I want exactly the same as starting point of my twentyeleveng editing.
I did my child theme and i succesfully remove the greyline at the top of the header. It is a very obvious border defined by the style.css at the “header” or something like that section. I only switched the border from 2px to 0px so now its gone.
editing, now i succesfull remove the search form by deleting this line in header.php
<?php get_search_form(); ?>
