sp-menu > .sp-column, #sp-menu .sp-megamenu-wrapper {
    display: flex;
    justify-content: center !important;
}

Here is the related documentation:

https://www.joomshaper.com/documentation/helix-framework/customization-tips#how-to-change-the-position-of-the-menu

Custom code related doc: https://www.joomshaper.com/documentation/helix-framework/custom-code-css-js-meta

Hope this helps!

Best Regards