In order to change header background, you will go to AdminCP >> Appearance >> Themes >> Edit >> Design >> find "HEADER BACKGROUND" field to change >> Save to take effect.

But on Mobile View, this field will not apply so let us guide you how to adjust header background below

1. On "Edit theme" page, please click "CSS"

At the bottom of the page, please add the following code

 .navbar.main-navigation.main-navigation-toggle .site-logo{
 background-color: ;
 }

2. Rebuild Core Theme and Clear Cache

May 16, 2019