Vertical Site Navigation

Hi,

Does anyone know how to make my site navigation a vertical list rather than a horizontal list. Like this:

Home

Work 

About

Rather than:
Home Work About

Thanks

Site: https://ashwingunawardana.squarespace.com/

Password: password

3 hours ago, tuanphan said:

Add to Design > Custom CSS

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

 

Awesome, it works. Thank you

Also want to say I've used code you've posted onto other forum posts in the past, thanks for all the great work