header background color changed after drop & import database in phpmyadmin

In general, things that are not content, better not be in the DB in the first place. Site header images should be in you CSS, making them part of your code which you manage with GIT.

This is obviously easier said than done with the way wordpress core and many plugins geared towards storing everything possible in the DB, but some things are just a “no brainer” and clearly should go into code. Even horrible plugins (from the POV of abusing DB as a replacement for proper coding) like ACF, let you now declare DB structure as json files you can manage as code.