Reply To: again: css: differentiate front page header and single post header

@dianoia: Hello there,
You seem to have used the following code in the Additional CSS section

#page .custom-header-content.entry-content-wrapper.sections.header-media-section {
    background-image: url("https://imnebel.de/wp-content/uploads/2020/07/Logo-gross-transparent2.png"); 
    background-position: center; 
    background-repeat: no-repeat; 
    background-size: cover;
}

Add the code body:not(.home) ahead of #page in the above code so that it becomes
body:not(.home) #page .custom-header-content.entry-content-wrapper.sections.header-media-section

Let me know if this works out!
Kind Regards,
Skandha