navigation How do I achieve stacked column navigation in Squarespace 7.0 with CSS?

Site URL: https://harmonica-silver-l6sn.squarespace.com/

Site password: lottie 

I managed to achieve exactly what I want for the navigation on a previous website for a client (which is Squarespace 7.1) LInk: https://www.peteredgebaritone.com/

I am trying to achieve this same navigation in a site for a client using Squarespace 7.0, but the same code does not work. Can anyone help me? Link: https://harmonica-silver-l6sn.squarespace.com/ Password: lottie

I have attached a screenshot of the navigation that I am trying to achieve. 

This is the code I used in 7.1: 

/* Vertical nav */
.header-nav-list {
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
        -ms-flex-direction: column;
            flex-direction: column;
}

I just can't get it to work also for 7.0!

Thank you in advance,

Poppy

Use this code

.Header-nav-inner {
    display: flex;
    flex-direction: column;
}