WordPress mobile and desktop header problems [closed]

The problem either in your theme setting or in css. if the theme setting
try make header backround #000 on mobile and align logo center.

So that will how your site look on mobile

if you write custom css, here is the solution

@media screen and (max-width: 767px) {
    #masthead_TesseractTheme .site-branding {
       text-align: center !important;
    }
    #masthead_TesseractTheme {
       background: #000 !important;
    }
}