Hello Steve,

You can increase you r logo height with 

#logo img {
    height: 40px;
}

just change the height (in pixels) as it will try to cover the available width (auto)

and add the code to customizer -> additional CSS

Hello,

you can include the CSS code below in a media query for desktop, for example

@media only screen and (max-width: 1024px){

#logo img {
    height: 40px;
}

}