Thanks Sakin for your answer.
1)The problem is that some css does not change if i put the code in my child theme style.css, and yes if i write it in the custom box. I think this is due to changes i’m doing to responsive.css too that only apply if i write in the custom css box. I think i should import the style-reponsive.css to mi child too.. Is it possible? and how to do it??
2)All the css code appearing above the metas keywords belong to some plugin too, like table press and fancybox. You think i can write the css for this elements in style.css of my child theme, or for the fact the plugins are outside the theme folder this option will not work?
3)You say: It doesn’t matter until it’s above <body> tag.
So you think that even if in my html code there’s a bunch of stuff before body tag and it looks not “elegant” at all, this content will not affect my ranking with the searches engines??if you say this, then i can forget the point 1 and 2 and leave my site as it is.
Thank you