I know there is 2 ways to create css of the child theme :
– create a file with only differences
– create a copied file of the parent theme + the differences
I choose the second way to speed up loading.
But I just activated a few moments the parent theme to see if it worked and the magnifying glass reappeared.
So I will change the CSS when I have more time.
However, the problem of the hamburger persists despite the activation of the parent theme.