Custom CSS to create a vertical header

Hi, I'm using a version 7.1 site and would like to use custom CSS to create a vertical layout header that resembles the header layout of the site https://www.breadwright.com/. I believe it was created with 7.0.  Here is a link to my site, https://dominiquechristiansen.com. What CSS would I need to achieve this?

Thank you in advance!

This CSS should give you a start:

.header-nav-list {
    display: inline-flex;
}