In the site
thenorthernbeaches.info/
in Templates –> Styles –> jp-advocat –> settings –> styles –> customizer –> section logo
I have set the background color to #1b4369 (blue).
This works fine for desktop but mobile devices continue to have a white background.
Can anyone assist please.

The section "logo" is only avaible in desktop view.
Please add a logo to the position > logo-small too.

Thank you for the quick response.
I have already done that.
The problem is not with the logo itself (which is white) but with the background which shows #1b4369 (blue) in the desktop version but white in the mobile version.

The mobile menubar is always white and can not be changed

I tried with custom.css but this seems not possible too. Am I correct?

It should work with this css code into your custom.css

.logo-small {
background: #1b4369;
}