Centering main navigation and logo on desktop

Site URL: https://mox-media.squarespace.com/

I would like to have my logo and main navigation items centered on the page on desktop. It is currently placed on the left, and no matter which css codes I try, I cannot make it work. Ideally I would want the logo on top, and the main navigation items place under the logo if possible.

I am using Squarespace 7.1 but I am not sure what the name of the theme is. 

Thanks in advance!

What is access password?

Thanks for replying. I appreciate you wanting to help! The website is now online with no access password – go to mox-media.dk 

Add to Home > Design > Custom CSS

.header-display-desktop {
    flex-direction: column;
    justify-content: center;
}
.header-title-nav-wrapper {
    flex-direction: column;
    justify-content: center;
    flex: 100% !important;
}