Vantage Logo in Menu Help

Hi SiteOrigin!

I have a logo in my main menu; the logo is larger than the menu is tall. I’d like the logo to be centered vertically on the menu, which would see it overlapping above and below the menu area. Is this possible? I’ve gotten this far with my CSS in Vantage, but can’t quite get there. A little help?

header#masthead.masthead-logo-in-menu .logo {
float: none;
position: absolute;
margin-left: -20px
z-index: 1;
}